Arthroplasty, Ligament, Spine MCQs - Part 149

Orthopedic Surgery Board Review MCQs: AAOS Master Bank Part 149

About This Board Review Set

This is Part 149 of the comprehensive OITE and AAOS Orthopedic Surgery Board Review series authored by Dr. Mohammed Hutaif, Consultant Orthopedic & Spine Surgeon.

This set has been strictly audited and contains 100 100% verified, high-yield multiple-choice questions (MCQs) modelled on the exact format of the Orthopaedic In-Training Examination (OITE) and the American Academy of Orthopaedic Surgeons (AAOS) board examinations.

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Two distinct learning modes are available:

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Pro Tip: Use keyboard shortcuts A–E to select options, F to flag a question for review, and Enter to jump to the next unanswered question.

Topics Covered in Part 149

This module focuses heavily on: Arthroplasty, Ligament, Spine.

Sample Questions from This Set

Sample Question 1: With the arm abducted 90 degrees and fully externally rotated, which of the following glenohumeral ligaments resists anterior translation of the humerus? Review Topic...

Sample Question 2: An awake and alert patient with neck pain arrives at the emergency department after an automobile crash. Upon examination he is weak in the left deltoid and biceps muscles (3/5 strength). CT scans performed 2 hours after admission are shown...

Sample Question 3: Figure 93 shows the axial T2-weighted MRI scan of the lumbar spine of a 70-year-old man. The arrow points to which of the following structures? Review Topic...

Sample Question 4: During a retroperitoneal approach to the L4-5 disk, what structure must be ligated to safely mobilize the common iliac vessels toward the midline from laterally and gain exposure?...

Sample Question 5: A patient undergoing joint arthroplasty is put on a drug that competitively inhibits the activation of an enzyme that breaks down Factor Ia. The drug is...

Why Active MCQ Practice Works

Evidence consistently demonstrates that active recall through spaced MCQ practice yields substantially greater long-term retention than passive reading alone (Roediger & Karpicke, 2006). All questions in this specific module have been algorithmically verified for clinical integrity and complete explanations.

Comprehensive 100-Question Exam

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Question 1

With the arm abducted 90 degrees and fully externally rotated, which of the following glenohumeral ligaments resists anterior translation of the humerus? Review Topic

Explanation

With the arm in the abducted, externally rotated position, the anterior band of the inferior glenohumeral ligament complex moves anteriorly, preventing anterior humeral head translation. Both the coracohumeral ligament and the superior glenohumeral ligament restrain the humeral head to inferior translation of the adducted arm, and to external rotation in the adducted position. The middle glenohumeral ligament is a primary stabilizer to anterior translation with the arm abducted to 45 degrees. The posterior band of the inferior glenohumeral ligament complex resists posterior translation of the humeral head when the arm is internally rotated.

Question 2

An awake and alert patient with neck pain arrives at the emergency department after an automobile crash. Upon examination he is weak in the left deltoid and biceps muscles (3/5 strength). CT scans performed 2 hours after admission are shown in Figures 70a and 70b. His weakness deteriorates to 1/5 strength in the upper and lower extremities. What is the most appropriate treatment? A B

Explanation

DISCUSSION
Facet subluxation reduction may be performed in awake patients. Posterior spinal laminectomy and fusion can result in worsening neurologic status and is not recommended in this setting. Generally, corpectomy in the setting of facet subluxation is not recommended because it does not facilitate reduction or fully alleviate spinal cord compression. High-dose steroid use is not supported by current literature.
RECOMMENDED READINGS
Fehlings MG, Perrin RG. The timing of surgical intervention in the treatment of spinal cord injury: a systematic review of recent clinical evidence. Spine (Phila Pa 1976). 2006 May 15;31(11 Suppl):S28-35; discussion S36. Review. PubMed PMID: 16685233. View Abstract at PubMed
Lee AS, MacLean JC, Newton DA. Rapid traction for reduction of cervical spine dislocations. J Bone Joint Surg Br. 1994 May;76(3):352-6. PubMed PMID: 8175833.View Abstract at PubMed

Question 3

Figure 93 shows the axial T2-weighted MRI scan of the lumbar spine of a 70-year-old man. The arrow points to which of the following structures? Review Topic

Explanation

The ligamenta flava (singular, ligamentum flavum, Latin for yellow ligament) are ligaments that connect the laminae of adjacent vertebra, all the way from the axis to the first segment of the sacrum. In T2-weighted sequencing, ligamentous structures possess a low signal intensity. The ligamentum in this patient is markedly thickened, resulting in severe spinal stenosis. The epidural space lies ventral and medial to the ligamentum flavum and should possess a high signal intensity secondary to the presence of cerebrospinal fluid. However, in the case of high-grade stenosis, there may be little if any cerebrospinal fluid present, making the epidural space and central canal difficult to identify. A lumbar synovial cyst should also have high signal intensity because of the presence of synovial fluid.
(SBQ12SP.14) A 36-year-old male presents with acute onset of right buttock and leg pain following lifting a heavy object. On physical exam he has weakness to knee extension, numbness over the medial malleolus, and a decreased patellar reflex. Which of the following would most likely explain this clinical presentation. Review Topic
Lumbar arachnoiditis
L4/L5 paracentral disc herniation
L3/L4 far lateral (foraminal) disc herniation
L4/L5 far lateral (foraminal) disc herniation
L5/S1 far lateral (foraminal) disc herniation
The clinical presentation is consistent with a L4 radiculopathy. A L4/L5 far lateral (foraminal) disc herniation would compress the exiting root (L4) and cause these symptoms.
The location of a prolapsed lumbar disc determines its symptoms. Central disc herniations may give rise to back pain or cauda equina syndrome. Paracentral disc herniations (90-95% of cases) affect the traversing nerve root. Far lateral disc herniations (5-10%) affect the exiting nerve root.
Gregory et al. summarize physical signs in lumbar disc herniation. They state that the straight-leg-raise is the most sensitive (73-98% sensitive) test and the crossed straight-leg-raise is the most specific (88-98% specific) test for lumbar disc herniation. Other specific tests include weak ankle dorsiflexion (89% specific), absent ankle reflex (89% specific), and calf wasting (94% specific, but a late finding).
Illustration A shows how a paracentral L4/L5 disc herniation affects the traversing L5 root, but a far lateral L4/L5 disc herniation affects the L4 root. Illustration B shows the dermatomal distribution of pain with root involvement from L3 to S1.
Incorrect Answers:

Question 4

During a retroperitoneal approach to the L4-5 disk, what structure must be ligated to safely mobilize the common iliac vessels toward the midline from laterally and gain exposure?

Explanation

DISCUSSION: To mobilize the common iliac vessels across the midline, the iliolumbar vein must be ligated. It has a short trunk and can be torn if mobilization is attempted without ligation. It is the only branch off the common iliacs (there are no arterial branches) prior to the terminal branches, the internal (hypogastric) and external iliacs. The middle sacral vessels run distally from the axilla of the bifurcation and are a factor when accessing the L5-S1 disk.
REFERENCES: Baker JK, Reardon PR, Reardon MJ, et al: Vascular injury in anterior lumbar surgery. Spine 1993;18:2227-2230.
Lewis WH: Gray’s Anatomy of the Human Body: The Veins of the Lower Extremity, Abdomen, and Pelvis, ed 20. Philadelphia, PA, Lea & Febiger, 2000.

Question 5

A patient undergoing joint arthroplasty is put on a drug that competitively inhibits the activation of an enzyme that breaks down Factor Ia. The drug is

Explanation

Factor Ia is fibrin. The enzyme that breaks down fibrin is plasmin. Tranexamic acid (TXA) is an antifibrinolytic that prevents the activation of plasmin from the inactive zymogen plasminogen.
Tranexamic acid competitively inhibits the activation of plasminogen to plasmin by binding to specific sites on both plasminogen and plasmin. Tranexamic acid has roughly eight times the antifibrinolytic activity of an older analogue, e-aminocaproic acid. It is used during joint replacement surgery to reduce blood loss and the need for transfusion.
Watts et al. review strategies for minimizing blood loss and transfusion. They recommend 1g of TXA prior to incision, and 1g at wound closure. They also recommend giving fluids for symptoms of anemia, rather than transfusion, as even high risk patients do well with sufficient intravascular volume even with low hemoglobin levels.
Imai et al. evaluated TXA in 107 patients undergoing THA. They found that intraoperative blood loss after preoperative TXA administration was lower than both control and postoperative TXA administration groups. They recommend using 1 g of TXA 10 minutes before surgery and 6 hours after the first administration to best reduce blood loss during THA.
Gillette et al. retrospectively reviewed 2046 patients receiving TXA for THA or TKA together with either aspirin, warfarin or dalteparin. They found that the rates of symptomatic DVT (0.35%, 0.15%, and 0.52%, respectively) and nonfatal PE were similar (0.17%, 0.43%, and 0.26%, respectively) for the 3 drugs respectively. They recommend TXA to decrease blood loss and transfusion.
Illustration A shows the role of tranexamic acid in the fibrinolytic cycle and the
clotting cascade.
Incorrect Answers:

Question 6

Figures 2a and 2b show the radiograph and MRI scan of a 56-year-old woman who has low back pain and right leg pain. She has grade 3/5 toe and ankle dorsiflexion strength on the right side. Nonsurgical management has failed to provide relief; therefore, surgery should include Review Topic

Explanation

The lateral radiograph and MRI scan demonstrate a grade 2 isthmic spondylolisthesis of L5 on S1. The radiograph shows a pars defect of L5. Isthmic spondylolistheses are most common at L5-S1. Degenerative spondylolistheses rarely progress beyond a grade 1 slip. The patient has frank neurologic weakness on the right side and nonsurgical management has failed to provide relief. In patients with significant motor weakness, neurologic decompression is indicated. An L5 pars repair is not recommended in patients with more than a grade 1 slip. Laminectomy alone can destabilize the spine and lead to further slippage and thus it is recommended to fuse the segment. A stand-alone anterior lumbar interbody fusion has a high failure rate with isthmic spondylolisthesis. Isthmic spondylolisthesis is a contraindication for lumbar total disk replacement. While there is some literature that supports fusion without laminectomy or decompression for patients with isthmic slips and radicular pain without neurologic deficit, this patient does not fulfill these criteria.

Question 7

Which of the following factors is most closely associated with early postoperative migration of “stand-alone” lumbar interbody fusion cages?

Explanation

DISCUSSION: Postoperative migration of lumbar interbody fusion cages is a rare complication. It is most commonly seen after placement of the cages through a posterior approach, with instability of the final construct. It is not associated with the design of the cage, the type of graft used, or a resultant pseudarthrosis.
REFERENCES: McAfee PC: Interbody fusion cages in reconstructive operations on the spine. J Bone Joint Surg Am 1999;81:859-880.
McAfee PC, Cunningham BW, Lee GA, et al: Revision strategies for salvaging or improving failed cylindrical cages. Spine 1999;24:2147-2153.

Question 8

Which of the following factors has NOT been found to be a significant independent predictor of moderate or severe pain 6 months after musculoskeletal injury?

Explanation

Age and gender have not been found to be significant independent predictors of moderate or severe pain 6 months after musculoskeletal injury.
Williamson et al. performed a prospective cohort study of 1290 trauma patients in 2 Australian hospitals using a self-rated pain scale and a SF-12. They found that the prevalence of moderate or severe pain was 48% at discharge and 30% at 6 months post-injury. Failure to complete high school, self-reported preinjury pain-related disability, eligibility for compensation (payment for medical treatment, rehabilitation services, disability services, and income assistance), and moderate or severe pain at discharge from the acute hospital were found to be independent predictors of moderate or severe pain at 6 months post-injury.
Vranceanu et al. published a Level 5 review reporting that psychosocial factors are important and treatable correlates of disabling musculoskeletal pain. They encourage orthopaedic surgeons to diminish pain intensity and pain-related disability by teaming up with psychologists and other health-care providers in multidisciplinary teams to address cognitive, affective, behavioral, and social aspects of pain.
Incorrect Answers:

Question 9

A 45-year-old man has had left thigh pain for the past 4 months. An AP radiograph, bone scan, MRI scans, and biopsy specimens are shown in Figures 6a through 6f. What is the most appropriate treatment?

Explanation

DISCUSSION: The radiograph demonstrates thickened trabeculae and thickened cortices in the left proximal femur compared to the right, and the bone scan shows increased uptake in this area. The MRI scans show thickened trabeculae with normal marrow signal. These findings are diagnostic of Paget’s disease. Medical treatment, including bisphosphonates and calcitonin, is indicated for painful bone lesions.
REFERENCES: Hadjipavlou AG, Gaitanis IN, Kontakis GM: Paget’s disease of the bone and its management. J Bone Joint Surg Br 2002;84:160-169.
Vaccaro AR (ed): Orthopaedic Knowledge Update 8. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 187-196.

Question 10

Which factor is most important when attempting to prevent interbody graft subsidence?

Explanation

DISCUSSION
Osteoporosis can affect all aspects of spinal stability and is the most critical factor regarding spinal implant failure. Burring of the end plates may decrease strength of the interface with the uncovering of "softer" cancellous bone. Increasing the surface contact area may help prevent subsidence but is not as important as bone quality. Stress shielding through rigid fixation may lead to construct failure.
RECOMMENDED READINGS
Benzel E (ed): Biomechanics of Spine Stabilization. Rolling Meadows, IL, American Association of Neurological Surgeons, 2001, pp 446-447.
Goldhahn J, Reinhold M, Stauber M, Knop C, Frei R, Schneider E, Linke B. Improved anchorage in osteoporotic vertebrae with new implant designs. J Orthop Res. 2006 May;24(5):917-25. PubMed PMID: 16583445. View Abstract at PubMed

Question 11

A patient with an intertrochanteric hip fracture undergoes reduction and dynamic hip screw application. The post-operative radiographs demonstrate that the lag screw is superior in the femoral head with a tip-apex distance of 40 millimeters. This patient is at increased risk of what complication?

Explanation

Anterior portion of humeral head

Lesser tuberosity

Entire humeral head except posteroinferior portion of lesser tuberosity and head
Entire humeral head except posteroinferior portion of greater tuberosity and head

Entire humeral head except entire greater tuberosity
DISCUSSION: The anterolateral branch of the anterior circumflex artery, called the arcuate artery terminally, provides blood supply to the entire humeral head, lesser tuberosity and greater tuberosity except for a small posterior area. The posterior portion of the greater tuberosity and a small posteroinferior portion of the humeral head are supplied by the posterior circumflex artery. This was supported by a cadaveric study by Gerber et al who performed an anatomical study of the arteries of the humeral head to determine their intraosseous distributions. They injected a radiopaque suspension into the anterior circumflex, posterior circumflex, suprascapular, thoracoacromial, or subscapular artery and then analyzed the specimens macroscopically and radiographically. The humeral head was shown to have been perfused by the anterolateral ascending branch of the anterior circumflex artery in all specimens. The posterior circumflex artery vascularized only the posterior portion of the greater tuberosity and a small posteroinferior part of the head. Illustration A depicts the humeral head vascular supply with #2 being the posterior circumflex, #3 being the anterior circumflex arteries, and #4 being the anterolateral humeral circumflex artery.

Question 12

Figures 100a and 100b are the radiographs of a 90-year-old woman who is seen in the emergency department after a fall from a height. She has right hip and thigh pain and is unable to bear weight. Based on this patient’s history and imaging, what is the best next step?

Explanation

CLINICAL SITUATION FOR QUESTIONS 101 THROUGH 104
Figures 101a and 101b are the right hip radiographs of a 26-year-old active man who has had pain in his right hip for 4 months. His pain is worse with prolonged periods in a seated position. He has no pain at rest and denies pain in other joints or systemic illness. Examination reveals passive range of motion of full extension, 80 degrees of flexion, internal rotation in flexion of 0 degrees, and external rotation in flexion of 30 degrees. Forced flexion, internal rotation, and adduction are very painful. A flexion, abduction, and external rotation test result is negative.

Question 13

A large circumferential proximal femoral allograft is to be used in the reconstruction of a failed femoral component in a total hip arthroplasty. To enhance fixation of the graft to the implant, which of the following strategies should be used?

Explanation

DISCUSSION: The optimum treatment is cementing the implant to the allograft. Press-fit stability is unreliable. Wires and screws may be used for an incomplete proximal femoral allograft but cannot be used to anchor a complete proximal femoral allograft.
REFERENCES: Allan DG, Lavoie GJ, Rudan JF, et al: The use of allograft bone in revision total hip arthroplasty, in Friedlaender GE, Goldberg VM (eds): Bone and Cartilage Allografts: Biology and Clinical Applications. Park Ridge, IL, American Academy of Orthopaedic Surgeons, 1991, pp 263-264.
Gross AE, Lavoie MV, McDermott P, Marks P: The use of allograft bone in revision of total hip arthroplasty. Clin Orthop 1985;197:115-122.
Head WC, Berklacich FM, Malinin TI, Emerson RH Jr: Proximal femoral allografts in revision total hip arthroplasty. Clin Orthop 1987;225:22-36.

Question 14

A 16-year-old competitive female swimmer has a 1-year history of left shoulder pain. She denies any specific injury to her shoulder. She reports that the pain is worse with swimming but also has pain with daily activities. She also notes similar occasional symptoms in her right shoulder. Examination reveals symmetric range of motion and rotator cuff strength. Examination of the left shoulder reveals 2+ anterior and posterior translation with pain in both directions and a 2-cm sulcus sign. The right shoulder also has 2+ anterior and posterior translation and a 2-cm sulcus sign with no pain. She also has hyperextension of the elbows and the ability to touch the radial border of her thumb to her forearm. What is the next step in management? Review Topic

Explanation

The patient has symptomatic multidirectional instability. A comprehensive program involving physical therapy to restore dynamic stability to her shoulder is indicated as a first-line treatment. Periscapular strengthening focusing on the serratus anterior and rhomboids and rotator cuff strengthening should be emphasized. A sling might be used occasionally for comfort but will not provide long-term relief of her symptoms. Thermal capsulorrhaphy, although widely used in the past for shoulder instability, has been abandoned because of a high complication rate. Surgical interventions, such as capsular plications or open capsular shift procedures, might be indicated if rehabilitation fails to relieve her symptoms.

Question 15

What type of cementless femoral fixation results in the highest rate of distal femoral osteolysis?

Explanation

DISCUSSION: Despite the relatively few problems with porous-coated cementless stems, stress shielding and thigh pain do occur. One design feature of proximally coated stems that has been associated with a higher incidence of distal osteolysis is the presence of noncircumferential proximal porous coating. Tapered, modular with sleeve, and hydroxyapatite proximally porous-coated stems have all performed well. Fully porous-coated straight stems have a high survivorship rate as well.
REFERENCES: Pellicci PM, Tria AJ Jr, Garvin KL (eds): Orthopaedic Knowledge Update: Hip and Knee Reconstruction 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2000, pp 175-180.
Koval KJ (ed): Orthopaedic Knowledge Update 7. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 417-451.
Emerson RH Jr, Sanders SB, Head WC, Higgins L: Effect of circumferential plasma-spray porous coating on the rate of femoral osteolysis after total hip arthroplasty. J Bone Joint Surg Am 1999;81:1291-1298.

Question 16

Figures 163a through 163c show the radiograph and MRI scans of a 45-year-old woman with severe right arm pain. She has had symptoms for 6 months without resolution despite multiple nonsurgical treatments. Examination reveals weakness in the right triceps and wrist flexors with decreased sensation in the middle finger and a positive Spurling's sign. What is the most appropriate treatment for the patient's symptoms? Review Topic

Explanation

The patient has symptoms and signs of cervical radiculopathy despite a long course of nonsurgical management. Therefore, surgical decompression is indicated and is best performed through an anterior cervical diskectomy and arthrodesis. Single level anterior cervical diskectomy and arthrodesis have been shown to produce significant improvements in arm pain and neurologic function. Anterior cervical foraminotomy, while reported, has insufficient data to support its use and it places the vertebral artery at significant risk. Posterior cervical foraminotomy is contraindicated given the ventral spinal cord compression; foraminotomy places the patient at risk for spinal cord injury. The patient has one-level cervical disease, therefore a corpectomy is unnecessary. Posterior laminoplasty is used to treat myelopathy, not radiculopathy.

Question 17

The blood supply to the anterior cruciate ligament is primarily derived from what artery?

Explanation

DISCUSSION: Microvascular studies have shown that the majority of the blood supply to the cruciate ligaments comes from the middle geniculate artery, although there is collateral flow through the other geniculates and from bone.
REFERENCES: Arnoczky SP: Blood supply to the anterior cruciate ligament and supporting structures. Orthop Clin North Am 1985;16:15-28.
Arnoczky SP, Rubin RM, Marshall JL: Microvasculature of the cruciate ligaments and its response to injury. J Bone Joint Surg Am 1979;61:1221-1229.

Question 18

A patient sustains a displaced scapular neck fracture. What is the internervous plane for a posterior approach to the glenohumeral joint?

Explanation

CORRECT
DISCUSSION: Surgical fixation of a scapular neck fracture is performed via the Judet approach, a posterior approach to the scapula/glenoid. The internervous plane is between the infraspinatus (suprascapular nerve) and the teres minor (axillary nerve). As outlined by Ball et al, the posterior branch of the axillary nerve has intimate association with the inferior aspects of the glenoid and shoulder joint capsule, which may place it at particular risk during a posterior approach to the shoulder.

Question 19

A 16-year-old boy has a symptomatic flatfoot deformity that is causing pain, skin breakdown, and shoe wear problems. Shoe modification and an orthosis have failed to provide relief. Examination reveals hindfoot valgus, talonavicular sag, and forefoot abduction that are all passively correctable. Treatment should consist of

Explanation

DISCUSSION: The patient has a supple planovalgus deformity that is passively fully correctable, and nonsurgical management has failed to provide relief. Lateral column lengthening with medial soft-tissue tightening will correct the deformity and maintain a flexible foot. Arthrodesis is not recommended for a supple, correctable deformity because of loss of motion and long-term degeneration of surrounding joints. Medial displacement calcaneal osteotomy is generally reserved for an adult-acquired flexible flatfoot.
REFERENCES: Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 613-631.
Evans D: Calcaneo-valgus deformity. J Bone Joint Surg Br 1975;57:270-278.
Mosca VS: Calcaneal lengthening for valgus deformity of the hindfoot: Results in children who had severe, symptomatic flatfoot and skewfoot. J Bone Joint Surg Am 1995;77:500-512.

Question 20

Figures below represent the radiographs obtained from a 37-year-old man with severe right knee pain. He has a history of prior tibial osteotomy for adolescent tibia vara but notes residual bowing of his legs. On examination, he is 5'8" tall and weighs 322 pounds. He has a waddling gait with a bilateral varus thrust and 20° varus deformity of both legs. His right knee range of motion is 0° to 120° with a fixed varus deformity. What is the best next step?

Explanation

DISCUSSION:
This patient has severe, uncorrectable varus deformity and pain from end-stage osteoarthritis secondary to prior adolescent tibia vara. Although he is young to consider arthroplasty, this option is likely to give him the most functional limb, compared with arthrodesis with a long antegrade nail. During arthroplasty surgery, his knee will likely require extensive medial release to achieve anatomic limb alignment. Standard components in total knee arthroplasty likely would result in lateral instability, so this option is
not the best answer. The best choice is total knee arthroplasty with a constrained device, which adds
constraint to the knee to provide balance.

Question 21

The images reveal T2-weighted MRI sequences with edema isolated to the infraspinatus. In the absence of a tear in the infraspinatus tendon, the edema is most likely due to compression of the suprascapular nerve in the spinoglenoid notch. As this pathology persists, progressive muscle atrophy and fatty infiltration can result. Compression of the suprascapular nerve in the suprascapular notch would have resulted in edema and weakness in both the supra- and infraspinatus muscles. Compression is commonly caused by cysts from the joint secondary to labral tears. A rotator cuff tear of the infraspinatus is not identified on these images, and there is no history of trauma provided. There is no evidence of an anteroinferior labral tear, nor would this be expected to result in external rotation weakness or MRI abnormality of the infraspinatus. Quadrilateral space syndrome results in compression of the axillary nerve, which supplies the teres minor. Correcr answer : C 40- A 41-year-old right-hand-dominant man has been treated nonsurgically for right elbow arthritis. His radiographs reveal end-stage ulnohumeral arthritis with complete loss of the joint space. He reports pain during the mid-arc of elbow flexion and extension. During the last 8 years, he has attempted activity modification, medication, physical therapy, and multiple cortisone injections. His symptoms have progressed, resulting in constant pain, loss of a functional range of motion, and an inability to perform many activities of daily living. Secondary to his age and activity demands, he undergoes a soft-tissue interposition arthroplasty of his elbow with an Achilles allograft. Which presurgical finding correlates with elevated risk for postsurgical complications?

Explanation

Figure 1 is the radiograph of a 12-year-old baseball player who has posterolateral elbow pain with throwing. The area of interest is designated by the black arrow. His range of motion and strength are full. No previous treatment has been provided. What is the most appropriate initial treatment?
A. Elbow arthroscopy with debridement
B. Immobilization and rest for 6 weeks
C. Corticosteroid injection
D. Open osteochondral autograft transfer
Osteochondritis dissecans of the capitellum is a painful condition that affects immature athletes who undergo repetitive compression of the radiocapitellar joint. Management is based primarily on the integrity of the articular cartilage surface and the stability of the lesion. Nonsurgical treatment is typically selected for patients
with early-grade, stable lesions, and it involves activity modification with cessation of sports participation. The duration of activity modification is dictated by symptoms, with 3 to 6 weeks of rest followed by return to sport in 3 to 6 months commonly used as a guideline. Strengthening and stretching exercises are commonly incorporated after the pain has subsided. Surgical intervention or corticosteroid injection would not be first-line treatment.
42- Figures 1 and 2 are the radiographs of a 69-year-old man with a history of treated prostate cancer and hemodialysis-dependent end- stage renal disease who presents to the emergency department with progressively worsening right shoulder pain and stiffness. Laboratory tests reveal a white blood cell count of 17,000, erythrocyte sedimentation rate, 75, and CRP, 10.1. He has a draining sinus located along the anterior shoulder. What is the best next step?

Question 22

A college football player performs bicep curls as part of his weight lifting routine. During the flexion phase of the curl, what term defines the type of muscle contraction?

Explanation

DISCUSSION: Muscle contractions can be classified by tension, length, and velocity. Isometric contractions involve changing tension in the muscle while the muscle stays at a constant length. An example would be pushing against a wall. Isokinetic contractions occur when the muscle maximally contracts at a constant velocity. Isotonic contractions involve constant tension throughout the range of motion. Eccentric contraction is when the muscle lengthens during contraction. Eccentric contractions have the highest risk of injury. Plyometrics are eccentric contractions at a rapid rate.
REFERENCES: Simon SR (ed): Orthopaedic Basic Science. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 89-125.
Evans WJ: Effects of exercise on senescent muscle. Clin Orthop 2002;403:S211-S220.

Question 23

A 5-year-old boy is seen in the emergency department with a 2-day history of refusing to walk. Examination shows that he has a temperature of 102.2 degrees F (39 degrees C) and limited range ot motion of the right hip. The AP pelvic radiograph is normal. The WBC count is normal but the C-reactive protein and erythrocyte sedimentation rate (ESR) are elevated. What is the next step in management?

Explanation

DISCUSSION: The history, physical examination, and laboratory studies suggest a septic hip. Recent studies indicate that a child with elevated ESR, a WBC count of greater than 12,000/mm3, a temperature of greater than 38.5 degrees, and unwillingness to walk is very likely to have septic arthritis of the hip versus toxic synovitis. The best way to confirm the diagnosis is by hip aspiration. No medications should be started until a diagnosis is made. Toxic synovitis is common, but significantly less likely if three of the above criteria are present. This condition usually responds well to ibuprofen, but requires close observation. Septic hips are considered urgent conditions and therefore a repeat evaluation in 2 weeks is inappropriate.
REFERENCES: Herring JA: Tachdjian’s Pediatric Orthopaedics, ed 4. Philadelphia, PA, WB Saunders, 2008, pp 2109-2113.
Abel MF (ed): Orthopaedic Knowlede Update: Pediatrics 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 62-65.
Kocher MS, Mandiga R, Murphy JM, et al: A clinical practice guideline for treatment of septic arthritis
in children: Efficacy in improving process of care and effect on outcome of septic arthritis of the hip. J Bone Joint Surg Am 2003;85:994-999.
Kocher MS, Mandiga R, Zurakowski D, et al: Validation of a clinica l prediction rule for the differentiation between septic arthritis and transient synovitis of the hip in children. J Bone Joint Surg Am 2004;86:1629-1635.

Question 24

A 57-year-old woman had right total knee arthroplasty for varus gonarthrosis. Before surgery, her range of motion was 5 to 110 degrees. At skin closure, her range of motion was 0 to 120 degrees. Her range of motion at 10 weeks after surgery is 0 to 70 degrees. What is the best next treatment step?

Explanation

Question.18 . Figure 197 is the radiograph of a 62-year-old woman who is seen in the emergency department with a dislocated left total hip arthroplasty. This is her seventh dislocation during the last 3 months and she most recently had a liner revision. What is the best next treatment step?
Skeletal traction
Open reduction
Closed reduction
Component revision
Hip abduction orthosis

Question 25

Reconstruction of the posterior cruciate ligament (PCL) via the inlay technique involves exposure of the PCL tibial insertion site by a posterior

Explanation

DISCUSSION: The posterior medial approach through the semimembranosus/medial gastrocnemius interval is used in the inlay technique for PCL reconstruction. Exposure of the posterior capsule of the knee through this interval provides the greatest margin of safety to avoid injury to the tibial nerve, motor branch of the medial gastrocnemius, and the peroneal nerve. The direct posterior approach using the medial sural cutaneous nerve allows exposure of the popliteal neurovascular structures, but deep dissection through this interval places the motor branch of the medial gastrocnemius at risk. The interval between the semitendinosus and semimembranosus is used in accessory incisions with medial meniscus repairs but does not allow exposure of the PCL insertion.
REFERENCES: Berg EE: Posterior cruciate tibial inlay reconstruction. Arthroscopy 1995;11:69-76.
Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics: The Anatomic Approach, ed 1. Philadelphia, PA, JB Lippincott, 1984, pp 427-435.

Question 26

The preferred surgical approach to the elbow of a child with an irreducible type III supracondylar distal humerus fracture and pulseless extremity is through which of the following muscle intervals?

Explanation

DISCUSSION: In a type III supracondylar distal humerus fracture of the elbow, the brachial artery can become incarcerated, yielding a pulseless extremity. In this situation, closed reduction may not be effective; therefore, open management is often necessary. The preferred surgical approach to the brachial artery and to this fracture is the anterior approach to the cubital fossa. The lacertus fibrosis is incised, and the dissection is carried out between the brachialis (musculocutaneous nerve) and the pronator teres (median nerve), mobilizing the brachial artery. Once the brachial artery is mobilized, the anterior elbow joint capsule may be exposed. The interval between the brachialis and the biceps describes the anterolateral approach to the elbow more commonly used for exposure of the proximal aspect of the posterior interosseous nerve. The dissection interval between the brachioradialis and the pronator teres describes the proximal extent of the anterior approach to the radius.
REFERENCES: Tubiana R, McCullough CJ, Masquelet AC: An Atlas of Surgical Exposures of the Upper Extremity. Philadelphia, PA, JB Lippincott, 1990, p 115.
Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics: The Anatomic Approach, ed 2. Philadelphia, PA, Lippincott-Raven, 1992, p 119.

Question 27

Figure below shows the radiograph obtained from a 68-year-old man who fell 3 weeks after undergoing a successful left primary total hip arthroplasty. He is experiencing a substantial increase in pain and an inability to bear weight. What is an appropriate treatment plan?

Explanation

DISCUSSION:
The fracture has occurred around the stem, representing a Vancouver type B fracture, and the stem is clearly loose, making it a type B2 fracture. The appropriate treatment is removal of the loose in situ stem; ORIF of the femur using cerclage wires, cables, or a plate; and insertion of a longer revision stem such as a tapered fluted modular titanium or fully porous coated cylindrical stem to bypass the fracture. All of the other options are incorrect, because they represent inappropriate treatment options for a Vancouver type B2 fracture.

Question 28

Compared to metal-on-polyethylene total hip bearing surfaces, the debris particles generated by metal-on-metal articulations are

Explanation

DISCUSSION: Retrieval studies have shown that the debris particles produced by

metal-on-metal articulations in total hip arthroplasty are several orders of magnitude smaller

and may be up to 100 times more numerous than those found with metal-on-polyethylene articulations.
REFERENCES: Davies AP, Willert HG, Campbell PA, et al: An unusual lymphocytic perivascular infiltration in tissues around contemporary metal-on-metal joint replacements.

J Bone Joint Surg Am 2005;87:18-27.
Firkins PJ, Tipper JL, Saadatzadeh MR, et al: Quantitative analysis of wear and wear debris from metal-on-metal hip prostheses tested in a physiological hip joint simulator. Biomed Mater Eng 2001;11:143-157.

Question 29

Each of the following are guidelines for management of a domestic violence victim EXCEPT:

Explanation

DISCUSSION: It is important to fully document the abuse as it has been described to you, however there is no federal law mandating photographic documentation of domestic violence injuries. Photographs may be taken but only with the patient's permission. Disclosure of a diagnosis of abuse to any third party and reporting it to the authorities should be done only with the abused patient’s knowledge and consent, unless there is a mandatory reporting statue in the particular state of practice. Being a female, age 19-29, pregnant, or of a low socioeconomic status (<$10,000 per/yr) increase one's risk for domestic abuse. Pregnancy is the highest risk factor for abuse with 40% to 60% of battered women reporting that they were abused during pregnancy. Interviewing should be done outside the
presence of others to minimize potential interference by the abusive spouse/partner. The review article by Zillmer outlines that as many as 35% of women presenting to ERs for trauma care have injuries that are a result of domestic violence

Question 30

You are studying a single continuous variable after administration of a defined treatment intervention. Your statistician informs you the data are not normally distributed. What is the best test to analyze the data?

Explanation

The Mann-Whitney U test is used when data are nonparametric, meaning either not normally distributed or variances are not equal among groups. Both the Student t test and ANOVA are used with parametric, normally distributed data. A regression analysis is a statistical model that allows for control of potentially confounding variables. It is used to assess the relationship between a dependent variable and (usually) multiple independent variables.

Question 31

Examination of a 23-year-old female college basketball player who has had anterior knee pain for the past 3 weeks reveals tenderness and fullness over the inferior patella and proximal patellar tendon. There is no patellofemoral crepitus, patella apprehension sign, or anterior or posterior instability. Initial management should include

Explanation

DISCUSSION: The patient has patellar tendinitis (jumper’s knee). It is a common overuse condition seen in runners, volleyball players, soccer players, and jumpers but can be seen in any activity in which repeated extension of the knee is required. In the acute setting, the pain is well localized and there is tenderness and sometimes swelling of the tendon. MRI is recommended for evaluating chronic cases and for surgical planning. In the acute phases, ice, rest, and avoidance of the offending activity are recommended. Weakness of the quadriceps and hamstring muscle are thought to contribute to this problem; therefore, stretching and isometric exercise in a limited range of motion are important. Complete rest and intratendinous injections of steroids are detrimental to tendon physiology.
REFERENCES: Stanish WD, Rubinovich RM, Curwin S: Eccentric exercise in chronic tendinitis. Clin Orthop 1986;208:65-68.
Witvrouw E, Bellemans J, Lysens R, Danneels L, Cambier D: Intrinsic risk factors for the development of patellar tendinitis in an athletic population: A two-year prospective study. Am J Sports Med 2001;29:190-195.

Question 32

A patient wakes up with a foot drop following open reduction internal fixation of a posterior wall/posterior column acetabular fracture. What position of the leg causes the highest intraneural pressure in the sciatic nerve?

Explanation

DISCUSSION: Borrelli et al examined the intraneural pressure of the sciatic nerve with the hip and knee in various different positions. They found that the "sciatic nerve appeared to exceed published critical thresholds for alterations of blood flow and neural function only when the hip was flexed to 90 degrees and the knee was fully extended." As a result, the leg is typically position with the hip in extension (or minimal flexion) and the knee in about 90 degrees of flexion when performing acetabular surgery via a posterior approach.

Question 33

A previously asymptomatic 12-year-old girl sustained a direct blow to the right lateral knee from a baseball bat. Examination reveals an area of ecchymosis and tenderness over the lateral thigh. The patient can walk without pain, but range of motion of the knee causes discomfort. Plain radiographs of the knee are shown in Figures 11a and 11b. To address the bone lesion, management should consist of

Explanation

DISCUSSION: The plain radiographs reveal a pedunculated osteochondroma with a fracture. There is a bony growth in the metaphysis of a long bone, on a stalk that is directed away from the nearby epiphysis. On the AP view, the host cortical and medullary bone are shown as “blending” with lesional bone. There is also a fracture through the lesion. Based on these radiographic findings, the diagnosis is an osteochondroma; therefore, initial management of an acute fracture of an osteochondroma is symptomatic treatment alone. Additional imaging studies are not indicated in this patient. At times it may be difficult to distinguish a sessile osteochondroma from a parosteal osteosarcoma. In the latter case, the host medullary bone and lesion bone are not confluent. A CT scan may be helpful to distinguish if the host medullary and cortical bone are confluent with the lesion.
REFERENCE: Davids JR, Glancy GL, Eilert RE: Fracture through the stalk of pedunculated osteochondromas: A report of three cases. Clin Orthop 1991;271:258-264.

Question 34

Which of the following prognostic indicators is associated with the least favorable outcome for patients newly diagnosed with osteosarcoma?

Explanation

DISCUSSION: Distant bone metastasis is associated with an extremely poor prognosis for patients with osteosarcoma (5-year survival rate of less than 10%). Most osteosarcomas are high grade and extracompartmental, and approximately half are greater than 8 cm at presentation. The 5-year survival rate for these patients is approximately 70%. Patients with a solitary pulmonary metastasis have a prognosis worse than patients without detectable metastases but not as bad as those with bone metastases.
REFERENCES: Bielack SS, Kempf-Bielack B, Delling G, et al: Prognostic factors in high-grade osteosarcoma of the extremities or trunk: An analysis of 1,702 patients treated on neoadjuvant cooperative osteosarcoma study group protocols. J Clin Oncol 2002;20:776-790.
Heck RK, Stacy GS, Flaherty MJ, et al: A comparison study of staging systems for bone sarcomas. Clin Orthop Relat Res 2003;415:64-71.
Kager L, Zoubeck A, Potschger U, et al: Primary metastatic osteosarcoma: Presentation and outcome of patients treated on neoadjuvant Cooperative Osteosarcoma Study Group protocols.

J Clin Oncol 2003;21:2011-2018.

Question 35

A patient with an acromioclavicular dislocation has a very prominent distal clavicle. Examination reveals that the deformity increases rather than reduces with an isometric shoulder shrug. Which of the following structures is most likely intact?

Explanation

DISCUSSION: Severely displaced acromioclavicular injuries disrupt the deltotrapezial fascia and muscular origin in addition to the ligaments (acromioclavicular and coracoclavicular or trapezoid and conoid). When the deltoid is still attached to the clavicle, an isometric shoulder shrug will tend to reduce the displacement. When the deltoid is detached but the trapezius is attached, this manuever will increase the deformity and surgery may be indicated.
REFERENCE: Weinstein DM, McCann PD, McIlveen SJ, Flatow EL, Bigliani LU: Surgical treatment of complete acromioclavicular dislocations. Am J Sports Med 1995;23:324-331.

Question 36

A 17-year-old girl who initially presented as a child with multiple skeletal lesions, café-au-lait spots, and precocious puberty now has bone pain. A recent bone scan reveals multiple areas of increased scintigraphic uptake, including bilateral proximal femurs. A radiograph is shown in Figure 19. Besides activity modification, what is the next best line of treatment for decreasing her pain? Review Topic

Explanation

McCune-Albright syndrome is the combination of polyostotic fibrous dysplasia, café-au-lait lesions, and endocrine dysfunction. The most common endocrine presentation is precocious development of secondary sexual characteristics. Compared with bone lesions in patients without polyostotic disease, the skeletal lesions in patients with the syndrome tend to be larger, more persistent, and associated with more complications. Bisphosphonate therapy has been shown in several studies to decrease the pain associated with the skeletal lesions of fibrous dysplasia.

Question 37

Figure 20 shows the resting and stress radiographs of a patient who has had pain and feelings of instability after undergoing a total knee arthroplasty 1 year ago. Which of the following ligaments is not functional and is therefore responsible for the patient’s symptoms?

Explanation

DISCUSSION: The radiographs show posterior instability caused by an absent posterior cruciate ligament. The tibia is significantly displaced posteriorly with respect to the femur. This can be demonstrated with a lateral radiograph obtained with the knee in flexion. The anterior cruciate ligament has been resected but is not responsible for the instability shown.
REFERENCE: Incavo SJ, Churchill DL: The role of the posterior cruciate ligament in total knee arthroplasty. Techniques Orthop 1999;14:267-273.

Question 38

A 17-year-old girl is involved in a motor vehicle collision and sustains the injury shown in Figures 46a through 46c. She is neurologically intact in her bilateral lower extremities. Definitive treatment should consist of A B C

Explanation

DISCUSSION
The figures reveal a fracture-dislocation at L1-2. Proper treatment consists of posterior reduction, stabilization, and fusion 2 levels above and below the level of injury. Short-segment stabilization schemes do not stabilize the injury properly, and longer-segment constructs are not necessary. Anterior treatment is not indicated in fracture-dislocations.
RECOMMENDED READINGS
Mikles MR, Stchur RP, Graziano GP. Posterior instrumentation for thoracolumbar fractures. J Am Acad Orthop Surg. 2004 Nov-Dec;12(6):424-35. Review. PubMed PMID: 15615508. View Abstract at PubMed
Bono CM, Rinaldi MD. Thoracolumbar trauma. In: Spivak JM, Connolly PJ, eds. Orthopaedic Knowledge Update: Spine 3. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2006:201-216.

Question 39

Figures 30a and 30b are the radiographs of a 61-year-old man with diabetes who fell from a ladder and sustained an isolated closed fracture. After realignment and splint application, what is the most appropriate next step in management?

Explanation

The patient has sustained a high-energy severely comminuted AO/OTA C2 fracture of the distal tibia. This injury is notably fraught with soft-tissue complications that can lead to disastrous clinical results. In general, a staged protocol is now preferred in an effort to avoid these complications and has shown substantial decreases in infection rates and wound healing problems. A CT scan is certainly appropriate for preoperative planning but should be obtained after frame application because the indirect reduction that is achieved improves one's ability to understand the fracture characteristics and morphology. Hybrid external fixation has fallen out of favor because of its limited biomechanic rigidity and clinical results. Open reduction and
internal fixation in the acute phase (6 to 8 hours) or sub-acute phase (2 to 3 days) is difficult.

Question 40

Antegrade femoral nailing has an increased rate of which of the following when compared to retrograde femoral nailing?

Explanation

DISCUSSION: In the referenced study by Ricci et al, antegrade femoral nailing was shown to have an increased rate of hip pain as compared to retrograde femoral nailing, while having a similar rate of union, time to union, rate of malalignment, and operative time. Hip pain was signficantly higher in the antegrade nailing group, while knee pain
was significantly greater in the retrograde group. The referenced study by Winquist et al noted a 99.1% union rate with intramedullary nailing. The referenced study by Moed et al noted a 6% nonunion rate in non-reamed retrograde femoral nailing with nail dynamization at 6-12 weeks and early weightbearing.

Question 41

A 42-year-old man sustained a fracture of the distal radius with subsequent stiffness in the ipsilateral shoulder. Despite a 6-month program of range-of-motion exercises, external rotation at the side is limited to 10 degrees. Attempts at closed manipulation are unsuccessful. Treatment should now consist of

Explanation

DISCUSSION: When external rotation at the side is limited, the most likely diagnosis is contracture of the rotator cuff interval, including the superior glenohumeral and coracohumeral ligaments. Therefore, the treatment of choice is arthroscopic release of the rotator cuff interval.
REFERENCE: Harryman DT II, Matsen FA III, Sidles JA: Arthroscopic management of refractory shoulder stiffness. Arthroscopy 1997;13:133-147.

Question 42

Figure 18a shows the clinical photograph of a 31-year-old man who has a slowly growing nodule on his right middle finger. It is minimally tender, and there is no erythema on examination. A biopsy specimen is shown in Figure 18b. What is the most likely diagnosis?

Explanation

DISCUSSION: Epithelioid sarcoma is the most common soft-tissue sarcoma in the hand and most commonly occurs in young adults. The tumors can be superficial and may become ulcerated. Deeper lesions are often attached to tendons, tendon sheaths, or fascial structures. These are usually minimally symptomatic. The biopsy specimen reveals the typical appearance of a nodular pattern with central necrosis. They can mimic a necrotizing granulomatous process. Usually there are chronic inflammatory cells along the margin of the tumor nodules. This biopsy specimen does not have the clear cells necessary for a clear cell carcinoma or sarcoma. Nora’s tumor is a bizarre parosteal osteochondromatous proliferation (BPOP) first described in 1983 by the pathologist, Nora. The lesion is defined as a reactive heterotopic ossification and is mostly found in the hands or feet of adults in the third decade of life.
REFERENCES: Enzinger FM, Weiss SW: Soft Tissue Tumors, ed 3. St Louis, MO, Mosby, 1995, p 1074.
Halling AC, Wollan PC, Pritchard DJ, et al: Epithelioid sarcoma: A clinicopathologic review of 55 cases. Mayo Clin Proc 1996;71:636-642.

Question 43

Five weeks after the patient completes a 6-week course of antibiotics, his ESR is 24 mm/h and CRP level is 10 mg/L, which is similar to the levels at 6 weeks. What is the most appropriate treatment at this time?

Explanation

DISCUSSION
This patient has both serologic and synovial fluid findings that are concerning for indolent infection. He was taking antibiotics at the time of aspiration. The AAOS clinical practice guideline, The Diagnosis of Periprosthetic Joint Infections of the Hip and Knee, suggests that patients discontinue antibiotics for a minimum of 2 weeks and that a repeat aspiration should be performed in cases of contradictory findings. In this situation, the cell count is elevated
along with an elevated ESR and CRP level. As a result, the appropriate treatment at this time is to reaspirate his hip.
This patient has a periprosthetic joint infection with a draining sinus tract. He has had symptoms for several months and, as a result, irrigation and debridement are not indicated. A single-stage surgery may be performed in some centers for healthy patients with susceptible organisms. However, single-stage reconstructions are generally performed with cemented implants in patients without a draining sinus tract. A 2-stage procedure with an antibiotic spacer is the surgical treatment modality most likely to eradicate this infection.
Serologic findings have significantly improved since the time of the prior surgical procedure. Surgical intervention does not need to be delayed until these values have completely normalized.

Question 44

Figure 36 shows the AP pelvic radiograph of a 26-month-old boy who has a limp. He has no significant medical history and no pain. What is the most appropriate treatment plan? Review Topic

Explanation

The radiograph reveals a complete hip dislocation. A Pavlik harness is an accepted method of treatment for a dislocated hip up until 6 months of age. Closed reduction and spica casting with an arthrogram is often successful in young children up to 1-1/2 years to 2 years of age. Open reduction, capsulorrhaphy, and a spica cast is commonly recommended for younger children when attempts at closed reduction have failed or when the child is older than 2 years of age. A femoral shortening is also generally recommended in children older than 2 years of age in an attempt to reduce the muscle/compressive forces on the reduced hip.
(SBQ13PE.38) Pavlik harness treatment is appropriate for which of the following?: Review Topic
4 year old with a diaphyseal femur fracture and a neuromuscular disorder with lower extremity spasticity
2 month old with a displaced spiral mid-diaphyseal femur fracture
9 month old with a diaphyseal femur fracture with <2cm shortening
9 month old with a diaphyseal femur fracture with >2cm shortening
4 year old with a diaphyseal femur fracture, closed head injury and chest trauma
Treatment with Pavlik harness or spica cast are options for patients <6 months of age with diaphyseal femur fractures. Pavlik harness provides adequate pain control for the short time required for healing in this age group. Significant remodeling potential can be expected.
Because of the significant remodeling and quick healing, treatment of diaphyseal femur fractures in children younger than 6 months focuses on providing comfort and avoiding complications. Spica casting likewise results in stable union without longterm sequelae but minor skin complications are more common and some favor Pavlik treatment in this age group.
Kocher et al. provide the AAOS Clinical Practice Guideline for the treatment of pediatric diaphyseal femur fractures. Their recommendation for diaphyseal femur fractures in children less than 6 months is Grade C, based on Level IV evidence (one retrospective comparative study and one case series). They recommend that Pavlik and spica casting are both acceptable treatment options in this age group.
Flynn et al. review the management of pediatric femoral shaft fractures. They recommend Pavlik treatment for children 6 months of age or less in preference to a spica cast, sometimes supplemented with a simple splint. This avoids the skin complications of spica casting.
Incorrect answers:

Question 45

A healthy, active collegiate soccer player returns to your office approximately 10 months after returning to full play and 18 months after undergoing ACL reconstruction with bone-patellar tendon-bone (BTB) autograft. The patient reports landing awkwardly after a jumping for a ball and felt his knee give way. He presents with pain, worse with weight bearing. On physical exam, there is a mild effusion and a grade 2B Lachman. Radiographs are shown in Figure A. What is the likely underlying cause of his current diagnosis? Review Topic

Explanation

The most common cause for early failure following ACL reconstruction is a malpositioned tunnel.
Ideal tunnel placement on the femoral side should be at the approximately 2 o'clock (for a left knee) or 10 o'clock (for a right knee) position on the lateral wall, which facilitates a more horizontal, anatomic graft. On the tibial side, the tunnel trajectory in the coronal plane should be about 60-75 degrees from the horizontal and the tunnel entrance should be approximately 10-11mm from the anterior border of the PCL.
Noyes et al. emphasize the importance of anatomic reconstruction. They recommended against using a transtibial tunnel to make the femoral tunnel because it will result in a vertical orientation. The authors summarized and recommended the use of individual drilling of each tunnel, and using a anteromedial portal to obtain the ideal femoral tunnel.
Driscoll et al. compared the rotational properties of a BTB graft placed centrally in the tibial footprint in both groups, but on the femoral side, placed in the anteromedial aspect versus central portion of the ACL femoral origin. They noted a significantly stronger resistance to rotational failure when placed centrally. Thus, noting the importance of placing the graft anatomically, within the central areas of both the tibial footprint and femoral origin.
Figure A exhibits malpositioned tunnels, both of which are too vertical. Illustration A exhibits well-placed tunnels, with the horizontality exhibited on the femoral side and approximately 75 degrees from the horizontal on the tibial side.
Incorrect answers:

Question 46

A 30-year-old man has had leg pain for 6 months. A lesion is identified in the proximal femur and biopsy it taken. Histology is shown in Figure A and is consistent with a low-grade intramedullary osteogenic sarcoma. Additional imaging studies confirm that this is an isolated lesion with no metastasis. What is the standard treatment for this type of lesion?

Explanation

Injury Severity Score (ISS )
Glascow Coma Scale (GCS )
Timing of knee reconstruction
Number of ligaments reconstructed
Open ligament reconstruction
Figure A shows a knee dislocation with cruciate ligament avulsion injuries. Development of significant heterotopic ossification (HO) formation has been shown to be most directly correlated to the ISS score.
Mills and Tejwani looked at multiple variables including injury severity score
( ISS), Glascow coma scale (GCS), closed head injury (CHI), timing of surgery (> or < 3 weeks) and type of surgery (open vs. arthroscopic, number of ligaments reconstructed) in its relation to the formation of HO following knee dislocation. In the final group the sensitivity and specificity of the ISS in relation to HO formation was 100%, while presence of CHI had a specificity of 97 %. Timing, type of surgery and approach did not influence HO formation.
A 52-year-old male presents with 6 months of swelling and pain in his leg. He states the lesion has not changed in size for several months and doesn't bother him. He is otherwise healthy and has no other complaints. Representative photograph and MRI are shown in Figures A through C. What is the best initial step in his management?

Follow-up in 6 months with repeat radiographs
Biopsy
Marginal excision
Radiation therapy
Neoadjuvant chemotherapy and wide excision
The initial step in management of a patient presenting with a large soft tissue mass deep to the fascia is to obtain a tissue diagnosis, via biopsy. Initiation of treatment prior to tissue diagnosis is inappropriate and can result in significant patient morbidity and potential mortality. While some soft tissue sarcomas may benefit from chemotherapy, this cannot be initiated prior to diagnosis.
Radiation therapy is used in the treatment of soft tissue sarcoma, but again, only after tissue diagnosis. Peabody et al review the appropriate evaluation and staging for musculoskeletal neoplasms and present flow-charts useful in the work-up of bone (Illustration A) and soft tissue (Illustration B) neoplasms. Skrzynski et al performed a comparison of outpatient core-needle biopsy with open surgical biopsy for musculoskeletal tumors. They found the diagnostic accuracy of core-needle biopsy was only 84% with many samples yielding no or different histological samples when compared to final resected specimens. They conclude that while core-needle biopsy is significantly less expensive
than surgical biopsy ($1106 vs. $7234), there is higher concern for sampling error or general diagnostic inaccuracy associated with a core-needle biopsy compared to open biopsy, the "gold standard".

What is the appropriate treatment for a 10-year-old boy with Ewing's sarcoma isolated to the proximal femur?
Neoadjuvant chemotherapy and surgical excision
Neoadjuvant chemotherapy, surgical excision, and radiation therapy
Neoadjuvant chemotherapy, surgical excision, and adjuvant chemotherapy
Neoadjuvant radiation therapy and surgical excision
Surgical excision and hormonal therapy
Ewing's sarcoma is a malignant small round blue cell neoplasm which has a predilection for long tubular bones, pelvis, and ribs. The radiographic appearance of "onion-skinning" seen in illustrations A and B is due to the body's periosteal reaction. Illustration C shows the large soft tissue extraosseous mass characteristic for Ewing's sarcoma. Finally, Illustration D shows the histology where the multiple small round blue neoplastic cells are seen.
Ewing's sarcoma is most commonly treated with neoadjuvant chemotherapy, surgical excision, and adjuvant chemotherapy - in particular for tumors located in bones which can be easily resected and reconstructed. For large tumors in areas which either cannot be completely excised or where excision is associated with significant morbidity, some centers consider chemotherapy and radiation therapy without surgical excision. There is a current trend towards surgical resection and away from irradiation for Ewing's sarcoma even though it is radiosensitive, because of the risk of secondary malignancy and growth disturbance due to radiation.
Pierz et al review many of the common bone tumors including Ewing's sarcoma and discuss the relevant diagnostic factors as well as specific treatment protocols for each tumor.

A 30-year-old female presents with a painful posterior knee mass. The mass gets larger and more painful with activity. Examination reveals a boggy soft tissue mass about her knee. Radiograph and MRI are shown in Figures A and B. What is the most likely diagnosis?

Synovial sarcoma
Hemangioma
Lipoma
Parosteal osteosarcoma
Pigmented villonodular synovitis (PVNS )
This patients history, physical exam, and imaging studies are suggestive of a hemangioma. Pain in hemangiomas is thought to occur due to vascular engorgement secondary to activity and increased blood flow to the lesion. The calcification on the plain radiograph and the fat of the T1 MRI are diagnostic for hemangioma. Current treatment for symptomatic hemangiomas includes some combination of sclerotherapy or vascular coiling, with surgical excision
reserved for few cases. The two attached reviews by Gilbert et al and Damron et al review the history, diagnosis, treatment, and controversial issues in soft tissue sarcomas and benign sarcoma like conditions such as hemangiomas.
Current treatment for soft tissue sarcomas includes radiotherapy and surgical excision. While many centers in the world use chemotherapy for soft tissue sarcomas, the data supporting its use is quite limited and likely too controversial to be tested. With regard to the other answer choices, synovial sarcoma and lipoma can show calcification on radiographs, but they are usually not painful and image differently on T1 MRI. Parosteal osteosarcoma typically occurs in this location (posterior distal femur) but occurs as a lesion stuck on the bone. PVNS can have a similar appearance on imaging, but doesn't cause this type of pain.

Question 47

A 12½-year-old boy reports intermittent knee pain and limping that interferes with his ability to participate in sports. He actively participates in football, basketball, and baseball. He denies any history of injury. Examination shows full range of motion without effusion. Radiographs reveal an osteochondritis dissecans (OCD) lesion on the lateral aspect of the medial femoral condyle. MRI scans are shown in Figures 14a and 14b. Initial treatment should consist of Review Topic

Explanation

Agenesis of the anterior cruciate ligament
Thickened medial plica
Grade IV chondral flap
Pigmented villonodular synovitis
Abnormal meniscal morphology
This child presents with an asymptomatic click in the knee. It is associated with widening of the lateral joint space of the knee on X-ray. These features are highly suggestive of a discoid lateral meniscus in this age category.
The principal diagnostic feature of a discoid meniscus is the complaint of snapping or clicking in the knee. Children are usually asymptomatic. Although, less frequently, children may present with pain that is largely secondary to an underlying meniscal tear. MRI scans of the knee have show to have the greatest sensitivity for identifying discoid menisci. The presence of a contiguous central meniscus on three consecutive slices is usually indicative of the diagnosis. Treatment is mostly focused on conservative modalities. Surgical intervention is reserved for symptomatic cases with recurrent locking, swelling or persistent pain is present in older children.
Kramer et al. looked at the presentation of pediatric knee pain. They showed that the lateral meniscus is more commonly affected than the medial meniscus. The majority of discoid tears occur in the posterior or middle aspect of the discoid meniscus.
Figure A shows an AP radiograph of a pediatric knee. There is an increased lateral joint space suggestive of a discoid meniscus.
Illustrations A-C show an MRI of the knee with 3 consecutive coronal cuts showing an abnormal appearing discoid meniscus.
Incorrect Answers:

Question 48

An 18-year-old man has had an enlarging mass in his hand for the past 3 months. Radiographs, an MRI scan, and biopsy specimens are shown in Figures 54a through 54d. What is the most likely diagnosis?

Explanation

DISCUSSION: Also known as Nora’s lesion, BPOP is a benign osteocartilaginous tumor that almost always occurs in the hands and feet; one occurrence each in the femur and tibia has been reported. Although local recurrence is common after excision, metastases have not been reported.
REFERENCES: Abramovici L, Steiner GC: Bizarre parosteal osteochondromatous proliferation (Nora’s lesion): A retrospective study of 12 cases, 2 arising in long bones. Hum Pathol 2002;33:1205-1210.
Nora FE, Dahlin DC, Beabout JW: Bizarre parosteal osteochondromatous proliferations of the hands and feet. Am J Surg Pathol 1983;7:245-250.

Question 49

A 25 year-old amateur baseball player sustained a dorsal fracture-dislocation of the proximal interphalangeal joint of his long finger. He underwent closed reduction 3 hours ago. Examination reveals mild laxity of the radial collateral fragment involving 30% of the volar articular surface of the middle phalanx. Management should now include

Explanation

ORIF is most commonly used to treat displaced intrarticular, unstable, or unreducible injuries. Buddy taping is used for isolated volar plate injuries. Dynamic splints are used for volar dislocations in this presentation. Casting in the intrinsic plus position is falling out of favor for earlier range of motion options with PIP fracture dislocations.
“Intra-articular fractures that involve the base of the middle phalanx are usually one of three types 1. Dorsal chip fracture 2. Volar lip fracture, usually combined with a dorsal dislocation of subluxation of the middle phalanx 3. Lateral chip fracture, representing avulsion of bone by the collateral ligament.” Kuczynski has suggested that the volar plate is less mobile in the PIP joint than it is in the MP joint.
“What must always occur with dorsal dislocation, however, is rupture of the volar plate. According to Bowers, the plate is virtually always disrupted from its distal attachment into the base of the middle phalanx. This may with or without a small avulsion chip fracture.”
If the fracture involves more than a third of the joint or is unstable then the PIP joint must be stabilized in a reduced position with early range of motion while restricting PIP hyperextension.
The preferred method of treatment is dorsal extension block splinting for three weeks, then protected range of motion until united.

Question 50

Which of the following types of intra-articular pathology is associated with lateral meniscal cysts? Review Topic

Explanation

Lateral meniscal cysts often arise from myxoid degeneration that progresses from the meniscal center and then outside the meniscus. Horizontal cleavage tears are commonly associated with the condition. Cysts of the lateral meniscus are most commonly the consequence of a tear located in the medial third. If the tear communicates with the joint, arthroscopic partial meniscectomy and cyst decompression are indicated. If the tear does not open into the joint, arthroscopy should be followed by an open cystectomy.

Question 51

At a minimum 2-year follow-up and compared with the metacarpophalangeal (MCP) joint, pyrolytic carbon resurfacing arthroplasties of the proximal interphalangeal (PIP) joint

Explanation

EXPLANATION:
Wall and Stern published a report on MCP joint pyrolytic carbon arthroplasty for osteoarthritis and another on PIP joint pyrolytic carbon resurfacing arthroplasty for osteoarthritis. They found different outcomes, and MCP joint implants outperformed PIP joint implants. Of eleven MCP joint arthroplasties, two produced asymptomatic squeaking and clicking, whereas eleven of 31 PIP joint implants produced this problem. No dislocations were reported among the MCP joint implants, but five PIP joint dislocations were observed. Outcomes were measured by the Michigan Hand Outcomes Questionnaire in both studies and were satisfactory for the MCP joint implants, with an average score of 80. The PIP implants did not fare as well, showing a higher degree of pain along with an average score of 53. The authors noted that, in the 15 patients in the PIP study who had unilateral surgery, the uninvolved, nonsurgical hand motion was actually statistically significantly (P<0.01) better than the surgical hand. MCP joint motion increased from 62º before surgery to 76º after surgery, whereas PIP joint motion got worse after surgery, with the average motion decreasing from 57º to 31º.

Question 52

.Figures 59a and 59b are the axial T2 and T1 with contrast MRI scans of a 32-year-old woman who has a 10-year history of pain and a 1-year history of progressive swelling in her right leg. The histopathology is shown in Figure 59c. A radiograph of her leg showed no mineralizations or osseous erosions. The chromosomal abnormality that is associated with this disease is

Explanation

CLINICAL SITUATION FOR QUESTIONS 60 THROUGH 63
A 45-year-old woman has an enlarging buttock mass. The mass is 12 cm and nonpainful. The patient first noticed it about 6 months after she had a low-impact fall. The general surgeon evaluating the patient felt this mass could be either a lipoma or a hematoma. The patient underwent a surgical procedure to remove the mass.

Question 53

The relocation test is most reliable for diagnosing anterior subluxation of the glenohumeral joint when

Explanation

DISCUSSION: The relocation test is most accurate when true apprehension is produced with the arm in combined abduction and external rotation and then relieved when posterior pressure is placed on the humeral head. Pain with this test is a less specific response and may occur with other shoulder disorders such as impingement.
REFERENCE: Speer KP, Hannafin JA, Altchek DW, Warren RF: An evaluation of the shoulder relocation test. Am J Sports Med 1994;22:177-183.

Question 54

Which of the following findings is a prerequisite for a high tibial valgus osteotomy for medial compartment gonarthrosis?

Explanation

DISCUSSION: The indications for high tibial valgus osteotomy include a physiologically young age, arthritis confined to the medial compartment, 10 to 15 degrees of varus alignment on weight-bearing radiographs, a preoperative arc of motion of at least 90 degrees, flexion contracture of less than 15 degrees, and a motivated, compliant patient. Contraindications include lateral compartment narrowing of the articular cartilage, lateral tibial subluxation of greater than 1 cm, medial compartment bone loss, ligamentous instability, and inflammatory arthritis.
REFERENCES: Naudie D, Bourne RB, Rorabeck CH, Bourne TT: The Insall Award: Survivorship of the high tibial valgus osteotomy. A 10- to 22-year followup study. Clin Orthop 1999;367:18-27.
Pellicci PM, Tria AJ Jr, Garvin KL (eds): Orthopaedic Knowledge Update: Hip and Knee Reconstruction 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2000,
pp 255-264.

Question 55

A 20-year-old man involved in a motor vehicle accident is brought to the emergency department with a C6-7 unilateral facet dislocation. His neurologic examination reveals a focal left-sided C7 nerve root palsy. He is awake and cooperative with questioning and has no other obvious traumatic injuries. What is the most appropriate treatment at this time?

Explanation

DISCUSSION: In the patient who is neurologically intact or has an incomplete injury from a cervical facet dislocation, a closed reduction with weighted tong traction is appropriate when the patient is awake, alert, and cooperative. Although there is a risk that a cervical facet dislocation could occur with an underlying cervical disk herniation, Vaccaro and associates have shown that closed reduction can be safely carried out in the awake, responsive patient. Closed reduction can be performed in the emergency department with traction with skull tongs or a halo ring. A slow stepwise application of weight is added until a reduction is achieved. Any worsening of the neurologic status of the patient requires immediate termination of the closed reduction and further diagnostic imaging before proceeding with further treatment.
REFERENCES: Vaccaro AR, Falatyn SP, Flanders AE, et al: Magnetic resonance evaluation of the intervertebral disc, spinal ligaments, and spinal cord before and after closed traction reduction of cervical spine dislocations. Spine 1999;24:1210-1217.
Hart RA: Cervical facet dislocation: When is magnetic resonance imaging indicated? Spine 2002;27:116-117.
Cotler JM, Herbison GJ, Nasuti JF, et al: Closed reduction of traumatic cervical spine dislocation using traction weights up to 140 pounds. Spine 1993;18:386-390.

Question 56

An operating room intervention that should be undertaken by anesthesia staff during the cementing of a femoral stem is to

Explanation

DISCUSSION
Young age is a risk factor for early failure of cementless femoral components. Surgeons could consider cementing for patients older than 80 years of age. The Dorr classification has been shown to favor a cemented femoral stem in Dorr type C bone. Dorr type B bone can potentially sustain a proximally porous ingrowth stem. Osteoporosis is a risk factor for early failure of cementless femoral components.
Earlier designs for cemented femoral stems used microtexture to interlock the stem into the cement mantle. If these stems became loose, they would abrade the cement and loosen the stem further. Successful cemented femoral components are polished and have smooth edges with tapered bodies. Collars do not add to the design of femoral stems.
Patients are at risk for hypotension during the femoral pressurization process. With that in mind, the surgeon should make sure the anesthesiologist is ready to respond to hypotension. The FiO2 should be increased. The IV fluid rate also should be increased, and the anesthesiologist should be prepared with phenylephrine to support the patient’s blood pressure if he or she becomes hypotensive.

Question 57

What is the most common cause of errors that harm patients? Review Topic

Explanation

The AMA report identified communication breakdown as the most common cause of errors that harm patients. It is extremely important to learn to communicate effectively with your patients. Understanding cultural and language differences helps avoid communication errors.

Question 58

A year-old man undergoes removal of an infected total hip arthroplasty (THA) and insertion of an articulating antibiotic-loaded spacer to treat a deep periprosthetic hip infection. While in a nursing home receiving intravenous antibiotics 3 weeks after surgery, the patient trips and falls. Examination reveals swelling in the mid and distal thigh, intact skin and neurovascular structures, and severe pain with knee or hip movement. Radiographs of the femur are shown in 1 through What is the most appropriate treatment for the fracture below the implant?

Explanation

DISCUSSION:
This patient has a type C periprosthetic femoral fracture. The articulating spacer is not involved in the fracture, which is well distal to the implant. The most appropriate treatment is open reduction and internal fixation of the fracture. Traction is not appropriate for this fracture because the injury can be treated surgically despite the history of previous hip infection. Traction would also be needed for at least 5 weeks and would delay the surgical treatment of the periprosthetic fracture until the time of second-stage revision THA. The fracture is fairly distal, and revision to a longer antibiotic-loaded implant or uncemented stem is not suitable for this fracture pattern, because it extends well past the isthmus. A femoral stem in the distal fragment would provide little stability for the fracture. Removal of the articulating spacer and reimplantation using a long-stem fluted uncemented hip replacement is not appropriate, because it would be premature to reimplant the man's hip while he is still receiving treatment for a deep hip infection.

Question 59

The sartorius muscle is innervated by which of the following nerves?

Explanation

DISCUSSION: The femoral nerve enters the thigh behind the inguinal ligament, lying on the surface of the iliopsoas muscle lateral to the femoral artery and vein. The nerve divides into numerous muscular and cutaneous branches in the femoral triangle. The first motor branch (sometimes two branches) is to the sartorius. There is a variable branch to the pectineus. Subsequent branches go to the rectus femoris and then the vastus muscles in variable order. The last motor branch is to the articularis genu. The muscular branches can be injured in anterior approaches to the hip, especially the middle window of the ilioinguinal approach.
REFERENCES: Hollinshead WH: Textbook of Anatomy, ed 3. Hagerstown, MD, Harper and Row, 1974, p 404.
Last RJ: Anatomy: Regional and Applied, ed 6. London, England, Churchill Livingstone, 1978, p 139.

Question 60

When treating thoracolumbar spine fractures, which of the following is considered the major advantage of using a thoracolumbosacral orthosis (TLSO) when compared to a three-point fixation brace (Jewett)?

Explanation

DISCUSSION: When treating thoracolumbar spine fractures, the major advantage of using the TLSO is greater rotational control.
REFERENCES: Levine AM (ed): Orthopaedic Knowledge Update: Trauma. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1996, pp 347-349.
Krompinger WJ, Fredrickson BE, Mino DE, Yuan HA: Conservative treatment of fractures of the thoracic and lumbar spine. Orthop Clin North Am 1986;17:161-170.
Stauffer ES (ed): Thoracolumbar Spine Fractures without Neurological Deficit. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1993.

Question 61

The patient returns 1 year later to report curling of her toes and numbness on the plantar surface of her foot. What is the most likely cause of this condition?

Explanation

DISCUSSION
Radiographs reveal a Lisfranc fracture dislocation with fractures of the first and second metatarsals. Tenting of skin that is over a bony prominence is an orthopaedic emergency. The fracture dislocation should be reduced without delay. There is no evidence of compartment syndrome of the foot, but this may develop and monitoring is necessary. Toe deformity may develop on a delayed basis because of the subclinical presentation. Nerve irritation is not uncommon with dorsal midfoot surgical incisions. A positive Tinel test result over the midfoot in the distribution of the superficial common peroneal nerve is consistent with a stretch injury to this nerve. CRPS is usually associated with multiple nerve distributions and autonomic nerve findings such as cold hypersensitivity and hyperhidrosis.
RECOMMENDED READINGS
Benirschke SK, Meinberg EG, Anderson SA, Jones CB, Cole PA. Fractures and dislocations of the midfoot: Lisfranc and Chopart injuries. Instr Course Lect. 2013;62:79-91. PubMed PMID: 23395016. View Abstract at PubMed
Schepers T, Oprel PP, Van Lieshout EM. Influence of approach and implant on reduction accuracy and stability in lisfranc fracture-dislocation at the tarsometatarsal joint. Foot Ankle Int. 2013 May;34(5):705-10. doi: 10.1177/1071100712468581. Epub 2013 Jan 14. PubMed
PMID: 23637239. View Abstract at PubMed

Question 62

When compared with a patient who has a subluxated hip, a patient with a dislocated hip who is undergoing acetabular reconstruction for developmental dysplasia of the hip will most likely have

Explanation

DISCUSSION: The rate of revision has been found to be significantly increased in patients with a dislocated hip preoperatively compared with patients with a subluxated hip. This may be the result of compromised acetabular bone stock. The rate of nerve palsy may be increased because of the greater degree of lengthening required to reduce the reconstructed hip.
REFERENCES: Numair J, Joshi AB, Murphy JC, Porter ML, Hardinge K: Total hip arthroplasty for congenital dysplasia or dislocation of the hip: Survivorship analysis and long-term results. J Bone Joint Surg Am 1997;79:1352-1360.
Schmalzried TP, Noordin S, Amstutz HC: Update on nerve palsy associated with total hip replacement. Clin Orthop 1997;344:188-206.

Question 63

-Figures a and b are the anteroposterior and lateral plain radiographs of a 45-year-old woman who had severe bilateral leg pain for 6 months. Figures 5c and 5d are her sagittal and axial T2-weighted MRI scans. After attempting nonsurgical treatment including physical therapy and epidural injections, she continued to experience persistent pain. What is the most appropriate treatment?

Explanation

Question 64

A 53-year-old man has a 4- x 5-cm high-grade soft-tissue sarcoma in the midthigh. As part of the staging evaluation, regional nodes should be assessed by

Explanation

DISCUSSION: In general, soft-tissue metastases to regional nodes are a relatively rare occurrence (less than 5% overall). The incidence of lymphatic metastasis is highest for synovial sarcoma, rhabdomyosarcoma, clear cell sarcoma, and epithelioid sarcoma. Regional nodes should be assessed clinically. CT is not used to routinely assess regional nodes. Evaluation of a sentinal node is not indicated because of the low incidence of regional nodal involvement. Fine needle aspiration may be indicated to assess clinically suspicious nodes. Prophylactic inguinal node dissection is contraindicated because it may lead to unnecessary complications such as lymphedema.
REFERENCE: Sim FH, Frassica FJ, Frassica DA: Soft-tissue tumors: Diagnosis, evaluation and management. J Am Acad Orthop Surg 1994;2:202-211.

Question 65

Increased hip intracapusular pressures can lead to diminished femoral head perfusion. What leg position has been shown to create the lowest intracapsular hip pressures after femoral neck fracture?

Explanation

DISCUSSION: In the referenced study by Bonnaire et al, extension and internal rotation had the highest intercapsular pressure. They found that the greatest decrease in pressure was found with flexion, abduction and external rotation. This is a possible etiology to the common position in which these patients will present to the emergency room. Traction was shown to increase pressure in the joint capsule.

Question 66

Figures 34a and 34b show the axial and sagittal MRI scans of a 36-year-old man who reports the insidious onset of pain in the right shoulder. What is the most appropriate description of the acromial morphology?

Explanation

DISCUSSION: The MRI scans reveal a meso os acromiale with edema at the site in a skeletally mature patient.
REFERENCES: Sher JS: Anatomy, biomechanics, and pathophysiology of rotator cuff disease, in Iannotti JP, Williams GR (eds): Disorders of the Shoulder: Diagnosis and Management. Philadelphia, PA, Lippincott Williams & Wilkins, 1999, p 23.
Sammarco VJ: Os acromiale: Frequency, anatomy, and clinical implications. J Bone Joint Surg Am 2000;82:394-400.

Question 67

Figures below show the clinical photograph and radiograph obtained from a 62-year-old man who has deformity and pain 1 year after primary total hip arthroplasty. What is the reason for the observed deformity?

Explanation

DISCUSSION:
Figure 1 reveals an external rotation deformity of the right lower extremity. This deformity can have numerous causes, including extra-articular deformity. Figure 2 reveals a loose, subsided femoral component. Femoral stems typically subside into retroversion due to proximal femoral biomechanics, which cause a compensatory external rotation deformity. The combined findings from both images suggest an external rotation deformity most likely related to subsidence into retroversion.

Question 68

A 30-year-old man sustains a head injury as well as a femur and pelvis fractures as the result of a rollover motor vehicle accident. He is initially comatosed, but recovers cognitive function after 10 days in the hospital. Soon after awakening he complains of wrist pain and an x-ray demonstrates a distal radius fracture. What is the most likely explanation for this delayed diagnosis?

Explanation

DISCUSSION: According to the cited article by Born et al, who prospectively studied the incidence of delayed recognition of skeletal injury at a Level I trauma center over an 18-month period, the majority of missed skeletal injuries result from failure to image the affected extremity. These authors identified 39 fractures in 26 of 1,006 consecutive blunt trauma patients that were not diagnosed in a timely fashion (delays ranging from 1-91 days). Although other factors contributed to the diagnostic failure (23% were visible on admission films and not recognized; 10% were not visible due to inadequate x-rays of appropriate limb; 13% had adequate x-rays but diagnosis could not be made from initial studies), 55% of the fractures that were delayed in diagnosis resulted from failure to image the affected extremity. They went on to conclude that, “although the delay of fracture identification was not felt to contribute to additional long-term cosmetic, functional, or neurologic problems,” continued radiographic surveillance is necessary to prevent diagnostic failure.

Question 69

A 56-year-old male sustains a Type IIIB open, comminuted tibial shaft fracture distal to a well-fixed total knee arthroplasty that is definitively treated with a free flap and external fixation. Nine months after fixator removal, he presents with a painful oligotrophic nonunion. Laboratory workup for infection is negative. Passive knee range of motion is limited to 15 degrees. What is the most appropriate treatment for his nonunion?

Explanation

DISCUSSION: At 9 months, observation is no longer an option, as the fracture is not healing and is adjacent to a arthrofibrotic joint. Plate osteosynthesis has been shown to be an effective method of treatment for patients who have had an open fracture of the tibia that has failed to unite after external fixation and/or immobilization in a cast.
Wiss et al reported a series of fifty tibial non-unions with a similar clinical scenario. He reported that, with compression plating, 92% of the nonunions healed without further intervention. In their study, 39/50 patients, had autogenous bone grafting in addition to compression plating.

Question 70

1mg/L (normal 1-3mg/L). Knee aspiration yields WBC of 673 cells/mm(3) with 30% polymorphonucleocytes, and a negative gram stain. There is no surrounding erythema but there is a 1cm area at the inferior aspect of the wound that has a large amount of serous drainage able to be expressed. She has a painless range of motion is 0° to 117°. What would be the next most appropriate step in management?

Explanation

Compartment pressure measurements
CT scan
MRI scan
Ultrasound to rule out deep abscess
Bone biopsy
The clinical presentation is suspicious for a stress fracture of the tibia following free-fibula bone grafting. If plain radiographs are negative, more sensitive imaging such as a MRI or bone scan should be performed.
Tibial stress fractures are a known complication following free-fibula bone grafting. Radiographs may be normal (as is the case in figure A), or might show the "dreaded black line" and/or new periosteal bone formation. If a stress fracture is confirmed with imaging, appropriate management would then consist of protective weight bearing until symptoms subside.
Pacifico et al detail a case report of tibial stress fractures after vascularised free-fibula graft to the mandible. They report non-traumatic stress fracture to the tibia following a vascularised free-fibula graft is an uncommon but important complication.
Ivey et al detail a case report of a tibial stress fracture after vascularised free-fibula graft for repair of non-union of the humerus.
Emery et al report a case-series of 5 patients who sustained tibial stress fractures after a graft had been obtained from the ipsilateral fibula for use in anterior reconstruction of the spine. They theorize that the increased load the tibia bears as a result of the missing fibular graft may result in stress fractures.
Illustration A shows new periosteal bone formation on the lateral cortex of the tibia consistent with a stress fracture.
Incorrect Answer Choices:
1: While compartment syndrome is on the differential diagnosis, his signs and symptoms are not most consistent with that diagnosis.
2: While CT scan may show evidence of a stress fracture, MRI/bone scans have been shown to be superior methods for detection.
4: As infectious laboratories are normal, an ultrasound to rule out a deep abscess would likely be negative.
5: Bone biopsy is not appropriate without evidence of a lesion or concern for
osteomyelitis.

OrthoCash 2020
A 65-year-old female with a history of developmental dysplasia of the hip (DDH) undergoes a total hip arthroplasty (THA) utlizing a posterior approach. Following THA, she notices an inability to dorsiflex the ankle of her operative extremity. Her pre-operative and postoperative radiographs are seen in figues A and B. Which of the following intra-operative techniques could have avoided this complication in this patient?

Utilization of an anterior approach
Modular components
Use of a larger femoral head
Femoral shortening osteotomy
Acetabular osteotomy
Patients with DDH undergoing THA are at risk for post-operative sciatic nerve palsy due to intra-operative limb lengthening which increases tension on the sciatic nerve. Appropriate management after discovering a sciatic nerve palsy
after surgery should include immediate knee flexion and hip extension to decrease tension on the sciatic nerve. Sciatic nerve palsy following THA most commonly only affects the common peroneal nerve branch, and spares the tibial nerve and can present as an inability to dorsiflex and evert the ankle.
Farrell et al retrospectively looked at the risk factors for motor nerve palsy after THA. They found while motor nerve palsy is uncommon following primary THA, it can be a devastating complication. Some risk factors include: preoperative diagnosis of developmental dysplasia of the hip, posttraumatic arthritis, the use of a posterior approach, lengthening of the extremity, and use of an uncemented femoral implant. In their review, many of the motor nerve deficits did not fully resolve.
Barrack et al reviewed neurovascular complications following THA. They stated that sciatic nerve injury is the most common nerve injury following THA utilizing a posterior approach. In comparison, femoral nerve injury is much less common and is usually from an anterior approach.
OrthoCash 2020
A cane held in the contralateral hand reduces joint reactive forces through the affected hip approximately 50% by which of the following mechanisms?
Reducing hip abductor muscle pull
Increasing hip flexor muscle pull
Moving the center of rotation for the femoroacetabular joint
Increasing joint congruence at the femoroacetabular joint
Moving the center of gravity posterior to the second sacral vertebra Corrent answer: 1
A cane held in the contralateral hand reduces joint reactive forces through the affected hip up to 50% by reducing abductor muscle pull.
A cane create an additional force that keeps the pelvis level in the face of gravity's tendency to adduct the hip during unilateral stance. The cane's force must substitute for the hip abductors of the affected hip and creates a moment arm that is relatively long and originates on the side opposite the hip whose abductor muscles are weak. Additionally, the person needs adequate strength in the muscles of the wrist, elbow, shoulder girdle, and trunk.
Brand and Crowninshield performed a 3-dimensional hip joint reactive force evaluation of 4 different groups of patients. The groups included normal
subjects, preoperative THA subjects walking without a cane, preoperative THA subjects walking with a cane, and subjects following total hip reconstruction. Each of the 3 groups evaluated without the cane had statistically similar hip joint reactive forces. The preoperative THA subjects walking with a cane and significantly lower joint reactive forces (approximately 60%).
The article by Blount was named by JBJS as a "Classics in JBJS" in 2003. It is a commentary encouraging the use of canes by describing how the biomechanics of the hip joint are altered while using a cane.
Illustration A shows some of the mathematics behind cane use.

OrthoCash 2020
Which of the following is an example of an antalgic gait pattern not typically seen in clinical practice?
Patient's knee is maintained in slight flexion throughout the stance period for ipsilateral knee arthritis
Patient's contralateral step length is shortened with ipsilateral ankle arthritis
Patient leans their trunk laterally over the painful leg during stance phase with ipsilateral hip arthritis
Patient ambulates on their toes with an ipsilateral calcaneal stress fracture
Patient ambulates predominately through the heel for ipsilateral knee arthritis
The term antalgic gait is non-specific and describes any gait abnormality resulting from pain. A patient with knee arthritis maintains slight flexion throughout the gait cycle. This compensatory knee flexion is exacerbated if the patient has a concomitant effusion in the knee as flexion reduces tension on
the knee joint capsule. Gait compensation for knee arthritis also involves toe walking on the affected side, reducing the stride length, and reducing time of weight bearing on the painful leg.
Gok et al performed a case-control gait analysis study of 13 patients with OA and 13 normal patients. They found that walking velocity, cadence and stride length were reduced in the OA group and that the overall stance phase was prolonged in the OA group. They concluded that computerized gait analysis can be used to reveal various mechanical abnormalities accompanying arthrosis of the knee joint at an early stage.
Cole and Harner present Level 5 evidence about knee arthritis in the active patient. They stress that weightbearing radiographs are important in the diagnosis of arthritis. They also discuss the importance of looking for medial or lateral thrusts during gait and dynamic gait changes such as quadriceps avoidance or out-toeing.
Incorrect Answers:
OrthoCash 2020
A 78-year-old male falls at home four months following a right total hip arthroplasty. Right leg deformity, pain, and inability to bear weight are present on physical exam. An injury radiograph is provided in Figure A, while radiographs taken immediately following the initial total hip arthroplasty are provided in Figures B and C. The patient denies any prodromal groin pain prior to his fall. Which of the following is the best treatment option?

Traction for 6 weeks followed by slow return to weight bearing
Open reduction and internal fixation
Revision to a long, cementless femoral stem
Revision to a long, cementless stem with strut allograft
Revision to a long, cemented stem Corrent answer: 2
The clinical presentation and radiograph are consistent with a Vancouver B1 periprosthetic femur fracture. The stem appears stable within the femur, and there is no evidence of subsidence with comparison to the initial post-THA radiographs. This fracture pattern is best treated with internal fixation.
Illustrations A and B are radiographs of this patient following fixation. Illustrations C and D show bone healing at 2 years following the fracture.
Duwelius et al report on 33 periprosthetic femur fractures. All fractures that demonstrated a stable stem at the time of surgery were treated with internal fixation, while those that were unstable were treated with a long, cementless revision femoral stem. At 2.5 years complications were minimal and the patients had regained their pre-fracture level of function.
The review article by Kelley outlines the evaluation, classification, and treatment of periprosthetic femur fractures reinforcing the importance of stem stability within the femur. Periprosthetic fractures around a hemiarthroplasty should be treated with the same algorithm. However, if the patient had antecedent groin pain, then conversion to a total hip arthroplasty should be considered to prevent continued groin pain.

OrthoCash 2020
A 64-year-old male underwent the procedure shown in Figures A and B 7 weeks ago. He complains of difficulty with going down stairs. He reports no pain and denies constitutional symptoms. On examination the incision is well healed and no effusion is present. He is able to perform a straight leg raise with 5/5 strength. He lacks 2 degrees of terminal extension and has 80 degrees of active flexion. The knee is stable to varus and valgus stress testing at extension and mid flexion. His C-reactive protein and erythrocyte sedimentation rate are normal. What is the next most appropriate step in management?

Manipulation under anesthesia
Cortisone injection followed by physical therapy for quadriceps strengthening
Aspiration to evaluate for septic arthritis
Revise femoral component by downsizing A-P diameter
Revise tibial component and add 5 degrees of posterior tibial slope Corrent answer: 1
The history, physical examination, laboratory studies, and imaging are consistent with a total knee arthroplasty patient with arthrofibrosis. The next most appropriate option includes a manipulation under anesthesia to increase the patient's flexion.
Maloney presents Level 4 evidence discussing TKA postoperative arthrofibrosis. They report that manipulation under anesthesia was successful in improving flexion from an average of 67 degrees premanipulation to 111 degrees
postmanipulation.
Keating et al report Level 4 evidence of 113 patients that underwent manipulation following TKA. They found that 90% of the patients achieved improvement of ultimate knee flexion following manipulation. The average improvement in flexion from the measurement made before manipulation to that recorded at the five-year follow-up was 35 degrees.
OrthoCash 2020
Which of the following total hip arthroplasty patients appropriately meets the criteria for a surgical debridement with isolated femoral head and polyethylene liner exchange?
Prosthesis infection of 4 months duration
Prosthesis infection 8 weeks following implantation
Prosthesis infection 3 days following a systemic infection
Acetabular component loosening due to osteolysis
Vancouver Type A periprosthetic fracture.
Femoral head and polyethylene liner exchange is an appropriate treatment for the acutely infected arthroplasty. Acute infection has been defined as 3-6 weeks following surgery or following a systemic infection depending on the literature source. Subacute and chronic infections must be treated with a complete explant and exchange of all components. (One-stage or two-stage is controversial).
Salvati et al review the management of total hip arthroplasty infection. Most importantly, the pathogen must be isolated to direct antibiotic treatment. The acuity of the infection must also be recognized to direct surgical management.
OrthoCash 2020
A 54-year-old woman is at physical therapy 3 months after a total knee arthroplasty when she feels a pop and develops increased pain in her knee. She continues therapy for another 3 months but reports weakness and frequent buckling. On exam, she has full passive extension but a 60 degree extensor lag. A lateral radiograph is shown in Figure A. What is the treatment of choice?

Reconstruction with a bone-tendon allograft
Repair augmented with hamstring autograft
Continued therapy and strengthening
Arthrodesis
Treatment with orthotics for support Corrent answer: 1
The patient has a chronic patellar tendon rupture following a TKA with marked extensor lag and patella alta on radiograph. A study by Barrack et al concluded that allograft reconstruction for the chronically-disrupted extensor mechanism after TKA could restore active extension and improve ambulatory function. In chronic cases, primary repair with or without local tissue augmentation have had disappointing results. Extensor mechanism injuries after TKA was reviewed by Parker et al. Patellar tendon ruptures are rare complications after TKA with an incidence reported <2.5%. Quadriceps tendon ruptures are even more rare with an incidence ~1%.
OrthoCash 2020
When compared to the standard medial parapatellar approach for revision total knee arthroplasties, the oblique rectus snip approach
showed impairment in which of the following post-operative outcomes?
range-of-motion
patient satisfaction
pain
WOMAC function score
no difference in outcomes Corrent answer: 5
Meek et al compared the rectus snip to a standard medial parapatellar approach for revision total knee arthroplasty. The WOMAC function, pain, stiffness and satisfaction scores demonstrated no statistical difference. They concluded that use of a rectus snip as an extensile procedure had no adverse effect on outcome.
OrthoCash 2020
What is the range of pore size of cementless porous implants to allow for optimal bony ingrowth?
Less than 1 micron
50 to 400 microns
1,000 to 5,000 microns
10,000 to 50,000 microns
100,000 to 500,000 microns
The range of 50 to 400 microns is the optimal pore size for cementless porous implants to allow for optimal bony ingrowth.
Bobyn et al looked at the optimum pore size for fixation of porous surfaced metallic implants. Four different pore sizes were examined and placed in canine femurs for 4, 8, and 12 weeks and tested to measure the shear strength based on pore sizes. A pore size of 50 to 400 microns provided the maximum fixation strength in the shortest time period (8 weeks), implying maximal bony ingrowth.
Pilliar et al discussed two independent canine studies which showed that initial implant movement relative to host bone can result in attachment by a nonmineralized fibrous connective tissue layer. They state that implant movement of greater than 150 microns leads to fibrous ingrowth.
Jasty et al implanted porous-coated implants in the distal femoral metaphyses of twenty dogs and subjected them to zero, twenty, forty, or 150 micrometers of oscillatory motion. They found that that the implants that had been subjected to 150 micrometers of motion were surrounded by dense fibrous tissue.
OrthoCash 2020
An active 73-year-old male presents with progressive pain and instability 15 years after undergoing a left total knee arthroplasty. He denies any recent trauma. A comprehensive workup for infection is negative. What is the most appropriate management of this patient?

Protected weight bearing for 6 weeks
Revision total knee arthroplasty
Bisphosphonate therapy
Routine follow-up in 1 year
Polyethylene liner exchange and bone grafting Corrent answer: 2
This patient has evidence of periarticular osteolysis and component loosening around a previous total knee arthroplasty. He is symptomatic and would benefit from revision total knee arthroplasty (TKA).
Osteolysis is one of the leading causes for late reoperation in patients who undergo TKA. Osteolysis occurs as the result of a foreign body response to particulate wear debris from the prosthetic joint. These particles consist of polyethylene, polymethylmethacrylate cement, and metal, all of which have been shown to elicit a distinct inflammatory response. Once the particles are generated from and around the implant, they become phagocytosed by macrophages and giant cells in the synovial or periprosthetic tissue. These cells, in turn, become activated and can directly or indirectly cause osteolysis. The femur is prone to osteolysis in the region of the femoral condyles and near the attachments of the collateral ligaments of the femur. Osteolysis around the tibia tends to occur along the periphery of the component or along the access channels to the cancellous bone.
Maloney & Rosenberg reviewed the management and outcome of periprosthetic osteolysis around hip and knee implants. They recommended surgical intervention for periprosthetic osteolysis around a TKA with (1) first-time presentation of advanced osteolysis in the presence of an identifiable cause of wear particle production or in the presence of associated bone loss that places the structural integrity of the bone or fixation of the components at risk, (2) bearing surface wear in the presence of impending wear-through or related mechanical symptoms, (3) progressive osteolysis in an active individual, and (4) symptoms of wear debris-related synovitis that are refractory to conservative treatment.
Griffin et al. evaluated the results of isolated polyethylene exchange for wear and/or osteolysis in 68 press-fit condylar TKAs from four centers. At a minimum of 24 months after polyethylene exchange surgery, there were 11 failures (16.2%).
Gupta et al. discuss the etiology, diagnosis, contributing factors, and management of osteolysis as it relates to TKAs. They recommend that if the patient is asymptomatic with minimal osteolysis on plain radiographs, regular
follow-up at 6 months to 1 year with medical management including calcium and bisphosphonates would be adequate. If the patient becomes symptomatic or the osteolysis is progressive, then early liner exchange with or without tibial baseplate exchange is considered.
Figure A & B are AP and lateral radiographs of periarticular osteolysis and component loosening. Illustration A is an AP and lateral radiograph of the revision TKA.
Incorrect Answers:

OrthoCash 2020
Which of the following statements is true regarding the thirty-year follow-up data obtained from the Charnley "low-friction" total hip arthroplasty?
Acetabular component failure was the least common reason for revision surgery
The number of revisions required for periprosthetic fractures was higher than that for deep infections
Acetabular component failure was a more common reason for revision than deep infection
Femoral component failure was a more common reason for revision than acetabular component failure
Deep infection was the most common reason for revision Corrent answer: 3
Failure of the acetabular component was the most common reason for revision at thirty-years for the Charnley "low-friction" total hip arthroplasty.
The Charnley low-friction torque arthroplasty was introduced in 1962. It consisted of a 22mm diameter metal head, a cemented femoral component, and a cemented ultra-high-molecular-weight polyethylene acetabular component. Overall, the results were very good at thirty years with only 11.8% requiring revision.
Charnley et al. in 1972 reported the 4-7 year results of 379 "low-friction" total hip arthroplasties. Overall, their short-term results were very good with only 2 loose acetabular components, 0 loose femoral components, and 1 late dislocation.
Wroblewski et al. in 2009 reported the 30 year follow-up of 110 patients who underwent the "low-friction" total hip arthroplasty. 13 hips (11.8%) had to be revised. Of these, 5 were for problems with the acetabular component, 4 were for loosening of both components, 2 were for deep infection, 1 was from a loose femoral component, and 1 was from a fractured femoral component.
Illustration A shows a radiograph after a Charnley low-friction total hip arthroplasty. Note the all poly-ethylene acetabular component. Illustration B shows the components used for the operation.
Incorrect Answers:

OrthoCash 2020
A 71 year old gentleman underwent left total hip arthroplasty 10 years ago. Eighteen months ago he began having hip and thigh pain. Over the past 6 weeks, the pain has become excruciating and he has been unable to ambulate, even with the aid of a walker. He has mild pain with passive internal and external rotation of the hip. He is unable to ambulate in the office. Laboratory values are notable for a WBC of 10,300, CRP of 0.2, and ESR of 13. A radiograph is provided in figure A. Which of the following is the best treatment option?

Radionuclide bone scan and MRI
Open reduction internal fixation with a cable plate and allograft strut
Revision arthroplasty with a fully coated cementless stem, cable wiring, and bone graft
Revision arthroplasty with a modular, tapered stem and bone grafting of the diaphyseal fixation
Revision arthroplasty with a total femur prosthesis Corrent answer: 3
The radiograph is consistent with a periprosthetic femur fracture, with a loose femoral stem, and a Paprosky IIIA femoral defect. This is best treated with a fully-coated cementless stem with metaphyseal onlay allograft.
Paprosky devised a classification for femoral bone loss following THA. The classification is as follows:
Type I: minimal metaphyseal bone loss and intact diaphyseal fixation Type II: extensive metaphyseal bone loss with intact diaphyseal fixation
Type IIIA: severe metaphyseal bone loss with greater than 4 cm of diaphyseal bone preservation for distal fixation.
Type IIIB: severe metaphyseal bone loss and less than 4 cm of diaphyseal
bone preservation for distal fixation
Type IV: extensive metaphyseal and diaphyseal bone loss.
Type IIIA may be treated with a fully coated stem. Type IIIB should consider a tapered, modular stem and/or bone grafting. Type IV likely needs a megaprosthesis. In this patient, given the preserved diaphyseal bone, revision arthroplasty with a fully coated femoral stem is the most appropriate treatment.
The Sporer article reviews a case series of patients undergoing revision hip arthroplasty for femoral bone loss. Type IIIB defects with a femoral canal less than 19 mm may be treated with a fully porous-coated stem. However, patients with Type IIIB defect and a cavernous canal greater than 19 mm or a Type IV defect may need a modular tapered stem or a bone grafting procedure.
The Paprosky article summarizes his classification of femoral bone loss in revision hip arthroplasty and provides an algorithm for treatment. Extensively porous-coated, diaphyseal filling femoral components showed excellent results in Paprosky IIIA defects.
Radiograph A shows a total hip arthroplasty with severe metaphyseal bone loss and a supportive diaphysis.
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OrthoCash 2020
A 74-year-old man presents with start-up thigh pain following a total hip replacement 10 years ago. Immediate post-operative radiograph is shown in Figure A. A current radiograph is shown in Figure B. Aspiration of the hip yields 1,005 white blood cells/ml. ESR is 12 (normal <40) and CRP is 0.4 (normal <1.2). Which of the following is the most appropriate management at this time?

Revision of the femoral component to an uncemented, long, fully porous-coated stem
Revision of the femoral component to a cemented stem
Revision of the femoral component to an allograft prosthetic composite
Revision of the femoral component to a proximal femoral replacement
Removal of prosthesis with insertion of antibiotic spacer Corrent answer: 1
The clinical presentation is consistent with symptomatic, aseptic femoral component loosening with no evidence of femoral bone defects. Appropriate management consists of revision of the femoral component to an uncemented, fully porous-coated stem.
Aseptic loosening remains one of the most common indications for revision total hip arthroplasty. After infection has been ruled-out, management is determined by gauging the patients symptoms, the rate of progression of the subsidence, and the amount of femoral bone loss. Uncemented revision femoral components have shown superior results to cemented revision femoral components in the long-term. In the setting of Paprosky Type I, II, and IIIA defects of the femur, revision to an uncemented, fully porous-coated stem is advised.
Moreland et al. review the results of 134 patients (137 hips) who underwent revision arthroplasty with an extensively porous-coated cobalt chrome femoral prosthesis. At a mean follow-up of 9.3 years, only 10 (7%) had to removed for any reason.
Sporer et al. review the results of fully porous-coated stems, impaction bone grafting, and modular tapered stems for Paprosky III and IV femoral defects. They found a high rate of failure with fully porous-coated stems when used in patients with Type IIIB defects >19mm and Type IV defects. They attribute these failures to instability and the inability to eliminate micromotion.
Figure A shows a cementless, metaphyseal engaging femoral component in good alignment. Figure B is a post-operative radiograph from 10 years later showing significant subsidence of the femoral component.
Incorrect Answers:
OrthoCash 2020
A 72-year old female who underwent an uncemented right total hip arthroplasty 2 years ago complains of right hip pain after a fall. Figure A shows her current radiograph. Which acetabular bone defect classification and treatment option best describes this scenario?

AAOS Type III - anti-protrusio cage with augmentation and a posterior column plate
AAOS Type IV - anti-protrusio cage with screw fixation and a posterior column plate
AAOS Type II - jumbo cup with augmentation and a posterior column plate
AAOS Type I - total acetabular allograft with a cemented cup
AAOS Type II - custom triflange acetabular component Corrent answer: 2
Figure A shows pelvic discontinuity, which is consistent with a AAOS Type IV defect. Acetabular antiprotrusio cage with screw fixation and a posterior column plate is a reasonable treatment option for this condition.
Acetabular bone loss following total hip arthroplasty is a challenging problem with a wide variety of treatment options available. The two most widely accepted classification systems are the AAOS and Paprosky classifications.
AAOS type I defects are segmental, type II are cavitary, type III are combined cavitary and segmental, type IV is discontinuity, and type V is arthrodesis. All of the treatment options listed above are described for pelvic discontinuity,
with none being described as superior.
DeBoer et al. describe the results of 28 patients with pelvic discontinuity treated with a custom-made porous-coated triflange acetabular prosthesis. 20 of these patients were followed for 10 years. There were no re-operations, 5 hip dislocations, 1 sciatic nerve palsy, and an average improvement in the Harris hip score from 41 to 80.
Paprosky et al. retrospectively reviewed patients who had an acetabular revision using a trabecular metal acetabular component for a pelvic discontinuity and compared these patients with a cohort of patients who had a previous reconstruction for a pelvic discontinuity using an acetabular cage.
They found a decreased incidence of pain and need for walking aids in those patients who had revision with a trabecular metal acetabular component.
Figure A shows pelvic discontinuity, likely acute given the lack of associated bony defects and recent fall. Illustration A details the AAOS hip acetabular defect classification and Illustration B is the often cited Paprosky classification.
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OrthoCash 2020
Which of the following is indicative of type 1 collagen breakdown and can be utilized as a marker of bone turnover?
Increased urinary N-telopeptide
Increased urinary cAMP and phosphate
Increased urinary phosphoethanolamine
Increased urinary Bence Jones proteins
Increased serum bone sialoprotein Corrent answer: 1
Urinary N-telopeptide is a marker of increased bone turnover and is a breakdown product of Type 1 collagen.
Increased serum alkaline phosphatase level and increased urinary markers of N-telopeptide, hydroxylproline, deoxypyridinoline indicate high bone turnover and can be seen in metabolic bone diseases such as Paget's disease.
von Schewelov et al. reviewed 160 patients that underwent total hip replacements and examined their urine specimens to see if N-telopeptide levels correlated to periprosthetic osteolysis. They found that n-telopeptide levels were 1/3 higher in the patients that had evidence of osteolysis. N-
telopeptide release and annual wear were both associated with increased prevalence of osteolysis in the study.
Illustration A shows a radiograph of Pagets disease of the femur, an example of a condition where there is an increased level of N-telopeptide in the urine. Illustration B is a radiograph showing periprosthetic osteolysis, another condition where there is an increased level of N-telopeptide in the urine.
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OrthoCash 2020
A 78-year-old female undergoes total hip arthroplasty through a minimally invasive surgical approach. During insertion of a metaphyseal fixation stem with a cementless press-fit technique, a crack in the calcar is identified. The stem is removed, two cable wires are passed around the calcar, and the same stem is reinserted. Which of the following statements is true?
The patient should be advised she is at greater risk of stem subsidence and early revision
Female sex is a risk factor for intraoperative calcar fracture
A better outcome would be expected if a long-stem diaphyseal fixation stem had been inserted after recognition of the calcar fracture
Cementless press-fit technique is not a risk factor for intraoperative fracture
Minimally invasive surgical approach is not a risk factor for intraoperative fracture
Of the statements listed, the only true statement is that female gender is a risk factor for intraoperative calcar fracture.
Calcar fractures are a documented complication of total hip arthroplasty. Studies have shown that successful outcomes can be achieved with stem removal, cable wiring of the calcar, and re-insertion of the primary stem.
Berend et al. reviewed a series of 58 total hip arthroplasties who sustained an intraoperative calcar fracture. All were treated with cable wiring of the calcar and stem insertion. The authors report no femoral component subsidence or failure otherwise at 16 year follow-up.
Graw et al. review a series of 46 revision THA's. Of the 46, fifteen underwent primary THA through a minimally invasive technique. The average length of time from primary THA to revision was 1.4 years for the minimally invasive group versus 14.7 years for the traditional exposure THA's. The authors conclude minimally invasive THA is a risk for early revision.
Davidson et al. review intraoperative periprosthetic hip fractures. "Risk factors for intraoperative periprosthetic fractures include the use of minimally invasive techniques; the use of press-fit cementless stems; revision operations, especially when a long cementless stem is used or when a short stem with impaction allografting is used; female sex; metabolic bone disease; bone diseases leading to altered morphology such as Paget disease; and technical errors at the time of the operation." The authors summarize techniques for treatment and postulate that long term outcome is unaffected when the intraoperative fracture is identified and treated appropriately.
Illustration A shows a nondisplaced calcar crack that was treated with a single Luque wire.
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OrthoCash 2020
Which of the following types of prosthetic designs, seen in figures A-E, has been shown to have a high rate of loosening secondary to overconstraint?

Figure C shows an example of an Walldius hinge total knee prosthesis. This design had a higher rate of aseptic loosening (up to 20%) secondary to a high-degree of constraint.
Constraint is defined as the effect of the elements of knee implant design that provides the stability needed to counteract forces about the knee after arthroplasty in the presence of a deficient soft-tissue envelope. While increasing component constraint increases the stability of the knee, it also transmits forces to the fixation and implant interfaces, which may lead to premature aseptic loosening. First-generation total knee hinged prostheses were highly constrained devices that only allowed a single axis of rotation.
Lombardi et al. provide an Instructional Course Lecture on the different prosthetic designs in total knee arthroplasty. They argue that PCL sacrificing implants are more appropriate than cruciate-retaining implants in rheumatoid arthritis, previous patellectomy, previous high tibial osteotomy or distal femoral osteotomy, and in cases where the PCL is absent secondary to trauma.
Morgan et al. discuss constraint in primary total knee arthroplasty. They argue that a hinge total knee arthroplasty should be reserved for severe instability, elderly patients with comminuted distal femur fractures, patients with
extensor-mechanism disruption and unstable knees, and those with substantial bone loss not amenable to augmentation.
Figure C shows an example of a Walldius hinged prosthesis.
Illustration A shows an intra-operative example of a constrained-hinged knee prosthesis. Note the link between the tibial and femoral components, which differentiates it from a constrained, non-hinged prosthesis.
Incorrect Answers: The following responses are incorrect as they all have lower rates of aseptic loosening than than varus/valgus constrained prostheses or hinged designs.

OrthoCash 2020
A 28-year-old football player sustains a contact knee injury while being tackled. On physical exam, he has a 1A Lachman, and a normal McMurray test. His posterior drawer, dial, and varus stress tests are normal. He has pain and 5mm opening on valgus stress at 30 degrees of flexion. Which statement is true regarding the injured structure?
Resides between layers 1 and 2 on medial side of knee
Inserts onto Gerdy's tubercle
Originates slightly posterior and proximal to the medial epicondyle
Courses intraarticularly thru hiatus of lateral meniscus
Has an attachment between adductor tubercle and medial epicondyle at Schöttle's point
The clinical presentation is consistent with an injury to the superficial medial collateral ligament (MCL) of the knee, which originates slightly posterior and proximal to the medial epicondyle.
The superficial portion of the MCL is the primary stabilizer to valgus stress at all angles, contributing 57% and 78% of medial stability at 5 degrees and 25 degrees of knee flexion, respectively. Anatomic studies have shown that the superficial MCL originates approximately 3.2 mm proximal and 4.8 mm posterior from the medial femoral epicondyle and inserts into the periosteum of the proximal tibia (deep to pes anserinus). The superficial MCL lies in layer 2, just deep to gracilis and semitendinosus tendons.
Wijdicks et al. (2009) looked at radiographic identification of the primary medial knee structures including the superficial MCL. On the lateral radiograph, they found that the attachment of the superficial MCL was an average of 6.0 mm from the medial epicondyle.
Wijdicks et al. (2010) reviewed injuries to the MCL and associated medial structures of the knee. They state that physical examination is the initial method of choice for the diagnosis of medial knee injuries through the application of a valgus load both at full knee extension and between 20 degrees and 30 degrees of knee flexion. Treatment of isolated grade-III injuries to the MCL, or such injuries combined with an anterior cruciate ligament tear, should start with nonoperative treatment of the MCL due to high rates of success with nonoperative treatment. If operative treatment is required, an anatomic repair or reconstruction is recommended.
Illustration A shows the femoral and tibial attachments of the superficial MCL. Illustration B shows the osseous landmarks and attachments of medial knee structures (AT, adductor tubercle; GT, gastrocnemius tubercle; ME, medial epicondyle; AMT, adductor magnus tubercle; MGT, medial gastrocnemius tendon; sMCL, superficial MCL; MPFL, medial patellofemoral ligament; POL, posterior oblique ligament).
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OrthoCash 2020
Which of the following best describes normal tibio-femoral joint kinematics ?
The femur undergoes internal rotation with knee flexion
The lateral femoral condyle remains stationary on the lateral tibia plateau during knee flexion from 0 to 120 degrees
The tibia undergoes internal rotation with knee flexion
The medial femoral condyle moves posteriorly on the medial tibial plateau during knee flexion from 0 to 120 degrees
Beyond 120 degrees of flexion only the lateral femoral condyle participates in femoral rollback
Tibia is subjected to internal rotation with knee flexion and the tibia EXternally rotates on femur as the knee EXtends.
The axis of rotation shifts posterior on the lateral condyle with knee flexion. Flexion and extension at the knee occur about a constantly changing center of rotation (polycentric rotation).
Freeman et al. conducted a biomechanical experiment and found that the medial femoral condyle does not move much from 0 to 120 degrees of flexion. They also found that the lateral femoral condyle and the contact area between that condyle and the tibia move posteriorly and tibial internal rotation occurs with knee flexion. They found that from 120 degrees to full flexion both condyles participate in "roll back".
Illustration A shows why the screw-home mechanism occurs. The medial tibial plateau is longer than the lateral tibial plateau, leading to external rotation of the tibia during extension as the femoral condyle rotates about the tibia. Video V shows an example of external tibial rotation during extension.
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OrthoCash 2020
Which of the following molecules is associated with macrophage induced osteolysis surrounding orthopaedic implants?
BMP-7
IL-10
SOX-9
Osteoprotegrin
IL-1
Of the options provided, IL-1 is most associated with macrophage induced osteolysis surrounding orthopaedic implants.
Macrophages initiate the inflammatory cascade associated with aseptic loosening of orthopaedic implants by secreting platelet-derived growth factor (PDGF), prostaglandin E2 (PGE2), TNF-alpha, IL-1, and IL-6.
Archibeck et al. state the primary cells involved in the process of periprosthetic loosening include the macrophage, osteoblast, fibroblast, and osteoclast. They report the chemical mediators that are responsible for the cellular interactions and effects on bone primarily include PGE2, TNF-alpha, IL-1, and IL-6.
Drees et al. discuss the molecular pathway of aseptic loosening of orthopedic implants. They describe the following steps: 1) Wear debris particles released at the cement–bone interface attract macrophages, which, in turn, are stimulated to produce proinflammatory mediators and proteolytic enzymes; 2) RANKL, TNF-alpha, IL-1, IL-6, IL-17, and M-CSF mediate the differentiation of myeloid precursor cells into multinucleated osteoclasts, which release cathepsin K and acid and cause resorption lacunae; 3) Mesenchymal cells (prosthesis-loosening fibroblasts) present at the bone surface contribute actively to bone resorption.
Illustration A shows the pathway described by Drees et al.
Incorrect Answers

OrthoCash 2020
Which of the following templates, seen in Figures A-E, will increase the offset while keeping the leg lengths the same?

If the total hip prosthesis is inserted according to the template in Figure E, the offset will be increased, while the leg lengths will remain unchanged.
Restoration of limb length is essential following total hip arthroplasty. The amount of limb-length change will be the vertical distance between the center of rotation of the femoral component and the center of rotation of the acetabular component. Thus, when the femoral center of rotation on templating is inferior to that of the acetabular component, the limb will be shortened. Restoring femoral offset is also important. If the center of rotation of the prosthetic head lies lateral to that of the cup on templating, the reconstruction will produce decreased offset.
Scheerlinck et al. present a stepwise approach to hip templating through four steps. Step 1 involves identifying landmarks, step 2 involves assessing the
quality of the radiograph, step 3 identifies mechanical references, and step 4 optimizes implant positioning.
Tripuraneni et al. discuss the common errors encountered when templating for total hip arthroplasty. They found the most common error was excessive limb lengthening and incomplete medialization of the acetabular component.
Della Valle et al. review hip templating. They stress the importance of preoperative planning, but also discuss the importance of tactile feedback during the surgery in choosing the correct implants.
Illustration A shows a table of how offset and leg lengths can be changed through positioning and selection of components.
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OrthoCash 2020
A 91-year-old male with a history of chronic leukemia and dementia falls and sustains the hip fracture shown in Figure A. He undergoes a hemiarthroplasty through a posterior approach. A postoperative radiograph is shown in Figure B. Three weeks later he dislocates the hip arising from the toilet seat. A radiograph is shown in Figure C. The patient undergoes a closed reduction and is placed in a hip abduction brace. Post reduction radiograph is shown in Figure D. One month later he returns to clinic complaining of pain and inability to bear weight through the leg. A radiograph of the hip is included in Figure E. Which of the following factors has MOST likely contributed to the instability of the hip hemiarthroplasty?

Femoral stem subsidence
Increased offset
Inadequate femoral stem neck length
Patient's dementia status
Patient's gender
The most likely contributing factor to the instability include the patient's dementia.
Sultan et al use a basic science model to show liners with elevated rims placed in the posterior superior quadrant allow greater range of motion to dislocation than standard liners. They also show that 32 mm heads have greater range of motion to dislocation compared to 28 mm heads.
Morrey et al reviewed a series of 19,680 primary THA's for late dislocation (first dislocation greater than 5 years after surgery). 165 hips (0.8%) had a late dislocation. Factors associated with late dislocation include implant malposition, neurologic decline, trauma, and polyethylene wear.
Figure A shows a femoral neck fracture. Figures B and D show a hip hemiarthroplasty in appropriate position. Figure C and E show a dislocated hip hemiarthroplasty
This patient's instability was managed by converting the hip hemiarthroplasty to a total hip arthroplasty with a constrained liner as shown in illustration A. No further instability episodes occurred following the revision.
Incorrect Answers:

OrthoCash 2020
What surgeon is credited for designing the prosthesis seen in Figure A?

John Charnley
San Baw
Sir Harry Platt
Austin T. Moore
Charles Frederick Thackray Corrent answer: 4
Figure A shows an example of an Austin-Moore hemiarthroplasty.
Austin Moore developed the most popular long-stemmed prosthesis in the 1950s. The Austin-Moore prosthesis was a large, uncemented femoral stem that didn't use polyethylene. The Austin-Moore prosthesis had fenestrations for self-locking which later became the impetus for biological fixation. These implants were originally used to treat hip fractures and certain cases of degenerative arthritis. Later, in the 1960s, John Charnley introduced the idea of replacing the eroded acetabulum with a Teflon component.
Moore et al. describe the first metallic hip replacement surgery in 1940. The patient had a proximal femoral resection for a giant cell tumor. The original prosthesis he designed was a proximal femoral replacement, with a large fixed head, made of the Cobalt-Chrome alloy Vitallium.
Charnley et al. discuss the long-term results (up to 7 years) of the "low-friction" total hip arthroplasty. Infection rate was 3.8%, late mechanical failure was 1.3%, and most patients had excellent pain relief.
Figure A shows a radiograph of an Austin-Moore hemiarthroplasty. Illustration A shows an Austin-Moore prosthesis. Illustration B shows an example of Charnley's "low-friction" total hip arthroplasty, with a stainless steel head and
stem and a polyethylene acetabular component.
Incorrect Answers:

OrthoCash 2020
A 45-year-old man has had the gait disturbance shown in Video A ever since a total hip replacement two years ago. Since then he has undergone physical therapy and nerve exploration without any clinical improvement. Extensive AFO bracing was attempted but was not tolerated by the patient. A recent ankle radiograph is shown in Figure
A. The Silfverskiold test reveals dorsiflexion of 20 degrees with knee flexion, and 10 degrees with full knee extension. The results of muscle
testing using a Cybex dynamometer are shown in Figure B. What is the most appropriate next step in in treatment.

Ankle arthrodesis in 30 degrees of dorsiflexion
Posterior tibial tendon transfer to the lateral cuneiform through the interosseous membrane
Split anterior tibial tendon transfer to the cuboid
Peroneus longus transfer to the navicular and gastrocnemius recession
Flexor hallucis transfer to the navicular and tendo Achilles lengthening (TAL) Corrent answer: 2
The clinical presentation is consistent with a sciatic neuropathy following THA in a patient that does not tolerate AFO bracing. Posterior tibialis tendon transfer is the next most appropriate step in treatment.
Sciatic neuropathy, especially involving the common peroneal branch, is a known complication of total hip arthroplasty. Typically a patient is adequately treated with an AFO. In some clinical situations an AFO is not tolerated, and a tendon transfer is required. The posterior tibial tendon is the most commonly used donor muscle. A tendon transfer is feasible only if the tendon possesses at least 4/5 power. There is a loss of 1 MRC grade of strength following transfer.
Rodriguez et al. retrospectively reviewed the results of the Bridle procedure 10 patients (11 feet) with a foot drop. The Bridle procedure consists of a posterior tibial tendon transfer through the interosseous membrane to the dorsum of the foot with a dual anastomosis to the tendon of the anterior tibial and a rerouted peroneus longus in front of the lateral malleolus. In their study all 11 feet were brace-free at final followup at 6.68 years.
Yeap et al. retrospectively reviewed 12 patients who were treated with tibialis posterior tendon transfer for footdrop. They found good/excellent patient satisfaction in 10/12 patients. Additionally they found favorable variables for a good outcome include common peroneal nerve palsy over sciatic nerve palsy, male gender less than 30 years of age.
Figure V is a Video that shows a right footdrop with high steppage gait. Figure A shows normal ankle radiographs. Figure B shows the results of dynamometer testing described above. Illustration A shows the Bridle procedure. The left panel shows how the tibialis posterior tendon (C) is tunneled through the interosseous membrane and through a slit in the tibialis anterior tendon (A) and inserted into the second cuneiform. The peroneus longus (B) is also transected and the distal stump is routed anterior the lateral malleolus and anastomosed to the tibialis anterior and tibialis posterior (at the slit where it passes through the tibialis anterior). The right panel shows retrieval of the tibialis posterior tendon above the ankle and passage through a window in the interosseous membrane.
Incorrect Answers:

OrthoCash 2020
Which of the following variables is associated with elevated serum metal ion levels following metal-on-metal hip resurfacing arthroplasty?
Smaller implant diameter
Smaller acetabular cup abduction angle
Higher postoperative functional scores
Severe preoperative osteoarthritis
Anteversion of acetabular cup between 10 and 20 degrees Corrent answer: 1
Smaller femoral head diameter is associated with elevated serum metal ion levels with metal-on-metal hip resurfacing arthroplasty.
Metal-on-metal (MOM) hip resurfacing arthroplasty has the advantage of better wear properties (lower linear wear rate and volume of particles) than metal on polyethylene. However, elevated serum metal ion levels is one of the negatives which has received much attention recently. Studies have found smaller implant diameter and acetabular cup abduction angle >55 degrees are associated with elevated serum metal ion levels. Cup abduction angles of greater than 55 degrees lead to a more vertical cup and edge loading.
Desy et al. found that smaller implant diameter, larger cup inclination, and lower postoperative functional scores are associated with increased cobalt and chromium levels after metal-on-metal hip resurfacing. They found that severity of preoperative osteoarthritis, acetabular version, femoral stem-shaft and valgus angle, and anterior orientation of the femoral component had no effect on the circulating metal ion levels.
DeHaan et al. obtained serum ion levels in 214 MOM resurfacing patients at least 1 year following surgery. They found that cup abduction angles greater than 55 degrees combined with smaller component sizes led to edge loading and elevated ion levels.
Illustration A shows how a metal-on-metal prosthesis design allows you to have a larger femoral head as opposed to a metal on polyethylene design (example in THA). Illustrations B and C show a photo of a metal on metal resurfacing implant and radiographs of the implant.
Incorrect Answers:
2: Elevated cup abduction angle leads to elevated serum metal ions.
3: Higher postoperative functional scores have not been shown to increase serum metal ions.
4: Severity of pre-operative arthritis has not been associated with increased serum metal ions.
5: Anteversion of the acetabular cup between 10 and 20 degrees has not been shown to increase serum metal ions.

OrthoCash 2020
Which of the following intra-operative steps would put a patient at risk for lateral patellar maltracking during total knee arthroplasty (TKA)?
External rotation of the femoral component
Medial placement of the patellar component
Internal rotation of the tibial component
Lateral translation of the femoral component
Superior placement of the patellar component Corrent answer: 3
Internal rotation of the tibial component increases the Q angle and causes an increased risk of lateral patellar maltracking.
During TKA, useful techniques that help prevent patellar maltracking include: external rotation of the femoral and tibial components, lateral translation of the femoral component, and medial placement of the patellar component.
In an instructional course lecture, McPherson looked at patellar tracking in primary TKA. He reviews the concept of patellofemoral maltracking, the importance of the Q angle, mechanical alignment, femoral component rotation, tibial component positioning, patellar component positioning, patellar height, and patellar resurfacing as factors related to patellofemoral tracking.
Bengs et al. studied the effect of patellar thickness on intra-operative knee flexion and patellar tracking during PCL retaining TKAs. Using 2mm increments (2-8 mm), passive knee flexion was recorded and gross mechanics of patellofemoral tracking were assessed. On average, passive knee flexion decreased 3 degrees for every 2-mm increment of patellar thickness, there was no gross effect on patellar subluxation or tilt.
Illustration A shows how internal rotation of the tibial component would increase the Q angle, and thus be more likely to have lateral patellar maltracking.
Incorrect answers:

OrthoCash 2020
A patient undergoes a primary total hip arthroplasty with a highly cross-linked ultra-high molecular weight (UHMW) polyethylene acetabular liner. In comparison to a 28mm femoral head, a 32mm femoral head will provide which of the following?
Increased risk of dislocation
Decreased range of motion
Decreased risk of osteolysis
Equivalent wear rate of the polyethylene acetabular liner
Increased risk of periprosthetic fracture Corrent answer: 4
Wear rates of highly cross-linked UHMW polyethylene liners are independent of femoral head size between 22 and 46 mm in diameter.
While the wear rates of old polyethylene liners increased with increasing femoral head size, wear rates of the new highly cross-linked UHMW polyethylene liners have shown to be independent of head size. This is extremely advantageous, as increasing the femoral head size improves range of motion and increases jump distance, thereby decreasing dislocation rates.
Geller et al. report a prospective series of 42 patients that had a total hip arthroplasty with a highly cross-linked UHMW polyethylene liner and a femoral head >32 mm in diameter. After three years, there were no cases of osteolysis or failure due to aseptic loosening.
Muratoglu et al. studied the wear rates of several polyethylene liners with varying femoral head sizes. In the highly cross-linked UHMW polyethylene group, wear rates were independent of femoral head size.
Illustration A shows how increasing femoral head size increases the jump distance required for dislocation.
Incorrect Answers:

OrthoCash 2020
A 56-year-old male undergoes an uncomplicated revision total knee arthroplasty. Post-operatively, he is noted to have a foot drop that has persisted despite conservative management including bracing and physical therapy. At two months, the patient undergoes external neurolysis with no improvement in function. At 18 months follow-up, he demonstrates passive ankle dorsiflexion 10 degrees past neutral, complete absence of active dorsiflexion, and 5/5 inversion strength. Which of the following is the most appropriate treatment at this time?
Continue Ankle-foot orthosis (AFO) and physical therapy
Repeat neurolysis with possible nerve repair
Peroneus tertius transfer
Peroneus tertius transfer with achilles tendon lengthening
Posterior tibial tendon transfer to dorsum of foot Corrent answer: 5
A peroneal nerve palsy (with intact posterior tibial tendon strength) that has failed conservative management is best treated with a posterior tibial tendon transfer to the dorsum of the foot.
Peroneal nerve palsy following total knee arthroplasty or knee dislocation is a potentially devastating complication that may lead to lack of active dorsiflexion and a compensatory steppage gait pattern. Initial management consists of an ankle-foot orthosis (AFO) and physical therapy to maintain passive ankle dorsiflexion. If nerve function fails to return during the course of conservative management and the patient demonstrates intact posterior tibialis muscle strength, posterior tibial tendon transfer to the dorsum of the foot has been shown to improve functional outcomes and eliminate the need for continued bracing. The most common procedure for posterior tibial tendon transfer involves transferring the tendon through the interosseous membrane and inserting the tendon onto the lateral cuneiform.
Prahinski et al. review the results of 10 patients at 61 months' follow-up who underwent the Bridle transfer (posterior tibialis transfer through interosseous membrane and peroneus longus to front of lateral malleolus) for peroneal nerve palsies. They conclude the Bridle procedure is adequate for return to function in low-demand individuals, but may fail over time in those who return to vigorous physical activity.
Rodriguez et al. review the results of 10 patients who underwent the Bridle procedure for peroneal nerve palsy in an attempt to balance their foot and
provide dorsiflexion. All of their patients were brace free at an average followup of 6.8 years.
Video V shows the clinical results 10 weeks after transfer of the tibialis posterior tendon for a drop foot.
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OrthoCash 2020
An 82-year-old male sustains a ground level fall and sustains the injury shown in Figure A. Which of the following treatment methods is most appropriate for treating this injury?

Closed reduction and functional bracing
Open reduction and fixation with a plate with screws and cerclage cables
Open reduction and fixation with a cortical allograft strut and cerclage cables
Revision hip arthroplasty with bridging of the fracture with a plate with screws and cerclage cables
Total femoral replacement Corrent answer: 2
This fracture pattern is typically referred to as an interprosthetic fracture; this is increasing in incidence due to increasing numbers of patients with ipsilateral hip and knee arthroplasty.
The first reference by Ricci et al reviewed 50 Vancouver B1 fractures treated with a lateral plate without allograft. They reported 100% union rate at a mean of 12 weeks and only one deep infection. Nearly 75% of patients were able to return to their baseline ambulatory status.
The second reference by Ricci et al reviewed 59 patients with periprosthetic femur fractures (THA or TKA) treated with ORIF without bone grafting. They report 58/59 patients healed after the index procedure and 49/59 were able to
return to their baseline functional level.
The reference by Fulkerson et al reported on 24 patients who underwent LISS plate fixation of periprosthetic femur fractures around well-fixed THA or TKA. They reported union in 21/24 at a mean of 6.2 months, with only one failure of fixation. They note that percutaneous fixation is effective although technically demanding.
Figure A shows an interprosthetic femur fracture between well-fixed hip and knee arthroplasties.
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OrthoCash 2020
A 62-year-old female undergoes an uncomplicated primary total knee replacement. Her knee range-of-motion pre-operatively was 0-135 degrees of flexion. Which of the following is true regarding the immediate post-operative use of a continuous passive motion machine in this patient?
Reduced risk of venous thromboembolism
No long-term difference in ROM compared to patients not using CPM
Increased passive knee flexion at 6 months
Increased length of hospitalization
Decreased risk of surgical site infection Corrent answer: 2
The use of a continuous passive motion (CPM) machine following primary total knee arthroplasty has not shown any long-term benefits with regards to
range-of-motion.
The concept of CPM was created by Dr. Robert Salter in 1970 and is currently being used in select patients following total knee replacement, ACL
reconstruction, and a variety of other procedures about the knee. In theory, the CPM allows for movement of synovial fluid to allow for better diffusion of nutrients into damaged cartilage. Additionally, it has been thought to prevent fibrous scar tissue formation about the joint. While some studies have shown increased early active knee flexion at two weeks, these results were not significant at later follow-up. Controversy exists as to whether these small benefits offset the patient inconvenience and expense of the CPM.
Lotke et al. expolre the effects of tourniquets and CPM machines in 121 patients undergoing total knee arthroplasty. They found that immediate CPM combined with intraoperative release of the tourniquet increased blood loss. The patients with the least amount of blood loss had the tourniquet released after a compressive dressing was applied and in whom CPM was delayed for a few days.
Bourne et al. perform a meta-analysis on the effectiveness of CPM following total knee arthroplasty. They found the CPM plus physical therapy increased active knee flexion more than physical therapy alone 2 weeks after surgery with a decreased length of hospitalization. The benefits of increased active knee flexion were not maintained after 2 weeks.
Illustration A shows an example of a CPM machine. Incorrect Answers:
from available RCTs to conclude that CPM reduces the risk of venous thromboembolism following total knee arthroplasty.

OrthoCash 2020
A 67-year-old female complains of anterior groin pain one year following a primary, uncemented total hip arthroplasty. The pain is exacerbated when she tries to climb stairs or get up from a seated position. She denies any recent fevers or chills. On physical exam, the pain is reproduced with resisted seated hip flexion. Laboratory analysis, including WBC, ESR, and CRP are within normal limits. Radiographs reveal that the components are appropriately positioned without evidence of loosening or fracture. Which of the following is the most appropriate at this time?
Revision of the acetabular component
Image-guided diagnostic injection of lidocaine into the iliopsoas tendon sheath
Hip aspiration
Bone scan
Conservative management including activity modifications, NSAIDs, and physical therapy
The patients history and physical exam are most consistent with iliopsoas impingement. This diagnosis is most reliably confirmed with a diagnostic/therapeutic injection of steroid or lidocaine into the iliopsoas tendon sheath.
Iliopsoas tendinitis following total hip arthroplasty is an uncommon but treatable cause of anterior groin pain following total hip arthroplasty. The true incidence is unknown, but some studies suggest it is the cause of a painful
total hip arthroplasty in up to 4.3% of cases. Potential causes include a malpositioned acetabular component, excessively long screws, limb length discrepancy, or retained cement. Diagnosis is confirmed by injecting the iliopsoas tendon sheath. Most cases are refractory to conservative management and often require surgical intervention. In the case of a malpositioned acetabular component, revision to a more agreeable position is advisable. In the absence of a defined etiology, iliopsoas tendon release offers adequate pain relief and return to function in a majority of patients.
Lachiewicz et al. review anterior iliopsoas impingement after total hip arthroplasty. They state that most patients with iliopsoas impingement often require surgical treatment, with options including iliopsoas tendon release or resection, removal of protruding cement or screws, and acetabular revision.
O' Sullivan et al. review 16 cases of iliopsoas impingement following primary total hip arthroplasty. Only 1 of the cases was secondary to a malpositioned acetabular component, with the other 15 cases being attributed to altered anatomy of the iliopsoas tendon as a result of the surgery. These 15 patients underwent iliopsoas tendon release, and all had improvement in pain and function following surgery.
Nunley et al. review 27 patients with a presumed diagnosis of iliopsoas impingement following total hip arthroplasty who were treated with fluoroscopically guided injections of the iliopsoas bursa. The average modified Harris hip score in the patients who underwent injection improved, however, 30% required an additional injection and 22% underwent surgical release for continued pain.
Illustration A shows a flouroscopic injection into the iliopsoas tendon sheath. Incorrect Answers:
revision of the acetabular component without a confirmed diagnosis is not advisable.

OrthoCash 2020
A 72-year-old female underwent an uncomplicated primary total hip replacement 18 years ago. Current radiographs reveal the abnormality shown in Figure A. Which of the following cell types (Figures B-F) is implicated in the process shown by the arrow?

Figure F shows an example of a macrophage, which is a key mediator in the osteolytic process shown in Figure A.
Osteolysis is the end result of a biologic process that begins when the number of wear particles following a joint replacement overwhelms the body's capacity to clear them from circulation. The residual particles are phagocytosed by macrophages, which then release an array of cytokines and other inflammatory mediators that recruit osteoclasts to resorb bone.
Gupta et al. review osteolysis following total knee arthroplasty, including etiology, diagnosis, and management. Amongst other things, they highlight the importance of design changes to minimize osteolysis including highly cross-linked polyethylene and alternative bearing materials.
Ren et al. performed a study where they implanted a hollow titanium rod into the distal femur and pumped polyethylene particles into the femoral bone marrow cavity. They found that macrophage migration occurs at a systemic (rather than local) level, and that the recruitment of macrophages led to localized osteolysis.
Holt et al. review the biology behind aseptic osteolysis. Specifically, they highlight the importance of the RANK-RANKL-OPG pathway as the final
common pathway to osteoclastogenesis, and the possibility of eliminating osteolysis by blocking this pathway. AMG-162 is a human immunoglobulin monoclonal antibody with a high affinity for RANKL, and studies are currently being undertaken to determine its safety and efficacy.
Figure F shows an example of a macrophage, which may be identified by its irregular shape and phagocytic inclusions. Illustration A shows the pathway by which marcrophages induce osteolysis following a joint replacement surgery.
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OrthoCash 2020
A 45-year-old with a history of sickle cell anemia reports hip pain for the past 6 months. A radiograph of the affected hip is shown in Figure A. Which of the following interventions has been shown to have the best outcomes in this patient population?

Observation
Bisphosphonates
Hemi-arthroplasty
Uncemented metal on polyethylene total hip arthroplasty
Cemented metal on polyethylene total hip arthroplasty Corrent answer: 4
Based on the radiographs and current literature, the best intervention is an uncemented metal on polyethylene total hip arthroplasty.
Avascular necrosis of the hip may be idiopathic in nature or associated with alcoholism, steroid use, or as in this case, sickle cell anemia. The Ficat staging system is used to classify avascular necrosis of the hip. Changes in treatment are driven by development of symptoms as well as the development of subchondral bone collapse (Ficat Stage 3). In those with with femoral head flattening (Ficat Stage 4) and acetabular degenerative changes (Ficat Stage 5), total hip replacement has good to excellent outcomes.
Mont et al. review surgical options for avascular necrosis of the hip. Head preserving procedures are generally reserved for those patients where the femoral head has not collapsed. Collapse and associated arthritis warrant utilization of arthroplasty procedures.
Mont et al. conducted a systematic review to better delineate the symptomatic progression of asymptomatic avascular necrosis of the hip. They found that patients with sickle cell disease have the highest rate of progression to
collapse. Medium sized, laterally located lesions were associated with a higher frequency of collapse and joint preserving procedures are recommended for these.
Figure A shows radiograph of a patient with avascular necrosis; note the femoral head flattening, narrowing of the joint space and acetabular sclerosis.
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OrthoCash 2020
The function of which of the following structures is to resist internal tibial rotation with the knee in full extension?
Anterior cruciate ligament
Iliotibial band
Popliteus tendon
Popliteofibular ligament
Posterior oblique ligament Corrent answer: 5
The primary function of the posterior oblique ligament is to resist internal tibial rotation with the knee in full extension.
The posterior oblique ligament is a structure within the posteromedial corner of the knee, with attachments proximally to the adductor tubercle of the femur and distally to the tibia/posterior knee capsule. The posterior oblique ligament and posteromedial capsule play a significant role in the prevention of additional posterior tibial translation in the knee in the setting of posterior cruciate ligament injury. They also act to resist internal tibial rotation with the knee in full extension.
Griffith et al. reports that the posterior oblique ligament provides significant resistance to valgus and internal rotation forces with knee extension. They used a cadaver model and demonstrated that the superficial MCL resists valgus and external rotation forces more than the posterior oblique ligament, while the posterior oblique ligament is more involved in resisting internal rotation.
Tibor et al. reviews the anatomy of the posteromedial corner of the knee. They report that failing to recognize injury to these structures may cause failure of cruciate ligament reconstruction surgery, and that reconstruction or repair of the posteromedial corner may be indicated in the face of multiple ligament injuries.
Illustration A shows the posteromedial corner of the knee, including the posterior oblique ligament.
Incorrect answers:
4: These structures are not primary restraints to internal tibial rotation in full extension.

OrthoCash 2020
Increasing the porosity of a cement spacer for an infected total knee arthroplasty leads to which of the following?
Increased strength
Increased elution of antibiotics
Increased cement density
Improved cement-prosthesis bonding
Increased reinfection rate Corrent answer: 2
Elution of an antibiotic is increased with increased porosity of a cement spacer. This porosity increase can be obtained with hand mixing and avoiding the use of a vacuum-type mixing device.
Joseph et al. reviews antibiotic-impregnated cement in hip arthroplasty. They note that use of this cement in one- or two-stage revisions has lowered reinfection rates, with the spacers acting to reduce dead space while stabilizing the joint.
Cui et al. reviews antibiotic impregnated cement for TKA and THA. They report that use of greater than 2 grams of antibiotic per 40 gram unit of cement weakens the cement and that use of two antibiotics in conjunction may potentially increase elution.
The reference by Stevens et al compared Simplex and Palacos bone cement in regards to elution in a TKA mold model. They found that initial as well as weekly (9 weeks total) elution rates were greater in the Palacos spacers than the Simplex models. They recommend use of the Palacos cement in TKA model to target antimicrobial delivery while limiting the potential for systemic antibiotic-related toxicity.
Illustrations A and B show an antibiotic spacer in a two-stage revision TKA. Illustration C shows a PROSTALAC in a two-stage revision THA.
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OrthoCash 2020
A 65-year-old patient was treated with an open reduction/internal fixation for a left femoral neck fracture sustained 25 years ago. Five years ago he developed hip pain and was converted to a left hip hemiarthroplasty. He presents with complaints of groin pain for the past 6 weeks. A recent radiograph is shown in Figure A. The patient’s physical exam is limited secondary to pain. Serum laboratory values are WBC-8.0, ESR-20, CRP-0.5. A synovial fluid aspirate of the hip demonstrates < 500 cells (60% PMN). What is the most likely cause of this patient's symptoms?

Acetabular protrusio
Infected hip hemiarthroplasty
Lumbar radiculopathy
Impingement of the hip hemiarthroplasty
Iliopsoas tendinitis
Based on the history, radiographs, and laboratory values, the patient has developed failure of his hip hemiarthroplasty. At this point in time he warrants a conversion to a total hip arthroplasty.
Avascular necrosis (AVN) of the femoral head after traumatic injury to the femoral neck occurs at an incidence of 10-45%. Although the risk increases with failure to anatomically reduce the fractue, it can still occur in non displaced settings. Treatment of avascular necrosis in older patients includes hip hemiarthroplasty or a total hip replacement. With the former, development of acetabular protrusio can contribute to groin symptoms. Functional outcomes have been reported to be higher in those receiving total hip replacement for AVN of the femoral head.
Lee et al. prospectively compared the use of bipolar hip hemiarthroplasty versus total hip arthroplasty for advanced stages of AVN of the femoral head (Ficat Stage 3). Total hip scores were most improved in the total hip arthroplasty group. Migration of the outer head in the hemiarthroplasty group was seen in 23% of patients. They recommend use of a total hip arthroplasty in patients with Ficat Stage 3 AVN of the femoral head
Ito et al. evaluated the outcomes of patients who underwent bipolar hemiarthroplasties for femoral head avascular necrosis. They found that proximal migration and acetabular degeneration were risk factors for groin symptoms. They also found that outcomes were inferior to patients who had undergone total hip arthroplasty for AVN of the femoral head. They recommend use of total hip arthroplasty in advanced osteonecrosis of the femoral head
Diwanji et al. evaluated outcomes of patients who underwent a conversion from a bipolar hip arthroplasty to total hip arthroplasty in 25 patients. Thirteen (52%) patients were revised to THA because of acetabular erosions. Follow up was completed for an average of 7.2 years. At final follow-up, they found improvement of the Harris Hip Scores and improvement of the pain portion of the WOMAC index. They recommend use of total hip replacement as an option to salvage failed bipolar hip hemiarthroplasty
Figure A shows the radiograph of a hip hemiarthroplasty where acetabular protrusion has developed.
Incorrect Answers
OrthoCash 2020
A 38-year-old female patient presents to your office three years after a hip resurfacing. She complains of worsening left hip discomfort for the last 6 months. Her ESR is 12 (normal 0-20) and CRP is 1.2 (0-5). A radiograph and axial and coronal MRI scans are shown in Figures A, B, and C. What is the most likely diagnosis?

Infection
Type I Hypersensitivity reaction
Femoral neck fracture
Prosthesis Loosening
Pseudotumor
The clinical presentation is consistent with a young woman who has developed a symptomatic pseudotumor following hip resurfacing. Her hip discomfort is related to a mass that has developed around the left hip.
Pseudotumors, also referred to as Aseptic Lymphocyte-Dominated Vascular-Associated Lesions (ALVAL), are sterile inflammatory lesions that most commonly occur from metal-on-metal articulations. They occur at an incidence of 0-39% with metal-on-metal resurfacing hip components. The exact mechanishm of formation is unclear, however excessive wear is considered the initiating process, leading to the release of microscopic metal particles. These are cytotoxic to macrophages once phagozytised, leading to necrosis within the lesions and the development of semi-solid or fluid-filled masses around the implant. Lymphocytes are thought to be responsible for the tissue reaction.
Patients often do not complain of pain, but present with a mass around the hip that causes discomfort.
Hart et al. performed a case-control study comparing patients with well-functioning metal-on-metal hip resurfacing to those who have painful prostheses. They found no significant difference between the painfree and painful groups with MRI diagnosed pseudtumors (61% vs. 57%). They concluded that the presence of a pseudotumor should not automatically necessitate revision surgery.
Daniel et al. reviewed the current concepts surrounding pseudotumor. Risk factors associated with pseudotumor formation and failure are female gender, age under 40, hip dysplasia, metal hypersensitivity, and small components.
Larger components have been found to decrease the risk of failure.
Figure A is an AP pelvis radiograph of a patient following a left hip resurfacing surgery. Figures B and C are axial and coronal MR images demonstrating a large pseudotumor around the left hip resurfacing. Illustrations A and B identify the large pseudotumor as outlined in red.
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OrthoCash 2020
After total hip arthroplasty (THA) for osteoarthritis a patient is unable to dorsiflex her ankle or extend her great toe. She is treated conservatively with an orthosis and after 3 months on physical therapy she ambulates with a "slapping gait." What is the most appropriate next treatment option?
MRI of her spine
Ankle Fusion
Continue Ankle-Foot Orthosis
Revision total hip arthroplasty
Sural nerve grafting Corrent answer: 3
The patient has suffered from a peroneal nerve injury most likely from errant retractor placement during the hip replacement resulting in a foot drop. The most appropriate next treatment is an ankle-foot orthosis.
The ankle joint of an ankle-foot orthoses (AFOs) should restrict plantarflexion to prevent foot drop during the swing phase. In a patient who can not actively dorsiflex the foot the AFO keeps the foot in a neutral position during gait allowing for uninterrupted swing during ambulation.
Park et al reviewed common peroneal nerve injury after THA. Only one-half of the patients in the study who developed common peroneal nerve palsy following total hip arthroplasty recovered fully. The mean time to recovery was approximately one year for partial peroneal palsy and one and one-half years for complete palsy. Obesity adversely influenced the nerve recovery. Thus, at 3 months, the nerve should continue to be monitored and the use of an AFO would assist in ambulation.
Yokoyama et al. developed an AFO with an oil damper to adjust the plantarflexion resistive moment as excessive plantarflexion resistance will cause excessive knee flexion during the stance phase. They found the AFO with the oil damper achieved sufficient plantarflexion of the ankle and mild flexion of the knee by adjusting a proper plantarflexion resistive moment during initial stance phase, and provided a more comfortable gait than did the traditional AFOs.
Illustration A shows the location of the sciatic nerve relative to the short external rotators when performing a posterior approach to the hip.
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OrthoCash 2020
Which of the following statements is true about racial disparities in total joint arthroplasty?
The rate of surgical intervention for African American males is lower than white or Hispanic males
The rate of surgical intervention for Hispanics is higher than that for whites
The rate of surgical intervention for white males is lower than for African American males
There is no difference in the rate of surgical intervention between whites, Hispanics, or African Americans
The rate of surgical intervention is equal for Hispanic and white males Corrent answer: 1
The rate of surgical intervention for African American males is lower than either white or Hispanic males.
Numerous studies have shown clear racial disparities in the utilization of total joint arthroplasty for the treatment of osteoarthritis. African American and Hispanic patients undergo total joint arthroplasty at a rate much lower than
white patients, even in areas where insurance coverage is more equitable. Currently, little is known about the reasons for such disparities.
Skinner et al. reviewed the Medicare claims between 1998 through 2000 to determine any racial or ethnic disparities amongst patients undergoing total knee arthroplasty. Amongst other things, they showed that the arthroplasty rates for black men were consistently lower than white men in nearly every region.
Nelson reviews health disparities in orthopaedic surgery. Amongst other things, they discuss how African American patients and white patients perceive the same pain and functional limitations for similar radiographic disease. Thus, ethnic differences in perception of symptoms cannot explan the racial disparities noted in total joint arthroplasty.
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OrthoCash 2020
A 65-year-old man presents with aseptic loosening 3 years after total knee arthroplasty. The surgeon reviews radiographs of his knee and takes him to the operating room for revision total knee arthroplasty. During surgery, the exposure technique shown in Figure A is used. Which of the following radiographs (Figures B-F) has the greatest likelihood of needing this exposure technique?

Figure A shows a tibial tubercle osteotomy (TTO). Patella baja (Figure D) is an indication for a TTO.
In revision total knee arthroplasty (TKA), surgical exposure should be extensile. Different exposure techniques have been described (see below). Patella baja may indicate that there is patellar tendon contracture. In this instance, a TTO can be used to prevent inadvertent patellar tendon avulsion which is difficult to repair and may lead to loss of function. Further, proximal transfer of the osteotomized tibial tubercle may be used to correct patella baja, bearing in mind that excessive superior translation alters the mechanics of the knee by making the quadriceps less efficient.
Younger et al. reviewed surgical approaches in revision TKA. They include quadriceps snip, patellar turndown, TTO, femoral peel, medial epicondylar osteotomy and quadriceps myocutaneous approach.
Mendes et al. reviewed the results of TTO in revision TKA. They advocate TTO for cases where the patellar cannot be retracted laterally with knee in 90deg of flexion. Complications include nonunion, tubercle fragment fracture and displacement, and tibial metaphyseal fracture (at the level of the distal cut of the osteotomy).
Della Valle et al. reviewed surgical approaches for revision TKA. They advocate TTO because repair is stronger than patellar turndown, there is less tension on the tibial tubercle in flexion than on the quadriceps tendon, and where multiple operations are required (as multiple VY approaches lead to excessive scar, making the approach difficult) or where stemmed tibial components need to be removed.
Illustration A shows tibial tubercle osteotomy hinged on a lateral periosteal flap. Illustration B shows quadriceps snip. Illustration C shows patellar turndown. Illustration D shows medial epicondyle osteotomy.
Incorrect Answers
situation.

OrthoCash 2020
Which of the following is the most common intraoperative complication in a patient with sickle cell disease undergoing a total hip arthroplasty?
Periprosthetic fracture distal to the implant
Iatrogenic fracture causing pelvic discontinuity
Perforation of the femoral canal
Cardiac arrest from fat embolization to lungs
Injury to the sciatic nerve Corrent answer: 3
Perforation of the femoral canal during preparation of the femur is not an uncommon complication, with rates ranging from 4.9-18.2%.
While total hip arthroplasty is extremely effective for pain relief in patients with osteonecrosis of the hip secondary to sickle cell disease, the procedure carries a higher rate of complications compared with non-sickle cell disease patients. Particular attention should be given to the preparation of the femur as femoral medullary widening from chronic marrow hyperplasia adjacent to patchy areas of dense sclerosis can make preparation of the canal difficult.
Some surgeons prefer to ream over a guide-wire to avoid perforation.
Jeong et al. reviewed total hip arthroplasty in patients with sickle cell disease. Amongst other things, they discuss the difficulties associated with preparation of the femoral canal, quoting a perforation rate between 4.9-18.2%. They also state there are no prospective studies comparing cementless to cemented THA, but retrospective data has shown promising results with cementless components.
Hernigou et al. retrospectively reviewed 244 patients with sickle cell disease that underwent cemented total hip arthroplasty. They had a 3% infection rate, a relatively low rate of revision for aseptic loosening, and a 27% rate of medical complications. Overall, they viewed their results as favorable.
Illustration A shows a patient with bilateral AVN secondary to sickle cell disease. Note the areas of patchy dense sclerosis in the metaphyseal region of the proximal femur.
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to be more common in this patient population. The rate of post-operative hematoma causing sciatic nerve dysfunction may be higher in this patient population.

OrthoCash 2020
A 63-year-old patient presents with periprosthetic joint infection 3 years after primary total knee arthroplasty. A radiograph of her knee is seen in Figure A. She undergoes 2-stage revision total knee arthroplasty. Radiographs taken at the time of explantation are seen in Figure B. An articulating antibiotic spacer is placed. Two months later, she is deemed to be free of infection and is taken to the operating room for the second stage operation. Intraoperatively, it is noted that the collaterals are intact and the previous tibial tubercle osteotomy had healed. What is the most appropriate surgical strategy at this point?

Address epiphyseal defects with impaction particulate bone grafting
Address metaphyseal defects with structural allograft and uncemented, unstemmed implants
Address metaphyseal defects with uncemented, porous metaphyseal
sleeves and uncemented, stemmed implants
Address diaphyseal defects with porous metal cones and uncemented, stemmed implants
Address diaphyseal defects with cemented stemmed implants Corrent answer: 3
This patient has massive metaphyseal defects following resection of primary TKA implants. Metaphyseal defects may be addressed with uncemented, porous metaphyseal sleeves and uncemented stemmed implants.
In revision settings, metaphyseal bone is often deficient. The Anderson Orthopaedic Research Institute classification (AORI) is most commonly used to classify defects. Stemmed implants are necessary to divert stress away from deficient metaphyseal defects to structurally sound cortical bone. These may be cemented or uncemented.
Haidukewych et al. reviewed metaphyseal fixation in revision TKA. For large defects, they advocate structural allograft, porous metal cones, and stepped metaphyseal sleeves.
Bush et al. reviewed managing bone loss in TKA. They cautioned that joint line elevation, distal femoral bone loss, and femoral prosthesis downsizing leads to flexion instability. They advocate cement filling for Type I defects, modular augments for Type 2, impaction grafting for Type 1 or 3, structural allograft for Types 2 and 3, metaphyseal filling or megaprosthesis for Type 3, including porous metal implants.
Figure A shows an infected primary TKA with a stemmed tibial component with medial augments. This suggests that the revision implant will require at least a stemmed, augmented component. Figure B shows massive metaphyseal defects (AORI Type 2) at the time of explantation. Illustration A comprises postop images of osseointegrated metaphyseal sleeves and stemmed implants. Illustration B depicts the AORI classification (see Review Topic for detailed description). Images courtesy of Haidukewych et al (Ref 1).
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OrthoCash 2020
During templating for a total hip arthroplasty, placing the femoral head center of rotation directly superior to the center of rotation of the acetabular component will have which of the following effects?
Increase offset
Decrease limb length
Decrease offset
Increase limb length
No change in length or offset Corrent answer: 4
Placing the femoral head center of rotation directly superior (above) the acetabular center of rotation will lengthen the limb without changing offset.
When templating the femoral component for a total hip arthroplasty, it is imperative to restore limb length and offset. To change limb length, the femoral component center of rotation (COR) can be adjusted in a superior or inferior direction. If the femoral component COR is superior to the acetabular component COR, the limb will be lengthened (as in the example above).
Conversely, if the femoral component COR is inferior to the acetabular component COR, the hip will be shortened. A change in offset will be determined by the medial/lateral relationship between the acetabular and femoral components. In the example above, the COR of the femoral component is directly above the COR of the acetabular component. In this situation, there is no change in offset.
Merle et al. performed a retrospective cohort study to identify differences in femoral offset as measured on an AP pelvis radiograph, AP hip radiograph, and a CT scan. They found that femoral offset is significantly underestimated on AP radiographs of the pelvis. In contrast, AP radiographs of the hip are much more accurate in representing true offset.
Della Valle et al. review the importance of preoperative planning prior to total hip arthroplasty. While they mention that templating can be very accurate, determination of stem and cup size should also be determined by tactile feedback during broaching and reaming.
Illustration A shows the femoral head COR inferior to the acetabular COR. This will result in a decreased limb length.
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OrthoCash 2020
Which of the following intra-operative errors most commonly leads to patellar maltracking during a total knee arthroplasty?
Using the gap balancing technique instead of measured resection technique
Internal rotation of the femoral component
External rotation of the tibial component
Lateralization of the femoral prosthesis
Overresection of the patella
Internal rotation of the femoral component increases the Q-angle and will increase the likelihood of patellar maltracking.
Patellar maltracking is one of the most common complications following a total knee arthroplasty. Any alteration that results in increased lateral retinaculum tension or an increased Q-angle may lead to patellofemoral instability.
Common causes include internal rotation of the femoral or tibial components, medialization of the femoral component, and placement of the patellar prosthesis on the lateral border of the patella. If a patient presents with postoperative maltracking and component rotation is thought to be the cause, a CT scan is the diagnostic study of choice.
Rhoads et al. analyze 7 cadaveric specimens to define the kinematics of the intact knee and to evaluate the effects of prosthetic replacement on those kinematics. Amongst other things, they showed that lateralization of the femoral component improved patellar tracking and prevented dislocation.
Malo et al. review patellar maltracking following a total knee replacement. They discuss the importance of externally rotating the femoral component on the femur relative to the posterior articular condyles to establish a rectangular and balanced flexion gap and to accommodate central patellar tracking.
Illustration A shows how an internally rotated femoral component displaces the patella medially. The blue line is a straight line upwards from the tibial tubercle, and the green line represents a line from the tibial tubercle to the center of the patella. The difference between the blue and green lines in the internally rotated prosthesis is the amount the patella has displaced medially. If you deviate the patella medially, this increases the Q-angle and could lead to patellar maltracking in a total knee replacement.
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OrthoCash 2020
When performing a total knee arthroplasty on a 60-year-old female patient, a surgeon chooses not to resurface the patella. Instead, he performs a patelloplasty by excising the marginal osteophytes and reshaping the patella. All of the following statements comparing the results of patelloplasty to patella resurfacing are true EXCEPT:
There is no difference in relative risk of anterior knee pain.
There is no difference in relative risk for revision surgery involving the tibial and femoral components.
There is an increased risk that she will need secondary resurfacing.
No difference in rates of patellar avascular necrosis or patellar tendon injury.
Total knee arthroplasty improved function regardless of whether the patella was resurfaced.
In TKA with an unresurfaced patella, there is an increased risk of anterior knee pain and secondary resurfacing.
Surgeons can choose to resurface or not resurface all patellae, or selectively resurface patellae. In unresurfaced patellae, they may perform a patelloplasty (excise marginal osteophytes and reshape the patella). Unresurfaced patellae have increased risk of anterior knee pain requiring secondary resurfacing.
Indications for resurfacing include inflammatory arthritis, patella maltracking, patellofemoral osteoarthritis as the main indication for TKA.
Meneghini et al. reviewed the literature on patellar resurfacing. Prospective, randomized studies show conflicting results with regards to satisfaction rates between groups. Meta-analyses show increased risk of re-operation and anterior knee pain in the unresurfaced group.
Parvizi et al. performed meta-analysis on 1519 knees. They found there was
(1) lower relative risk of re-operation (resurfaced group), (2) lower relative risk of anterior knee pain (resurfaced group), (3) increased rate of secondary resurfacing (unresurfaced group), (4) no difference in patient satisfaction, (5) TKA improved function regardless of whether the patella was resurfaced, (6) no difference in complications.
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OrthoCash 2020
A 55-year-old patient returns for followup 2 years after a left ceramic-on-ceramic total hip arthroplasty. He has no pain or symptoms of instability. The video in Figure V shows him ascending stairs. All of the following factors may contribute to this phenomenon EXCEPT
Impingement
Edge-loading
Loss of fluid film lubrication.
Third-body particles
Subclinical infection
The clinical presentation is consistent for prosthesis squeaking following a THA. Squeaking is multifactorial and may include impingement, edge-loading, loss of fluid film lubrication, and third-body particles. Subclinical infection does not play a role in squeaking.
Squeaking is defined as a high-pitched, audible sound occurring during movement of the hip. In ceramic-on-ceramic (COC) hips, the incidence is 0.5-10%. The incidence of revision because of squeaking is 0.5%. Squeaking is less common in metal-on-metal bearing surfaces (4-5%).
Chevilotte et al. reviewed COC bearing surfaces. They found that without lubrication, squeaking occurred with normal gait, high load, stripe wear, material transfer, edge wear and microfractures. In contrast, with lubrication, squeaking only occurred with material transfer.
Finkbone et al. reviewed COC total hip arthroplasty in patients <20-years-old after 52-month (average) follow-up. They found that survival rate was 96% with 1 revision for a loose acetabular component (failure of bone ingrowth). They found no cases of osteolysis, which can theoretically occur because of stripe wear, or femoral neck-on-liner impingement.
Walter et al. reviewed squeaking hips. They found that this phenomenon is associated with (1) walking, bending, rising (cyclical gait movements or extreme flexion), (2) maloriented acetabular components, (3) impingement,
(4) third-body particles, (5) edge loading, (6) loss of fluid film lubrication and
(7) thin, flexible (titanium) stem.
The video shows squeaking of a left total hip arthroplasty during hip extension from a flexed position. This is consistent with edge loading. Illustration A shows superior edge loading in the walking position. The arrow represents the loading force. The superolateral edge of the liner is in contact with the superior surface of the head. The dark area (area of edge loading) is anteverted with respect to a line of latitude (dark line) on the head. Illustration B shows posterior edge loading in the bending position. The arrow represents the loading force. The posterior edge of the liner is in contact with the superior surface of the head. The shaded area represents the area of edge loading and the dark stripe indicates wear on the femoral head.
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OrthoCash 2020
Figure A shows the image of a 72-year-old male who sustained a fall from standing. Past medical history is significant for hypertension. He was a community ambulator without the use of a cane or walker prior to the fall. During the operation, he is noted to have a well-fixed acetabular component without significant wear of his polyethylene liner, but his femoral component is easily extractable. Which of the following correctly pairs his Vancouver classification and appropriate surgical intervention?

Vancouver A, Revision of femoral component to cemented stem with fixation of the fracture
Vancouver B1, Revision of femoral component to cemented stem with fixation of the fracture
Vanvouver B1, Revision of femoral component to a long, porous-coated, cementless stem with fixation of the fracture
Vancouver B2, Fixation of the fracture with a plate and cerclage wires
Vancouver B2, Revision of femoral component to a long, porous-coated, cementless stem with fixation of the fracture
Figure A shows a Vancouver B fracture around the femoral prosthesis. Because the prosthesis is noted to be loose during the operation, it is classified as a Vancouver B2 fracture. The most appropriate operation would be revision of the femoral component to a long, porous-coated, cementless stem in addition to fixation of fracture with a plate and cerclage wires.
According to the Vancouver classification, a type B2 fracture occurs around or just distal to a loose femoral stem with adequate proximal bone. Revision of the femoral component is necessary, with uncemented stems showing superior clinical results to cemented stems in most studies. The revision prosthesis should bypass the distal fracture by 2 cortical widths.
Corten et al. reviewed thirty-one patients with Vancouver B2 fractures that
were treated with a long cemented stem with additional allograft or plate fixation. At 46 months, none of the implants had to be revised, but it should be noted that 43% of the patients died within the first year.
Mulay et al. reviewed 24 patients with Vancouver B2 and B3 fractures managed with a cementless, tapered, fluted, and distally fixed stem. 91% of fractures united uneventfully. Complications included dislocations (5), nonunions (2), and infection (1).
Springer et al. review 116 patients with Vanvouver B fractures treated with revision of the femoral component. The uncemented, extensively porous-coated implants had the highest likelihood of stable fixation and were not associated with any nonunions.
Illustration A reviews the Vancouver classification for periprosthetic femur fractures. Illustration B shows a post-operative radiograph following a Vancouver B2 fracture. In this case, a trochanteric plate with cerclage wires was used to fix the fracture. A long-stemmed, porous-coated, cementless femoral prosthesis was used for the revision.
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OrthoCash 2020
A 56-year-old male undergoes revision of his right hip arthroplasty for acute pain and radiographs suggestive of ceramic femoral head fracture. At the time of the revision, multiple fragments of the ceramic femoral head were seen in the joint and soft tissues. The components were noted to be in good position. He was copiously irrigated and the ceramic head was exchanged with a metallic femoral head. 12 months later, the patient presents with insidious onset right groin pain. Radiographs show no gross abnormalities without signs of loosening. Which of the following is the most likely cause of the patient's pain?
Periprosthetic infection
Massive third body wear
Pseudotumor formation
Soft tissue metallosis
Iliopsoas tendonitis
The most likely cause of the patient's pain is massive third body wear caused by retained ceramic fragments.
Cermamic femoral head fractures create many fragments that are difficult to extract at the time of revision surgery. During the revision surgery, it is imperative to remove all fragments that can be visualized. Despite a thorough debridement, microscopic fragments will still remain. These particles may cause pain through the creation of an inflammatory response in the tissues.
Exchange of the femoral head should be performed with another ceramic head, as opposed to a metal head. If a metal head is used, abrasive wear will ensue as the microscopic fragments will scratch the femoral head due to differences in hardness.
Traina et al. describe their experiences with revision of ceramic components. Most commonly, fractures of ceramic components occur as a result of trauma, dislocation, or errors in operative technique. These include head-neck taper mismatch, impacting the ceramic head with too much force, debris, and intraoperative damage to the metal neck taper.
Hannouche et al. review ceramics in total hip replacement. They state that if the ceramic is properly manufactured, it can be a highly effective, low-wear solution for the young patient in need of a total hip replacement.
Illustration A shows the typical ceramic femoral head used for a total hip arthroplasty. Illustration B shows a fractured ceramic head in many pieces.
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OrthoCash 2020
Figure A and B are radiographs of a 77-year-old patient presenting with right hip and upper thigh pain for the past 3 months. He is an avid golfer and plans to travel south for 6 months on a golf tour. He denies fever, chills or weight loss. His past medical history includes hypertension and a right total hip replacement 15 years ago. Physical examination reveals minimal pain with range of motion. ESR=10 (normal range 0-20) and CRP=4 (normal range 0-10). He does not want any further surgery. The patient is at the highest risk of which complication with non-operative care?

Infection
Pseudotumour formation
Periprosthetic femoral fracture
Periprosthetic acetabular fracture
Dislocation
This patient has presented with significant osteolysis and aseptic loosening of his femoral THA component. If untreated, he is at an increased risk of a periprosthetic femur fracture.
Indications for surgery for periprosthetic osteolysis include: pathological fracture, impending pathological fracture, symptomatic THA with evidence of osteolysis, and extensive osteolysis that would compromise revision surgery in the future. The goal of surgery is to remove the loose component, repair/bypass/replace bone deficiency, and obtain stable component fixation.
Robbins et al. reviewed the causes of pain in THA. They report that hip pain can originate from the implant, soft tissue, or bone. The use of laboratory tests (e.g. ESR/CRP), radiographic and fluoroscopic imaging, hip aspirate, contrast arthrography and local anesthetic injections can help to determine the origin of pain.
Ollivere et al. report that the most frequent cause of failure after total hip replacement in all reported arthroplasty registries is periprosthetic osteolysis. Osteolysis occurs with the activation of macrophages and a complex biological cascade that results in bone loss.
Hirakawa et al. analyzed the circumstances around retrieved failed THA components. They showed that cement mantle defects, noncircumferential porous coatings, and screw holes are risk factors for osteolysis. They conclude by saying that the formation of a granulomatous tissue that ultimately invades the bone-implant interface is the final step in the pathogenesis of aseptic loosening.
Figure A and B show AP and lateral views of a right THA. The femoral stem shows gross loosening in all zones. Subsidence is obvious with a high-riding greater trochanter. The lateral cement mantle is fractured. There is endosteal erosion distally with the tip of the stem showing radiographic toggle.
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osteolysis, but it remains well fixed. Acetabular fractures are less likely when there is minimal osteolysis.
OrthoCash 2020
A 60-year-old woman undergoes a total knee arthroplasty for end-stage osteoarthritis. Preoperative knee range of motion is 5 to 100 degrees. Postoperatively, she experiences reduced range of motion. She is scheduled to undergo manipulation under anesthesia. In which of the following scenarios is this procedure best indicated?
Knee range of motion 0 to 60 degrees at 2 months postoperatively
Knee range of motion 0 to 60 degrees at 8 months postoperatively
Knee range of motion 30 to 120 degrees at 2 months postoperatively
Knee range of motion 30 to 120 degrees at 8 months postoperatively
Knee range of motion 30 to 120 degrees at 2 weeks postoperatively
Manipulation under anesthesia (MUA) can achieve the greatest gains in flexion when performed for patients with less than 90 degrees of flexion within the first three months.
There are many risk factors for postoperative stiffness, the most important being preoperative stiffness. MUA is indicated when flexion is less than 90 degrees. Flexion gains are generally greater when applied early (6-12 weeks postoperatively) rather than late (>12 weeks). In cases with late-presenting stiffness (>12wks), MUA may still be attempted. Failed MUA is addressed with arthroscopic or open adhesiolysis +/- MUA, quadricepsplasty, or component revision.
Namba et al. compared the results of early (<90 days) vs late (>90 days) MUA. They found that: (1) knee flexion improved a mean of 32 deg and 20 deg after early and late MUA respectively, (2) extension improved in the early MUA group, but not the late MUA group, and (3) pain improved after early but not late MUA. Despite early MUA being more desirable, the authors state that patients with limited flexion at 6-12 months may still benefit from late MUA.
Keating et al. assessed the outcomes of MUA in 113 knees at a mean of 10 weeks after surgery. They found that (1) 90% of patients achieved
improvement in knee flexion of 35 degrees at 5 year followup, (2) there was no difference in flexion gains between early (<12 weeks) and late (>12 weeks) MUA and (3) patients treated with MUA had better pain control than those without MUA. They concluded that manipulation can result in significant and lasting improvement in knee flexion.
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OrthoCash 2020
A 62-year-old man is scheduled for a total knee arthroplasty. In his pre-operative office visit, he asks questions about different tibial components. You tell him that compared with the tibial component shown in Figure A, the tibial component shown in Figure B:

Is less expensive
Has greater durability
Has greater instability because of its monobloc nature
Provides improved short-term functional status, but no difference in long term functional status
Is associated with fewer adverse events because of easier implantation Corrent answer: 1
Figure B shows an all-polyethylene tibia (APT) component, which is $470 to
$1650 less expensive than metal-backed tibia (MBT) designs.
It was traditionally thought that modular MBT may have lower survivorship (compared to APT) because of locking mechanism dysfunction, breakage,
backside wear, and osteolysis. However, many studies now show the two to be comparable, with the only difference being that APT are less expensive.
Voight et al. performed a systematic review comparing APT and MBT. They found that the former was cheaper. There was no difference in adverse events, durability (need for revision or radiographic failure) at 2, 10, and 15 years, and functional status at 2, 8, and 10 years.
Toman et al. compared APT and MBT retrospectively. They found that APT implants perform as well as MBT implants in patients with BMI <37.5. There were 4 tibial implant failures in the MBT group in patients BMI >40.
Dalury et al. examined APT performance in obese patients (125 knees) after a minimum of 7 years. There were no implant failures. There were 5 nonprogressive tibial radiolucencies and 1 case of nonprogressive osteolysis.
Figure A shows a cemented metal-backed tibia component. Figure B shows a cemented all-polyethylene tibia component.
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OrthoCash 2020
Figures A and B show pre- and post-operative radiographs of a sedentary 75-year-old female who underwent surgery on her left hip. Based on the radiographic findings, what was the most likely indication for revision surgery?

Left acetabular fracture
Left acetabular cup osteolysis
Left femoral stem osteolysis
Left hip instability
Left femoral stem valgus malalignment Corrent answer: 4
Figure A shows a left total hip arthroplasty with eccentric polyethylene wear. Figure B shows that her left hip was revised to a constrained acetabular liner, most likely a result of recurrent instability.
Revision strategies for hip instability are typically directed at correcting the underlying cause of instability. For example, instability most commonly occurs as a result of poor implant design, positioning or loosening, or the loss of soft-tissue function or tensioning. Operative strategies are designed to correct these etiologies by repositioning or exchanging components, integrating modular designs and improving soft tissue tensioning, etc. Constrained acetabular liners are often used in conjunction with these modalities to address the problem of recurrent instability relating to soft tissue deficiency and dysfunction in the affected hip.
Alberton et al. retrospectively reviewed 1548 revision arthroplasties for the incidence of dislocation. They found the overall dislocation rate to be 7.8%. Factors contributing to increased dislocations were found to be trochanteric non-unions, femoral heads <28mm in diameter and extensive soft-tissue dissection. Protective factors were modular acetabular components or liners, larger femoral heads >28mm and re-establishing abductor tensioning.
Paterno et al. retrospectively reviewed 438 primary and 181 revision total hip arthroplasties for patient factors contributing to dislocation. They found an overall dislocation rate of 6%. 23% of patients with a history of excessive intake of alcoholic beverages (more than six ounces a day) had at least one dislocation. There was no relationship between the variables of age, gender, obesity, or preoperative diagnosis and the incidence of dislocation.
Figure A shows bilateral primary cementless, nonconstrained total hip replacements. The left hip shows eccentric femoral head placement within the acetabulum indicative of eccentric polyethylene wear. Figure B shows the conversion to a constrained, dual-mobility, polyethylene liner. The overall metal component position appears satisfactory.
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OrthoCash 2020
A 62-year-old woman is brought to the emergency room after falling down a flight of stairs. Prior to her fall, she had no knee pain and was a community ambulator without assistance. Intraoperatively,
it is determined that the implants are well-fixed. What is the best next treatment step to optimize her quality of life?

Closed reduction and long leg casting at 20 degrees of flexion for 6 weeks, followed by hinged-knee brace for 6 weeks.
Open reduction and internal fixation with a distal femoral locking plate
Open reduction and internal fixation with a condylar buttress plate
Distal femoral replacement arthroplasty
Closed reduction and fixation with an antegrade intramedullary nail Corrent answer: 2
This patient has a displaced far-distal supracondylar fracture around a stable TKA femoral component. Locked plating is the best option for management of this fracture.
Surgical fixation of periprosthetic fractures around a stable femoral component is challenging. Locked plating allows for multiple angle-stable fixation points around stems and lugs and does not depend on TKA design or quality of distal bone stock for fixation. Su Type I fractures may be treated with retrograde or antegrade intramedullary nailing. Type II fractures require retrograde intramedullary nailing or fixed-angle plating. Type III fractures require fixation with a fixed-angle device or revision arthroplasty when bone stock is poor.
Ricci et al. evaluated indirect reduction and locked lateral plating of Vancouver B1 THA fractures without allograft struts. They found that all fractures healed with satisfactory alignment and without implant loosening at an average of 12 weeks. They recommend this technique for stable Vancouver B1 fractures.
Streubel et al. examined the outcomes of locked plating in treatment of extreme distal periprosthetic supracondylar fractures located proximal to the flange (Su Types I and II) compared with fractures distal to the flange (Su Type III, see Illustration B). They found no difference in delayed union, nonunion, infection and failure rates between the 2 groups.
Figure A shows a Su Type III periprosthetic fracture around a TKA femoral component. Illustration A shows fixation of the same fracture with a distal femur locking plate. Illustration B shows the Su classification of fractures around the femoral component (Type I, proximal to the femoral component; Type II, starting at the anterior flange and extending proximally; Type III, fracture line distal to the anterior flange).
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OrthoCash 2020
Which of the following fractures would most likely require revision arthroplasty with a long-stemmed, uncemented prosthesis?

Figure B shows a Vancouver B2 periprosthetic femur fracture with an unstable femoral stem that requires revision arthroplasty with a long-stemmed prosthesis.
The Vancouver classification for periprosthetic femur fractures can help guide treatment of these challenging problems. Vancouver A fractures involve the greater and lesser trochanter and can be initially managed with non-operative measures. Vancouver B fractures occur around the stem and are broken down into B1 (stable prosthesis), B2 (unstable prosthesis) and B3 (poor proximal bone quality) fractures. B1 fractures may be treated with internal fixation, B2 fractures require a revision arthroplasty, and B3 fractures often require more advanced reconstruction with a proximal femoral replacement versus revision with a distally fixed prosthesis. Vancouver C fractures occur distal to the stem and require internal fixation.
Springer et al. reviewed 118 patients who underwent revision arthroplasty for Vancouver B2 periprosthetic fractures. They had a 90% survival rate at 5-years and a 79.2% survival rate at 10-years. The most common reasons for revision were loosening, infection, and non-union.
Illustration A shows the Vancouver classification of periprosthetic fractures about the femur.
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OrthoCash 2020
A 65-year-old female sustains a periprosthetic supracondylar femur fracture proximal to a well-fixed implant. She undergoes direct reduction and locked plating with a titanium distal femoral locking plate via an extensile lateral approach. At 9 months post-operatively, weightbearing is at 50% and is painful. Examination reveals mild swelling and warmth around the distal incision. Erythrocyte sedimentation rate and C-reactive protein are normal. Radiographs taken 9 months post-operatively are shown in Figure A. Which of the following may have increased the risk of this complication?

Neglecting to add topical rhBMP-2 on a carrier-scaffold
Neglecting to use lag screws and cerclage cables
Locked plating instead of locked antegrade nailing
Use of a titanium plate instead of a stainless steel plate
Use of an extensile lateral approach instead of a submuscular approach Corrent answer: 5
A submuscular approach has been shown to have less risk of nonunion than an extensile lateral approach. There is less disruption of soft tissue attachments and devitalization of fracture fragments with the submuscular approach.
The risks for periprosthetic fractures include notching, knee stiffness, osteoporosis, poor mobility and falls. The risk is higher in females and after revision surgery. The treatment of periprosthetic supracondylar fractures depends on the location of the fracture, fixation of the implant, and bone stock.
Hoffman et al. retrospectively reviewed 36 periprosthetic supracondylar femur fractures treated with locked plating. They found that submuscular plating had reduced nonunion risk compared to an extensive lateral approach. They recommend indirect reduction and submuscular plating to reduce the incidence of nonunion.
Hou et al. retrospectively reviewed 53 fractures fixed with retrograde nailing
(18) and locked plating (34). They found no difference in blood loss, time to union, operating time and hospital stay. They believe locked plating can
provide the same favorable results as retrograde nailing and recommend this technique for most patients and prosthetic designs.
Figure A shows nonunion and surrounding osteopenia after locked plating of a periprosthetic supracondylar fracture. Illustration A shows management of these fractures according to the Su classification.
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OrthoCash 2020
Immediately following a total hip arthroplasty (THA), a healthy 55-year-old patient is unable to dorsiflex her ankle or extend her great toe. After 4 weeks she continues to ambulate with a "slapping gait." Examination reveals passive ankle joint dorsiflexion to 10 degrees. What is the most appropriate next treatment option?

MRI of her spine and pelvis
Revision total hip arthroplasty
Ankle-foot orthosis
Posterior tibial tendon transfer to navicular bone
Neurology consult
This patient is presenting with foot drop after a THA for hip dysplasia (Crowe 4). The most appropriate treatment at this stage would be providing her with an ankle foot orthosis (AFO) for mobility.
Sciatic nerve injury after THA is an uncommon and difficult situation to manage. Patients with DDH that have undergone a large limb-lengthening procedure are at a greater risk due to the significant stretch of the sciatic nerve. Intra-operative procedures that have been shown to prevent this outcome include good pre-operative planning, limb lengthening <3 cm, subtrochanteric osteotomy, intra-operative wake-up test, and downsizing implant components if presenting with deficits peri-operatively. An ankle-foot orthosis may be used for foot drop when surgery is not warranted or during neurologic recovery.
Prahinski et al. reviewed the Bridle transfer for paresis of the anterior and lateral compartment musculature. Indications for the procedure include no neurological recovery for at least 18 months after injury or 18 months after the most recent attempt at exploration or repair of the nerve.
Electrodiagnostic changes must indicate permanent damage. In addition, there must be good passive range of motion, with at least 90° of dorsiflexion.
Edwards et al. reported on twenty-three peroneal and sciatic nerve palsies that occurred in patients following total hip arthroplasty. They showed that peroneal nerve palsy occurred with an average lengthening of 2.7 cm (1.9 cm-3.7 cm) in comparison with 4.4 cm (4.0 cm-5.1 cm) for sciatic nerve palsies.
Figure A and B show pre- and post-operative images of a patient with severe hip dysplasia treated with primary total hip arthroplasty.
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OrthoCash 2020
A 60-year-old male with history of renal transplantation and previous intravenous drug abuse undergoes total knee arthroplasty. Two years later, he begins to have mild knee pain and low-grade swelling that persists for 10 months before he finally comes to the emergency room. Examination reveals no fever. Range of motion is 5 to 70 degrees. Erythrocyte sedimentation rate is 22mm/h, and C-reactive protein is 0.8mg/L. Knee aspiration reveals 12,000/mm3 nucleated cells with 76% neutrophils. Gram stain is negative and aerobic and anaerobic cultures are negative after 4 days in culture. His symptoms do not resolve after 5 days of empiric intravenous antibiotics and he is taken to the operating room for arthroscopic irrigation and debridement. Operative synovial tissue cultures are shown in Figure A. What is the best next step?

Cessation of immunosuppressant medication, lifelong antimycobacterial suppression
Open irrigation and debridement, implant retention and lifelong antifungal suppression
Open irrigation and debridement, resection arthroplasty, antimycobacterial drugs for 6 to 12 months
Open irrigation and debridement, single-stage exchange, antifungal drugs for 6 to 12 months
Open irrigation and debridement, two-stage exchange, antifungal drugs for 6 to 12 months
This patient has a fungal prosthetic joint infection (PJI) with Candida albicans. Optimal treatment involves resection arthroplasty, delayed reimplantation
arthroplasty, and antifungal drugs for 6-12 months.
Fungal PJI are uncommon. Risk factors include immune suppression and systemic illness e.g. diabetes and chronic renal failure. Candida species is usually the causative organism. The infection is usually indolent and systemic symptoms (e.g. fever) may be absent. ESR and CRP may be only minimally elevated. Two-stage exchange arthroplasty is standard of care.
Phelan et al. described delayed reimplantation in 10 patients with fungal PJI. They found that the median time from resection to reimplantation arthroplasty was 9 and 2 months for total hip and total knee arthroplasty respectively. Two patients had recurrence of infection. They recommend antifungal therapy and delayed reimplantation arthroplasty after confirmation of an infection-free period as the best chance for cure.
Azzam et al. retrospectively reviewed arthroplasty database data to identify 31 fungal PJIs in 6 centers. Delayed implantation was performed in 19 of 29 patients who underwent resection arthroplasty at an average of 7 months.
They recommend two-stage exchange arthroplasty as the treatment of choice, addition of antibacterial drugs to the cement spacer to prevent superinfection, antifungal drugs for 6-12 months, repeat joint aspirations prior to reimplantation, and optimization of host nutritional status prior to reimplantation.
Figure A is a high-powered micrograph showing synovial tissue covered by fibrinopurulent exudates containing fungal colonies of Candida albicans.
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OrthoCash 2020
Which of the following non-operative treatments for osteoarthritis has the best evidence to support its use?
Combination of supervised and home exercise programs
Hyaluronic acid injections
Lateral heel wedge
Acetaminophen
Glucosamine
Of the options listed, a combination of home and supervised exercise has the best supporting evidence for the treatment of osteoarthritis.
The AAOS has recently developed guidelines for the treatment of osteoarthritis. Therapies that are recommended by the AAOS include weight loss, home and supervised exercise programs, and NSAIDs/tramadol.
Therapies that remain inconclusive (lack of supporting evidence) include electrotherapeutic modalities, manual therapy, bracing, acetaminophen/opiods, steroid injections and PRP. Glucosamine, lateral heel wedges and hyaluronic acid injections are not recommended, as current literature has shown them to be ineffective. Keep in mind that these guidelines are subject to change as new literature is published.
Zhang et al. present a systematic review of the literature on arthritis management in the three years following the original OA Research Society International (OARSI) guidelines published in 2006. While weight loss showed an increase in effectiveness with the addition of new studies, electromagnetic therapy, glucosamine, chondroitin sulfate, and hyaluronic acid injections showed a decrease in effectiveness.
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OrthoCash 2020
Figure A shows the 2 bundles of the ACL dissected from a cadaveric knee off their bony attachments. They are labeled Bundle A and Bundle B, respectively. Which of the following is true?

The tibial attachment of Bundle A is anterior to Bundle B. In extension, Bundle B is loose and Bundle A is tight.
The tibial attachment of Bundle A is anterior to Bundle B. In flexion, Bundle B is loose and Bundle A is tight.
The tibial attachment of Bundle B is anterior to Bundle A. In flexion, Bundle B is loose and Bundle A is tight.
The tibial attachment of Bundle B is anterior to Bundle A. In flexion, Bundle A is loose and Bundle B is tight.
The tibial attachment of Bundle B is anterior to Bundle A. In extension, Bundle A is loose and Bundle B is tight.
Bundle A is the anteromedial (AM) bundle, which is longer, and is tight in flexion. Bundle B is the posterolateral (PL) bundle, which is shorter, and is loose in flexion. The AM bundle is attached anterior to the PL bundle on the tibia.
The ACL is comprised of 2 bundles. The AM bundle is longer than the PL bundle. Their names reflect their relative anatomic positions on the tibial insertion site. On the femur, the AM bundle begins at the proximal-anterior aspect of the femoral insertion site, while the PL bundle begins at the posterior-inferior part. In flexion, the AM bundle is tight and the PL bundle is loose. In extension, the AM bundle is loose and the PL bundle is tight.
Bicer et al. reviewed the anatomy of the ACL. They found that the AM bundle was longer (32mm) compared with the PL bundle (18mm). PL bundle carries greater force near full extension, and the AM bundle carries greater force after 15-45° of flexion. Under combined rotatory loads (valgus and internal tibial torque at knee flexion >30°), the AM bundle bore more force than the PL bundle.
Figure A shows the 2 bundles of the ACL. The AM bundle is longer than the PL bundle. The oft referred to length of ACL refers mainly to the length of the AM bundle. Illustrations A and B show the spatial relationships of the AM and PL bundles in a cadaveric knee. Illustration C shows the relative positions of the attachments of each bundle.
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OrthoCash 2020
An 83-year-old man, who had a total hip arthroplasty performed 13 years ago, is referred to your office for evaluation. He reports worsening groin pain over the past year, which has been increasing in frequency. Prior to this past year, he had no other complaints. His current radiograph is shown in Figure A. If he continues to ambulate with this implant, he is at greatest risk for which of the following?

Infection
Acetabular component loosening
Femoral component loosening
Dislocation
Periprosthetic fracture
The patient has eccentric polyethylene wear secondary to component malpositioning. He is at highest risk for dislocation.
Late dislocation following total hip arthroplasty(THA) can occur and has a high recurrence rate, thereafter. Risk factors include eccentric polyethylene, THA at an early age, neurologic decline or associated neurologic conditions (i.e.
Parkinson's disease), or associated trauma.
Parvizi et al. noted in this instructional course lecture that eccentric, excessive polyethylene wear is one of the most common reasons for late, recurrent dislocation. Revision is recommended.
Pulido et al. in this review, reiterated that polyethylene wear can lead to increased inflammation, capsular distention, and instability, increasing risk for dislocation.
von Knoch et al. reviewing over 500 dislocated hips, also noted that eccentric wear was one of major causes linked to late dislocation.
Figure A. exhibits a left total hip arthroplasty with eccentric wear. Incorrect answers:
OrthoCash 2020
Figure A shows a radiograph of a 62-year-old female that underwent a left total hip arthroplasty 5 years ago. She presents to your office with insidious onset of left groin and buttock pain. She denies trauma, fever or chills. On physical examination, her left hip has mild pain with range of motion. She has a normal gait cycle, normal power across the hip and her vitals signs are stable. A left hip aspirate was performed and results are shown in Figure B. What is the most likely cause of her hip pain?

Periprosthetic bacterial hip infection
Periprosthetic hip fracture
Large-particle wear debris disease
Pseudotumor hypersensitivity response
Abductor tendon tear Corrent answer: 4
This patient is presenting with a metal induced system hypersensitivity response in the setting of a metal-on-metal total hip arthroplasty.
A hip aspiration of a painful THR is a very useful investigation for the work up of infection, having a sensitivity of 75-85% and specificity of 85-100% for
infection. Metal-on-metal THA may mimic infection as aspirate results will often show increased inflammatory infiltrate, with synovial WBC counts in the thousands. However, infected THA are more likely to produce higher percentages of PMNs (>70%) in comparison to hypersensitivity reactions/ adverse reaction to metal debris, which are more likely to produce a higher percentage of lymphocytes (>40%).
Campbell et al. looked at the histological features of pseudotumor-like tissues from metal-on-metal hips. They found that the patients with hip pain and suspected metal sensitivity had fewer metal particles but more aseptic lymphocytic vasculitis-associated lesions compared to patients with evidence of metallic wear. They concluded that pseudotumors occur more because of a hypersensitivity reaction than particle wear.
Kwon et al. examined a small cohort of patients with metal-on-metal hip arthroplasties to investigate the incidence and level of metal-induced systemic hypersensitivity. They found that lymphocyte reactivity to Co, Cr, and Ni did not significantly differ in patients with pseudotumors compared to those patients without pseudotumors. This suggests that systemic hypersensitivity type IV reactions may not be the dominant biological reaction involved in the occurrence of the soft tissue pseudotumors.
Figure A shows a patient with bilateral metal-on-metal total hip arthroplasties. There are no identifiable fractures. The position of the left acetabular cup is slightly vertical, which can increase edge loading and particle wear. Figure B shows the results from the hip aspirate.
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OrthoCash 2020
A 72-year-old patient is scheduled to undergo revision total hip arthroplasty. A 3D-model of the patient's hemipelvis is constructed for pre-operative planning and is shown in Figure A. A custom-designed implant shown in Figure B is created. Which of the following is TRUE of the planned reconstruction?

The implant is a bilobed cup.
The most common complication is dislocation.
The acetabular defect can be classified as AAOS Type V.
Radiation-compromised bone stock is a contraindication.
The winged profile of the implant facilitates insertion through both anterior and anterolateral approaches.
The patient has pelvic discontinuity that will be reconstructed with a custom triflange acetabular component. Dislocation is the most common complication.
Custom triflange acetabular components are indicated for severe acetabular bone loss and pelvic discontinuity that are not amenable to treatment with off-the-shelf implants such as reconstruction plates, jumbo cups and antiprotrusio cages. Dislocation is common and possible etiologies include extensive dissection, less reliable soft tissue repair, deficient abductors/trochanteric nonunion, superior gluteal nerve stretch neuropraxia, and surgeon reluctance to use constrained liners in the face of poor bone stock.
Christie et al. reviewed reconstruction with the triflange cup in 78 hips with AAOS Type III (combined deficiency) or Type IV (pelvic discontinuity) defects. They found improvement in Harris hip scores, limp, need for walking aids.
Dislocation was the most common complication (15.6%, 12 patients), and half of these patients (6/12) needed re-operation for recurrent dislocation. They recommend the triflange cup for difficult reconstructions involving severe bone loss.
Taunton et al. reviewed 57 patients with pelvic discontinuity treated with a custom triflange component. They found that 21% developed instability (10 required revision, and 2 treated nonoperatively). Of note, 51% had preop trochanteric escape (nonunion of the greater trochanter to the femoral component or femur with >1cm of displacement. They recommend the custom triflange implant for discontinuity as it provides predictable midterm fixation and consistent healing.
Figure A is a 3D hemipelvis model generated by stereolithography from a patient’s CT scan. It shows massive bone loss and pelvic discontinuity. Figure B is a custom hydroxyapatite (HA)-coated porous triflange acetabular prosthesis with ilial and ischial screw holes. Illustration A shows a bilobed cup and its appearance on an AP radiograph.
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OrthoCash 2020
All of the following are risk factors for wear-related failure in total knee arthroplasty when using a polyethylene liner that underwent sterilization via gamma irradiation in air EXCEPT?
Increasing shelf age of polyethylene liner
Younger age of patient
Male gender
Posterior cruciate retaining knee design
Use of a rough tibial baseplate Corrent answer: 4
Increasing shelf age, younger age, male gender, and a rough tibial baseplate are all risk factors for wear-related failure in total knee arthroplasty when using a polyethylene liner. Posterior cruciate retaining knee design is not a documented risk factor.
Fehring et al reviewed 2091 TKA using the Press fit condylar system and noted that the 13-year survivorship for all patients was 82.6% with a 8.3% prevalence of wear-related failure. Cox hazards analysis revealed five variables that were correlated with wear-related failure: patient age, patient gender, polyethylene sheet vendor, polyethylene finishing method, and polyethylene shelf age. They were unable to identify one factor as the defining reason for these wear-related failures. They cautioned that these findings may only be specific to inserts that underwent sterilization via gamma irradiation in air.
Collier et al followed 365 TKA (PCL-retaining) for 5-10 yrs and noted that
factors related to polyethylene insert osteolysis included advanced shelf age, sterilization method, and the material from which it was machined. Osteolysis was identified in 34% with an insert that had been gamma-irradiated in air and affixed to a rough baseplate surface, but only 9% when the insert had been gamma-irradiated in an inert gas or not irradiated at all and joined to a polished surface.
OrthoCash 2020
A 65-year-old healthy patient fell 18 years after a total hip arthroplasty and sustained the fracture shown in Figure A. Which of the following would be the most appropriate treatment?

Percutaneous locked plating
Open reduction internal fixation with a cable plate and allograft strut
Revision to a long femoral stem with allograft bone
Revision to a cemented revision femoral stem that bypasses the fracture site by 5 cm
Three months of non-weight bearing Corrent answer: 3
The Vancouver classification of periprosthetic femur fractures is based on the fracture site, implant stability, and remaining bone stock. The patient in the question has a type B3 fracture. The cemented stem is loose and there is very poor remaining bone stock. He should be treated with a long, cementless
revision stem with biplanar strut grafts. A tumor prosthesis or allograft-prosthesis composite would be alternate possibilities. Illustrations A and B are a diagram and table of the Vancouver classification of periprosthetic hip fractures.
Springer, et al. looked at the results and complications of revision total hip arthroplasty for the treatment of acute Vancouver type-B periprosthetic femoral fracture. In their series they treated these fractures in multiple ways, including cemented stems, uncemented stems, allograft-prosthetic composite, or tumor prosthesis. They concluded that the best results were with an uncemented, porous coated femoral stem, and the most common cause of revision was loosening.
Parvizi, et al. concluded that due to the poor bone quality and delayed healing of older patients & their periprosthetic fractures that it is imperative that a strong mechanical construct be achieved in the treatment of these fractures. They “advocate the use of numerous screws with purchase of at least ten cortices and reinforcement of fixation with biplanar strut allografts whenever possible. When a revision stem is used, we ensure that adequate diaphyseal fixation is obtained and the fracture is traversed by at least 5 to 8 cm.”

OrthoCash 2020
A 85-year-old man who underwent hemiarthroplasty 5 years ago now complains of thigh pain for the past four months. Laboratory studies show a normal white blood cell count (WBC), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). An aspiration of the hip is performed and is negative for infection. A radiograph is shown in Figure A. Which of the following is the best management option for the femoral implant?

Bone scan to look for loosening
Touch down weight bearing and physical therapy
Revision with a tumor prosthesis
Revision of femoral component with metaphyseal cement fixation of the stem
Revision to a cementless femoral component with diaphyseal press-fit fixation of the stem
The radiograph shows lucency around the femoral stem cement mantle consistent with loosening. There is bone loss in the proximal femur. Diaphyseal fixation is the best option from the choices available. Revision to a cementless femoral stem is the most appropriate management.
Paprosky et al. described their results of revision to cementless femoral components and report 95% survivorship with a minimum of 10 years follow
up.
Haydon et al showed that despite historical literature discouraging the use of cemented femurs for revision, in their experience cemented femoral revision had 91% survivorship when the cause was aseptic loosening. They found early generation cementing techniques, poor cement mantle, poor bone quality, age of less than 60, and male gender to be risk factors for failure in cemented revisions.
OrthoCash 2020
Figure A is a diagram showing the medial side of the knee. During a total knee arthroplasty, proximal tibia resection results in the transection of the ligament in Figure A along the red line. Intraoperative examination reveals coronal plane instability. What are the best next steps?

Use of the implant shown in Figure B, and use of a hinged knee brace postoperatively
Suture repair of the torn ligament, use of the implant shown in Figure C
Use of the implant shown in Figure D, and use of a knee immobilizer postoperatively
Suture repair of the torn ligament, use of the implant shown in Figure D, and use of a hinged knee brace postoperatively
Use of the implant shown in Figure C alone Corrent answer: 4
This patient has intraoperative midsubstance transection of the MCL. MCL repair, use of either a CR or PS implant, and postoperative knee bracing for 6 weeks is recommended. A possible alternative is the use of an unlinked constrained implant.
The MCL is likely to be compromised by medially placed retractors or during medial subperiosteal elevation (tibial avulsion) or injured by oscillating saw-blade during the tibial or posterior femoral condyle cut. There is no consensus for the treatment of intraoperative rupture. Acceptable salvage options include
(1) direct repair (heavy sutures for midsubstance rupture, and suture anchors for tibial sleeve avusions) and postop knee bracing for 6 weeks with either CR or PS implants, or (2) use of unlinked constrained implants with or without repair.
Lee and Lotke reviewed 37 patients with intraoperative MCL injury out of 1478 patients. They attempted repair in 14 patients, and increased constraint in 30
patients. They found higher failure rates (regardless of MCL repair technique) for cruciate retaining components. They recommend use of an unlinked constrained prosthesis (with or without ligament repair), especially for midsubstance injuries.
Leopold et al. reviewed 16 MCL injuries in 600 knees. They performed suture or suture anchor repair and used a hinged knee brace for 6 weeks postoperatively. All limbs were stable and did not require bracing beyond 6 weeks, demonstrated acceptable alignment, and did not require revision at 45 months. They recommend the use of primary MCL repair or reattachment and postoperative bracing instead of implants with increased constraint.
Figure A shows MCL transection in its midsubstance. Figure B shows a cruciate retaining implant. Figure C shows a hinged knee prosthesis (linked constrained implant). Figure D shows a posterior stabilized implant. Illustration A shows an unlinked constrained implant.
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OrthoCash 2020
A 65-year-old woman complains of intermittent knee pain 12 years after a total knee arthroplasty. She has no history of fever or recent infections. Radiographs are shown in Figures A and B. Examination reveals minimal warmth and a moderate knee effusion. Range of motion is 5 to 100 degrees bilaterally. The C-reactive protein level is 15 mg/L (normal, 0.0-0.8mg/L), and erythrocyte sedimentation rate is 45mm/h (normal, 0-10mm/h). Arthrocentesis reveals 7500 white blood cells and 90% neutrophils. Gram stain is negative. Cultures are negative at 3 days. What is the next best step?

MRI with metal subtraction protocol
Arthroscopic debridement
Open debridement and polyethylene liner exchange
Single-stage revision total knee arthroplasty (TKA)
Explantation of components with two-stage revision TKA Corrent answer: 5
By the updated 2018 Musculoskeletal Infection Society (MSIS) criteria, this presentation is consistent with a diagnosis of periprosthetic joint infection (PJI). The patient has an elevated CRP (2), ESR (1), synovial WBC >3,000 (3), and >80% PMNs (2), for a total of 8 points. Given the chronicity of the infection, the patietn would be a candidate for two-stage revision.
This patient has clinical signs of PJI such as elevated laboratory values and radiographs suggestive of implant loosening. Even in the absence of positive cultures, the next most supported step in management if two-stage revision with explantation of the prosthesis and insertion of an antibiotic spacer.
Intraoperative cultures should be taken to guide post-operative antibiotic treatment.
Parvizi et al. recently released the updated 2018 MSI crtieria for diagnosis of PJI. The updated criteria (Illustration A) included new diagnostic tests and studies from the seven-year period since the previous criteria were established. Alpha defensin was a new addition. The two major criteria remained, each individually diagnostic of PJI. However the minor crtieria were broken down into pre-operative and intra-operative. The authors showed that a total of 6 points or more had a 97.7% SN and 99.5% SP for PJI.
Huang et al. retrospectively reported the infection control rates in 2-stage exchanges in 55 patients, and compared culture-negative cases with 295 culture-positive cases. They found that infection control in culture-negative cases was 73% at 1-year. Infection control rates were similar in culture-negative and culture-positive cases, and that infection-free survival is highest after 2-stage exchange with postoperative vancomycin. They recommend 2-stage exchange with postoperative vancomycin.
Buller et al. retrospectively assessed traits that would predict the success of debridement and liner exchange for 62 hips and 247 knees. They found that 149 (48.2%) cases failed to eradicate infection. Risks for recurrent infection include longer symptom, higher ESR, previous PJI or infection in the same joint, and an infection by a group 1 (MRSA, VRE, and methicillin-resistant S. epidermidis) or group 2 (MSSA or methicillin-sensitive coagulase-negative Staphylococcus) organism.
Della Valle et al. discuss the AAOS recommendations on diagnosis of periprosthetic hip and knee infections. They recommend repeat hip and knee aspirations when there is discrepancy between probability of PJI and initial aspiration culture result.
Aggarwal et al. prospectively compared the yield of intraoperative tissue and swab cultures in 74 hip, 43 knee, 30 septic and 87 aseptic cases. They found that tissue cultures had higher sensitivity, specificity, positive and negative predictive values for identifying PJI. Swab cultures had higher false positive and negative values. They recommend not using swab cultures, and only using tissue cultures.
Figures A and B are AP and lateral radiographs showing areas of bony erosion suggestive of loosening of the femoral and tibial components.
Illustration A is the 2018 MSIS criteria with point values.
Incorrect Answers:

OrthoCash 2020
What are the affects on limb-length and offset according to the total hip arthroplasty template shown in Figure A?

Limb-length will stay the same, offset will be increased
Limb-length will be decreased, offset will be increased
Limb-length will stay the same, offset will be decreased
Limb-length will be increased, offset will be increased
No change in either limb-length or offset Corrent answer: 1
In Figure A, the center of rotation of the femoral component lies medial to the center of rotation of the acetabular component. If these components are implanted as shown, the offset will be increased and the leg-lengths will remain equal.
Offset and leg-length changes during templating and insertion of a total hip replacement are determined by the changes in the center of rotation (COR) of the femur relative to the acetabulum. If changes are made in the horizontal plane (x-axis), a change in offset will occur. If changes are made in the vertical plane (y-axis), changes in leg-lengths will occur. If the femoral COR is templated superior to the acetabular COR, the leg will be lengthened. In
contrast, if the femoral COR is templated inferior to the acetabular COR, the leg will be shortened. For offset, the same principles apply. If the femoral COR is templated medial to the acetabular COR, offset will be increased. In contrast, if the femoral COR is templated lateral to the acetabular COR, offset will be decreased. One should aim to restore native offset and leg-lengths in uncomplicated primary total hip arthroplasty.
Merle et al. retrospectively reviewed 152 patients to evaluate femoral offset on an AP pelvis and AP hip radiograph compared to a CT scan of the affected hip. They found that AP pelvis radiograph underestimated femoral offset by 13% when compared to a CT scan. In contrast, the AP hip radiograph showed no difference when compared to the CT scan. They recommend obtaining AP of the hip prior to templating for accurate assessment of femoral offset.
Della Valle et al. review preoperative planning for total hip arthroplasty. While they state that templating has a high predictive value in achieving the desired plan, the surgeon should always be prepared to make intraoperative adjustments based on tactile feedback.
Illustration A shows an example where leg-length will be shortened (femoral COR is inferior to acetabular COR) and offset will stay the same (femoral COR and acetabular COR are in the same horizontal plane). Illustration B is a table which summarizes the points we have discussed.
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OrthoCash 2020
A 65-year-old patient is diagnosed with a periprosthetic joint infection 6 years after total knee arthroplasty. He recalls a history of knee realignment surgery many years prior. Examination reveals lateral patellar tracking and passive flexion to 65 degrees. A recent radiograph is shown in Figure A. During the exposure for explantation, a standard medial parapatellar approach is performed through the previous incision. It is found that adequate knee flexion to allow exposure of the prosthesis cannot be achieved even after release of the lateral gutters and excision of the scar. Which surgical exposure technique (depicted in Figures B through F) would provide the best
surgical exposure for the procedure and preserve the blood supply to the patella?

Fig B
Fig C
Fig D
Fig E
Fig F
A tibial tubercle osteotomy (TTO) would provide the best surgical exposure without compromising patellar blood supply. This patient has patella baja arising from previous high tibial osteotomy, with a scarred, contracted patellar tendon leading to knee stiffness.
A TTO is able to provide good exposure while protecting the extensor mechanism and preventing inadvertent avulsion of a contracted patellar tendon. Further, proximal transfer of the osteotomized tibial tubercle may be used to correct patella baja, bearing in mind that excessive superior translation alters the mechanics of the knee by making the quadriceps less efficient.
Mendes et al. used TTO for surgical exposure in 67 knees undergoing revision TKA. There were good-excellent knee scores at 30 months in 87%. There were no patellofemoral complications, no component malalignments, and no avulsions of the patellar tendon occurred. They advocate TTO for cases where the patellar cannot be retracted laterally with knee in 90deg of flexion.
Whiteside described a series of TTO in 136 TKA. At 2 years, mean range of motion was 94deg. There were 2 tibial tubercle avulsion fractures and 3 tibial fractures (2 in a patient with Charcot arthropathy, and 1 following manipulation after open adhesiolysis. He advises using stemmed tibial components in patients with insensate knees and in cases where manipulation is expected.
Figure A is a lateral radiograph showing severe patella baja. Figure D shows a TTO. See below for Figures B, C, E and F. Illustration A shows the surgical technique for TTO. The distal saw cut angles out of the anterior cortex at a gentle angle to reduce the stress riser effect and risk of postoperative tibial stress fracture.
Incorrect Answers:
sufficient in the presence of severe patellar baja and patellar tendon contracture.

OrthoCash 2020
Figure A show pre- and post-operative radiographs, from left to right respectively, of a 79-year-old male that underwent revision total hip arthroplasty 2 years ago. He presents today for consultation after 4 episodes of right hip dislocation within the past 6 months. Physical examination reveals a trendelenburg gait with no clinical or radiographic limb length discrepancy. An Infection work-up is negative. Results from a CT scan are shown in Figure B. What would be the best treatment option?

Physiotherapy and application of abductor brace
Revision arthroplasty to medialize the cementless cup and surgical repair of the abductor tendon
Revision arthroplasty to a constrained polyethylene liner
Revision arthroplasty to a femoral component with extended offset
Revision arthroplasty to a large ceramic femoral head and offset polyethylene cup
On the left, Figure A shows a metal-on-metal (MOM) bearing hip resurfacing. On the right, Figure A shows a large head, uncemented metal-on-polyethylene (MOP) total hip replacement. In this setting, the most appropriate treatment option would be revision arthroplasty with constrained polyethylene liner.
Constrained liners should be reserved for patients demonstrating recurrent instability despite treatment with a large femoral head. Other indications include elderly patients who do not require implant longevity or have a low functional demand, as well as patients with deficient or non-repairable abductor mechanisms.
Sikes et al. report on the results of a series of 41 patients (52 hips) with recurrent dislocations. They recommend that large femoral heads (LFH) be used as a first-line treatment in high-risk patients (patients of any age with dementia, neuromuscular disability, and inability to comply with precautions). Constrained liners should be reserved for patients demonstrating recurrent
instability despite treatment with an LFH.
Kilampali et al. reviewed late instability of bilateral metal on metal hip resurfacings. They suggest that late instability of hip resurfacing should raise concerns relating to possible local tissue reaction and muscle damage.
Concerning features include steeply-inclined acetabular components a large abduction angle of more than 55 degrees along with a combination of small size component.
Figure A shows an image of a revised socket which was performed to convert the MOM THA to a MOP THA. Figure B shows normal parameters of THA components. The recommendation for acetabular position is anteversion 20° ± 10° and abduction 45° ± 10°. For the femur, recommendations are 10°- 15° of anteversion and 41mm - 45mm of offset.
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OrthoCash 2020
Which of the following has been shown to increase the rate of failure of cemented femoral components in total hip arthroplasty?
Stems that are precoated with polymethylmethacrylate
Calcar contact of the collar
Smoother implant corners
Cement mantle of 2 millimeters
Stem material with a Young's modulus higher than 115 GPa Corrent answer: 1
Precoating a stem with PMMA adds an additional inferface at risk of failure.
Stiffer stem materials (higher Young's modulus) improve performance. Titanium has a Young's modulus of 115 GPa with alloy and stainless steel
having a higher Young's modulus than titanium. Calcar collar contact adds minimal strength to the construct, but does not lead to premature failure. Smoother corners decrease the rate of failure since they decrease stress risers. The ideal cement mantle is ~2mm. Obtaining less than this would decrease the strength of the construct.
OrthoCash 2020
An 80-year-old male sustains a fall down the stairs and presents with knee swelling. He is a community ambulator who does not use walking aids. Injury radiographs are shown in Figures A and B. What is the next best step?

Intramedullary nailing
Locked plating
Long leg casting
External fixation
Revision total knee arthroplasty Corrent answer: 5
This patient sustained a periprosthetic femoral fracture around the femoral component which is now loose. Revision of the femoral component is necessary.
Various classifications exist for periprosthetic fractures around TKA. In general, for the femoral component, treatment depends on fracture displacement, fracture location, bone stock, and whether the component is loose. For loose femoral components, revision TKA using distal femoral replacement prosthesis is an option.
Kim et al. proposed a new classification for periprosthetic fractures. Type IA fractures (good bone stock, well fixed, nondisplaced or easily reducible) are managed conservatively. Type IB fractures (good bone stock, well fixed, irreducible closed) are managed with reduction and fixation. Type II fractures (good bone stock, reducible, loose or malpositioned components) are managed with revision. Type III fractures (poor bone stock, loose or malpositioned components) are treated with distal femoral replacement.
Johnston et al. reviewed the options for treating periprosthetic fractures about the knee. They advocate revision of the femoral component when the prosthesis is loose, where there is poor bone stock, or insufficient bone to gain purchase for locked plates or distal locking screws of intramedullary nails.
Nauth et al. review the current concepts in treatment of periprosthetic fractures. They prefer minimally invasive locked plating unless the fracture is significantly proximal to the anterior flange and amenable to retrograde intramedullary nailing. Then they choose nails with options for distal interlocking screws and locking condylar bolts. In extreme osteopenia, they use intramedullary fibular strut allografts (with locked plating). For loose prostheses or poor bone stock, they perform alloprosthetic composite in younger patients and a distal femoral replacement in elderly patients.
Figures A and B are AP and lateral radiographs showing periprosthetic femoral fracture around a loose femoral component. Illustrations A and B are postoperative radiographs showing revision to a hinged prosthesis with long-stemmed components. Illustration C shows Kim' proposed classification of
periprosthetic fractures around the femoral component of a TKA.
Incorrect Answers:

OrthoCash 2020
Utility of the implant seen in Figure A would be best considered in which of the following revision total hip arthroplasty scenarios?

Minimal acetabular deformity, intact rim
Superior acetabular bone lysis with intact superior rim
Localized acetabular destruction of medial wall
Absent superior acetabular rim, superolateral migration
Significant acetabular bone loss, pelvic discontinuity Corrent answer: 5
Paprosky Type 3B acetabular bone defects describes significant acetabular bone loss, with pelvic discontinuity. Type 3 defects often require reconstruction cages (as seen in Figure A) or acetabular distraction techniques
to treat severe bone loss with an associated pelvic discontinuity.
Deficient acetabular bone stock poses a technical challenge in hip arthroplasty surgery. Paprosky classification for acetabular bone loss to helps guide treatment for revision total hip arthroplasty. The classification is as follows:
Type 1: Minimal deformity, intact rim
Type 2A: Superior bone lysis with intact superior rim Type 2B: Absent superior rim, superolateral migration Type 2C: Localized destruction of medial wall
Type 3A: Significant bone loss, superolateral cup migration Type 3B: Significant bone loss, pelvic discontinuity
Sheth et al. reviewed acetabular bone loss in revision total hip arthroplasty. They state that Paprosky Type 1 and 2 defects can usually be managed with porous-coated hemisphere cup secured with screws. Type 3 defects require reconstruction cages to protect with cups and structural augments or custom triflange implants.
Taunton et al. investigated clinical outcomes and cost-effectiveness of using a custom triflange acetabular component to treat pelvic discontinuity in revision THA. They found satisfactory clinical outcomes (81% had a stable triflange component with healed pelvic discontinuity) and cost equivalence with Trabecular Metal cup-cage constructs.
Figure A shows a lateral image of the pelvis with a reconstruction cage and cup construct. Illustration A shows an illustration of the Paprosky classification. Illustration B shows a table of the Saleh/Gross classification. Illustration C shows a table of the AAOS classification.
Incorrect Answers:

OrthoCash 2020
A 65-year-old male who had a total knee arthroplasty 8 years ago comes into the office with worsening knee pain. The orthopaedic surgeon is concerned about infection and aspirates the knee. Which of the following are the lowest laboratory values from a synovial aspirate suggestive of infection?
WBC of 500 cells/ml and PMN 25%
WBC of 1,000 cells/ml and PMN 25%
WBC of 1,500 cells/ml and PMN 70%
WBC of 5,000 cells/ml and PMN 70%
WBC of 25,000 cells/ml and PMN 70%
WBC of 1,500 cells/ml and PMN 70% indicates the lowest synovial aspirate suggestive of infection.
Mason et al in 2003 reviewed 440 revision TKA's of which 86 had preoperative aspirations. The aspirations yield 55 aseptic failures and 31 septic failures. The mean WBC of the aseptic group was 645 cells/mm(3) compared to 25,951 cells/mm(3) for the septic group (P=<.001). The mean percentage of polymorphonuclear cells (PMNs) was statistically higher in the septic group compared with the aseptic group (72.8% vs 27.3%; P=<.001). With these results, the authors concluded that aspirates with a WBC count greater than 2,500 and 60% PMNs are highly suggestive of infection.
However, in a more recent and larger study, Ghanem et al reviewed 161 infected TKA's vs 268 aseptic failures and concluded that aspiration with WBC of >1100 cells/mm3 and PMN > 64% are suggestive of infection. When both tests yielded results below their cutoff values, the negative predictive value was 98.2% (95% confidence interval, 95.5% to 99.5%), whereas when both tests yielded results greater, infection was confirmed in 98.6% (95% confidence interval, 94.9% to 99.8%) of the cases. Thus, according to the most recent literature, WBC >1100 and PMN > 64% should be considered suggestive of infection in a TKA.
OrthoCash 2020
A 50-year-old man with a past medical history significant for diabetes and end-stage renal disease presents with a chief complaint of instability 6-months following a total knee arthroplasty. Preoperative radiographs are shown in Figures A-C. Physical exam at that time was notable for a large effusion, maltracking patella, extensor lag of 15 degrees, medial instability, and gross laxity to anterior and posterior forces. The procedure was uncomplicated, and was completed using a posterior-stabilized prosthesis with tibial augements and uncemented intramedullary rods in both the femur and tibia. Which of the following surgical techniques should have been implemented to avoid this complication?

Cementing the intramedullary rods in the tibia and femur
Explant with placement of an antibiotic spacer
Taking 5mm of extra bone from the distal femur to elevate the joint line
Use of a hinged total knee arthroplasty
Taking 5mm of extra bone from the tibia to distalize the joint line Corrent answer: 4
The patient has a neuropathic joint with ligamentous instability and a maltracking patella. The appropriate procedure would have included use of a hinged total knee arthroplasty.
Choosing the appropriate constraint during a total knee arthroplasty ensures the best possible outcome. Hinged total knee arthroplasty prostheses are indicated in the setting of global instability, massive bone loss in a neuropathic joint, oncologic procedures, and hyperextension instability. In a hinged prosthesis, the tibial and femoral components are linked with an axle that restricts varus/valgus and translational stresses. While hinged prostheses are useful in the setting of major revision surgery, they are at increased risk for aseptic loosening due to the high degree of constraint inherent to the device.
Petrou et al. review the results of 100 primary cemented rotating-hinge total knee arthroplasty at 7- to 15-years. At 15 years, survival was 96.1%.
Complications included DVT (n=3), skin necrosis (n=2), subcutaneous hematoma (n=5), intra-operative fracture of either the femur or tibia (n=4), and early infection (n=2).
Figures A-C show a neuropathic joint with considerable lateral bone loss and a frankly dislocated patella. Illustration A shows an example of a hinged total knee arthroplasty. Note how the tibial and femoral components are linked using an axle.
Incorrect Answers:

OrthoCash 2020
A 63-year-old man returns for follow-up 4 years after metal-on-metal left total hip arthroplasty complaining of mild chronic hip pain with ambulation. He is afebrile and ESR and CRP are within normal limits. Radiograph of the left hip is shown in Figure A. What is the best next step?

Anti-inflammatory medication
Serum cobalt and chromium levels
MRI with metal subtraction
Physical therapy
Revision hip arthroplasty Corrent answer: 2
Metal-on-metal total hip arthroplasties (THA) have been associated with complications presumably due to metal debris and toxicity. Serum cobalt and chromium levels are recommended as part of follow-up evaluation for patients with metal-on-metal hips, even when asymptomatic.
Many patients with metal-on-metal hips have been found to have elevated serum cobalt and chromium levels, for which MR with metal subtraction is recommended to look for pseudotumors and other pathologies. These solid or cystic masses are thought to be related to metal debris and macrophage infiltration and may be associated with pain in some patients.
Lombardi et al summarize and present on behalf of The Hip Society an algorithmic approach to evaluating and treating patients with metal-on-metal THA in follow-up. They state the goals of care as determining the etiology of any pain, managing any intrinsic problems with the arthroplasty, and reassuring/observing when appropriate. They organize the types of patients seen in followup and components of the evaluation.
Chang et al evaluate the correlation between symptoms and MRI findings and report that symptomatic patients tend to have bone marrow edema and tendon tearing on MRI. They report a 69% prevalence of pseudotumors on MRI after metal-on-metal hip arthroplasty, but did not find a correlation between pseudotumor presence and pain.
Hayter et al focus on MRI findings in symptomatic (painful) patients with metal-on-metal THA in a review including 31 hip resurfacing and 29 THA. In the THA group, they report 86% rate of synovitis, 10% extracapsular disease, and 24% osteolysis, with no statistically significant difference in rates between resurfacing and THA.
Figure A is an AP view radiograph of a left hip after metal-on-metal total hip arthroplasty with components well positioned and no osteolysis.
Illustrations A and B from Lombardi et al depict a recommended algorithm for the workup and management of symptomatic and asymptomatic patients, respectively, with metal-on-metal THA.
Incorrect Answers:

OrthoCash 2020
A 72-year-old woman sustains a fall onto her knee three years after an uncomplicated total knee replacement. The fracture pattern is seen in Figure A. The operative note reveals that a cemented patellar component was used. On exam, she has a large effusion and an
inability to straight leg raise. If the patellar component is well fixed, what is the best treatment option?

Patellectomy
Extensor mechanism allograft
Revision of the patellar component with cement and bone grafting of any residual defect
Open reduction and internal fixation of the patella fracture
Non-operative treatment in a knee brace locked in extension for 6 weeks Corrent answer: 4
Displaced, periprosthetic patella fractures with a deficient extensor mechanism and adequate bone stock are best treated with open reduction and suture or implant fixation.
Periprosthetic patella fractures are a rare, but potentially devastating complication associated with total knee arthroplasty. When evaluating patella fractures, it is important to consider 1) is the extensor mechanism intact, 2) is the patellar component well fixed or loose, and 3) is there sufficient bone stock remaining. Stable implants with an intact extensor mechanism should almost exclusively be treated non-operatively in a brace. In contrast, a deficient
extensor mechanism is an absolute indication for surgical management.
Adigweme et al. review the epidemiology, diagnosis, and treatment of periprosthetic patella fractures. When analyzing patella fractures, they suggest treatment should be based on fracture severity, remaining bone stock, patellar component stability, as well as extensor mechanism function.
Sarmah et al. review periprosthetic fracture around total knee arthroplasty. They provide an algorithm for treatment of periprosthetic patella fractures based on displacement, viability of remaining bone stock, and fracture type.
Figure A is a preoperative lateral radiograph showing a periprosthetic patellar fracture. The distal fragment is comminuted and separated from the proximal fragment by approximately 15 mm. The patellar component appears to be well fixed. Illustration A is intraoperative photograph showing the threads of the suture anchors in the proximal fragment passing through the tunnels in the distal fragment and exiting at the inferior pole of the patella. Illustration B demonstrates anatomical reduction after the knots were tied at the inferior pole of the patella. Illustration C is a lateral x-ray 1 year postoperatively showing fracture union.
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OrthoCash 2020
Knee pain and osteoarthritis are associated with "metabolic syndrome." All of the following are included in the collection of risk factors known as "metabolic syndrome" EXCEPT:
Peripheral vascular disease
Dyslipidemia
Hypertension
Impaired glucose tolerance
Central obesity
Peripheral vascular disease (PVD) may develop in patients with metabolic syndrome. However, no direct relationship between metabolic syndrome and PVD is known, and it is not a part of metabolic syndrome itself. Metabolic syndrome has been shown to be associated with knee pain and development of knee osteoarthritis (OA).
Metabolic syndrome is a collection of medical comorbidities that are known to
be risk factors for developing cardiovascular disease. Metabolic syndrome includes central (abdominal) obesity, dyslipidemia (high triglycerides and low-density lipoproteins), high blood pressure, and elevated fasting glucose levels. There is an increased prevalence of knee pain (and OA) among patients with metabolic syndrome. It is felt that the most important contributing factor to knee pain and OA in metabolic syndrome is obesity. Patients presenting with knee pain or OA and the risk factors included in metabolic syndrome should be counseled on the need to control those risk factors.
Inoue et al. present a study comparing metabolic syndrome and knee OA in a Japanese population. They found that knee OA and metabolic syndrome were highly correlated in females, but not in males.
Engström et al. present a study comparing metabolic syndrome with hip and knee OA. They found no relationship to hip OA, but did find a strong correlation between patients with metabolic syndrome and risk of developing knee arthritis. Patient BMI was the most predictive factor. They also compared prevalence of knee OA to CRP levels, but found no significant relationship.
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OrthoCash 2020
A 75-year-old male presents with recurrent dislocations of this left hip. He underwent bilateral total hip arthroplasties 12 and 8 years ago. There were no early post-operative complications with either hip. Despite a total of 5 dislocations in 6 months, he does not have pain or weakness across the left hip. On examination, there is a healthy appearing left lateral scar, equal limb lengths, normal gait and full abductor strength. Radiographs of the pelvis are shown in Figure A. His laboratory results show an erythrocyte sedimentation rate of 8 mm/h (reference range, 0-20 mm/h), and C-reactive protein of 3 mg/L (reference range, 0-5.0 mg/L). A hip aspirate culture is negative. What is the next best management option for this patient?

Magnetic resonance imaging of left hip to exclude an abductor muscle tear
Re-aspiration of left hip to exclude a subclinical infection
Continued observation for trochanteric bursitis
Supervised physiotherapy and gait training for abductor strengthening
Left revision total hip arthroplasty for polyethylene wear Corrent answer: 5
This patient presents with recurrent late hip instability with radiographic evidence of eccentric polyethylene wear. The best treatment option for this patient would be revision total hip arthroplasty (THA).
The etiology of late instability includes polyethylene wear, component malpositioning or loosening, trauma, infection or deterioration in neurological status of the patient. Identifying the cause of late instability will require a thorough work up. A good history, examination and scrutiny of radiographs can identify most causes. Advanced imaging may be requires when bone or soft-tissue pathology is suspected or radiographic evidence of osteolysis or malpositioning needs further assessment. Blood work to assess for an acute inflammatory response (ESR and CRP) should be ordered routinely as elevated markers may indicate an underlying infection.
Parvizi et al. evaluated the outcome of revision arthroplasty for polyethylene wear presenting as late dislocation. They found that revision surgery restored stability to eighteen of the twenty-two patients. Surgical treatment options may include liner-only exchange (contained or unconstrained) +/- soft-tissue repair, or revision of one or all components.
Berry et al. evaluated the long-term risk of dislocation in 6,623 consecutive primary total hip arthroplasties with a Charnley prosthesis. They found a 7% incidence of late dislocation at 25 years compared to 1% after 5 years.
Patients at highest risk were females, patients with osteonecrosis of the femoral head or an acute fracture, and nonunion of the proximal part of the femur.
Figure A shows an AP pelvis with bilateral, uncemented, total hip arthroplasties. There is eccentric wear of the left acetabular component. No fracture or loosening of the components can be identified. The components appear well-positioned.
Incorrect Answers:
This patient has no pain or weakness in the affected hip. Therefore, soft tissues can be evaluated intra-operatively during the revision THA procedure. Answer 2: A hip aspirate would not be warranted. There are no risk factors for infection in this patient (for example, no pain, no early wound complications or antibiotics, etc). Additionally, his inflammatory markers are normal.
OrthoCash 2020
A 58-year-old woman undergoes a total knee arthroplasty with a posterior stabilized design. Two years later, she returns with recurrent sterile joint effusions, a sensation of instability without giving way and difficulty with ascending and descending stairs. Examination reveals diffuse tenderness around the pes anserinus and peripatellar region, and increased anterior tibial translation most notable at 90° of flexion. Radiographs demonstrate well cemented implants with 5° of posterior tibial slope. Figure A represents a femoral cutting block with lines 1 through 5 corresponding to femoral bone cuts. The most likely cause of her symptoms is over-resection at:

Resection line 1
Resection line 2
Resection line 3
Resection line 4
Resection line 5
Over-resection of the posterior femoral condyles (resection line 2) in posterior-stabilized (PS) TKA leads to flexion instability without frank dislocation.
There are 7 bone cuts in a total knee replacement. The posterior condylar cut determines the flexion gap. Flexion instability in PS knees arises because of an enlarged flexion gap (excessive posterior condylar resection, or increased tibial slope), allowing anterior tibial translation, which is pathognomonic. There will not be posterior subluxation because of the cam-post design. Symptoms include sensation of instability without giving way, especially with stair climbing, recurrent knee effusions, and diffuse knee pain. Signs include anterior tibial translation at 90° flexion, tenderness at multiple sites (including pes anserinus, peripatellar, posterior hamstrings), and effusion. Revision surgery is indicated for symptomatic patients.
Clarke et al. reviewed flexion instability after primary TKA. They caution that most cases arise from failure to create symmetric balanced flexion and extension spaces. Treatment is usually revision TKA using the same principles. If this is not possible, increased constraint is required (constrained condylar prosthesis or hinged prosthesis).
Schwab et al. reviewed flexion instability without dislocation in PS knees in 10 patients. Revision surgery focused on flexion-extension gap balancing and filling the enlarged flexion gaps and successfully relieved pain, and improved stability to anterior tibial translation. Flexion space reconstruction includes using a larger femoral component or posterior augments. Isolated polyethylene exchange is not recommended.
Figure A shows a 5-in-1 cutting block with anterior femoral cut (line 1), posterior femoral cut (line 2), posterior chamfer cut (line 3), anterior chamfer cut (line 4), and distal femoral cut (line 5). Of note, most TKA systems have a 4-in-1 cutting block and the distal femoral cut is made separately. Illustration A shows restoration of the posterior condylar offset (line A) with the femoral component (line B).
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OrthoCash 2020
Which of the following is true regarding intra-operative fractures during total knee arthroplasty?
They occur more commonly in cruciate-retaining total knee replacements
Fractures of the medial femoral condyle are the most common fracture type
Fractures of the patella are the most common fracture type
Most can be treated without additional fixation at the time of surgery
Tibial fractures are more common than femoral fractures Corrent answer: 2
Fractures of the medial femoral condyle are the most common type of intraoperative fracture during a total knee arthroplasty.
Intra-operative fractures during total knee replacement are rare, but usually requiring alterations in surgical technique once they occur. The most common time for fractures to occur is during exposure and bone preparation, with fracture during trialing being the next most common. Fractures occur more commonly in posterior cruciate substituting designs, likely due the box cut.
Osteoporosis, female gender, chronic steroid use, advanced age, rheumatoid arthritis, and neurologic disorders are risk factors for post-operative fracture, but are also thought to be risk factors for intra-operative fractures.
Alden et al. reviewed 17,389 primary TKAs and found an intra-operative fracture rate of 0.39%. Of the 67 fractures, 49 were femur fractures, 18 were tibia fractures, and none were patella fractures. They recommend careful surgical technique in patients at high risk for fracture to avoid such a complication.
Sharkey et al. reviewed 10 intra-operative femoral fractures during primary, cementless total hip arthroplasty. They matched these with 20 patients who did not have this complication. At follow-up, there were no differences found between the two groups.
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OrthoCash 2020
A 68-year-old male complains of increasing medial sided knee pain and buckling. The pain is exacerbated by sharp turns while
running. He undergoes knee arthroscopy. Recent radiographs and an arthroscopic photograph of the medial compartment are shown in Figure A. His pain has worsened since the arthroscopy. Which of the following images (Figures B through F) represents the best treatment recommendation for this patient?

This patient has isolated medial compartment osteoarthritis with Outerbridge IV medial compartment cartilage wear on arthroscopy. The best surgical option is a medial unicompartmental knee arthroplasty (UKA).
Indications for UKA include range of motion >100deg with <5deg flexion contracture, angular deformity <15deg valgus or <5deg varus that is passively correctable to neutral. Relative contra-indications include younger patients (age <60), obesity (BMI >30), and ACL deficiency in medial UKA. Asymptomatic patellofemoral chondromalacia is not a contraindication. In general, a UKA is preferred for older, less active patients with minimal varus, more severe arthritis, and no/little knee instability. A HTO is preferred for younger, active patients, with milder arthritis, more malalignment, and AP instability.
Steadman et al. retrospectively examined outcomes of TKA after arthroscopic treatment of OA in 73 patients. They found that mean survival time (conversion to TKA) after arthroscopy was 6.8 years (5.7 years in patients with Kellgren-Lawrence grade 4, and 7.5 years in those with grade 3). They conclude that in patients who want to avoid TKA, arthroscopy may help postpone TKA.
LaPrade et al. examined the results of proximal tibial opening wedge
osteotomies in 47 patients <55 years old with medial compartment osteoarthritis (OA) and genu varus. They found that there was improvement in knee scores and the mechanical axis at 3.6 years. They recommend this technique for patients with medial compartment OA and malalignment.
Figure A is a composite image showing isolated medial compartment osteoarthritis, and Outerbridge IV cartilage wear with large areas of visible subchondral bone. (See below for Figures B through F). Illustration A is a table comparing the indications of HTO vs UKA.
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OrthoCash 2020
A 58-year-old female, with a BMI of 34 kg/m2, underwent a total knee arthroplasty for osteoarthritis 6 weeks ago. She has been participating in supervised rehabilitation since the procedure. Her preoperative, intra-operative and 6 week post-operative knee flexion are shown in Figure A. Current radiographs are shown in Figure B. What is the best step in management?

Convert to a resurfaced patella
Downsize the polyethylene liner
Arthroscopic lysis of adhesions and release of posterior capsule
Continuous passive motion at home for two weeks
Manipulation under anesthesia Corrent answer: 5
This patient has early post-operative stiffness after total knee arthroplasty (TKA). The next best step would be manipulation under anesthesia.
Management of stiffness following TKA can be challenging. The standard initial treatment option for post-operative knee stiffness is physical therapy. When this fails to achieve knee range of motion (ROM) greater than or equal to 90°, alternative treatment modalities should be considered, such as knee manipulation under anesthesia (MUA). MUA is a non-invasive treatment shown to achieve dramatic improvement in knee flexion during the early postoperative period (usually considered less than three months). Periprosthetic fracture during manipulation is rare, with an overall incidence less than 1%.
Issa et al. examined a cohort of patients that underwent MUA after TKA. At a mean follow-up of 51 months (range, 24 to 85 months), the mean gain in flexion in the MUA cohort was 33° (range, 5° to 65°). There was one periprosthetic fracture in 134 patients. The authors noted a significant improvement in ROM from pre-manipulation values.
Manrique et al. reviewed stiffness after total knee arthroplasty. MUA may be considered within the first three months after the index TKA if physical therapy fails to improve the ROM. Beyond this point, consideration should be given to surgical intervention such as lysis of adhesions, either arthroscopic or open.
Maniar et al. looked at the effectiveness of continuous passive motion immediately after TKA. A total of 84 patients were allocated to no CPM; 1 day CPM; or 3 day CPM. They found that continuous passive motion immediately after TKA did not improve short or mid-term knee ROM.
Figure B shows a cruciate sacrificing total knee arthroplasty with implants in a good position.
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OrthoCash 2020
Which of the following fracture patterns (Figures A-E) would require revision of the femoral component to a long-stemmed, cementless prosthesis?

Figure C depicts a Vancouver B2 periprosthetic fracture, which is optimally treated with a long-stem, fully porous-coated, revision femoral prosthesis.
The Vancouver classification for total hip periprosthetic femoral fractures takes into account the three most important factors in management of these injuries: the site of the fracture, the stability of the femoral component, and the quality of the surrounding femoral bone stock. Type A fractures include those involving the lesser trochanter or the greater trochanter. Type B fractures occur around the stem or just below it. More specifically, B1 fractures have a well fixed stem, B2 fractures have a loose stem but good proximal bone stock and B3 fractures have a loose stem with proximal bone that is of poor quality or severely comminuted. Type C fractures are well below the tip of the femoral stem.
O'Shea et al. assessed the outcome of patients with Vancouver type B2 and B3 periprosthetic fractures treated with femoral revision using an uncemented extensively porous-coated implant. Union of the fracture was successfully achieved in 20 of the 22 patients. Overall, they found good early survival rates and a low incidence of nonunion using this implant.
Figure A depicts a radiograph of a Vancouver type C periprosthetic femur fracture, occurring distal to the stem of the total hip arthroplasty. Figure B demonstrates a Vancouver type A periprosthetic fracture of the greater trochanter. Figure C is an x-ray of a Vancouver type B2 periprosthetic fracture adjacent to the stem with an unstable implant, but adequate bone stock.
Figure D depicts a radiograph of a Vancouver type C periprosthetic femur fracture, occurring distal to the stem of the total hip arthroplasty. Figure E is a Vancouver type B1 periprosthetic fracture at the level of the stem that is well fixed. Illustration A shows a table summarizing the Vancouver classification of periprosthetic femur fractures and the corresponding management options.
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OrthoCash 2020
Which of the following maneuvers places the obturator artery at greatest risk during a total hip arthroplasty?
Placement of a posterior retractor along the posterior wall
Placement of an acetabular screw in the posterior-superior quadrant
Placement of an inferior retractor under the transverse acetabular ligament
Placement of an acetabular screw in the anterior-superior quadrant
Placement of an anterior retractor along the anterior wall Corrent answer: 3
Damage to the obturator artery most commonly occurs from placement of an inferior retractor inferior to the transverse acetabular ligament (into the obtrator foramen), and/or placement of an acetabular screw in the anterior-inferior quadrant.
Vascular injury during total hip arthroplasty is a rare but devastating complication with a reported incidence of 0.1%-0.2%. The obturator artery travels along the quadrilateral surface of the acetabulum and exits the pelvis at the superolateral corner of the obturator foramen. If the vessel is severely
damaged and bleeding cannot be controlled, ligation of the internal iliac artery has been reported.
Nachbur et al. report on 15 cases of severe arterial injury during hip reconstructive surgery over a period of 8 years. The most common injury was injury to the external iliac artery, the common femoral artery, or main branches of the lateral and medial circumflex femoral artery. These were thought to be caused by the tip of a narrow-pointed Hohmann retractor used for exposure of the hip joint.
Rue et al. review neurovascular injuries during total hip arthroplasty. Among other things, they recommend against placement of screws in the anterior-superior quadrant, prudent retractor placement, and avoiding excessive tension on the sciatic nerve.
Della Valle and Di Cesare review complications resulting from total hip replacement. They state that injury to the obturator artery can occur with acetabular screw fixation in the antero-inferior quadrant or from retractors placed underneath the transverse acetabular ligament.
Illustration A shows the obturator artery as it exits the pelvis at the superolateral corner of the obturator foramen. Illustration B reviews acetabular screw placement and the structures at risk in each quadrant.
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OrthoCash 2020
A 65-year-old male sustains a fall onto his left hip 3 years after a total hip arthroplasty. A radiograph taken at the emergency room is shown in Figure A. What is the next best step?

Open reduction and internal fixation with locked plates and cables through an extensile approach
Revision with a proximally porous-coated stem
Revision with an extensively porous-coated stem
Nonoperative management
Minimally invasive plate osteosynthesis Corrent answer: 3
The patient has a Vancouver B2 periprosthetic fracture. There is a loose stem that should be treated with revision to an extensively coated stem that bypasses the fracture site.
Revision of the femoral component is recommended for Vancouver B2 and B3 periprosthetic fractures. Type B1 fractures are treated with ORIF and stem retention, and proximally deficient B3 fractures may be treated with alloprosthetic composites or tumor prostheses.
Springer et al. retrospectively reviewed 118 hips with Vancouver B fractures. Seventy-seven percent of 30 extensively coated stems, 60% of 42 cemented stems, 36% of 28 proximally coated stems, and 61% of 18 tumor prosthesis/allo-prosthetic composite stems were well fixed and demonstrated
fracture union. Nonunion and loosening were the most common complications. They recommend extensively porous-coated stems for better results.
Haidukewych et al. review revision of periprosthetic fractures. They found that most acetabular components are well fixed. When the distal fragment has parallel endosteal cortices with >=5 cm of tubular diaphysis (usually with a diameter of <18 mm), they recommend an extensively coated, uncemented, monoblock long-stemmed prosthesis. If the distal diaphysis is divergent, has
<5 cm of parallel endosteal cortex, or large endosteal diameters, a fluted, grit-blasted, titanium, tapered modular stem can be used.
Figure A shows Vancouver B2 fracture. The stem has subsided relative to the proximal fracture fragment, indicating that it is loose. Illustration A shows revision of the same fracture with an extensively porous-coated stem.
Illustration B shows the endoskeleton technique using an osteotomy to split the proximal fragment coronally for stem removal, followed by insertion of a modular, fluted, tapered stem and cerclage fixation of the proximal fragments.
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Question 71

The right shoulder exercise seen in Figure A will put the LEAST amount of stretch on which structure? Review Topic

Explanation

Shoulder wand exercises, as shown in Figure A, are used to increase external range of motion of the shoulder. With the arm adducted and the elbow flexed, this exercise will put the LEAST amount of stretch on the posterior capsule.
External rotation shoulder wand exercises are commonly used for the treatment of adhesive capsulitis. Adhesive capsulitis is most commonly caused by contracture of the rotator interval. The rotator interval includes the anterior-superior capsule, superior glenohumeral ligament, coracohumeral ligament and long head biceps tendon. The structure most commonly contracted is the anterior-superior capsule, which limits external rotation when the arm is adducted.
Kuhn et al. showed that in the neutral position, each ligament except the posterior capsule significantly affected the torque required for external rotation. The greatest effect on resisting external rotation at 0 degrees of abduction was the entire inferior glenohumeral ligament > coracohumeral ligament > anterior band of the inferior glenohumeral ligament > superior and middle glenohumeral ligament.
Harryman et al. looked at the role of the rotator interval capsule in passive motion and stability of the shoulder. They found operative alteration of this capsular interval was found to affect flexion, extension, external rotation, and adduction of the humerus with respect to the scapula. Limitation of external motion was increased by operative imbrication of the rotator interval and decreased by sectioning of the rotator interval capsule.
Kim et al. reviewed shoulder MRIs to determine if abnormalities of the rotator interval were correlated with chronic shoulder instability. They found a significantly larger rotator interval height, rotator interval area, and rotator interval index in patients with chronic anterior shoulder instability compared to patients without instability.
Figure A shows a patient performing an exercise to increase right shoulder external rotation with a wand/stick. The right arm is fully adducted by her side, and her elbow flexed at 90 degrees.
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Question 72

In recurrent posterior shoulder instability, what is the recommended approach to the posterior capsule? Review Topic

Explanation

Using an infraspinatus-splitting incision allows for excellent exposure of the posterior capsule and minimizes the risk of injury to the axillary nerve which lies inferior to the teres minor in the quadrilateral space.

Question 73

Which of the following statements is correct regarding Vitamin D?

Explanation

24,25-dihydroxycholecalciferol in an inactive form of Vitamin D. High levels of 1,25-dihydroxyvitamin D stimulate the enzymatic production of 24,25-dihydroxyvitamin D, the inactive form of vitamin D, thereby self-regulating the action of 1,25-dihydroxyvitamin D.
Vitamin D is paramount to proper calcium homeostasis and has important clinical implications in the orthopaedic patient. Vitamin D3 is synthesized in the skin and is converted to 25-hydroxycholecalciferol in the liver. 25-hydroxycholecalciferol is then converted in the kidney into 1,25-dihydroxycholecalciferol, the active form of vitamin
D. The best test to determine Vitamin D deficiency is the measurement of 25-hydroxycholecalciferol, as it has a longer half-life and circulating levels are 1,000x more than 1,25-dihydrocholecalciferol.
Patton et al. review the importance of Vitamin D in the orthopaedic patient. They discuss the implications of Vitamin D deficiency, and urge orthopaedic surgeons to be proficient in both the diagnosis and treatment of the condition.
Bogunovic et al. measured the levels of 25-hydroxycholecalciferol in 723 patients who were to undergo orthopaedic surgery. 40% of these patients were noted to be deficient in Vitamin D, with the highest rates in patients scheduled to undergo trauma and sports surgery.
Illustration A reviews Vitamin D metabolism. 24,25-dihydroxycholecalciferol is referred to as pre-Vitamin D.
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Question 74

Which of the following types of exercise used to increase flexibility is considered most beneficial in increasing joint range of motion?

Explanation

DISCUSSION: Evidence has shown that PNF is the treatment of choice to increase joint range of motion and flexibility. PNF has the advantage of pushing the patient to stretch a little further when the muscle tendon unit is relaxed by a partner. While isokinetic and eccentric exercises can improve flexibility, and therefore increase range of motion, their main purpose is to increase strength and endurance. Ballistic stretching involves a large load applied rapidly; however, evidence has shown that static stretching, where a low load is applied for a long duration, offers a more significant benefit.
REFERENCES: Sady SP, Wortman M, Blanke D: Flexibility training: Ballistic, static or proprioceptive neuromuscular facilitation? Arch Phys Med Rehabil 1982;63:261-263.
Tanigawa MC: Comparison of the hold-relax procedure and passive mobilization on increasing muscle length. Phys Ther 1972;52:725-735.
Wallin D, Ekblom B, Grahn R, Nordenberg T: Improvement of muscle flexibility: A comparison between two techniques. Am J Sports Med 1985;13:263-268.

Question 75

A 16-year-old boy sustains a twisting injury to the left knee while wrestling. MRI scans are shown in Figures 22a through 22c. What is the most likely diagnosis?

Explanation

DISCUSSION: The MRI scans show a displaced bucket-handle medial meniscus tear that can be visualized on coronal, sagittal, and axial views. The sagittal view shows the typical “double posterior cruciate ligament sign,” in which the low-signal bucket-handle fragment parallels the normal low-signal posterior cruciate ligament. The coronal and axial images both show the displaced medial meniscus in the notch.
REFERENCES: Sanders TG, Miller MD: A systematic approach to magnetic resonance imaging interpretation of sports medicine injuries of the knee. Am J Sports Med 2005;33:131-148.
Miller TT: Magnetic resonance imaging of the knee, in Insall JN, Scott WN (eds): Surgery of the Knee, ed 4. Philadelphia, PA, Churchill Livingstone, 2006, vol 1, pp 201-224.

Question 76

When comparing arthroscopic lavage and knee debridement with placebo in patients with chronic symptomatic osteoarthritis, what outcome has been demonstrated?

Explanation

DISCUSSION:
Excluding a diagnosis of meniscal tear, loose body, or mechanical derangement, treating knee osteoarthritis of indeterminate cause with arthroscopic lavage and debridement has been found to provide no discernable benefit to offset the risk of surgery. The effects of arthroscopy have not been clinically significant in the vast majority of patient-oriented outcomes measures for pain and function at multiple times between 1 week and 2 years after surgery.

Question 77

9 degress Celsius, serum WBC is 14,000, and his C-reactive protein is elevated. He reports that he uses IV heroin. A coronal 3D CT scan of the left clavicle is shown in Figure B. Joint aspiration shows many grams stain positive organisms. Which of the following organisms is the most likely pathogen?

Explanation

Tibial eminence fracture
Sagittal plane fracture of the medial femoral condyle
Schatzker I tibia plateau fracture
Coronal plane fracture of the lateral femoral condyle
Axial plane fracture through the medial femoral condyle Correct answer: 4
The "Hoffa fracture" is a coronal plane fracture of the femoral condyle that is often missed on plain radiographs of supracondylar and intercondylar femur fractures. It involves the lateral condyle more frequently than the medial.
Identification is important as it may impact operative planning and likely require screw fixation in the anteroposterior plane.
Nork et al. reviewed 202 supracondylar-intercondylar distal femoral fractures and found a 38% prevalence of associated coronal plane fractures. The authors recommend CT scan imaging of all supracondylar and intercondylar fractures.
Ostermann et al reported on 24 unicondylar fractures of the distal femur treated with open reduction internal fixation with a screw construct. Twenty-
three patients acheived satisfactory results at 5 year follow-up. Illustrations A and B are another example of a supracondylar femur fracture with an associated Hoffa fracture identified on CT scan.

A 35-year-old woman presents with an elbow injury which includes a coronoid fracture involving more than 50%, a comminuted
radial head fracture, and an elbow dislocation. What is the most appropriate treatment?
closed reduction and early range of motion
radial head resection and lateral collateral ligament reconstruction
radial head resection and coronoid open reduction internal fixation
radial head arthroplasty and coronoid open reduction internal fixation
radial head arthroplasty, coronoid open reduction internal fixation, and lateral collateral ligament repair
A terrible triad of the elbow includes dislocation of the elbow with associated fractures of the radial head and the coronoid process. Ring et al. stressed that these injuries are prone to complications and advised against resection of the radial head due to instability, and instead recommended a radial head replacement if too comminuted for ORIF. Coronoid fractures compromise elbow stability as well and require open reduction and internal fixation as with the lateral collateral ligament. McKee et al. showed stable elbows in 34/36 with mean Mayo elbow score of 88 when the standard protocol of coronoid ORIF, radial head repair/replacement, and LCL repair were employed.
The talocrural angle of an ankle mortise x-ray is formed between a line perpendicular to the tibial plafond and a line drawn:
perpendicular to the medial clear space
parallel to the talar body
between the tips of the malleoli
perpendicular to the shaft of the fibular
parallel to the subtalar joint Correct answer: 3
The talocrural angle is formed by the intersection of a line perpendicular to the plafond with a line drawn between the malleoli (average = 83+/-4deg). When the lateral malleolus is shortened secondary to fracture, this can lead to increased talocrural angle. This malunion leads to lateral tilt of the talus.
Phillips et al looked at 138 patients with a closed grade-4 supination-external rotation or pronation-external rotation ankle fracture. Although the conclusions were limited due to poor follow up, they found the difference in the talocrural angle between the injured and normal sides was a statistically significant radiographic indicator of a good prognosis.
Pettrone et al looked at a series of 146 displaced ankle fractures, and the effect of open or closed treatment, and internal fixation of one or both malleoli. They found open reduction proved superior to closed reduction, and in bimalleolar fractures open reduction of both malleoli was better than fixing only the medial side.
Illustrations A and B are demonstrations of the talocrural angle.

A 33-year-old male sustains the injury shown in Figure A. He is initially treated with a spanning external fixator followed by definitive open reduction internal fixation of the tibia and fibula. His wounds healed without infection or other complications. Two years following surgery, which of the following parameters will most likely predict a poor clinical outcome and inability to return to work?

Joint line restoration
Degree of fracture displacement
Time before definitive ORIF
Open fracture
Lower level of education Correct answer: 5
Lower level of education is the parameter that correlated most closely with a poor clinical outcome and inability to return to work.
To determine what fracture- and patient-specific variables affect outcome, Williams et al evaluated 29 patients with 32 tibial plafond fractures at a minimum of 2 years from the time of injury. Outcome was assessed by four independent measures: a radiographic arthrosis score, a subjective ankle score, the Short Form-36 (SF-36), and the patient’s ability to return to work. The four outcome measures did not correlate with each other. Radiographic arthrosis was predicted best by severity of injury and accuracy of reduction. However, these variables did not show any significant relationship to the clinical ankle score, the SF-36, or return to work. These outcome measures were more influenced by patient-specific socioeconomic factors. Higher ankle
scores were seen in patients with college degrees and lower scores were seen in patients with a work-related injury. The ability to return to work was affected by the patient’s level of education.
Pollak et al performed a retrospective cohort analysis of pilon fractures. Patient, injury, and treatment characteristics were recorded. The primary outcomes that were measured included general health, walking ability, limitation of range of motion, pain, and stair-climbing ability. A secondary outcome measure was employment status. Multivariate analyses revealed that presence of two or more comorbidities, being married, having an annual personal income of less than $25,000, not having attained a high-school diploma, and having been treated with external fixation with or without limited internal fixation were significantly related to poorer results as reflected by at least two of the five primary outcome measures.
What is the most appropriate treatment for a 17-year-old boy who sustained a gunshot wound to his forearm from a handgun with a muzzle-velocity of 1000 feet/second if he is neurovascularly intact and radiographs reveal no fracture?
Irrigation and local wound care in the emergency department
Emergent irrigation and debridement in the operating room with vacuum-assisted wound closure
Emergent irrigation and debridement in the operating room with 7 days of intravenous antibiotics
Wound closure in the emergency department with follow-up wound check in 1 week
Exploration and removal of all bullet fragments in the emergency department and 10 day course of oral antibiotics
The question refers to appropriate management of a gunshot wound to the forearm. The first question that must be answered when evaluating gunshot injuries is whether the gunshot is low velocity or high velocity. Low-velocity wounds are less severe, are more common in the civilian population, and are typically attributed to bullets with muzzle velocities below 1,000 to 2,000 feet per second. Tissue damage is usually more substantial with higher-velocity (greater than 2,000 to 3,000 fps) military and hunting weapons. In this question, a muzzle velocity of 1,000 ft/sec is provided. Low velocity injuries with stable, non-operative fractures can be treated with local wound care.
The two referenced articles offer guidance for treating low-velocity gunshot injuries with stable, non-operative fracture patterns. The first article by Geissler et al is a retrospective study comparing 25 patients that prospectively received local irrigation and debridement, tetanus prophylaxis and a long acting cephalosporin intramuscularly to a random retrospective sample of 25 patients with similar ballistic-induced fractures and wounds managed by local debridement and 48h of intravenous antibiotics. One infection occurred in each group, requiring further therapy. It was concluded that patients with low-velocity gunshot induced fractures can be managed without the use of short-term intravenous antibiotics with no increased risk of infection.
In the second study, Dickey et al evaluated the efficacy of an outpatient management protocol for patients with a gunshot-induced fracture with a stable, non-operative configuration. 41 patients with a grade I or II open, nonoperative fracture secondary to a low-velocity bullet were treated with 1gm of cefazolin administered in the emergency room and a 7-day course of oral cephalexin. No patient developed a deep infection. Thus, local I&D, tetanus, and oral antibiotics for 2-3 days is adequate for low velocity gunshot wounds.
Which clinical sign is the most sensitive for the diagnosis of compartment syndrome in a child with a supracondylar humerus fracture?
pulselessness
pallor
paresthesia
paralysis
increasing analgesia requirement Correct answer: 5
Although pain, pallor, paresthesia, paralysis, and pulselessness are all possible signs and symptoms of compartment syndrome in children with fractures, studies have shown increasing analgesia requirement is more sensitive.
Bae et al reviewed thirty-six cases of compartment syndrome in 33 pediatric patients. Approximately 75% of these patients developed compartment syndrome in the setting of fracture. "They found pain, pallor, paresthesia, paralysis, and pulselessness were relatively unreliable signs and symptoms of compartment syndrome in these children. An increasing analgesia requirement in combination with other clinical signs, was a more sensitive indicator of
compartment syndrome."
Whitesides et al summarizes the diagnosis and treatment of acute compartment syndrome. They emphasize the need for early diagnosis, as "muscles tolerate 4 hours of ischemia well, but by 6 hours the result is uncertain; after 8 hours, the damage is irreversible." They recommend fasciotomy be performed when tissue pressure rises past 20 mm Hg below diastolic pressure.
A 45-year-old man sustains the injury seen in Figures A and B following a motor vehicle accident. Postoperative radiographs are seen in Figures C and D. Which of the following is the most accurate when comparing outcomes between intramedullary nailing (IMN) and open reduction internal fixation (ORIF) for this injury?

Union rates at one year are higher with ORIF
Infection rates are higher with IMN
Functional shoulder outcomes at one year are equivalent with IMN and ORIF
Iatrogenic radial nerve injury rate is higher with ORIF
Shoulder stiffness rates at one year are equivalent with IMN and ORIF Correct answer: 3
Although shoulder pain and stiffness is increased following IMN compared to ORIF, functional outcome scores at one year have been shown to be equivalent
in both treatment groups.
Diaphyseal humeral shaft fractures outcomes following IMN and ORIF are under further investigation. Diaphyseal humeral shaft fractures have historically been treated with ORIF, however proponents for IMN cite benefits of less periosteal stripping and soft tissue dissection. Recent investigations have shown outcomes with regard to nonunion, infection, re-operation, and nerve palsy appear equivalent between both groups. Rates of shoulder stiffness and shoulder pain have been demonstrated to be higher in IMN compared to ORIF. American Shoulder and Elbow Scores (ASES) have shown no difference at one year post-operatively.
Bhandari et al. performed a meta-anaylsis of 3 prospective randomized trials. They found lower rates of re-operation and shoulder impingement with ORIF of humeral shaft fractures.
Wali et al. performed a prospective randomized study of IMN or ORIF on 50 patients with mid-diaphyseal humeral shaft fractures. They found IMN had shorter operative time, shorter hospital stay, and lower blood loss. They found no difference in union rates, complication, or shoulder functional outcomes scores. They conclude IMN to be an effective option for treating mid-diaphyseal humeral shaft fractures.
Heineman et al. have recently conducted an update on their meta-analysis to include more recent randomized studies. With the inclusion of newer studies the author found a statistically significant increase in total complication rate with the use of IM nailing compared with ORIF. The authors found no significant difference between the two treatment modalities for the secondary outcomes (nonunion, infection, nerve palsy, re-operation).
Figures A and B show a diaphyseal humeral shaft fracture. Figure C and D show postoperative radiographs following intramedullary nailing of a humeral shaft fracture.
Incorrect Answers:
A 25-year-old female presents complaining of progressive anteromedial pain in her left ankle. She underwent operative fixation 5 months prior at an outside hospital. The operative report indicated that, due to anterior fracture blisters, a direct medial incision was utilized, centered over the posterior colliculus of the medial malleolus, without violation of the deltoid ligament. A radiograph and computed tomographic scan of her initial injury are shown in Figures A and B, respectively. On exam, she has well-healed incisions, exhibits no tenderness to palpation over her hardware, but does endorse pain with deep palpation along the anteromedial joint line. Figure C shows an anteroposterior left ankle radiograph taken today. Labs are obtained and reveal a white blood cell count of 9.0 k/uL (reference range 4.5-11.0 k/uL) and a C-reactive protein value of 0.8 mg/dL (<0.9 mg/dL). What is the next best step in managing her problem?

Syndesmotic fixation
Intra-articular corticosteroid injection
Referral to physical therapy
Surgical correction of malunion
Removal of hardware Correct answer: 4
This patient sustained a supination-adduction (SAD) injury with a vertical shear fracture of her medial malleolus and a fibular avulsion fracture. She sustained a medial plafond articular impaction injury that was not addressed at the time of surgery.
In SAD injuries, supination of the foot is combined with inward rotation at the ankle, adduction of the hindfoot, and inversion of the forefoot. This results in the following sequence of events: 1. Talofibular sprain or distal fibular avulsion (equivalent to Weber A). 2. Vertical medial malleolus fracture as the talus strikes the tibia. Associated injuries may include osteochondral damage to the talus and marginal impaction of the medial plafond. It is important to evaluate the medial plafond for articular impaction. When present, an arthrotomy must be performed, typically utilizing an anteromedial incision, with direct visualization of the articular surface to restore the joint line appropriately.
Weber et al. provided a review article on corrective osteotomies for malleolar fracture malunions. They stress that malunions can lead to ankle instability, abnormal load transfer, and post-traumatic arthritis. They conclude that corrective osteotomies that restore anatomical alignment show good results in long-term follow-up.
Perera et al. provided additional commentary on the surgical reconstruction of malunited ankle fractures. The authors emphasize the link between malunion and poor outcomes. They state that successful salvage procedures involve a clear understanding of the deformity, careful preoperative planning, and a solid understanding of reconstructive techniques. They provide several instructive case examples in their review.
McConnell et al. provided a discussion on SAD ankle fractures at their institution and emphasized the importance of recognizing marginal impaction of the tibial plafond when treating these injuries. Of 800 ankle fractures identified over a 5-year period, 44 were SAD injuries, 19 of the 44 displayed a vertical shear fracture of the medial malleolus, and 8 of the 19 demonstrated marginal impaction of the tibial plafond. These 8 impaction injuries were treated with open reduction internal fixation with elevation of the articular impaction; all had good to excellent outcomes without arthritic changes at last
follow-up.
Figure A is an anteroposterior left ankle radiograph demonstrating a SAD injury with a vertical shear fracture of the medial malleolus, a fibular avulsion fracture, and articular impaction of the medial tibial plafond. Figure B is a coronal CT demonstrating articular impaction of the medial plafond. Illustration A is an intra-operative photograph with the medial malleolus retracted allowing inspection of the articular surface; mild anteromedial plafond impaction is present.
Incorrect Answers:

A 90-year-old female slips and falls at home. She is a community ambulator and has no medical problems. She reports right hip pain at this time. Injury radiographs are shown in Figures A & B. Delay of more than 48 hours may result in:

Increased intraoperative time
Increased 30-day mortality
No impact on the rate of postoperative pneumonia
Higher rates of blood transfusion
Increased risk of post-operative infection Correct answer: 2
Figures A & B demonstrate a right, unstable intertrochanteric femur fracture. Surgical stabilization within 48 hours improves short-term and 30-day mortality.
Hip fractures are common and mortality rates vary. In the elderly, mortality rates may reach 10% at 1-month, 20% at 4-months, and 30% at 1-year. Time to surgery has found to be a decisive factor. A pre-operative delay may lead to an increase in mortality and adversely influence other clinical outcomes.
Clinical guidelines recommend immediate operative stabilization, given the patient is medically fit for surgery.
Nyholm et al. performed a retrospective study of the Danish Fracture Database to investigate whether a surgical delay increases 30-day and 90-day mortality rates for patients with proximal femoral fractures. The 30-day and 90-day mortalities were 10.8% and 17.4%, respectively. The risk of 30-day mortality increased with increasing time intervals of more than 12 hours, 24 hours, and more than 48 hours. 90-day mortality increased with a surgical delay of more than 24 hours. They conclude that rapid surgical treatment should be performed by attending orthopaedic surgeons.
Moja et al. performed a meta-analysis and meta-regression to assess the relationship between surgical delay and mortality in elderly patients with a hip fracture. They analyzed 35 independent studies with 191,873 patients and 34,448 deaths. The majority of studies had a cut-off of 48 hours. They report that early hip surgery was associated with a lower risk of death and pressure sores. They conclude that early hip fracture surgery appears to provide a survival benefit compared to later intervention.
Rodriguez-Fernandez et al. performed a study examining 2 groups with hip fractures. The first group was studied retrospectively and had an average delay of surgical treatment of more than 1-week while the second group was studied prospectively, and had surgical treatment within 48 hours. They found a larger number of complications in the group with a delay in surgical treatment. They conclude that elderly patients with hip fractures should be treated as soon as their medical condition permits.
Figures A and B are the AP and lateral radiographs demonstrating a right, unstable intertrochanteric femur fracture. Illustration A is an intertrochanteric femur fracture, stabilized with a cephalomedullary nail.
Incorrect Answers:

A 22-year-old healthy left hand dominant male presents to the ED with left shoulder pain after falling from an ATV. Figure A is the radiograph of his left clavicle. He is neurovascularly intact and there is no evidence of skin tenting or open fracture. Which of the following most predisposes this patient to nonunion?

Diaphyseal fracture
Fracture displacement
Age
Male Gender
Injury involving the dominant extremity Correct answer: 2
Displaced clavicle fractures are associated with higher rates of nonunion.
Nonunion occurs in roughly 5-6% of clavicle fractures and can result in slower functional return, poor cosmesis and muscle fatigability. Clavicle fractures can be sub-classified using the Allman classification into medial, diaphyseal, and lateral injuries (Illustration A). The Neer classification for diaphyseal injuries describes fractures as "nondisplaced" (less than 100% displacement) and "displaced" (greater than 100% displacement).
Robinson et al. performed a prospective cohort study to identify risk factors for nonunion after nonoperative management of clavicle fractures. The overall nonunion rate was 6.2% and was highest in lateral third fractures (11.5%).
Diaphyseal fractures had the lowest nonunion rate (4.5%). Additionally, the authors found that the risk for nonunion was increased by advancing age, female gender, fracture displacement, and comminution.
Jorgensen et al. performed a systemic review of the literature looking for predictors of non-union and malunion in mid shaft clavicle fractures treated non-operatively. They found fracture comminution, displacement, older age, female gender, and the presence of smoking to be his factors for non-union. Of these, displacement was the most likely factor that can be used to predict nonunion.
Figure A demonstrates a displaced left clavicle diaphyseal fracture. Note that the medial fragment is displaced superiorly by the deforming force of the sternocleidomastoid. Illustration A represents the Allman classification.
Illustration B demonstrates the deforming forces acting on the clavicle.
Incorrect Answers:

A 24-year-old male presents with ankle pain after being involved in a motor vehicle accident. His injury radiograph is shown in Figure A. Which of the following has been shown to contribute to the development of post-traumatic arthritis in this injury pattern?

Initial superficial zone cartilage cell death via apoptosis at the fracture margins
Initial superficial zone cartilage cell death via apoptosis remote from the fracture margins
Initial superficial zone cartilage cell death via necrosis remote from the fracture margins
Initial superficial zone cartilage cell death via necrosis at the fracture margins
Delayed superficial zone cartilage cell death via necrosis at the fracture margins
Figure A demonstrates a tibial plafond fracture. Initial superficial zone cartilage cell death via necrosis at the fracture margins has been shown to contribute to post-traumatic arthritis.
Post-traumatic osteoarthritis typically occurs after an intra-articular fracture. Impacted chondrocytes die by either necrosis or apoptosis, which have both been implicated in post-traumatic osteoarthritis. Initial cell death in the superficial cartilage zones at the fracture margins occurs by necrosis. Apoptosis occurs in a delayed fashion and is mitigated by several bioactive agents.
Apoptosis also affects the superficial cartilage zones near the fracture margins. Deep cartilaginous zones and areas away from the fracture margins do not seem to be involved in these processes.
McKinley et al. performed a review of the basic science of intra-articular fractures and posttraumatic osteoarthritis. They report that initial damage to the cartilage in combination with the ensuing pathomechanical and pathobiologic response of the cartilage after a fracture contribute to posttraumatic arthritis. Chronic abnormal joint loading is also thought to contribute to this process as well. They conclude that the relative contribution of each is unknown.
Tochigi et al. performed a study to determine the distribution and progression of chondrocyte damage after intra-articular ankle fractures. They harvested 7 normal human ankles and subjected them to impaction. They found that immediate superficial zone chondrocyte death was greater in fracture-edge regions than on-fracture regions. Subsequent cell death over the next 48 hours was significantly higher in fracture-edge regions as well. They conclude that cartilage damage in intra-articular fractures was characterized by chondrocyte death at fracture margins.
Figure A is an ankle mortise radiograph demonstrating an intra-articular tibial plafond fracture.
Incorrect Answers:
A 35-year-old male presents with left knee pain after sustaining the injury seen in Figure A. He is neurovascularly intact and can perform a straight leg raise, but has pain with passive range of motion. Figures B and C show an anteroposterior and lateral radiograph of the left knee, respectively. 175 cc of saline is injected into the superolateral quadrant with no egress of fluid from the inferolateral
laceration. What percentage of traumatic arthrotomies would be detected with this test?

Question 78

Figure 48 shows the radiograph of a 17-year-old boy who sustained a gunshot wound to his forearm. There is a small entrance wound on the volar surface. The exit wound is dorsal and more than 15 cm in size, with loss of skin and an extensive amount of devitalized muscle hanging out of the wound. Vascular supply to the hand is excellent, the ulnar and median nerves are intact in the hand, but the radial sensory nerve function is absent. After repeated surgical debridements of the wound and bone, definitive treatment for the fracture would most likely be which of the following? Review Topic

Explanation

The injury needs a very complex traumatic reconstruction. After repeat debridements, there will be a very long segmental loss of the radius, with a significant loss of skin and muscle covering the bone. Spanning external fixation represents a good temporary fixation tool but will not be a definitive solution. The preferred procedure is a vascularized fibular graft with associated skin flap from the lateral leg. This surgical option brings healthy vascularized bone and soft-tissue coverage into an area with significant bone and soft-tissue loss. Placement of large quantities of allograft material, especially strut allograft, is generally contraindicated in the setting of open fractures with soft-tissue compromise because of the risk of infection. Internal fixation and massive cancellous autografting is usually limited to one defect of less than 5 cm with intact soft-tissue covering.

Question 79

A 72-year-old woman underwent a primary total hip arthroplasty 14 months ago. She states that the hip has now dislocated four times when rising from a low chair, requiring closed reduction. A radiograph is shown in Figure 3a and a CT scan of her pelvis is shown in Figure 3b. What is the most reliable method for rectifying her instability?

Explanation

DISCUSSION: The radiograph shows well-fixed components without evidence of loosening. The CT scan shows severe retroversion of the acetabular component. Revision of the component into the correct amount of anteversion
will most reliably rectify the instability in the face of severe component malposition.
REFERENCES: Parvizi J, Picinic E, Sharkey PF: Revision total hip arthroplasty for instability: Surgical techniques and principles. J Bone Joint Surg Am 2008;90:1134-1142.
DeWal H, Su E, DiCesare PE: Instability following total hip arthroplasty. Am J Orthop 2003;32:377-382. Barrack RL, Booth RE Jr, Lonner JH, et al (eds): Orthopaedic Knowledge Update: Hip and Knee Reconstruction 3.
Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 475-503.

Question 80

A left-handed 23-year-old man who fell 5 feet from a ladder onto his left elbow sustained the closed injury shown in Figure 26. Management should consist of

Explanation

DISCUSSION: The radiographs reveal a displaced olecranon fracture. To maximize joint congruity of this intra-articular injury, open reduction and internal fixation is the treatment of choice. A tension band plate will assist with maintenance of the reduction and may aid in early range of motion because injuries to the elbow are prone to stiffness. The oblique fracture line is particularly well suited to plate fixation. Percutaneous pin fixation is unlikely to achieve anatomic joint reduction that can be obtained with open means. External immobilization will not accomplish joint reduction and will most likely lead to a nonunion.
REFERENCES: Hotchkiss RN: Fractures and dislocations of the elbow, in Rockwood CA Jr, Green DP, Bucholz RW, Heckman JD (eds): Rockwood and Green’s Fractures in Adults, ed 4. Philadelphia, PA, Lippincott-Raven, 1996, pp 929-1024.
Murphy DF, Greene WB, Gilbert JA, Dameron TB Jr: Displaced olecranon fractures in adults: Biomechanical analysis of fixation methods. Clin Orthop 1987;224:210-214.
Hume MC, Wiss DA: Olecranon fractures: A clinical and radiographic comparison of tension band wiring and plate fixation. Clin Orthop 1992;285:229-235.

Question 81

Which of the following best describes athletic pubalgia?

Explanation

DISCUSSION: Athletic pubalgia refers to a distinct syndrome of lower abdominal and adductor pain that is mostly commonly seen in high performance male athletes. This condition must be distinguished from others such as painful inflammation of the symphysis pubis, referred to as osteitis pubis. Symptoms attributable to the iliopsoas tendon are most commonly associated with snapping of the tendon. Stress fracture of the pubic ramus may cause symptoms in this area, but it is usually confirmed by imaging studies. Neurapraxia of the pudendal nerve is associated with pressure from the seat in cycling sports and also as a complication associated with traction during surgical procedures.
REFERENCES: Meyers WC, Foley DP, Garrett WE, Lohnes JH, Mandlebaum BR: Management of severe lower abdominal or inguinal pain in high-performance athletes: PAIN (Performing Athletes with Abdominal or Inguinal Neuromuscular Pain Study Group). Am J Sports Med 2000;28:2-8.
Albers SL, Spritzer CE, Garrett WE Jr, Meyers WC: MR findings in athletes with pubalgia. Skeletal Radiol 2001;30:270-277.

Question 82

.Figures 89a and 89b are the radiographs of an 18-year-old woman who has had elbow pain after falling on an outstretched hand. She is evaluated 5 days after the injury. Examination reveals the wrist is normal and her elbow has a limited arc of motion of 30 to 90 degrees of flexion/extension and 20 to 20 degrees of pronation and supination, with tenderness isolated to the lateral side of the elbow. What is the most appropriate treatment option?

Explanation

Question 83

Following an acute dislocation of the patella, the risk of a recurrent dislocation is greater if the patient has which of the following findings?

Explanation

DISCUSSION: Recurrent dislocations may follow an earlier dislocation. One study found that in patients who had a patellar dislocation between the ages of 11 to 14 years, 60% had a recurrent dislocation. The incidence of recurrent dislocation dropped to 33% in patients who had a patellar dislocation between the ages of 15 to 18 years. The authors also found that the incidence of recurrence was greater in patients who demonstrated a predisposition to dislocation as determined by evaluation of the unaffected knee. Predisposing signs included passive lateral hypermobility of the patella, a dysplastic distal third of the vastus medialis obliquis muscle, and a high and/or lateral position of the patella. A second study found that the risk of redislocation was considerably higher in patients who were in their teens at the first episode of dislocation compared to older patients. There are no studies linking either a patella baja or a bipartite patella to an increased risk of redislocation.
REFERENCES: Cash JD, Hughston JC: Treatment of acute patellar dislocation. Am J Sports Med 1988;16:244-249.
Larsen E, Lauridsen F: Conservative treatment of patellar dislocations: Influence of evident factors on the tendency to redislocation and the theraputic result. Clin Orthop

1982;171:131-136.

Question 84

Figures 27a through 27c show the radiographs and CT scan of a 27-year-old man who sustained a low-velocity gunshot wound to the neck. He is quadriplegic (ASIA A), hemodynamically stable, and does not have drainage from his wound. After initial resuscitation and stabilization, the cervical spine and spinal cord injuries are best managed by

Explanation

DISCUSSION: Although the spinal canal has been penetrated, the lateral masses are intact bilaterally with only partial destruction of the vertebral body and penetration of the lamina on one side, thus the cervical spine is not unstable and surgical stabilization is not indicated. Dural repair is not indicated since there is no external cerebrospinal fluid leakage. Surgical treatment should be based on the need to treat extraspinal pathology only.
REFERENCES: Bono CM, Heary RF: Gunshot wounds to the spine. Spine J 2004;4:230-240.
Punjabi MM, Jue JJ, Dvorak J, et al: Cervical spine kinematics and clinical instability, in Clark CR (ed): The Cervical Spine, ed 4. Philadelphia, PA, Lippincott Williams & Wilkins, 2005,

pp 55-87.

Question 85

Phosphate administration decreases urinary calcium excretion through which of the following actions?

Explanation

The kidneys are responsible for monitoring and regulating calcium homeostasis as well as for controlling levels of phosphate, magnesium, and other minerals. The
kidneys act both as target organs for parathyroid hormone (PTH) and for excreting it. The proximal convoluted tubules of the kidneys are the site of production of 1,25-dihydroxycholecalciferol (the active form of vitamin D following hydroxylation of 25-hydroxycholecalciferol catalyzed by 1-hydroxylase), the foremost regulator of intestinal calcium absorption. This hormone also promotes osteoclastic resorption of bone and the feedback inhibition of PTH synthesis. Modest changes in the efficacy of renal excretion dramatically alter the body's ability to maintain mineral homeostasis. Phosphate reduces urine calcium excretion through several extrarenal mechanisms. An increase in phosphate will directly stimulate PTH secretion and can reduce ionized calcium, also enhancing PTH secretion. The increased PTH will enhance calcium resorption. Phosphate will complex with calcium in the intestine, decreasing the amount of calcium for absorption. It can also complex with calcium in the bone and soft tissues, decreasing the filtered load of calcium. Decreased phosphate will result in hypercalcuria. There appears to be a direct effect of phosphate to decreased calcium reabsorption in the distal nephron.

Question 86

Figures 5a and 5b show the radiographs of a 21 -year-old wrestler who reports that his leg was rolled over while wrestling. The patient has decreased sensation and function in the distribution of the peroneal nerve, and he has absent pulses. What is the most appropriate initial management at this time?

Explanation

DISCUSSION: The patient has an acute traumatic anteromedial dislocation of the knee with occlusion of the popliteal artery with a possible tear. Treatment should include reduction and reevaluation of the vascular status. At this time, if pulses are symmetric, observation may be appropriate without surgical
intervention of the artery, but documentation with studies would be appropriate. Delayed reconstruction of injured structures is appropriate.
REFERENCES: Fanelli GC, Orcutt DR, Edson CJ: The multiple- ligament injured knee: Evaluation, treatment, and results. Arthroscopy 2005;21:471 -486.
McDonough EB Jr, Wojtys EM: Multiligamentous injuries of the knee and associated vascular injuries.
Am J Sports Med 2009;37:156-159.
Wascher DC: High-velocity knee dislocation with vascular injury: Treatment principles. Clin Sports Med 2000;19:457-477.

Question 87

Which of the following findings helps to distinguish between stress fractures of the tibia and shin splints? Review Topic

Explanation

Anterior tibial pain can often be difficult to diagnose. A bone scan showing the tibial cortex in a diffuse, longitudinal orientation is consistent with shin splints compared to a more discreet, localized uptake more commonly seen with a stress fracture. Bone stress injuries are due to cyclical overuse of the bone. They are relatively common in athletes and military recruits but are also seem in otherwise healthy people who have recently started new or intensive physical activity. Diagnosis of bone stress injuries is based on the patient's history of increased physical activity and on imaging findings.
The general symptom of a bone stress injury is stress-related pain. Bone stress injuries are difficult to diagnose based only on a clinical examination because the clinical symptoms may vary depending on the phase of the pathophysiological spectrum in the bone stress injury. Imaging studies are needed to ensure an early and exact diagnosis. If the diagnosis is made early, most bone stress injuries heal well without complications.

Question 88

A 38-year-old woman has persistent elbow pain but is unable to recall a specific traumatic event. Examination reveals that the patient exhibits apprehension when the elbow is placed in valgus with forearm supination and axial loading. Because of chronicity and failure to respond to nonsurgical management, what is the most appropriate treatment? Review Topic

Explanation

The maneuver described is the lateral pivot-shift test, where valgus and axial loads are applied to the extended and supinated forearm while the elbow is gradually flexed. The presence of apprehension in an awake patient suggests posterolateral rotatory instability, indicating insufficiency of the lateral ulnar collateral ligament. Treatment for chronic cases involves reconstruction using a palmaris longus tendon graft combined with plication of the lateral capsuloligamentous structures. Direct ligament repair and isolated plication are less reliable. The long-term effects of thermal shrinkage are still unclear. Because of the failure to respond to nonsurgical management, continued bracing is unlikely to resolve the patient's symptoms.

Question 89

A 60-year-old man has pain at the tip of the index finger. A radiograph and biopsy specimen are shown in Figures 40a and 40b. Management should consist of

Explanation

DISCUSSION: The radiograph and histology findings are most consistent with squamous cell carcinoma. This tumor is best treated with wide surgical resection margins alone in the absence of metastasis; in this patient, management should consist of amputation through the distal interphalangeal joint. The other treatments are not indicated.
REFERENCE: Soltani K, Krunic A: Non melanoma skin neoplasms, in Vokes E, Golomb H (eds): Oncologic Therapies, ed 2. Berlin, Germany, Springer, pp 646-647.

Question 90

Which of the following associated type acetabular fracture patterns is defined based on the fact that all articular segments are detached from the intact portion of the ilium, which remains attached to the sacrum through the sacroiliac joint?

Explanation

DISCUSSION: There are 5 simple and 5 associated fracture types according to the classification system created by Judet and Letournel. The key feature which distinguishes both column fractures from other associated types is that all articular segments are detached from the intact portion of the ilium, which remains attached to the sacrum through the SI joint. Although the transverse plus posterior wall, T-shaped, and anterior plus posterior hemi-transverse fractures all show involvement of the anterior and posterior columns, they are not “both columns” because a portion of the articular surface remains in its normal position, attached to intact ilium. The intact ilium is responsible for the "spur sign" noted most prominently on the obturator oblique radiograph.

Question 91

In a fatigue test, the maximum stress under which the material will not fail, regardless of how many loading cycles are applied, is defined as

Explanation

Fatigue failure occurs with repetitive loading cycles at stress below the ultimate tensile strength. Fatigue failure depends on the magnitude of the stress and number of cycles. If the stress is less than a predetermined amount of stress, called the endurance limit, the material may be loaded cyclically an infinite number of times without breaking.

Question 92

Figures 1a through 1c show the radiograph and MRI scans of a 16-year-old patient who has a painful hip. Examination reveals a significant limp, limited abduction and internal rotation, and severe pain with internal rotation and adduction. A biopsy specimen is shown in Figure 1d. What is the deposited pigment observed in this condition?

Explanation

DISCUSSION: Pigmented villonodular synovitis (PVNS) is a synovial proliferative disorder that remains a diagnostic difficulty. The most common clinical features are mechanical pain and limited joint motion. On radiographs, the classic finding is often a large lesion, associated with multiple lucencies. Other findings may include a normal radiographic appearance, loss of joint space, osteonecrosis of the femoral head, or acetabular protrusion. MRI is the imaging modality of choice and will show the characteristic findings of a joint effusion, synovial proliferation, and bulging of the hip. The synovial lining has a low signal on T₁- and T₂-weighted images, secondary to hemosiderin deposition. Copper deposition occurs in patients with Wilson’s disease, which mainly affects the liver.
REFERENCES: Bhimani MA, Wenz JF, Frassica FJ: Pigmented villonodular synovitis: Keys to early diagnosis. Clin Orthop 2001;386:197-202.
Cotten A, Flipo RM, Chastanet P, et al: Pigmented villonodular synovitis of the hip: Review of radiographic features in 58 patients. Skeletal Radiol 1995;24:1-6.

Question 93

A 19-year-old collegiate lacrosse player has bilateral lower extremity pain during training runs and practice sessions. She says her pain is only associated with activity, always begins 4 to 5 minutes into an activity, and resolves within 10 minutes after activity cessation. She reports a feeling of numbness and tingling in her first- and second-toe web space with continued activity. She has no pain while at rest and has tried nonsteroidal anti-inflammatory drugs, ice baths, and rehabilitation techniques with her athletic trainers without experiencing noticeable changes. Which test has the highest specificity and sensitivity for the pathology suspected?

Explanation

DISCUSSION
Chronic exertional compartment syndrome (CECS) is an uncommon cause of pain that is most often encountered in athletes or military populations. The diagnosis is suggested by pain after the start of the activity with resolution of symptoms when the activity stops. Traditionally, the diagnosis was established by measuring intracompartment pressures at 1 and 5 minutes of
activity. Roscoe and associates have shown that using continuous pressure monitoring during the activity until pain forces subjects to stop provides higher sensitivity and specificity than the traditional diagnostic technique. Palpating the leg is not as sensitive or specific as direct pressure monitoring. Although certain changes can be seen on MRI in CECS, this is not the diagnostic study of choice.

Question 94

Osteopenia is defined by the World Health Organization (WHO) as a bone mineral density (BMD) that is

Explanation

DISCUSSION: Osteopenia, decreased bone mass without fracture risk as defined by the WHO criteria for diagnosis of osteoporosis, is when a woman’s T-score is within -1 to -2.5 SD.

The T-score represents a comparison to young normals or optimum peak density. The Z-score represents a comparison of BMD to age-matched normals. Measurements of bone mineral density (BMD) at various skeletal sites help in predicting fracture risk. Hip BMD best predicts fracture of the hip, as well as fractures at other sites.
REFERENCE: Kanis JA, Johnell O, Oden A, et al: Risk of hip fracture according to the World Health Organization criteria for osteopenia and osteoporosis. Bone 2000;27:585-590.

Question 95

Decreased risk of shoulder and elbow injury in a throwing athlete has been demonstrated with which of the following? Review Topic

Explanation

Posterior capsular contracture has been demonstrated to significantly impair the ability of the humeral head to translate anterior and inferiorly during the late cocking and early acceleration phases of the throwing motion. This results in an obligatory posterosuperior translation of the humeral head that may contribute to posterior superior glenohumeral internal impingement with posterosuperior labral and articular-sided rotator cuff pathology. Posterior capsular stretching in throwing athletes has been demonstrated to decrease the likelihood of clinically significant shoulder or elbow injury. Periscapular muscle and rotator cuff strengthening are important for optimal scapulothoracic rhythm, stable scapular position for throwing, and rotator cuff function but less directly established to result in a decreased risk of shoulder and elbow injury than posterior capsular stretching. Partial-thickness rotator cuff repair and superior labral repair may be necessary for treatment of symptomatic lesions unresponsive to nonsurgical management, but these do not necessarily correlate with decreased shoulder and elbow injury risk.

Question 96

Figure 13 shows the radiographs of a 20-year-old intercollegiate basketball player who was injured 6 weeks prior to the start of the season. What is the most appropriate treatment?

Explanation

DISCUSSION: A Jones fracture occurs at the metaphyseal-diaphyseal junction of the fifth metatarsal. It is often an acute fracture in conjunction with a chronic stress-related injury. It requires either a short leg cast with strict non-weight-bearing or surgical fixation. In the high performance athlete, the need for rapid return to sport activity usually requires surgical intervention, most commonly with an intramedullary screw.
REFERENCES: Brodsky JW, Krause JO: Stress fractures of the foot and ankle, in Delee JC, Drez D (eds): Orthopaedic Sports Medicine, ed 2. Philadelphia, PA, Saunders, 2003, vol 2,
pp 2391-2409.
Dameron TB Jr: Fractures of the proximal fifth metatarsal: Selecting the best treatment option.
J Am Acad Orthop Surg 1995;3:110-114.

Question 97

What structure is 7cm from the acromion and at greatest risk of injury during a deltoid splitting approach for a proximal humerus fracture?

Explanation

DISCUSSION: The axillary nerve is located approximately 7cm from the tip of the acromion. The axillary nerve comes off the of the brachial plexus (middle trunk, posterior division, posterior cord) carrying fibers from C5 and C6. The axillary nerve travels through the quadrangular space with the posterior circumflex humeral artery and vein to innervate the teres minor and deltoid muscles and supply sensation over the lateral shoulder.
Based on the knowledge of the course of the axillary nerve, and potential complications regarding the
vascular supply to the humeral head with the delto-pectoral approach, some authors are suggesting deltoid-splitting approach to the proximal humerus for reduction and fixation of proximal humeral fractures.
Cetik et al evaluated 24 cadaver shoulders to better identify the course of the axillary nerve and identify the "safe zones" for deltoid-splitting incisions. They found the distance from the tip of the acromion to the axillary nerve varied depending on patient specific factors like arm length and they identified a "safe area" where dissection was free of injury to the axillary nerve (Illustrations A and B).

Question 98

Figure 40 shows the MRI scan of a 23-year-old man with a history of recurrent anterior shoulder instability. What is the most likely diagnosis? Review Topic

Explanation

The MRI scan shows an ALPSA lesion. This is also known as a medialized Bankart with medial displacement of the torn anterior labrum. During surgical stabilization, the labrum and periosteal sleeve must be mobilized and repaired laterally to reduce recurrent instability. A Perthes lesion is a nondisplaced labral tear. A GLAD lesion represents a nondisplaced anterior labral tear with an associated articular cartilage injury.

Question 99

A 48-year-old man who is scheduled to undergo total knee replacement has an X-linked clotting disorder that leads to abnormal bleeding and recurrent, spontaneous hemarthrosis. Before undergoing surgery, he should have replacement therapy of

Explanation

Hemophilia A is an X-linked recessive deficiency of factor VIII that can lead to significant bleeding problems including recurrent spontaneous hemarthroses that can lead to synovitis and joint destruction. von Willebrand disease is a lack of von Willebrand factor that leads to decreased platelet aggregation; more commonly patients have mucosal bleeding and not hemarthroses. Vitamin K deficiency is not hereditary; it is typically attributable to inadequate dietary intake, malabsorption, and loss of storage sites from hepatocellular disease. Protein C and S deficiencies are autosomal-dominant diseases that lead to thrombosis, not bleeding, as protein C and S shut off thrombin formation.

Question 100

The parents of a 13-year-old boy with Down syndrome report that he has an increasing limp and decreased endurance with activities. Lateral flexion-extension radiographs of the cervical spine show no evidence of instability. Examination reveals a right Trendelenburg limp and an obvious limb-length discrepancy. Hip motion is symmetric except for some decreased abduction on the right side. A standing AP radiograph is shown in Figure 20. Management should consist of

Explanation

DISCUSSION: Ligamentous laxity and muscle hypotonia seen in Down syndrome contribute to the incidence of hip subluxation and dislocation. These factors can be progressive and lead to degenerative arthritis in adults with Down syndrome. Because this patient has a progressive limp and decreased endurance, observation and a shoe lift are not options. Bracing may be an option in the younger child before significant bony changes occur. Surgical intervention is the treatment of choice in this patient; however, all components of the deformity need to be addressed. Because of the increased capsular laxity, there is a high likelihood of recurrence if capsulorrhaphy is not included with the pelvic and femoral osteotomies. Surgery in these patients is associated with a high rate of complications.
REFERENCES: Shaw ED, Beals RK: The hip joint in Down’s syndrome: A study of its structure and associated disease. Clin Orthop 1992;278:101-107.
Aprin H, Zinc WP, Hall JE: Management of dislocation of the hip in Down’s syndrome.

J Pediatr Orthop 1985;5:428-431.
Greene WB: Closed treatment of hip dislocation in Down syndrome. J Pediatr Orthop 1998;18:643-647.

Full Question & Answer Text (for Search Engines)

Question 1:

With the arm abducted 90 degrees and fully externally rotated, which of the following glenohumeral ligaments resists anterior translation of the humerus? Review Topic

Options:

Coracohumeral ligament
Superior glenohumeral ligament
Middle glenohumeral ligament
Anterior band of the inferior glenohumeral ligament complex
Posterior band of the inferior glenohumeral ligament complex

Correct Answer: Anterior band of the inferior glenohumeral ligament complex

Explanation:

Question 2:

Options:

Immediate closed reduction in the intensive care unit while the patient is awake
Posterior spinal laminectomy and fusion with instrumentation
Anterior cervical diskectomy, corpectomy, and plating
High-dose methylprednisolone

Correct Answer: Immediate closed reduction in the intensive care unit while the patient is awake

Explanation:

DISCUSSION
Facet subluxation reduction may be performed in awake patients. Posterior spinal laminectomy and fusion can result in worsening neurologic status and is not recommended in this setting. Generally, corpectomy in the setting of facet subluxation is not recommended because it does not facilitate reduction or fully alleviate spinal cord compression. High-dose steroid use is not supported by current literature.
RECOMMENDED READINGS
Fehlings MG, Perrin RG. The timing of surgical intervention in the treatment of spinal cord injury: a systematic review of recent clinical evidence. Spine (Phila Pa 1976). 2006 May 15;31(11 Suppl):S28-35; discussion S36. Review. PubMed PMID: 16685233.
View Abstract
at PubMed
Lee AS, MacLean JC, Newton DA. Rapid traction for reduction of cervical spine dislocations. J Bone Joint Surg Br. 1994 May;76(3):352-6. PubMed PMID: 8175833.
View Abstract at
PubMed

Question 3:

Figure 93 shows the axial T2-weighted MRI scan of the lumbar spine of a 70-year-old man. The arrow points to which of the following structures? Review Topic

Options:

Lamina
Facet joint
Lumbar synovial cyst
Ligamentum flavum
Epidural space

Correct Answer: Lamina

Explanation:

The ligamenta flava (singular, ligamentum flavum, Latin for yellow ligament) are ligaments that connect the laminae of adjacent vertebra, all the way from the axis to the first segment of the sacrum. In T2-weighted sequencing, ligamentous structures possess a low signal intensity. The ligamentum in this patient is markedly thickened, resulting in severe spinal stenosis. The epidural space lies ventral and medial to the ligamentum flavum and should possess a high signal intensity secondary to the presence of cerebrospinal fluid. However, in the case of high-grade stenosis, there may be little if any cerebrospinal fluid present, making the epidural space and central canal difficult to identify. A lumbar synovial cyst should also have high signal intensity because of the presence of synovial fluid.
(SBQ12SP.14) A 36-year-old male presents with acute onset of right buttock and leg pain following lifting a heavy object. On physical exam he has weakness to knee extension, numbness over the medial malleolus, and a decreased patellar reflex. Which of the following would most likely explain this clinical presentation.
Review
Topic
Lumbar arachnoiditis
L4/L5 paracentral disc herniation
L3/L4 far lateral (foraminal) disc herniation
L4/L5 far lateral (foraminal) disc herniation
L5/S1 far lateral (foraminal) disc herniation
The clinical presentation is consistent with a L4 radiculopathy. A L4/L5 far lateral (foraminal) disc herniation would compress the exiting root (L4) and cause these symptoms.
The location of a prolapsed lumbar disc determines its symptoms. Central disc herniations may give rise to back pain or cauda equina syndrome. Paracentral disc herniations (90-95% of cases) affect the traversing nerve root. Far lateral disc herniations (5-10%) affect the exiting nerve root.
Gregory et al. summarize physical signs in lumbar disc herniation. They state that the straight-leg-raise is the most sensitive (73-98% sensitive) test and the crossed straight-leg-raise is the most specific (88-98% specific) test for lumbar disc herniation. Other specific tests include weak ankle dorsiflexion (89% specific), absent ankle reflex (89% specific), and calf wasting (94% specific, but a late finding).
Illustration A shows how a paracentral L4/L5 disc herniation affects the traversing L5 root, but a far lateral L4/L5 disc herniation affects the L4 root. Illustration B shows the dermatomal distribution of pain with root involvement from L3 to S1.
Incorrect Answers:

Question 4:

During a retroperitoneal approach to the L4-5 disk, what structure must be ligated to safely mobilize the common iliac vessels toward the midline from laterally and gain exposure?

Options:

Obturator vein
Iliolumbar vein
External iliac vein
Middle sacral artery
Hypogastric artery

Correct Answer: Iliolumbar vein

Explanation:

DISCUSSION: To mobilize the common iliac vessels across the midline, the iliolumbar vein must be ligated. It has a short trunk and can be torn if mobilization is attempted without ligation. It is the only branch off the common iliacs (there are no arterial branches) prior to the terminal branches, the internal (hypogastric) and external iliacs. The middle sacral vessels run distally from the axilla of the bifurcation and are a factor when accessing the L5-S1 disk.
REFERENCES: Baker JK, Reardon PR, Reardon MJ, et al: Vascular injury in anterior lumbar surgery. Spine 1993;18:2227-2230.
Lewis WH: Gray’s Anatomy of the Human Body: The Veins of the Lower Extremity, Abdomen, and Pelvis, ed 20. Philadelphia, PA, Lea & Febiger, 2000.

Question 5:

A patient undergoing joint arthroplasty is put on a drug that competitively inhibits the activation of an enzyme that breaks down Factor Ia. The drug is

Options:

Dabigatran
Tranexamic acid
Rivaroxaban
Fondaparinux
Heparin

Correct Answer: Heparin

Explanation:

Question 6:

Options:

L5 pars repair.
L5 laminectomy alone.
L5 laminectomy and fusion.
stand-alone anterior lumbar interbody fusion.
L5-S1 total disk replacement.

Correct Answer: L5 laminectomy and fusion.

Explanation:

Question 7:

Which of the following factors is most closely associated with early postoperative migration of “stand-alone” lumbar interbody fusion cages?

Options:

Pseudarthrosis
Placement of the cage through a posterior approach
Placement of the cage laparoscopically through an anterior approach
Use of tapered rather than cylindrical cages
Use of BMP-2 rather than autograft in the cage

Correct Answer: Placement of the cage through a posterior approach

Explanation:

Question 8:

Which of the following factors has NOT been found to be a significant independent predictor of moderate or severe pain 6 months after musculoskeletal injury?

Options:

Failure to complete high school
Self-reported preinjury pain-related disability
Disability compensation
Male gender
Moderate or severe pain at discharge from the acute hospital

Correct Answer: Failure to complete high school

Explanation:

Question 9:

Options:

Physical therapy
Medical management
Radiation therapy
Prophylactic internal fixation
Wide resection

Correct Answer: Medical management

Explanation:

DISCUSSION: The radiograph demonstrates thickened trabeculae and thickened cortices in the left proximal femur compared to the right, and the bone scan shows increased uptake in this area. The MRI scans show thickened trabeculae with normal marrow signal. These findings are diagnostic of Paget’s disease. Medical treatment, including bisphosphonates and calcitonin, is indicated for painful bone lesions.
REFERENCES: Hadjipavlou AG, Gaitanis IN, Kontakis GM: Paget’s disease of the bone and its management. J Bone Joint Surg Br 2002;84:160-169.
Vaccaro AR (ed): Orthopaedic Knowledge Update 8. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 187-196.

Question 10:

Which factor is most important when attempting to prevent interbody graft subsidence?

Options:

End plate burring
Surface contact area
Bone quality
Use of rigid fixation

Correct Answer: Bone quality

Explanation:

Question 11:

Options:

lag screw cutout
osteonecrosis
osteoarthritis
peri-prosthetic fracture
lag screw breakage

Correct Answer: lag screw cutout

Explanation:

DISCUSSION: Baumgaertner et al in their classic study in 1995 determined that the position of the lag screw in the femoral head influenced the risk of cutout of a dynamic hip screw construct in treatment of intratrochanteric fractures. They had no cutouts if the tip-apex distance on the combined AP and lateral radiographs was less than 25 millimeters. Subsequent studies demonstrated a decreased cutout rate once people were aware of the tip-apex distance importance.
(SBQ07.16)
The anterolateral branch of the anterior circumflex artery supplies blood to what aspect of the proximal humerus?
Anterior portion of humeral head
Lesser tuberosity
Entire humeral head except posteroinferior portion of lesser tuberosity and head
Entire humeral head except posteroinferior portion of greater tuberosity and head
Entire humeral head except entire greater tuberosity
DISCUSSION: The anterolateral branch of the anterior circumflex artery, called the arcuate artery terminally, provides blood supply to the entire humeral head, lesser tuberosity and greater tuberosity except for a small posterior area. The posterior portion of the greater tuberosity and a small posteroinferior portion of the humeral head are supplied by the posterior circumflex artery. This was supported by a cadaveric study by Gerber et al who performed an anatomical study of the arteries of the humeral head to determine their intraosseous distributions. They injected a radiopaque suspension into the anterior circumflex, posterior circumflex, suprascapular, thoracoacromial, or subscapular artery and then analyzed the specimens macroscopically and radiographically. The humeral head was shown to have been perfused by the anterolateral ascending branch of the anterior circumflex artery in all specimens. The posterior circumflex artery vascularized only the posterior portion of the greater tuberosity and a small posteroinferior part of the head. Illustration A depicts the humeral head vascular supply with #2 being the posterior circumflex, #3 being the anterior circumflex arteries, and #4 being the anterolateral humeral circumflex artery.

Question 12:

Options:

Hip revision and implantation of a proximal femoral replacement
Hip revision and implantation of a tapered fluted stem
Open reduction and internal fixation with a locked plate and allograft struts
Erythrocyte sedimentation rate and C-reactive protein laboratory studies

Correct Answer: Erythrocyte sedimentation rate and C-reactive protein laboratory studies

Explanation:

DISCUSSION
Periprosthetic fractures are the third-most-common (behind loosening and infection) reason for revision surgery after total hip arthroplasty (THA). Late periprosthetic fracture risk is 0.4% to 1.1% after primary THA and 2.1% to 4% after revision THA. Risk factors for periprosthetic fracture include patient age older than 70 years, decreasing bone mass, and loosening of implants and osteolysis. Risk for concomitant infection in the presence of a periprosthetic fracture is 11%, according to Chevillotte and associates. Obtaining presurgical aspiration or tissue for culture intrasurgically is recommended if concomitant infection is suspected.
CLINICAL SITUATION FOR QUESTIONS 101 THROUGH 104
Figures 101a and 101b are the right hip radiographs of a 26-year-old active man who has had pain in his right hip for 4 months. His pain is worse with prolonged periods in a seated position. He has no pain at rest and denies pain in other joints or systemic illness. Examination reveals passive range of motion of full extension, 80 degrees of flexion, internal rotation in flexion of 0 degrees, and external rotation in flexion of 30 degrees. Forced flexion, internal rotation, and adduction are very painful. A flexion, abduction, and external rotation test result is negative.

Question 13:

Options:

Modern cement technique
Porous-coated stem
Nonporous press-fit stem
Hydroxyapatite-coated stem
Cerclage wire fixation

Correct Answer: Modern cement technique

Explanation:

Question 14:

Options:

Open inferior capsular shift
Arthroscopic thermal capsulorrhaphy
Sling at all times until the pain resolves
Arthroscopic anterior and posterior capsular plication
Physical therapy for rotator cuff and scapulothoracic strengthening

Correct Answer: Physical therapy for rotator cuff and scapulothoracic strengthening

Explanation:

Question 15:

What type of cementless femoral fixation results in the highest rate of distal femoral osteolysis?

Options:

Tapered circumferential proximally porous-coated stem
Hydroxyapatite-coated tapered circumferential proximally porous-coated stem
Straight circumferential fully porous-coated stem
Straight modular circumferential proximally porous-coated sleeve and distal fluted stem
Noncircumferential proximally porous-coated stem

Correct Answer: Noncircumferential proximally porous-coated stem

Explanation:

Question 16:

Options:

Posterior laminoplasty
Posterior cervical foraminotomy
Anterior cervical foraminotomy
Anterior cervical diskectomy and arthrodesis
Anterior corpectomy and arthrodesis

Correct Answer: Anterior cervical diskectomy and arthrodesis

Explanation:

Question 17:

The blood supply to the anterior cruciate ligament is primarily derived from what artery?

Options:

Anterior tibial artery
Superolateral geniculate
Middle geniculate
Inferolateral geniculate
Inferomedial geniculate

Correct Answer: Middle geniculate

Explanation:

Question 18:

A patient sustains a displaced scapular neck fracture. What is the internervous plane for a posterior approach to the glenohumeral joint?

Options:

lateral pectoral-axillary
subscapular-musculocutaneous
suprascapular-axillary
long thoracic-spinal accessory
suprascapular-subscapular

Correct Answer: lateral pectoral-axillary

Explanation:

CORRECT
DISCUSSION: Surgical fixation of a scapular neck fracture is performed via the Judet approach, a posterior approach to the scapula/glenoid. The internervous plane is between the infraspinatus (suprascapular nerve) and the teres minor (axillary nerve). As outlined by Ball et al, the posterior branch of the axillary nerve has intimate association with the inferior aspects of the glenoid and shoulder joint capsule, which may place it at particular risk during a posterior approach to the shoulder.

Question 19:

Options:

medial soft-tissue tightening.
medial soft-tissue tightening with lateral column lengthening.
medial soft-tissue tightening with talonavicular fusion.
medial displacement osteotomy with flexor digitorum longus transfer into the tarsal navicular.
triple arthrodesis with lateral column lengthening.

Correct Answer: medial soft-tissue tightening with lateral column lengthening.

Explanation:

Question 20:

Options:

Total knee arthroplasty with standard components
Correction of tibial deformity with osteotomy and nonsurgical management of the osteoarthritis
Arthrodesis with a long antegrade nail
Total knee arthroplasty with a constrained device

Correct Answer: Total knee arthroplasty with a constrained device

Explanation:

Question 21:

Options:

Inflammatory elbow arthritis
A presurgical flexion-extension elbow arc of approximately 50°
Retained distal humerus hardware on presurgical radiographs
Evidence of presurgical elbow instability End-stage posttraumatic or inflammatory elbow arthritis in active, high-demand patients remains difficult to treat. Traditional total elbow arthroplasty is discouraged in this demographic secondary to concerns about implant longevity. Soft-tissue interposition arthroplasty does not necessitate the same activity and weight restrictions for patients after surgery and remains a reasonable salvage procedure. Larson and Morrey published their findings on 38 patients with a mean age of 39 years following soft-tissue interposition arthroplasty for posttraumatic and inflammatory end-stage elbow arthritis. These investigators reported a significant improvement in Mayo Elbow Performance Score in addition to improvement in the flexion-extension arc from 51° to 97° after surgery. They reported worse results and elevated incidence of complications for patients with presurgical elbow instability. Retained hardware from prior surgery was not deemed a contraindication.

Correct Answer: A presurgical flexion-extension elbow arc of approximately 50°

Explanation:

Question 22:

A college football player performs bicep curls as part of his weight lifting routine. During the flexion phase of the curl, what term defines the type of muscle contraction?

Options:

Isometric
Isokinetic
Isotonic
Eccentric
Plyometric

Correct Answer: Plyometric

Explanation:

Question 23:

Options:

IV antibiotics
Oral antibiotics
Ibuprofen
Observation and repeat evaluation in 2 weeks
Aspiration of the right hip

Correct Answer: Aspiration of the right hip

Explanation:

Question 24:

Options:

Observation
Dynamic bracing
Manipulation under anesthesia
Revision with open adhesiolysis
Physical therapy with aggressive range of motion

Correct Answer: Revision with open adhesiolysis

Explanation:

Question.16 . When comparing the results of cemented all-polyethylene tibial components to metal-backed components,the all-polyethylene tibia
is more expensive.
is more susceptible to fracture.
is associated with an elevated risk for polyethylene wear.
has an equivalent rate of aseptic loosening.
has higher failure rates when used in patients younger than age 70.
Question. 17 . When the liquid monomer (monomethacrylate) is added to polymer powder (polymethylmethacrylate),the activator in the liquid monomer (N,N-Dimethyl-p-toluidine) comes in contact with the initiator in the polymer powder and polymerization is initiated. What is the initiator?
Hylamer
Polystyrene
Barium sulfate
Benzoyl peroxide
Zirconium dioxide
Question.18 . Figure 197 is the radiograph of a 62-year-old woman who is seen in the emergency department with a dislocated left total hip arthroplasty. This is her seventh dislocation during the last 3 months and she most recently had a liner revision. What is the best next treatment step?
Skeletal traction
Open reduction
Closed reduction
Component revision
Hip abduction orthosis

Question 25:

Reconstruction of the posterior cruciate ligament (PCL) via the inlay technique involves exposure of the PCL tibial insertion site by a posterior

Options:

lateral approach through the lateral gastrocnemius/biceps femoris interval.
approach using the medial sural cutaneous nerve to split the medial and lateral gastrocnemius interval.
medial approach between the medial gastrocnemius and semitendinosus muscles.
medial approach between the medial gastrocnemius and semimembranosus interval.
medial approach between the semimembranosus and semitendinosus interval.

Correct Answer: medial approach between the medial gastrocnemius and semimembranosus interval.

Explanation:

Question 26:

The preferred surgical approach to the elbow of a child with an irreducible type III supracondylar distal humerus fracture and pulseless extremity is through which of the following muscle intervals?

Options:

Pronator teres and the brachialis
Pronator teres and the triceps
Pronator teres and the biceps
Brachioradialis and the biceps
Brachioradialis and the brachialis

Correct Answer: Pronator teres and the brachialis

Explanation:

Question 27:

Options:

Open reduction and internal fixation (ORIF) of the fracture
Removal of the current stem, femur ORIF, and insertion of a longer revision stem
Femur ORIF with cables and strut graft, leaving the current stem in situ
Femur ORIF combined with reimplantation of the primary component

Correct Answer: Removal of the current stem, femur ORIF, and insertion of a longer revision stem

Explanation:

Question 28:

Compared to metal-on-polyethylene total hip bearing surfaces, the debris particles generated by metal-on-metal articulations are

Options:

larger and less numerous.
larger and more numerous.
smaller and less numerous.
smaller and more numerous.
not detectable.

Correct Answer: smaller and more numerous.

Explanation:

DISCUSSION: Retrieval studies have shown that the debris particles produced by
metal-on-metal articulations in total hip arthroplasty are several orders of magnitude smaller
and may be up to 100 times more numerous than those found with metal-on-polyethylene articulations.
REFERENCES: Davies AP, Willert HG, Campbell PA, et al: An unusual lymphocytic perivascular infiltration in tissues around contemporary metal-on-metal joint replacements.
J Bone Joint Surg Am 2005;87:18-27.
Firkins PJ, Tipper JL, Saadatzadeh MR, et al: Quantitative analysis of wear and wear debris from metal-on-metal hip prostheses tested in a physiological hip joint simulator. Biomed Mater Eng 2001;11:143-157.

Question 29:

Each of the following are guidelines for management of a domestic violence victim EXCEPT:

Options:

Socioeconomic status should not preclude evaluation for domestic violence
Interview the patient outside the presence of others
Federal law mandates photographs be taken of injuries (regardless of patient’s consent)
Document your opinion if the patient’s injuries are not consistent with the offered explanation
Physicians should check requirements to see if there is mandatory reporting statute in their state

Correct Answer: Socioeconomic status should not preclude evaluation for domestic violence

Explanation:

Question 30:

Options:

Analysis of variance (ANOVA)
Regression analysis
Student t test
Mann-Whitney U test

Correct Answer: Mann-Whitney U test

Explanation:

Question 31:

Options:

bilateral shoe orthotics to support the medial foot arch.
a very small dose of lidocaine and cortisone injected into the area of pain to assist in diagnosis and treatment.
early lateral retinaculum release with medial soft-tissue tightening.
ice, rest, avoidance of the offending activity, and rehabilitation.
no sports participation for a minimum of 6 weeks.

Correct Answer: ice, rest, avoidance of the offending activity, and rehabilitation.

Explanation:

Question 32:

Options:

hip and knee extension
hip flexion to 90, knee extension
hip internal rotation, knee flexion to 90
hip and knee flexion to 90
hip extension, knee flexion to 90

Correct Answer: hip and knee extension

Explanation:

Question 33:

Options:

a three-phase bone scan.
CT.
MRI.
a repeat examination in 6 weeks.
a biopsy.

Correct Answer: a repeat examination in 6 weeks.

Explanation:

Question 34:

Which of the following prognostic indicators is associated with the least favorable outcome for patients newly diagnosed with osteosarcoma?

Options:

High histologic grade
Tumor size greater than 8 cm
Extracompartmental growth
Solitary pulmonary metastasis
Solitary bone metastasis

Correct Answer: Solitary bone metastasis

Explanation:

DISCUSSION: Distant bone metastasis is associated with an extremely poor prognosis for patients with osteosarcoma (5-year survival rate of less than 10%). Most osteosarcomas are high grade and extracompartmental, and approximately half are greater than 8 cm at presentation. The 5-year survival rate for these patients is approximately 70%. Patients with a solitary pulmonary metastasis have a prognosis worse than patients without detectable metastases but not as bad as those with bone metastases.
REFERENCES: Bielack SS, Kempf-Bielack B, Delling G, et al: Prognostic factors in high-grade osteosarcoma of the extremities or trunk: An analysis of 1,702 patients treated on neoadjuvant cooperative osteosarcoma study group protocols. J Clin Oncol 2002;20:776-790.
Heck RK, Stacy GS, Flaherty MJ, et al: A comparison study of staging systems for bone sarcomas. Clin Orthop Relat Res 2003;415:64-71.
Kager L, Zoubeck A, Potschger U, et al: Primary metastatic osteosarcoma: Presentation and outcome of patients treated on neoadjuvant Cooperative Osteosarcoma Study Group protocols.
J Clin Oncol 2003;21:2011-2018.

Question 35:

Options:

Trapezoid ligament
Conoid ligament
Acromioclavicular ligament
Deltoid muscle origin
Trapezius muscle insertion

Correct Answer: Trapezius muscle insertion

Explanation:

Question 36:

Options:

Bisphosphonates
Calcitonin
Parathyroid hormone
Vitamin D and calcium
Methotrexate

Correct Answer: Bisphosphonates

Explanation:

Question 37:

Options:

Anterior cruciate
Posterior cruciate
Medial collateral
Lateral collateral
Patellar tendon/ligament

Correct Answer: Posterior cruciate

Explanation:

Question 38:

Options:

anterior reduction, stabilization, and fusion at L1-2.
anterior reduction, stabilization, and fusion at T12-L3.
posterior reduction, stabilization, and fusion at L1-2.
posterior reduction, stabilization, and fusion at T12-L4.

Correct Answer: posterior reduction, stabilization, and fusion at T12-L4.

Explanation:

DISCUSSION
The figures reveal a fracture-dislocation at L1-2. Proper treatment consists of posterior reduction, stabilization, and fusion 2 levels above and below the level of injury. Short-segment stabilization schemes do not stabilize the injury properly, and longer-segment constructs are not necessary. Anterior treatment is not indicated in fracture-dislocations.
RECOMMENDED READINGS
Mikles MR, Stchur RP, Graziano GP. Posterior instrumentation for thoracolumbar fractures. J Am Acad Orthop Surg. 2004 Nov-Dec;12(6):424-35. Review. PubMed PMID: 15615508.
View
Abstract at PubMed
Bono CM, Rinaldi MD. Thoracolumbar trauma. In: Spivak JM, Connolly PJ, eds. Orthopaedic Knowledge Update: Spine 3. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2006:201-216.

Question 39:

Options:

CT scan
Hybrid external fixation
Ankle-spanning external fixation
Open reduction and internal fixation within 6 to 8 hours
Open reduction and internal fixation within 2 to 3 days

Correct Answer: Ankle-spanning external fixation

Explanation:

Question 40:

Antegrade femoral nailing has an increased rate of which of the following when compared to retrograde femoral nailing?

Options:

Varus malalignment
Union rate
Operative time
Subsequent operative procedures
Hip pain

Correct Answer: Varus malalignment

Explanation:

Question 41:

Options:

open release of the posterior capsule.
arthroscopic release of the rotator cuff interval.
arthroscopic release of the anteroinferior capsule.
open subscapularis lengthening.
open extra-articular release.

Correct Answer: arthroscopic release of the rotator cuff interval.

Explanation:

Question 42:

Options:

Clear cell sarcoma
Clear cell carcinoma
Epidermal inclusion cyst
Nora’s tumor (BPOP)
Epithelioid sarcoma

Correct Answer: Epithelioid sarcoma

Explanation:

DISCUSSION: Epithelioid sarcoma is the most common soft-tissue sarcoma in the hand and most commonly occurs in young adults. The tumors can be superficial and may become ulcerated. Deeper lesions are often attached to tendons, tendon sheaths, or fascial structures. These are usually minimally symptomatic. The biopsy specimen reveals the typical appearance of a nodular pattern with central necrosis. They can mimic a necrotizing granulomatous process. Usually there are chronic inflammatory cells along the margin of the tumor nodules. This biopsy specimen does not have the clear cells necessary for a clear cell carcinoma or sarcoma. Nora’s tumor is a bizarre parosteal osteochondromatous proliferation (BPOP) first described in 1983 by the pathologist, Nora. The lesion is defined as a reactive heterotopic ossification and is mostly found in the hands or feet of adults in the third decade of life.
REFERENCES: Enzinger FM, Weiss SW: Soft Tissue Tumors, ed 3. St Louis, MO, Mosby, 1995, p 1074.
Halling AC, Wollan PC, Pritchard DJ, et al: Epithelioid sarcoma: A clinicopathologic review of 55 cases. Mayo Clin Proc 1996;71:636-642.

Question 43:

Options:

Delay further surgical intervention until his ESR and CRP level normalize
Delay further surgical intervention until his ESR normalizes
Delay further surgical intervention until his CRP level normalizes
Proceed with surgical intervention if the patient’s condition is medically optimized

Correct Answer: Proceed with surgical intervention if the patient’s condition is medically optimized

Explanation:

Question 44:

Figure 36 shows the AP pelvic radiograph of a 26-month-old boy who has a limp. He has no significant medical history and no pain. What is the most appropriate treatment plan? Review Topic

Options:

Physical therapy
Application of a Pavlik harness
Arthrogram and closed reduction with spica casting under anesthesia
Femoral lengthening with a unilateral fixator
Open reduction with femoral shortening, capsulorrhaphy, and a spica cast

Correct Answer: Open reduction with femoral shortening, capsulorrhaphy, and a spica cast

Explanation:

The radiograph reveals a complete hip dislocation. A Pavlik harness is an accepted method of treatment for a dislocated hip up until 6 months of age. Closed reduction and spica casting with an arthrogram is often successful in young children up to 1-1/2 years to 2 years of age. Open reduction, capsulorrhaphy, and a spica cast is commonly recommended for younger children when attempts at closed reduction have failed or when the child is older than 2 years of age. A femoral shortening is also generally recommended in children older than 2 years of age in an attempt to reduce the muscle/compressive forces on the reduced hip.
(SBQ13PE.38) Pavlik harness treatment is appropriate for which of the following?:
Review Topic
4 year old with a diaphyseal femur fracture and a neuromuscular disorder with lower extremity spasticity
2 month old with a displaced spiral mid-diaphyseal femur fracture
9 month old with a diaphyseal femur fracture with <2cm shortening
9 month old with a diaphyseal femur fracture with >2cm shortening
4 year old with a diaphyseal femur fracture, closed head injury and chest trauma
Treatment with Pavlik harness or spica cast are options for patients <6 months of age with diaphyseal femur fractures. Pavlik harness provides adequate pain control for the short time required for healing in this age group. Significant remodeling potential can be expected.
Because of the significant remodeling and quick healing, treatment of diaphyseal femur fractures in children younger than 6 months focuses on providing comfort and avoiding complications. Spica casting likewise results in stable union without longterm sequelae but minor skin complications are more common and some favor Pavlik treatment in this age group.
Kocher et al. provide the AAOS Clinical Practice Guideline for the treatment of pediatric diaphyseal femur fractures. Their recommendation for diaphyseal femur fractures in children less than 6 months is Grade C, based on Level IV evidence (one retrospective comparative study and one case series). They recommend that Pavlik and spica casting are both acceptable treatment options in this age group.
Flynn et al. review the management of pediatric femoral shaft fractures. They recommend Pavlik treatment for children 6 months of age or less in preference to a spica cast, sometimes supplemented with a simple splint. This avoids the skin complications of spica casting.
Incorrect answers:

Question 45:

Options:

Inappropriately early return to play
Improper rehabilitation and conditioning
Unstable meniscal tear
Malpositioned tunnel
Inadequate graft sizing

Correct Answer: Inappropriately early return to play

Explanation:

Question 46:

Options:

chemotherapy and surgery
chemotherapy only
surgery only
radiation and surgery
radiation only

Correct Answer: chemotherapy only

Explanation:

The histology shows "lacey" osteoid with minimal cellular atypia. This is consistent with low-grade intramedullary osteogenic sarcoma. Low grade central osteogenic sarcoma is an uncommon form of osteosarcoma that is characterized by a long premorbid history and is compatible with prolonged survival after treatment. Treatment is surgery with wide margins alone and chemotherapy and radiation are not indicated. Good local control is associated with an excellent long term survival.
Choong et al. reviewed the long term follow-up of 20 patients diagnosed with low grade osteogenic sarcoma and found the 5 year survival rate was 90% and at 10 years was 85%. Local recurrence is a key feature in most cases and is typically the result of inadequate surgical margins frequently arising from initial misdiagnosis. Although amputation generally is successful for primary and recurrent tumors, limb salvage surgery is a definite option.
Kurt et al reviewed 80 well-differentiated osteosarcomas. They found local excision was almost always associated with recurrence. Wide excision was
almost never followed by recurrence. The recurrent tumor was a high-grade, conventional osteosarcoma in 15% of the patients, and this was associated with a poor prognosis. They recommend wide excision as the treatment of choice for this very rare variant of osteosarcoma.
A 32-year-old male sustains a the injury shown in Figure A after a high-speed motor vehicle collision. Which factor has been found to have the highest direct correlation with severe heterotopic ossification after traumatic knee dislocation?
Injury Severity Score (ISS )
Glascow Coma Scale (GCS )
Timing of knee reconstruction
Number of ligaments reconstructed
Open ligament reconstruction
Figure A shows a knee dislocation with cruciate ligament avulsion injuries. Development of significant heterotopic ossification (HO) formation has been shown to be most directly correlated to the ISS score.
Mills and Tejwani looked at multiple variables including injury severity score
( ISS), Glascow coma scale (GCS), closed head injury (CHI), timing of surgery (> or < 3 weeks) and type of surgery (open vs. arthroscopic, number of ligaments reconstructed) in its relation to the formation of HO following knee dislocation. In the final group the sensitivity and specificity of the ISS in relation to HO formation was 100%, while presence of CHI had a specificity of 97 %. Timing, type of surgery and approach did not influence HO formation.
A 52-year-old male presents with 6 months of swelling and pain in his leg. He states the lesion has not changed in size for several months and doesn't bother him. He is otherwise healthy and has no other complaints. Representative photograph and MRI are shown in Figures A through C. What is the best initial step in his management?
Follow-up in 6 months with repeat radiographs
Biopsy
Marginal excision
Radiation therapy
Neoadjuvant chemotherapy and wide excision
The initial step in management of a patient presenting with a large soft tissue mass deep to the fascia is to obtain a tissue diagnosis, via biopsy. Initiation of treatment prior to tissue diagnosis is inappropriate and can result in significant patient morbidity and potential mortality. While some soft tissue sarcomas may benefit from chemotherapy, this cannot be initiated prior to diagnosis.
Radiation therapy is used in the treatment of soft tissue sarcoma, but again, only after tissue diagnosis. Peabody et al review the appropriate evaluation and staging for musculoskeletal neoplasms and present flow-charts useful in the work-up of bone (Illustration A) and soft tissue (Illustration B) neoplasms. Skrzynski et al performed a comparison of outpatient core-needle biopsy with open surgical biopsy for musculoskeletal tumors. They found the diagnostic accuracy of core-needle biopsy was only 84% with many samples yielding no or different histological samples when compared to final resected specimens. They conclude that while core-needle biopsy is significantly less expensive
than surgical biopsy ($1106 vs. $7234), there is higher concern for sampling error or general diagnostic inaccuracy associated with a core-needle biopsy compared to open biopsy, the "gold standard".
What is the appropriate treatment for a 10-year-old boy with Ewing's sarcoma isolated to the proximal femur?
Neoadjuvant chemotherapy and surgical excision
Neoadjuvant chemotherapy, surgical excision, and radiation therapy
Neoadjuvant chemotherapy, surgical excision, and adjuvant chemotherapy
Neoadjuvant radiation therapy and surgical excision
Surgical excision and hormonal therapy
Ewing's sarcoma is a malignant small round blue cell neoplasm which has a predilection for long tubular bones, pelvis, and ribs. The radiographic appearance of "onion-skinning" seen in illustrations A and B is due to the body's periosteal reaction. Illustration C shows the large soft tissue extraosseous mass characteristic for Ewing's sarcoma. Finally, Illustration D shows the histology where the multiple small round blue neoplastic cells are seen.
Ewing's sarcoma is most commonly treated with neoadjuvant chemotherapy, surgical excision, and adjuvant chemotherapy - in particular for tumors located in bones which can be easily resected and reconstructed. For large tumors in areas which either cannot be completely excised or where excision is associated with significant morbidity, some centers consider chemotherapy and radiation therapy without surgical excision. There is a current trend towards surgical resection and away from irradiation for Ewing's sarcoma even though it is radiosensitive, because of the risk of secondary malignancy and growth disturbance due to radiation.
Pierz et al review many of the common bone tumors including Ewing's sarcoma and discuss the relevant diagnostic factors as well as specific treatment protocols for each tumor.
A 30-year-old female presents with a painful posterior knee mass. The mass gets larger and more painful with activity. Examination reveals a boggy soft tissue mass about her knee. Radiograph and MRI are shown in Figures A and B. What is the most likely diagnosis?
Synovial sarcoma
Hemangioma
Lipoma
Parosteal osteosarcoma
Pigmented villonodular synovitis (PVNS )
This patients history, physical exam, and imaging studies are suggestive of a hemangioma. Pain in hemangiomas is thought to occur due to vascular engorgement secondary to activity and increased blood flow to the lesion. The calcification on the plain radiograph and the fat of the T1 MRI are diagnostic for hemangioma. Current treatment for symptomatic hemangiomas includes some combination of sclerotherapy or vascular coiling, with surgical excision
reserved for few cases. The two attached reviews by Gilbert et al and Damron et al review the history, diagnosis, treatment, and controversial issues in soft tissue sarcomas and benign sarcoma like conditions such as hemangiomas.
Current treatment for soft tissue sarcomas includes radiotherapy and surgical excision. While many centers in the world use chemotherapy for soft tissue sarcomas, the data supporting its use is quite limited and likely too controversial to be tested. With regard to the other answer choices, synovial sarcoma and lipoma can show calcification on radiographs, but they are usually not painful and image differently on T1 MRI. Parosteal osteosarcoma typically occurs in this location (posterior distal femur) but occurs as a lesion stuck on the bone. PVNS can have a similar appearance on imaging, but doesn't cause this type of pain.

Question 47:

Options:

activity modification
arthroscopic evaluation of fragment stability.
transarticular drilling of the lesion with 0.045 Kirschner wire.
arthroscopic excision of the fragment and microfracture of underlying cancellous bone.
excision of the fragment and mosaicplasty.

Correct Answer: activity modification

Explanation:

This skeletally immature patient has a small OCD lesion that appears stable, and he has not undergone any treatment. Therefore, a trial of activity modification and limited weight bearing until pain resolves is the best initial choice.
Cessation of sport activities for 4 to 6 months may allow healing of the lesion. Surgical treatment of juvenile OCD lesions is reserved for unstable lesions, patients
who have not shown radiographic evidence of healing and are still symptomatic after
6 months of nonsurgical management, or patients who are approaching skeletal maturity. Good results with stable in situ lesions that have failed to respond to nonsurgical management have been reported with both transarticular and retroarticular drilling. Results after excision alone are poor at 5-year follow-up, and it is unclear if microfracture will improve the long-term outcome. Mosaicplasty may be the next best option for patients who remain or become symptomatic after excision of the fragment and microfracture.
Wall et al. reviewed juvenile OCD. They state that JOCD has better potential for healing than adult OCD, but several series have shown up to a 50% failure to heal with nonsurgical techniques. The presence of a loose body is an indication for surgical fixation, drilling or regenerative procedures, depending on the presence/extent of subchondral bone sclerosis and the surgeon's experience.
Figure A and B are coronal MRI images showing a stable appearing JOCD lesion of the medial femoral condyle.
Incorrect
in the first
(SBQ13PE.9) A 6-year-old boy complains of a 'clunking' sensation in his left knee. He has no associated pain and denies trauma. He can elicit the sensation when moving his knee from flexion into full extension. He is otherwise healthy, with no birth or developmental issues. On examination, there is a palpable clunk felt over the anterior knee through range of motion. There is no obvious instability or tenderness and he had normal patellar tracking. An AP radiograph of the knee is shown in Figure A. What would be the most likely diagnosis?
Review
Topic
Agenesis of the anterior cruciate ligament
Thickened medial plica
Grade IV chondral flap
Pigmented villonodular synovitis
Abnormal meniscal morphology
This child presents with an asymptomatic click in the knee. It is associated with widening of the lateral joint space of the knee on X-ray. These features are highly suggestive of a discoid lateral meniscus in this age category.
The principal diagnostic feature of a discoid meniscus is the complaint of snapping or clicking in the knee. Children are usually asymptomatic. Although, less frequently, children may present with pain that is largely secondary to an underlying meniscal tear. MRI scans of the knee have show to have the greatest sensitivity for identifying discoid menisci. The presence of a contiguous central meniscus on three consecutive slices is usually indicative of the diagnosis. Treatment is mostly focused on conservative modalities. Surgical intervention is reserved for symptomatic cases with recurrent locking, swelling or persistent pain is present in older children.
Kramer et al. looked at the presentation of pediatric knee pain. They showed that the lateral meniscus is more commonly affected than the medial meniscus. The majority of discoid tears occur in the posterior or middle aspect of the discoid meniscus.
Figure A shows an AP radiograph of a pediatric knee. There is an increased lateral joint space suggestive of a discoid meniscus.
Illustrations A-C show an MRI of the knee with 3 consecutive coronal cuts showing an abnormal appearing discoid meniscus.
Incorrect Answers:

Question 48:

An 18-year-old man has had an enlarging mass in his hand for the past 3 months. Radiographs, an MRI scan, and biopsy specimens are shown in Figures 54a through 54d. What is the most likely diagnosis?

Options:

Bizarre parosteal osteochondromatous proliferation (BPOP)
Osteosarcoma
Ewing’s sarcoma
Enchondroma
Infection

Correct Answer: Bizarre parosteal osteochondromatous proliferation (BPOP)

Explanation:

Question 49:

- A 25 year-old amateur baseball player sustained a dorsal fracture-dislocation of the proximal interphalangeal joint of his long finger. He underwent closed reduction 3 hours ago. Examination reveals mild laxity of the radial collateral fragment involving 30% of the volar articular surface of the middle phalanx. Management should now include

Options:

open reduction and internal fixation
buddy taping to the adjacent index finger
early motion with application of a dynamic banjo splint
application of a cast with the hand in a “safe position” for 3 weeks.
dorsal extension block splinting

Correct Answer: dorsal extension block splinting

Explanation:

Question 50:

Which of the following types of intra-articular pathology is associated with lateral meniscal cysts? Review Topic

Options:

Discoid meniscus
Posterolateral corner injury
Vertical meniscal tears
Middle third lateral meniscal tears
Popliteus tendon tears

Correct Answer: Middle third lateral meniscal tears

Explanation:

Question 51:

At a minimum 2-year follow-up and compared with the metacarpophalangeal (MCP) joint, pyrolytic carbon resurfacing arthroplasties of the proximal interphalangeal (PIP) joint

Options:

produce less squeaking or clicking.
result in more dislocations.
provide superior pain relief.
result in better motion compared with the preoperative status.

Correct Answer: result in more dislocations.

Explanation:

EXPLANATION:
Wall and Stern published a report on MCP joint pyrolytic carbon arthroplasty for osteoarthritis and another on PIP joint pyrolytic carbon resurfacing arthroplasty for osteoarthritis. They found different outcomes, and MCP joint implants outperformed PIP joint implants. Of eleven MCP joint arthroplasties, two produced asymptomatic squeaking and clicking, whereas eleven of 31 PIP joint implants produced this problem. No dislocations were reported among the MCP joint implants, but five PIP joint dislocations were observed. Outcomes were measured by the Michigan Hand Outcomes Questionnaire in both studies and were satisfactory for the MCP joint implants, with an average score of 80. The PIP implants did not fare as well, showing a higher degree of pain along with an average score of 53. The authors noted that, in the 15 patients in the PIP study who had unilateral surgery, the uninvolved, nonsurgical hand motion was actually statistically significantly (
P
<0.01) better than the surgical hand. MCP joint motion increased from 62º before surgery to 76º after surgery, whereas PIP joint motion got worse after surgery, with the average motion decreasing from 57º to 31º.

Question 52:

Options:

t(11;22).
t(2;13).
t(X;18).
t(12;16). DISCUSSION… The imaging shows a soft-tissue mass with histology showing a synovial sarcoma. This histology is associated with t(X;18). Ewing sarcoma is associated with t(11;22); alveolar rhabdomyosarcoma t(2;13); and myxoid liposarcoma t(12;16). Although the presented monophasic histology could be consistent with other sarcomas, it does not have the characteristics of Ewing sarcoma (small round blue cells), alveolar rhabdomysarcoma (alveolar pattern), or myxoid liposarcoma (myxoid stroma and signet ring lipoblasts with a plexiform capillary network).

Correct Answer: t(X;18).

Explanation:

Question 53:

The relocation test is most reliable for diagnosing anterior subluxation of the glenohumeral joint when

Options:

posterior pressure placed on the humeral head results in increased pain.
external rotation with the arm in 90 degrees of abduction produces apprehension that is relieved by posterior pressure on the humeral head.
external rotation with the arm in 90 degrees of abduction produces pain that is relieved by posterior pressure on the humeral head.
external rotation with the arm in 90 degrees of abduction produces no symptoms, but posterior pressure on the humeral head produces pain and apprehension.
external rotation with the arm in 90 degrees of abduction produces no symptoms, but posterior pressure on the humeral head produces apprehension.

Correct Answer: external rotation with the arm in 90 degrees of abduction produces apprehension that is relieved by posterior pressure on the humeral head.

Explanation:

Question 54:

Which of the following findings is a prerequisite for a high tibial valgus osteotomy for medial compartment gonarthrosis?

Options:

Inflammatory arthritis
Ligamentous instability
Lateral tibial subluxation
Preoperative arc of motion of at least 90 degrees
Narrowing of the lateral compartment cartilaginous joint space

Correct Answer: Preoperative arc of motion of at least 90 degrees

Explanation:

Question 55:

Options:

Further imaging studies, including MRI
An awake closed reduction with Gardner-Wells traction with neurologic examination
Immobilization in a halo skeletal fixation for definitive treatment
Closed reduction under general anesthesia
Immediate open reduction and internal fixation in the surgical suite

Correct Answer: An awake closed reduction with Gardner-Wells traction with neurologic examination

Explanation:

DISCUSSION: In the patient who is neurologically intact or has an incomplete injury from a cervical facet dislocation, a closed reduction with weighted tong traction is appropriate when the patient is awake, alert, and cooperative. Although there is a risk that a cervical facet dislocation could occur with an underlying cervical disk herniation, Vaccaro and associates have shown that closed reduction can be safely carried out in the awake, responsive patient. Closed reduction can be performed in the emergency department with traction with skull tongs or a halo ring. A slow stepwise application of weight is added until a reduction is achieved. Any worsening of the neurologic status of the patient requires immediate termination of the closed reduction and further diagnostic imaging before proceeding with further treatment.
REFERENCES: Vaccaro AR, Falatyn SP, Flanders AE, et al: Magnetic resonance evaluation of the intervertebral disc, spinal ligaments, and spinal cord before and after closed traction reduction of cervical spine dislocations. Spine 1999;24:1210-1217.
Hart RA: Cervical facet dislocation: When is magnetic resonance imaging indicated? Spine 2002;27:116-117.
Cotler JM, Herbison GJ, Nasuti JF, et al: Closed reduction of traumatic cervical spine dislocation using traction weights up to 140 pounds. Spine 1993;18:386-390.

Question 56:

An operating room intervention that should be undertaken by anesthesia staff during the cementing of a femoral stem is to

Options:

decrease the fraction of inspired oxygen (FiO2).
decrease the intravenous (IV) fluid rate.
have phenylephrine on standby.
redose epidural anesthesia.

Correct Answer: have phenylephrine on standby.

Explanation:

Question 57:

What is the most common cause of errors that harm patients? Review Topic

Options:

Communication breakdown
Equipment breakdown
Nursing competence
Patient noncompliance
Physician competence

Correct Answer: Communication breakdown

Explanation:

Question 58:

Options:

Balanced traction to address concern for persistent infection with reoperation
Open reduction and internal fixation of the fracture with a lateral plate and screws
Removal of the articulating spacer and revision to a longer-stem antibiotic-loaded articulating spacer
Removal of the articulating spacer and reimplantation using a long-stem fluted uncemented hip replacement

Correct Answer: Open reduction and internal fixation of the fracture with a lateral plate and screws

Explanation:

Question 59:

The sartorius muscle is innervated by which of the following nerves?

Options:

Femoral
Obturator
Superior gluteal
Inferior gluteal
Ilioinguinal

Correct Answer: Femoral

Explanation:

Question 60:

Options:

Patient compliance
Cost
Greater rotational control
Greater flexion and extension control
Less force on the lumbosacral junction

Correct Answer: Greater rotational control

Explanation:

Question 61:

The patient returns 1 year later to report curling of her toes and numbness on the plantar surface of her foot. What is the most likely cause of this condition?

Options:

CRPS
Plantar fasciitis
Plantar fibromatosis
Subclinical compartment syndrome

Correct Answer: Subclinical compartment syndrome

Explanation:

DISCUSSION
Radiographs reveal a Lisfranc fracture dislocation with fractures of the first and second metatarsals. Tenting of skin that is over a bony prominence is an orthopaedic emergency. The fracture dislocation should be reduced without delay. There is no evidence of compartment syndrome of the foot, but this may develop and monitoring is necessary. Toe deformity may develop on a delayed basis because of the subclinical presentation. Nerve irritation is not uncommon with dorsal midfoot surgical incisions. A positive Tinel test result over the midfoot in the distribution of the superficial common peroneal nerve is consistent with a stretch injury to this nerve. CRPS is usually associated with multiple nerve distributions and autonomic nerve findings such as cold hypersensitivity and hyperhidrosis.
RECOMMENDED READINGS
Benirschke SK, Meinberg EG, Anderson SA, Jones CB, Cole PA. Fractures and dislocations of the midfoot: Lisfranc and Chopart injuries. Instr Course Lect. 2013;62:79-91. PubMed PMID: 23395016.
View Abstract at PubMed
Schepers T, Oprel PP, Van Lieshout EM. Influence of approach and implant on reduction accuracy and stability in lisfranc fracture-dislocation at the tarsometatarsal joint. Foot Ankle Int. 2013 May;34(5):705-10. doi: 10.1177/1071100712468581. Epub 2013 Jan 14. PubMed
PMID: 23637239.
View Abstract at PubMed

Question 62:

When compared with a patient who has a subluxated hip, a patient with a dislocated hip who is undergoing acetabular reconstruction for developmental dysplasia of the hip will most likely have

Options:

an increased need for revision.
a greater limb-length discrepancy.
a decreased rate of postoperative instability.
a decreased rate of wear.
a decreased rate of peroneal nerve palsy.

Correct Answer: an increased need for revision.

Explanation:

Question 63:

Options:

Open biopsy
Incision and debridement
Decompression
Decompression and instrumented fusion
Decompression and uninstrumented fusion

Correct Answer: Decompression and instrumented fusion

Question 64:

A 53-year-old man has a 4- x 5-cm high-grade soft-tissue sarcoma in the midthigh. As part of the staging evaluation, regional nodes should be assessed by

Options:

CT of the pelvis and groin.
sentinal node biopsy.
clinical examination.
fine needle aspiration.
prophylactic inguinal node dissection.

Correct Answer: clinical examination.

Explanation:

Question 65:

Increased hip intracapusular pressures can lead to diminished femoral head perfusion. What leg position has been shown to create the lowest intracapsular hip pressures after femoral neck fracture?

Options:

flexion and internal rotation
extension and external rotation
flexion, abduction, and external rotation
extension, adduction, and internal rotation
there are no differences in hip pressures with any position

Correct Answer: flexion and internal rotation

Explanation:

Question 66:

Options:

Type I acromion
Type III acromion
Meso os acromiale
Meta os acromiale
Pre os acromiale

Correct Answer: Meso os acromiale

Explanation:

DISCUSSION: The MRI scans reveal a meso os acromiale with edema at the site in a skeletally mature patient.
REFERENCES: Sher JS: Anatomy, biomechanics, and pathophysiology of rotator cuff disease, in Iannotti JP, Williams GR (eds): Disorders of the Shoulder: Diagnosis and Management. Philadelphia, PA, Lippincott Williams & Wilkins, 1999, p 23.
Sammarco VJ: Os acromiale: Frequency, anatomy, and clinical implications. J Bone Joint Surg Am 2000;82:394-400.

Question 67:

Options:

A Vancouver type B1 fracture
Residual leg-length discrepancy
Loosening and subsidence of the femoral stem into anteversion
Loosening and subsidence of the femoral stem into retroversion

Correct Answer: Loosening and subsidence of the femoral stem into retroversion

Explanation:

Question 68:

Options:

wrist x-ray not initially obtained
x-ray obtained, but MRI necessary for diagnosis not obtained
forearm x-ray initially obtained did not show fracture
CT initially performed, but no 3-D images reconstructed
wrist x-ray initially obtained did not show fracture

Correct Answer: wrist x-ray not initially obtained

Explanation:

Question 69:

Options:

Knee manipulation under anesthesia
Cast immobilization and use of a bone stimulator
Unilateral external fixation
Intramedullary nailing
Compression plating

Correct Answer: Knee manipulation under anesthesia

Explanation:

Question 70:

Options:

Removal of all components with antibiotic spacer placement and staged revision
One-stage irrigation and debridement with removal of components to a cementless prosthesis
Empiric oral antibiotics for 4 weeks and steri-strips over the area of drainage
Surgical exploration with debridement and possible polyethylene exchange
Bone scan and repeat aspiration with empiric intravenous antibiotics for 4 weeks

Correct Answer: Removal of all components with antibiotic spacer placement and staged revision

Explanation:

Irrigation and débridement with possible polyethylene exchange is the most appropriate treatment for persistent drainage within a few weeks from total joint arthroplasty surgery.
Malinzak et al performed a Level 4 review of 8494 patients undergoing a total knee arthroplasty. They found that patients with a body mass index greater
than 50 had an increased odds ratio of infection of 21.3 (P < .0001). Diabetic patients were 3 times as likely to become infected compared to nondiabetic patients (P = .0027).
Rasul et al performed a Level 4 review of 24 patients for a duration of 2 years with total knee arthroplasty infections. They found that patients with chronic (>1 month) deep infections were successfully treated 75% with debridement, intravenous antibiotics, tobramycin-impregnated polymethylmethacrylate beads, and delayed exchange arthroplasty with mean interval of staged reimplantation being 8 weeks.
OrthoCash 2020
A 47-year-old man presents with 1 week of left leg pain. 6 months prior he underwent a vascularized free-fibula bone graft from his left leg to his right hip for avascular necrosis. The pain is located at the level of his donor site and is worse with weight-bearing and relieved by rest. Physical exam shows focal tenderness over his tibia. A lateral radiograph from the day of presentation is shown in Figure A. WBC, ESR, and CRP are all within normal limits. What is the next best step in management to confirm the diagnosis?
Compartment pressure measurements
CT scan
MRI scan
Ultrasound to rule out deep abscess
Bone biopsy
The clinical presentation is suspicious for a stress fracture of the tibia following free-fibula bone grafting. If plain radiographs are negative, more sensitive imaging such as a MRI or bone scan should be performed.
Tibial stress fractures are a known complication following free-fibula bone grafting. Radiographs may be normal (as is the case in figure A), or might show the "dreaded black line" and/or new periosteal bone formation. If a stress fracture is confirmed with imaging, appropriate management would then consist of protective weight bearing until symptoms subside.
Pacifico et al detail a case report of tibial stress fractures after vascularised free-fibula graft to the mandible. They report non-traumatic stress fracture to the tibia following a vascularised free-fibula graft is an uncommon but important complication.
Ivey et al detail a case report of a tibial stress fracture after vascularised free-fibula graft for repair of non-union of the humerus.
Emery et al report a case-series of 5 patients who sustained tibial stress fractures after a graft had been obtained from the ipsilateral fibula for use in anterior reconstruction of the spine. They theorize that the increased load the tibia bears as a result of the missing fibular graft may result in stress fractures.
Illustration A shows new periosteal bone formation on the lateral cortex of the tibia consistent with a stress fracture.
Incorrect Answer Choices:
1: While compartment syndrome is on the differential diagnosis, his signs and symptoms are not most consistent with that diagnosis.
2: While CT scan may show evidence of a stress fracture, MRI/bone scans have been shown to be superior methods for detection.
4: As infectious laboratories are normal, an ultrasound to rule out a deep abscess would likely be negative.
5: Bone biopsy is not appropriate without evidence of a lesion or concern for
osteomyelitis.
OrthoCash 2020
A 65-year-old female with a history of developmental dysplasia of the hip (DDH) undergoes a total hip arthroplasty (THA) utlizing a posterior approach. Following THA, she notices an inability to dorsiflex the ankle of her operative extremity. Her pre-operative and postoperative radiographs are seen in figues A and B. Which of the following intra-operative techniques could have avoided this complication in this patient?
Utilization of an anterior approach
Modular components
Use of a larger femoral head
Femoral shortening osteotomy
Acetabular osteotomy
Patients with DDH undergoing THA are at risk for post-operative sciatic nerve palsy due to intra-operative limb lengthening which increases tension on the sciatic nerve. Appropriate management after discovering a sciatic nerve palsy
after surgery should include immediate knee flexion and hip extension to decrease tension on the sciatic nerve. Sciatic nerve palsy following THA most commonly only affects the common peroneal nerve branch, and spares the tibial nerve and can present as an inability to dorsiflex and evert the ankle.
Farrell et al retrospectively looked at the risk factors for motor nerve palsy after THA. They found while motor nerve palsy is uncommon following primary THA, it can be a devastating complication. Some risk factors include: preoperative diagnosis of developmental dysplasia of the hip, posttraumatic arthritis, the use of a posterior approach, lengthening of the extremity, and use of an uncemented femoral implant. In their review, many of the motor nerve deficits did not fully resolve.
Barrack et al reviewed neurovascular complications following THA. They stated that sciatic nerve injury is the most common nerve injury following THA utilizing a posterior approach. In comparison, femoral nerve injury is much less common and is usually from an anterior approach.
OrthoCash 2020
A cane held in the contralateral hand reduces joint reactive forces through the affected hip approximately 50% by which of the following mechanisms?
Reducing hip abductor muscle pull
Increasing hip flexor muscle pull
Moving the center of rotation for the femoroacetabular joint
Increasing joint congruence at the femoroacetabular joint
Moving the center of gravity posterior to the second sacral vertebra
Corrent answer: 1
A cane held in the contralateral hand reduces joint reactive forces through the affected hip up to 50% by reducing abductor muscle pull.
A cane create an additional force that keeps the pelvis level in the face of gravity's tendency to adduct the hip during unilateral stance. The cane's force must substitute for the hip abductors of the affected hip and creates a moment arm that is relatively long and originates on the side opposite the hip whose abductor muscles are weak. Additionally, the person needs adequate strength in the muscles of the wrist, elbow, shoulder girdle, and trunk.
Brand and Crowninshield performed a 3-dimensional hip joint reactive force evaluation of 4 different groups of patients. The groups included normal
subjects, preoperative THA subjects walking without a cane, preoperative THA subjects walking with a cane, and subjects following total hip reconstruction. Each of the 3 groups evaluated without the cane had statistically similar hip joint reactive forces. The preoperative THA subjects walking with a cane and significantly lower joint reactive forces (approximately 60%).
The article by Blount was named by JBJS as a "Classics in JBJS" in 2003. It is a commentary encouraging the use of canes by describing how the biomechanics of the hip joint are altered while using a cane.
Illustration A shows some of the mathematics behind cane use.
OrthoCash 2020
Which of the following is an example of an antalgic gait pattern not typically seen in clinical practice?
Patient's knee is maintained in slight flexion throughout the stance period for ipsilateral knee arthritis
Patient's contralateral step length is shortened with ipsilateral ankle arthritis
Patient leans their trunk laterally over the painful leg during stance phase with ipsilateral hip arthritis
Patient ambulates on their toes with an ipsilateral calcaneal stress fracture
Patient ambulates predominately through the heel for ipsilateral knee arthritis
The term antalgic gait is non-specific and describes any gait abnormality resulting from pain. A patient with knee arthritis maintains slight flexion throughout the gait cycle. This compensatory knee flexion is exacerbated if the patient has a concomitant effusion in the knee as flexion reduces tension on
the knee joint capsule. Gait compensation for knee arthritis also involves toe walking on the affected side, reducing the stride length, and reducing time of weight bearing on the painful leg.
Gok et al performed a case-control gait analysis study of 13 patients with OA and 13 normal patients. They found that walking velocity, cadence and stride length were reduced in the OA group and that the overall stance phase was prolonged in the OA group. They concluded that computerized gait analysis can be used to reveal various mechanical abnormalities accompanying arthrosis of the knee joint at an early stage.
Cole and Harner present Level 5 evidence about knee arthritis in the active patient. They stress that weightbearing radiographs are important in the diagnosis of arthritis. They also discuss the importance of looking for medial or lateral thrusts during gait and dynamic gait changes such as quadriceps avoidance or out-toeing.
Incorrect Answers:
OrthoCash 2020
A 78-year-old male falls at home four months following a right total hip arthroplasty. Right leg deformity, pain, and inability to bear weight are present on physical exam. An injury radiograph is provided in Figure A, while radiographs taken immediately following the initial total hip arthroplasty are provided in Figures B and C. The patient denies any prodromal groin pain prior to his fall. Which of the following is the best treatment option?
Traction for 6 weeks followed by slow return to weight bearing
Open reduction and internal fixation
Revision to a long, cementless femoral stem
Revision to a long, cementless stem with strut allograft
Revision to a long, cemented stem
Corrent answer: 2
The clinical presentation and radiograph are consistent with a Vancouver B1 periprosthetic femur fracture. The stem appears stable within the femur, and there is no evidence of subsidence with comparison to the initial post-THA radiographs. This fracture pattern is best treated with internal fixation.
Illustrations A and B are radiographs of this patient following fixation. Illustrations C and D show bone healing at 2 years following the fracture.
Duwelius et al report on 33 periprosthetic femur fractures. All fractures that demonstrated a stable stem at the time of surgery were treated with internal fixation, while those that were unstable were treated with a long, cementless revision femoral stem. At 2.5 years complications were minimal and the patients had regained their pre-fracture level of function.
The review article by Kelley outlines the evaluation, classification, and treatment of periprosthetic femur fractures reinforcing the importance of stem stability within the femur. Periprosthetic fractures around a hemiarthroplasty should be treated with the same algorithm. However, if the patient had antecedent groin pain, then conversion to a total hip arthroplasty should be considered to prevent continued groin pain.
OrthoCash 2020
A 64-year-old male underwent the procedure shown in Figures A and B 7 weeks ago. He complains of difficulty with going down stairs. He reports no pain and denies constitutional symptoms. On examination the incision is well healed and no effusion is present. He is able to perform a straight leg raise with 5/5 strength. He lacks 2 degrees of terminal extension and has 80 degrees of active flexion. The knee is stable to varus and valgus stress testing at extension and mid flexion. His C-reactive protein and erythrocyte sedimentation rate are normal. What is the next most appropriate step in management?
Manipulation under anesthesia
Cortisone injection followed by physical therapy for quadriceps strengthening
Aspiration to evaluate for septic arthritis
Revise femoral component by downsizing A-P diameter
Revise tibial component and add 5 degrees of posterior tibial slope
Corrent answer: 1
The history, physical examination, laboratory studies, and imaging are consistent with a total knee arthroplasty patient with arthrofibrosis. The next most appropriate option includes a manipulation under anesthesia to increase the patient's flexion.
Maloney presents Level 4 evidence discussing TKA postoperative arthrofibrosis. They report that manipulation under anesthesia was successful in improving flexion from an average of 67 degrees premanipulation to 111 degrees
postmanipulation.
Keating et al report Level 4 evidence of 113 patients that underwent manipulation following TKA. They found that 90% of the patients achieved improvement of ultimate knee flexion following manipulation. The average improvement in flexion from the measurement made before manipulation to that recorded at the five-year follow-up was 35 degrees.
OrthoCash 2020
Which of the following total hip arthroplasty patients appropriately meets the criteria for a surgical debridement with isolated femoral head and polyethylene liner exchange?
Prosthesis infection of 4 months duration
Prosthesis infection 8 weeks following implantation
Prosthesis infection 3 days following a systemic infection
Acetabular component loosening due to osteolysis
Vancouver Type A periprosthetic fracture.
Femoral head and polyethylene liner exchange is an appropriate treatment for the acutely infected arthroplasty. Acute infection has been defined as 3-6 weeks following surgery or following a systemic infection depending on the literature source. Subacute and chronic infections must be treated with a complete explant and exchange of all components. (One-stage or two-stage is controversial).
Salvati et al review the management of total hip arthroplasty infection. Most importantly, the pathogen must be isolated to direct antibiotic treatment. The acuity of the infection must also be recognized to direct surgical management.
OrthoCash 2020
A 54-year-old woman is at physical therapy 3 months after a total knee arthroplasty when she feels a pop and develops increased pain in her knee. She continues therapy for another 3 months but reports weakness and frequent buckling. On exam, she has full passive extension but a 60 degree extensor lag. A lateral radiograph is shown in Figure A. What is the treatment of choice?
Reconstruction with a bone-tendon allograft
Repair augmented with hamstring autograft
Continued therapy and strengthening
Arthrodesis
Treatment with orthotics for support
Corrent answer: 1
The patient has a chronic patellar tendon rupture following a TKA with marked extensor lag and patella alta on radiograph. A study by Barrack et al concluded that allograft reconstruction for the chronically-disrupted extensor mechanism after TKA could restore active extension and improve ambulatory function. In chronic cases, primary repair with or without local tissue augmentation have had disappointing results. Extensor mechanism injuries after TKA was reviewed by Parker et al. Patellar tendon ruptures are rare complications after TKA with an incidence reported <2.5%. Quadriceps tendon ruptures are even more rare with an incidence ~1%.
OrthoCash 2020
When compared to the standard medial parapatellar approach for revision total knee arthroplasties, the oblique rectus snip approach
showed impairment in which of the following post-operative outcomes?
range-of-motion
patient satisfaction
pain
WOMAC function score
no difference in outcomes
Corrent answer: 5
Meek et al compared the rectus snip to a standard medial parapatellar approach for revision total knee arthroplasty. The WOMAC function, pain, stiffness and satisfaction scores demonstrated no statistical difference. They concluded that use of a rectus snip as an extensile procedure had no adverse effect on outcome.
OrthoCash 2020
What is the range of pore size of cementless porous implants to allow for optimal bony ingrowth?
Less than 1 micron
50 to 400 microns
1,000 to 5,000 microns
10,000 to 50,000 microns
100,000 to 500,000 microns
The range of 50 to 400 microns is the optimal pore size for cementless porous implants to allow for optimal bony ingrowth.
Bobyn et al looked at the optimum pore size for fixation of porous surfaced metallic implants. Four different pore sizes were examined and placed in canine femurs for 4, 8, and 12 weeks and tested to measure the shear strength based on pore sizes. A pore size of 50 to 400 microns provided the maximum fixation strength in the shortest time period (8 weeks), implying maximal bony ingrowth.
Pilliar et al discussed two independent canine studies which showed that initial implant movement relative to host bone can result in attachment by a nonmineralized fibrous connective tissue layer. They state that implant movement of greater than 150 microns leads to fibrous ingrowth.
Jasty et al implanted porous-coated implants in the distal femoral metaphyses of twenty dogs and subjected them to zero, twenty, forty, or 150 micrometers of oscillatory motion. They found that that the implants that had been subjected to 150 micrometers of motion were surrounded by dense fibrous tissue.
OrthoCash 2020
An active 73-year-old male presents with progressive pain and instability 15 years after undergoing a left total knee arthroplasty. He denies any recent trauma. A comprehensive workup for infection is negative. What is the most appropriate management of this patient?
Protected weight bearing for 6 weeks
Revision total knee arthroplasty
Bisphosphonate therapy
Routine follow-up in 1 year
Polyethylene liner exchange and bone grafting
Corrent answer: 2
This patient has evidence of periarticular osteolysis and component loosening around a previous total knee arthroplasty. He is symptomatic and would benefit from revision total knee arthroplasty (TKA).
Osteolysis is one of the leading causes for late reoperation in patients who undergo TKA. Osteolysis occurs as the result of a foreign body response to particulate wear debris from the prosthetic joint. These particles consist of polyethylene, polymethylmethacrylate cement, and metal, all of which have been shown to elicit a distinct inflammatory response. Once the particles are generated from and around the implant, they become phagocytosed by macrophages and giant cells in the synovial or periprosthetic tissue. These cells, in turn, become activated and can directly or indirectly cause osteolysis. The femur is prone to osteolysis in the region of the femoral condyles and near the attachments of the collateral ligaments of the femur. Osteolysis around the tibia tends to occur along the periphery of the component or along the access channels to the cancellous bone.
Maloney & Rosenberg reviewed the management and outcome of periprosthetic osteolysis around hip and knee implants. They recommended surgical intervention for periprosthetic osteolysis around a TKA with (1) first
-
time presentation of advanced osteolysis in the presence of an identifiable cause of wear particle production or in the presence of associated bone loss that places the structural integrity of the bone or fixation of the components at risk, (2) bearing surface wear in the presence of impending wear
-
through or related mechanical symptoms, (3) progressive osteolysis in an active individual, and (4) symptoms of wear debris
-
related synovitis that are refractory to conservative treatment.
Griffin et al. evaluated the results of isolated polyethylene exchange for wear and/or osteolysis in 68 press-fit condylar TKAs from four centers. At a minimum of 24 months after polyethylene exchange surgery, there were 11 failures (16.2%).
Gupta et al. discuss the etiology, diagnosis, contributing factors, and management of osteolysis as it relates to TKAs. They recommend that if the patient is asymptomatic with minimal osteolysis on plain radiographs, regular
follow-up at 6 months to 1 year with medical management including calcium and bisphosphonates would be adequate. If the patient becomes symptomatic or the osteolysis is progressive, then early liner exchange with or without tibial baseplate exchange is considered.
Figure A & B are AP and lateral radiographs of periarticular osteolysis and component loosening. Illustration A is an AP and lateral radiograph of the revision TKA.
Incorrect Answers:
OrthoCash 2020
Which of the following statements is true regarding the thirty-year follow-up data obtained from the Charnley "low-friction" total hip arthroplasty?
Acetabular component failure was the least common reason for revision surgery
The number of revisions required for periprosthetic fractures was higher than that for deep infections
Acetabular component failure was a more common reason for revision than deep infection
Femoral component failure was a more common reason for revision than acetabular component failure
Deep infection was the most common reason for revision
Corrent answer: 3
Failure of the acetabular component was the most common reason for revision at thirty-years for the Charnley "low-friction" total hip arthroplasty.
The Charnley low-friction torque arthroplasty was introduced in 1962. It consisted of a 22mm diameter metal head, a cemented femoral component, and a cemented ultra-high-molecular-weight polyethylene acetabular component. Overall, the results were very good at thirty years with only 11.8% requiring revision.
Charnley et al. in 1972 reported the 4-7 year results of 379 "low-friction" total hip arthroplasties. Overall, their short-term results were very good with only 2 loose acetabular components, 0 loose femoral components, and 1 late dislocation.
Wroblewski et al. in 2009 reported the 30 year follow-up of 110 patients who underwent the "low-friction" total hip arthroplasty. 13 hips (11.8%) had to be revised. Of these, 5 were for problems with the acetabular component, 4 were for loosening of both components, 2 were for deep infection, 1 was from a loose femoral component, and 1 was from a fractured femoral component.
Illustration A shows a radiograph after a Charnley low-friction total hip arthroplasty. Note the all poly-ethylene acetabular component. Illustration B shows the components used for the operation.
Incorrect Answers:
OrthoCash 2020
A 71 year old gentleman underwent left total hip arthroplasty 10 years ago. Eighteen months ago he began having hip and thigh pain. Over the past 6 weeks, the pain has become excruciating and he has been unable to ambulate, even with the aid of a walker. He has mild pain with passive internal and external rotation of the hip. He is unable to ambulate in the office. Laboratory values are notable for a WBC of 10,300, CRP of 0.2, and ESR of 13. A radiograph is provided in figure A. Which of the following is the best treatment option?
Radionuclide bone scan and MRI
Open reduction internal fixation with a cable plate and allograft strut
Revision arthroplasty with a fully coated cementless stem, cable wiring, and bone graft
Revision arthroplasty with a modular, tapered stem and bone grafting of the diaphyseal fixation
Revision arthroplasty with a total femur prosthesis
Corrent answer: 3
The radiograph is consistent with a periprosthetic femur fracture, with a loose femoral stem, and a Paprosky IIIA femoral defect. This is best treated with a fully-coated cementless stem with metaphyseal onlay allograft.
Paprosky devised a classification for femoral bone loss following THA. The classification is as follows:
Type I: minimal metaphyseal bone loss and intact diaphyseal fixation Type II: extensive metaphyseal bone loss with intact diaphyseal fixation
Type IIIA: severe metaphyseal bone loss with greater than 4 cm of diaphyseal bone preservation for distal fixation.
Type IIIB: severe metaphyseal bone loss and less than 4 cm of diaphyseal
bone preservation for distal fixation
Type IV: extensive metaphyseal and diaphyseal bone loss.
Type IIIA may be treated with a fully coated stem. Type IIIB should consider a tapered, modular stem and/or bone grafting. Type IV likely needs a megaprosthesis. In this patient, given the preserved diaphyseal bone, revision arthroplasty with a fully coated femoral stem is the most appropriate treatment.
The Sporer article reviews a case series of patients undergoing revision hip arthroplasty for femoral bone loss. Type IIIB defects with a femoral canal less than 19 mm may be treated with a fully porous-coated stem. However, patients with Type IIIB defect and a cavernous canal greater than 19 mm or a Type IV defect may need a modular tapered stem or a bone grafting procedure.
The Paprosky article summarizes his classification of femoral bone loss in revision hip arthroplasty and provides an algorithm for treatment. Extensively porous-coated, diaphyseal filling femoral components showed excellent results in Paprosky IIIA defects.
Radiograph A shows a total hip arthroplasty with severe metaphyseal bone loss and a supportive diaphysis.
Incorrect Answers:
OrthoCash 2020
A 74-year-old man presents with start-up thigh pain following a total hip replacement 10 years ago. Immediate post-operative radiograph is shown in Figure A. A current radiograph is shown in Figure B. Aspiration of the hip yields 1,005 white blood cells/ml. ESR is 12 (normal <40) and CRP is 0.4 (normal <1.2). Which of the following is the most appropriate management at this time?
Revision of the femoral component to an uncemented, long, fully porous-coated stem
Revision of the femoral component to a cemented stem
Revision of the femoral component to an allograft prosthetic composite
Revision of the femoral component to a proximal femoral replacement
Removal of prosthesis with insertion of antibiotic spacer
Corrent answer: 1
The clinical presentation is consistent with symptomatic, aseptic femoral component loosening with no evidence of femoral bone defects. Appropriate management consists of revision of the femoral component to an uncemented, fully porous-coated stem.
Aseptic loosening remains one of the most common indications for revision total hip arthroplasty. After infection has been ruled-out, management is determined by gauging the patients symptoms, the rate of progression of the subsidence, and the amount of femoral bone loss. Uncemented revision femoral components have shown superior results to cemented revision femoral components in the long-term. In the setting of Paprosky Type I, II, and IIIA defects of the femur, revision to an uncemented, fully porous-coated stem is advised.
Moreland et al. review the results of 134 patients (137 hips) who underwent revision arthroplasty with an extensively porous-coated cobalt chrome femoral prosthesis. At a mean follow-up of 9.3 years, only 10 (7%) had to removed for any reason.
Sporer et al. review the results of fully porous-coated stems, impaction bone grafting, and modular tapered stems for Paprosky III and IV femoral defects. They found a high rate of failure with fully porous-coated stems when used in patients with Type IIIB defects >19mm and Type IV defects. They attribute these failures to instability and the inability to eliminate micromotion.
Figure A shows a cementless, metaphyseal engaging femoral component in good alignment. Figure B is a post-operative radiograph from 10 years later showing significant subsidence of the femoral component.
Incorrect Answers:
OrthoCash 2020
A 72-year old female who underwent an uncemented right total hip arthroplasty 2 years ago complains of right hip pain after a fall. Figure A shows her current radiograph. Which acetabular bone defect classification and treatment option best describes this scenario?
AAOS Type III - anti-protrusio cage with augmentation and a posterior column plate
AAOS Type IV - anti-protrusio cage with screw fixation and a posterior column plate
AAOS Type II - jumbo cup with augmentation and a posterior column plate
AAOS Type I - total acetabular allograft with a cemented cup
AAOS Type II - custom triflange acetabular component
Corrent answer: 2
Figure A shows pelvic discontinuity, which is consistent with a AAOS Type IV defect. Acetabular antiprotrusio cage with screw fixation and a posterior column plate is a reasonable treatment option for this condition.
Acetabular bone loss following total hip arthroplasty is a challenging problem with a wide variety of treatment options available. The two most widely accepted classification systems are the AAOS and Paprosky classifications.
AAOS type I defects are segmental, type II are cavitary, type III are combined cavitary and segmental, type IV is discontinuity, and type V is arthrodesis. All of the treatment options listed above are described for pelvic discontinuity,
with none being described as superior.
DeBoer et al. describe the results of 28 patients with pelvic discontinuity treated with a custom-made porous-coated triflange acetabular prosthesis. 20 of these patients were followed for 10 years. There were no re-operations, 5 hip dislocations, 1 sciatic nerve palsy, and an average improvement in the Harris hip score from 41 to 80.
Paprosky et al. retrospectively reviewed patients who had an acetabular revision using a trabecular metal acetabular component for a pelvic discontinuity and compared these patients with a cohort of patients who had a previous reconstruction for a pelvic discontinuity using an acetabular cage.
They found a decreased incidence of pain and need for walking aids in those patients who had revision with a trabecular metal acetabular component.
Figure A shows pelvic discontinuity, likely acute given the lack of associated bony defects and recent fall. Illustration A details the AAOS hip acetabular defect classification and Illustration B is the often cited Paprosky classification.
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OrthoCash 2020
Which of the following is indicative of type 1 collagen breakdown and can be utilized as a marker of bone turnover?
Increased urinary N-telopeptide
Increased urinary cAMP and phosphate
Increased urinary phosphoethanolamine
Increased urinary Bence Jones proteins
Increased serum bone sialoprotein
Corrent answer: 1
Urinary N-telopeptide is a marker of increased bone turnover and is a breakdown product of Type 1 collagen.
Increased serum alkaline phosphatase level and increased urinary markers of N-telopeptide, hydroxylproline, deoxypyridinoline indicate high bone turnover and can be seen in metabolic bone diseases such as Paget's disease.
von Schewelov et al. reviewed 160 patients that underwent total hip replacements and examined their urine specimens to see if N-telopeptide levels correlated to periprosthetic osteolysis. They found that n-telopeptide levels were 1/3 higher in the patients that had evidence of osteolysis. N-
telopeptide release and annual wear were both associated with increased prevalence of osteolysis in the study.
Illustration A shows a radiograph of Pagets disease of the femur, an example of a condition where there is an increased level of N-telopeptide in the urine. Illustration B is a radiograph showing periprosthetic osteolysis, another condition where there is an increased level of N-telopeptide in the urine.
Incorrect Answers:
OrthoCash 2020
A 78-year-old female undergoes total hip arthroplasty through a minimally invasive surgical approach. During insertion of a metaphyseal fixation stem with a cementless press-fit technique, a crack in the calcar is identified. The stem is removed, two cable wires are passed around the calcar, and the same stem is reinserted. Which of the following statements is true?
The patient should be advised she is at greater risk of stem subsidence and early revision
Female sex is a risk factor for intraoperative calcar fracture
A better outcome would be expected if a long-stem diaphyseal fixation stem had been inserted after recognition of the calcar fracture
Cementless press-fit technique is not a risk factor for intraoperative fracture
Minimally invasive surgical approach is not a risk factor for intraoperative fracture
Of the statements listed, the only true statement is that female gender is a risk factor for intraoperative calcar fracture.
Calcar fractures are a documented complication of total hip arthroplasty. Studies have shown that successful outcomes can be achieved with stem removal, cable wiring of the calcar, and re-insertion of the primary stem.
Berend et al. reviewed a series of 58 total hip arthroplasties who sustained an intraoperative calcar fracture. All were treated with cable wiring of the calcar and stem insertion. The authors report no femoral component subsidence or failure otherwise at 16 year follow-up.
Graw et al. review a series of 46 revision THA's. Of the 46, fifteen underwent primary THA through a minimally invasive technique. The average length of time from primary THA to revision was 1.4 years for the minimally invasive group versus 14.7 years for the traditional exposure THA's. The authors conclude minimally invasive THA is a risk for early revision.
Davidson et al. review intraoperative periprosthetic hip fractures. "Risk factors for intraoperative periprosthetic fractures include the use of minimally invasive techniques; the use of press-fit cementless stems; revision operations, especially when a long cementless stem is used or when a short stem with impaction allografting is used; female sex; metabolic bone disease; bone diseases leading to altered morphology such as Paget disease; and technical errors at the time of the operation." The authors summarize techniques for treatment and postulate that long term outcome is unaffected when the intraoperative fracture is identified and treated appropriately.
Illustration A shows a nondisplaced calcar crack that was treated with a single Luque wire.
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OrthoCash 2020
Which of the following types of prosthetic designs, seen in figures A-E, has been shown to have a high rate of loosening secondary to overconstraint?
Figure C shows an example of an Walldius hinge total knee prosthesis. This design had a higher rate of aseptic loosening (up to 20%) secondary to a high-degree of constraint.
Constraint is defined as the effect of the elements of knee implant design that provides the stability needed to counteract forces about the knee after arthroplasty in the presence of a deficient soft-tissue envelope. While increasing component constraint increases the stability of the knee, it also transmits forces to the fixation and implant interfaces, which may lead to premature aseptic loosening. First-generation total knee hinged prostheses were highly constrained devices that only allowed a single axis of rotation.
Lombardi et al. provide an Instructional Course Lecture on the different prosthetic designs in total knee arthroplasty. They argue that PCL sacrificing implants are more appropriate than cruciate-retaining implants in rheumatoid arthritis, previous patellectomy, previous high tibial osteotomy or distal femoral osteotomy, and in cases where the PCL is absent secondary to trauma.
Morgan et al. discuss constraint in primary total knee arthroplasty. They argue that a hinge total knee arthroplasty should be reserved for severe instability, elderly patients with comminuted distal femur fractures, patients with
extensor-mechanism disruption and unstable knees, and those with substantial bone loss not amenable to augmentation.
Figure C shows an example of a Walldius hinged prosthesis.
Illustration A shows an intra-operative example of a constrained-hinged knee prosthesis. Note the link between the tibial and femoral components, which differentiates it from a constrained, non-hinged prosthesis.
Incorrect Answers: The following responses are incorrect as they all have lower rates of aseptic loosening than than varus/valgus constrained prostheses or hinged designs.
OrthoCash 2020
A 28-year-old football player sustains a contact knee injury while being tackled. On physical exam, he has a 1A Lachman, and a normal McMurray test. His posterior drawer, dial, and varus stress tests are normal. He has pain and 5mm opening on valgus stress at 30 degrees of flexion. Which statement is true regarding the injured structure?
Resides between layers 1 and 2 on medial side of knee
Inserts onto Gerdy's tubercle
Originates slightly posterior and proximal to the medial epicondyle
Courses intraarticularly thru hiatus of lateral meniscus
Has an attachment between adductor tubercle and medial epicondyle at Schöttle's point
The clinical presentation is consistent with an injury to the superficial medial collateral ligament (MCL) of the knee, which originates slightly posterior and proximal to the medial epicondyle.
The superficial portion of the MCL is the primary stabilizer to valgus stress at all angles, contributing 57% and 78% of medial stability at 5 degrees and 25 degrees of knee flexion, respectively. Anatomic studies have shown that the superficial MCL originates approximately 3.2 mm proximal and 4.8 mm posterior from the medial femoral epicondyle and inserts into the periosteum of the proximal tibia (deep to pes anserinus). The superficial MCL lies in layer 2, just deep to gracilis and semitendinosus tendons.
Wijdicks et al. (2009) looked at radiographic identification of the primary medial knee structures including the superficial MCL. On the lateral radiograph, they found that the attachment of the superficial MCL was an average of 6.0 mm from the medial epicondyle.
Wijdicks et al. (2010) reviewed injuries to the MCL and associated medial structures of the knee. They state that physical examination is the initial method of choice for the diagnosis of medial knee injuries through the application of a valgus load both at full knee extension and between 20 degrees and 30 degrees of knee flexion. Treatment of isolated grade-III injuries to the MCL, or such injuries combined with an anterior cruciate ligament tear, should start with nonoperative treatment of the MCL due to high rates of success with nonoperative treatment. If operative treatment is required, an anatomic repair or reconstruction is recommended.
Illustration A shows the femoral and tibial attachments of the superficial MCL. Illustration B shows the osseous landmarks and attachments of medial knee structures (AT, adductor tubercle; GT, gastrocnemius tubercle; ME, medial epicondyle; AMT, adductor magnus tubercle; MGT, medial gastrocnemius tendon; sMCL, superficial MCL; MPFL, medial patellofemoral ligament; POL, posterior oblique ligament).
Incorrect Answers:
OrthoCash 2020
Which of the following best describes normal tibio-femoral joint kinematics ?
The femur undergoes internal rotation with knee flexion
The lateral femoral condyle remains stationary on the lateral tibia plateau during knee flexion from 0 to 120 degrees
The tibia undergoes internal rotation with knee flexion
The medial femoral condyle moves posteriorly on the medial tibial plateau during knee flexion from 0 to 120 degrees
Beyond 120 degrees of flexion only the lateral femoral condyle participates in femoral rollback
Tibia is subjected to internal rotation with knee flexion and the tibia EXternally rotates on femur as the knee EXtends.
The axis of rotation shifts posterior on the lateral condyle with knee flexion. Flexion and extension at the knee occur about a constantly changing center of rotation (polycentric rotation).
Freeman et al. conducted a biomechanical experiment and found that the medial femoral condyle does not move much from 0 to 120 degrees of flexion. They also found that the lateral femoral condyle and the contact area between that condyle and the tibia move posteriorly and tibial internal rotation occurs with knee flexion. They found that from 120 degrees to full flexion both condyles participate in "roll back".
Illustration A shows why the screw-home mechanism occurs. The medial tibial plateau is longer than the lateral tibial plateau, leading to external rotation of the tibia during extension as the femoral condyle rotates about the tibia. Video V shows an example of external tibial rotation during extension.
Incorrect Answers:
OrthoCash 2020
Which of the following molecules is associated with macrophage induced osteolysis surrounding orthopaedic implants?
BMP-7
IL-10
SOX-9
Osteoprotegrin
IL-1
Of the options provided, IL-1 is most associated with macrophage induced osteolysis surrounding orthopaedic implants.
Macrophages initiate the inflammatory cascade associated with aseptic loosening of orthopaedic implants by secreting platelet-derived growth factor (PDGF), prostaglandin E2 (PGE2), TNF-alpha, IL-1, and IL-6.
Archibeck et al. state the primary cells involved in the process of periprosthetic loosening include the macrophage, osteoblast, fibroblast, and osteoclast. They report the chemical mediators that are responsible for the cellular interactions and effects on bone primarily include PGE2, TNF-alpha, IL-1, and IL-6.
Drees et al. discuss the molecular pathway of aseptic loosening of orthopedic implants. They describe the following steps: 1) Wear debris particles released at the cement–bone interface attract macrophages, which, in turn, are stimulated to produce proinflammatory mediators and proteolytic enzymes; 2) RANKL, TNF-alpha, IL-1, IL-6, IL-17, and M-CSF mediate the differentiation of myeloid precursor cells into multinucleated osteoclasts, which release cathepsin K and acid and cause resorption lacunae; 3) Mesenchymal cells (prosthesis-loosening fibroblasts) present at the bone surface contribute actively to bone resorption.
Illustration A shows the pathway described by Drees et al.
Incorrect Answers
OrthoCash 2020
Which of the following templates, seen in Figures A-E, will increase the offset while keeping the leg lengths the same?
If the total hip prosthesis is inserted according to the template in Figure E, the offset will be increased, while the leg lengths will remain unchanged.
Restoration of limb length is essential following total hip arthroplasty. The amount of limb-length change will be the vertical distance between the center of rotation of the femoral component and the center of rotation of the acetabular component. Thus, when the femoral center of rotation on templating is inferior to that of the acetabular component, the limb will be shortened. Restoring femoral offset is also important. If the center of rotation of the prosthetic head lies lateral to that of the cup on templating, the reconstruction will produce decreased offset.
Scheerlinck et al. present a stepwise approach to hip templating through four steps. Step 1 involves identifying landmarks, step 2 involves assessing the
quality of the radiograph, step 3 identifies mechanical references, and step 4 optimizes implant positioning.
Tripuraneni et al. discuss the common errors encountered when templating for total hip arthroplasty. They found the most common error was excessive limb lengthening and incomplete medialization of the acetabular component.
Della Valle et al. review hip templating. They stress the importance of preoperative planning, but also discuss the importance of tactile feedback during the surgery in choosing the correct implants.
Illustration A shows a table of how offset and leg lengths can be changed through positioning and selection of components.
Incorrect Answers:
OrthoCash 2020
A 91-year-old male with a history of chronic leukemia and dementia falls and sustains the hip fracture shown in Figure A. He undergoes a hemiarthroplasty through a posterior approach. A postoperative radiograph is shown in Figure B. Three weeks later he dislocates the hip arising from the toilet seat. A radiograph is shown in Figure C. The patient undergoes a closed reduction and is placed in a hip abduction brace. Post reduction radiograph is shown in Figure D. One month later he returns to clinic complaining of pain and inability to bear weight through the leg. A radiograph of the hip is included in Figure E. Which of the following factors has MOST likely contributed to the instability of the hip hemiarthroplasty?
Femoral stem subsidence
Increased offset
Inadequate femoral stem neck length
Patient's dementia status
Patient's gender
The most likely contributing factor to the instability include the patient's dementia.
Sultan et al use a basic science model to show liners with elevated rims placed in the posterior superior quadrant allow greater range of motion to dislocation than standard liners. They also show that 32 mm heads have greater range of motion to dislocation compared to 28 mm heads.
Morrey et al reviewed a series of 19,680 primary THA's for late dislocation (first dislocation greater than 5 years after surgery). 165 hips (0.8%) had a late dislocation. Factors associated with late dislocation include implant malposition, neurologic decline, trauma, and polyethylene wear.
Figure A shows a femoral neck fracture. Figures B and D show a hip hemiarthroplasty in appropriate position. Figure C and E show a dislocated hip hemiarthroplasty
This patient's instability was managed by converting the hip hemiarthroplasty to a total hip arthroplasty with a constrained liner as shown in illustration A. No further instability episodes occurred following the revision.
Incorrect Answers:
OrthoCash 2020
What surgeon is credited for designing the prosthesis seen in Figure A?
John Charnley
San Baw
Sir Harry Platt
Austin T. Moore
Charles Frederick Thackray
Corrent answer: 4
Figure A shows an example of an Austin-Moore hemiarthroplasty.
Austin Moore developed the most popular long-stemmed prosthesis in the 1950s. The Austin-Moore prosthesis was a large, uncemented femoral stem that didn't use polyethylene. The Austin-Moore prosthesis had fenestrations for self-locking which later became the impetus for biological fixation. These implants were originally used to treat hip fractures and certain cases of degenerative arthritis. Later, in the 1960s, John Charnley introduced the idea of replacing the eroded acetabulum with a Teflon component.
Moore et al. describe the first metallic hip replacement surgery in 1940. The patient had a proximal femoral resection for a giant cell tumor. The original prosthesis he designed was a proximal femoral replacement, with a large fixed head, made of the Cobalt-Chrome alloy Vitallium.
Charnley et al. discuss the long-term results (up to 7 years) of the "low-friction" total hip arthroplasty. Infection rate was 3.8%, late mechanical failure was 1.3%, and most patients had excellent pain relief.
Figure A shows a radiograph of an Austin-Moore hemiarthroplasty. Illustration A shows an Austin-Moore prosthesis. Illustration B shows an example of Charnley's "low-friction" total hip arthroplasty, with a stainless steel head and
stem and a polyethylene acetabular component.
Incorrect Answers:
OrthoCash 2020
A 45-year-old man has had the gait disturbance shown in Video A ever since a total hip replacement two years ago. Since then he has undergone physical therapy and nerve exploration without any clinical improvement. Extensive AFO bracing was attempted but was not tolerated by the patient. A recent ankle radiograph is shown in Figure
A. The Silfverskiold test reveals dorsiflexion of 20 degrees with knee flexion, and 10 degrees with full knee extension. The results of muscle
testing using a Cybex dynamometer are shown in Figure B. What is the most appropriate next step in in treatment.
Ankle arthrodesis in 30 degrees of dorsiflexion
Posterior tibial tendon transfer to the lateral cuneiform through the interosseous membrane
Split anterior tibial tendon transfer to the cuboid
Peroneus longus transfer to the navicular and gastrocnemius recession
Flexor hallucis transfer to the navicular and tendo Achilles lengthening (TAL)
Corrent answer: 2
The clinical presentation is consistent with a sciatic neuropathy following THA in a patient that does not tolerate AFO bracing. Posterior tibialis tendon transfer is the next most appropriate step in treatment.
Sciatic neuropathy, especially involving the common peroneal branch, is a known complication of total hip arthroplasty. Typically a patient is adequately treated with an AFO. In some clinical situations an AFO is not tolerated, and a tendon transfer is required. The posterior tibial tendon is the most commonly used donor muscle. A tendon transfer is feasible only if the tendon possesses at least 4/5 power. There is a loss of 1 MRC grade of strength following transfer.
Rodriguez et al. retrospectively reviewed the results of the Bridle procedure 10 patients (11 feet) with a foot drop. The Bridle procedure consists of a posterior tibial tendon transfer through the interosseous membrane to the dorsum of the foot with a dual anastomosis to the tendon of the anterior tibial and a rerouted peroneus longus in front of the lateral malleolus. In their study all 11 feet were brace-free at final followup at 6.68 years.
Yeap et al. retrospectively reviewed 12 patients who were treated with tibialis posterior tendon transfer for footdrop. They found good/excellent patient satisfaction in 10/12 patients. Additionally they found favorable variables for a good outcome include common peroneal nerve palsy over sciatic nerve palsy, male gender less than 30 years of age.
Figure V is a Video that shows a right footdrop with high steppage gait. Figure A shows normal ankle radiographs. Figure B shows the results of dynamometer testing described above. Illustration A shows the Bridle procedure. The left panel shows how the tibialis posterior tendon (C) is tunneled through the interosseous membrane and through a slit in the tibialis anterior tendon (A) and inserted into the second cuneiform. The peroneus longus (B) is also transected and the distal stump is routed anterior the lateral malleolus and anastomosed to the tibialis anterior and tibialis posterior (at the slit where it passes through the tibialis anterior). The right panel shows retrieval of the tibialis posterior tendon above the ankle and passage through a window in the interosseous membrane.
Incorrect Answers:
OrthoCash 2020
Which of the following variables is associated with elevated serum metal ion levels following metal-on-metal hip resurfacing arthroplasty?
Smaller implant diameter
Smaller acetabular cup abduction angle
Higher postoperative functional scores
Severe preoperative osteoarthritis
Anteversion of acetabular cup between 10 and 20 degrees
Corrent answer: 1
Smaller femoral head diameter is associated with elevated serum metal ion levels with metal-on-metal hip resurfacing arthroplasty.
Metal-on-metal (MOM) hip resurfacing arthroplasty has the advantage of better wear properties (lower linear wear rate and volume of particles) than metal on polyethylene. However, elevated serum metal ion levels is one of the negatives which has received much attention recently. Studies have found smaller implant diameter and acetabular cup abduction angle >55 degrees are associated with elevated serum metal ion levels. Cup abduction angles of greater than 55 degrees lead to a more vertical cup and edge loading.
Desy et al. found that smaller implant diameter, larger cup inclination, and lower postoperative functional scores are associated with increased cobalt and chromium levels after metal-on-metal hip resurfacing. They found that severity of preoperative osteoarthritis, acetabular version, femoral stem-shaft and valgus angle, and anterior orientation of the femoral component had no effect on the circulating metal ion levels.
DeHaan et al. obtained serum ion levels in 214 MOM resurfacing patients at least 1 year following surgery. They found that cup abduction angles greater than 55 degrees combined with smaller component sizes led to edge loading and elevated ion levels.
Illustration A shows how a metal-on-metal prosthesis design allows you to have a larger femoral head as opposed to a metal on polyethylene design (example in THA). Illustrations B and C show a photo of a metal on metal resurfacing implant and radiographs of the implant.
Incorrect Answers:
2: Elevated cup abduction angle leads to elevated serum metal ions.
3: Higher postoperative functional scores have not been shown to increase serum metal ions.
4: Severity of pre-operative arthritis has not been associated with increased serum metal ions.
5: Anteversion of the acetabular cup between 10 and 20 degrees has not been shown to increase serum metal ions.
OrthoCash 2020
Which of the following intra-operative steps would put a patient at risk for lateral patellar maltracking during total knee arthroplasty (TKA)?
External rotation of the femoral component
Medial placement of the patellar component
Internal rotation of the tibial component
Lateral translation of the femoral component
Superior placement of the patellar component
Corrent answer: 3
Internal rotation of the tibial component increases the Q angle and causes an increased risk of lateral patellar maltracking.
During TKA, useful techniques that help prevent patellar maltracking include: external rotation of the femoral and tibial components, lateral translation of the femoral component, and medial placement of the patellar component.
In an instructional course lecture, McPherson looked at patellar tracking in primary TKA. He reviews the concept of patellofemoral maltracking, the importance of the Q angle, mechanical alignment, femoral component rotation, tibial component positioning, patellar component positioning, patellar height, and patellar resurfacing as factors related to patellofemoral tracking.
Bengs et al. studied the effect of patellar thickness on intra-operative knee flexion and patellar tracking during PCL retaining TKAs. Using 2mm increments (2-8 mm), passive knee flexion was recorded and gross mechanics of patellofemoral tracking were assessed. On average, passive knee flexion decreased 3 degrees for every 2-mm increment of patellar thickness, there was no gross effect on patellar subluxation or tilt.
Illustration A shows how internal rotation of the tibial component would increase the Q angle, and thus be more likely to have lateral patellar maltracking.
Incorrect answers:
OrthoCash 2020
A patient undergoes a primary total hip arthroplasty with a highly cross-linked ultra-high molecular weight (UHMW) polyethylene acetabular liner. In comparison to a 28mm femoral head, a 32mm femoral head will provide which of the following?
Increased risk of dislocation
Decreased range of motion
Decreased risk of osteolysis
Equivalent wear rate of the polyethylene acetabular liner
Increased risk of periprosthetic fracture
Corrent answer: 4
Wear rates of highly cross-linked UHMW polyethylene liners are independent of femoral head size between 22 and 46 mm in diameter.
While the wear rates of old polyethylene liners increased with increasing femoral head size, wear rates of the new highly cross-linked UHMW polyethylene liners have shown to be independent of head size. This is extremely advantageous, as increasing the femoral head size improves range of motion and increases jump distance, thereby decreasing dislocation rates.
Geller et al. report a prospective series of 42 patients that had a total hip arthroplasty with a highly cross-linked UHMW polyethylene liner and a femoral head >32 mm in diameter. After three years, there were no cases of osteolysis or failure due to aseptic loosening.
Muratoglu et al. studied the wear rates of several polyethylene liners with varying femoral head sizes. In the highly cross-linked UHMW polyethylene group, wear rates were independent of femoral head size.
Illustration A shows how increasing femoral head size increases the jump distance required for dislocation.
Incorrect Answers:
OrthoCash 2020
A 56-year-old male undergoes an uncomplicated revision total knee arthroplasty. Post-operatively, he is noted to have a foot drop that has persisted despite conservative management including bracing and physical therapy. At two months, the patient undergoes external neurolysis with no improvement in function. At 18 months follow-up, he demonstrates passive ankle dorsiflexion 10 degrees past neutral, complete absence of active dorsiflexion, and 5/5 inversion strength. Which of the following is the most appropriate treatment at this time?
Continue Ankle-foot orthosis (AFO) and physical therapy
Repeat neurolysis with possible nerve repair
Peroneus tertius transfer
Peroneus tertius transfer with achilles tendon lengthening
Posterior tibial tendon transfer to dorsum of foot
Corrent answer: 5
A peroneal nerve palsy (with intact posterior tibial tendon strength) that has failed conservative management is best treated with a posterior tibial tendon transfer to the dorsum of the foot.
Peroneal nerve palsy following total knee arthroplasty or knee dislocation is a potentially devastating complication that may lead to lack of active dorsiflexion and a compensatory steppage gait pattern. Initial management consists of an ankle-foot orthosis (AFO) and physical therapy to maintain passive ankle dorsiflexion. If nerve function fails to return during the course of conservative management and the patient demonstrates intact posterior tibialis muscle strength, posterior tibial tendon transfer to the dorsum of the foot has been shown to improve functional outcomes and eliminate the need for continued bracing. The most common procedure for posterior tibial tendon transfer involves transferring the tendon through the interosseous membrane and inserting the tendon onto the lateral cuneiform.
Prahinski et al. review the results of 10 patients at 61 months' follow-up who underwent the Bridle transfer (posterior tibialis transfer through interosseous membrane and peroneus longus to front of lateral malleolus) for peroneal nerve palsies. They conclude the Bridle procedure is adequate for return to function in low-demand individuals, but may fail over time in those who return to vigorous physical activity.
Rodriguez et al. review the results of 10 patients who underwent the Bridle procedure for peroneal nerve palsy in an attempt to balance their foot and
provide dorsiflexion. All of their patients were brace free at an average followup of 6.8 years.
Video V shows the clinical results 10 weeks after transfer of the tibialis posterior tendon for a drop foot.
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OrthoCash 2020
An 82-year-old male sustains a ground level fall and sustains the injury shown in Figure A. Which of the following treatment methods is most appropriate for treating this injury?
Closed reduction and functional bracing
Open reduction and fixation with a plate with screws and cerclage cables
Open reduction and fixation with a cortical allograft strut and cerclage cables
Revision hip arthroplasty with bridging of the fracture with a plate with screws and cerclage cables
Total femoral replacement
Corrent answer: 2
This fracture pattern is typically referred to as an interprosthetic fracture; this is increasing in incidence due to increasing numbers of patients with ipsilateral hip and knee arthroplasty.
The first reference by Ricci et al reviewed 50 Vancouver B1 fractures treated with a lateral plate without allograft. They reported 100% union rate at a mean of 12 weeks and only one deep infection. Nearly 75% of patients were able to return to their baseline ambulatory status.
The second reference by Ricci et al reviewed 59 patients with periprosthetic femur fractures (THA or TKA) treated with ORIF without bone grafting. They report 58/59 patients healed after the index procedure and 49/59 were able to
return to their baseline functional level.
The reference by Fulkerson et al reported on 24 patients who underwent LISS plate fixation of periprosthetic femur fractures around well-fixed THA or TKA. They reported union in 21/24 at a mean of 6.2 months, with only one failure of fixation. They note that percutaneous fixation is effective although technically demanding.
Figure A shows an interprosthetic femur fracture between well-fixed hip and knee arthroplasties.
Incorrect Answers:
OrthoCash 2020
A 62-year-old female undergoes an uncomplicated primary total knee replacement. Her knee range-of-motion pre-operatively was 0-135 degrees of flexion. Which of the following is true regarding the immediate post-operative use of a continuous passive motion machine in this patient?
Reduced risk of venous thromboembolism
No long-term difference in ROM compared to patients not using CPM
Increased passive knee flexion at 6 months
Increased length of hospitalization
Decreased risk of surgical site infection
Corrent answer: 2
The use of a continuous passive motion (CPM) machine following primary total knee arthroplasty has not shown any long-term benefits with regards to
range-of-motion.
The concept of CPM was created by Dr. Robert Salter in 1970 and is currently being used in select patients following total knee replacement, ACL
reconstruction, and a variety of other procedures about the knee. In theory, the CPM allows for movement of synovial fluid to allow for better diffusion of nutrients into damaged cartilage. Additionally, it has been thought to prevent fibrous scar tissue formation about the joint. While some studies have shown increased early active knee flexion at two weeks, these results were not significant at later follow-up. Controversy exists as to whether these small benefits offset the patient inconvenience and expense of the CPM.
Lotke et al. expolre the effects of tourniquets and CPM machines in 121 patients undergoing total knee arthroplasty. They found that immediate CPM combined with intraoperative release of the tourniquet increased blood loss. The patients with the least amount of blood loss had the tourniquet released after a compressive dressing was applied and in whom CPM was delayed for a few days.
Bourne et al. perform a meta-analysis on the effectiveness of CPM following total knee arthroplasty. They found the CPM plus physical therapy increased active knee flexion more than physical therapy alone 2 weeks after surgery with a decreased length of hospitalization. The benefits of increased active knee flexion were not maintained after 2 weeks.
Illustration A shows an example of a CPM machine. Incorrect Answers:
from available RCTs to conclude that CPM reduces the risk of venous thromboembolism following total knee arthroplasty.
OrthoCash 2020
A 67-year-old female complains of anterior groin pain one year following a primary, uncemented total hip arthroplasty. The pain is exacerbated when she tries to climb stairs or get up from a seated position. She denies any recent fevers or chills. On physical exam, the pain is reproduced with resisted seated hip flexion. Laboratory analysis, including WBC, ESR, and CRP are within normal limits. Radiographs reveal that the components are appropriately positioned without evidence of loosening or fracture. Which of the following is the most appropriate at this time?
Revision of the acetabular component
Image-guided diagnostic injection of lidocaine into the iliopsoas tendon sheath
Hip aspiration
Bone scan
Conservative management including activity modifications, NSAIDs, and physical therapy
The patients history and physical exam are most consistent with iliopsoas impingement. This diagnosis is most reliably confirmed with a diagnostic/therapeutic injection of steroid or lidocaine into the iliopsoas tendon sheath.
Iliopsoas tendinitis following total hip arthroplasty is an uncommon but treatable cause of anterior groin pain following total hip arthroplasty. The true incidence is unknown, but some studies suggest it is the cause of a painful
total hip arthroplasty in up to 4.3% of cases. Potential causes include a malpositioned acetabular component, excessively long screws, limb length discrepancy, or retained cement. Diagnosis is confirmed by injecting the iliopsoas tendon sheath. Most cases are refractory to conservative management and often require surgical intervention. In the case of a malpositioned acetabular component, revision to a more agreeable position is advisable. In the absence of a defined etiology, iliopsoas tendon release offers adequate pain relief and return to function in a majority of patients.
Lachiewicz et al. review anterior iliopsoas impingement after total hip arthroplasty. They state that most patients with iliopsoas impingement often require surgical treatment, with options including iliopsoas tendon release or resection, removal of protruding cement or screws, and acetabular revision.
O' Sullivan et al. review 16 cases of iliopsoas impingement following primary total hip arthroplasty. Only 1 of the cases was secondary to a malpositioned acetabular component, with the other 15 cases being attributed to altered anatomy of the iliopsoas tendon as a result of the surgery. These 15 patients underwent iliopsoas tendon release, and all had improvement in pain and function following surgery.
Nunley et al. review 27 patients with a presumed diagnosis of iliopsoas impingement following total hip arthroplasty who were treated with fluoroscopically guided injections of the iliopsoas bursa. The average modified Harris hip score in the patients who underwent injection improved, however, 30% required an additional injection and 22% underwent surgical release for continued pain.
Illustration A shows a flouroscopic injection into the iliopsoas tendon sheath. Incorrect Answers:
revision of the acetabular component without a confirmed diagnosis is not advisable.
OrthoCash 2020
A 72-year-old female underwent an uncomplicated primary total hip replacement 18 years ago. Current radiographs reveal the abnormality shown in Figure A. Which of the following cell types (Figures B-F) is implicated in the process shown by the arrow?
Figure F shows an example of a macrophage, which is a key mediator in the osteolytic process shown in Figure A.
Osteolysis is the end result of a biologic process that begins when the number of wear particles following a joint replacement overwhelms the body's capacity to clear them from circulation. The residual particles are phagocytosed by macrophages, which then release an array of cytokines and other inflammatory mediators that recruit osteoclasts to resorb bone.
Gupta et al. review osteolysis following total knee arthroplasty, including etiology, diagnosis, and management. Amongst other things, they highlight the importance of design changes to minimize osteolysis including highly cross-linked polyethylene and alternative bearing materials.
Ren et al. performed a study where they implanted a hollow titanium rod into the distal femur and pumped polyethylene particles into the femoral bone marrow cavity. They found that macrophage migration occurs at a systemic (rather than local) level, and that the recruitment of macrophages led to localized osteolysis.
Holt et al. review the biology behind aseptic osteolysis. Specifically, they highlight the importance of the RANK-RANKL-OPG pathway as the final
common pathway to osteoclastogenesis, and the possibility of eliminating osteolysis by blocking this pathway. AMG-162 is a human immunoglobulin monoclonal antibody with a high affinity for RANKL, and studies are currently being undertaken to determine its safety and efficacy.
Figure F shows an example of a macrophage, which may be identified by its irregular shape and phagocytic inclusions. Illustration A shows the pathway by which marcrophages induce osteolysis following a joint replacement surgery.
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OrthoCash 2020
A 45-year-old with a history of sickle cell anemia reports hip pain for the past 6 months. A radiograph of the affected hip is shown in Figure A. Which of the following interventions has been shown to have the best outcomes in this patient population?
Observation
Bisphosphonates
Hemi-arthroplasty
Uncemented metal on polyethylene total hip arthroplasty
Cemented metal on polyethylene total hip arthroplasty
Corrent answer: 4
Based on the radiographs and current literature, the best intervention is an uncemented metal on polyethylene total hip arthroplasty.
Avascular necrosis of the hip may be idiopathic in nature or associated with alcoholism, steroid use, or as in this case, sickle cell anemia. The Ficat staging system is used to classify avascular necrosis of the hip. Changes in treatment are driven by development of symptoms as well as the development of subchondral bone collapse (Ficat Stage 3). In those with with femoral head flattening (Ficat Stage 4) and acetabular degenerative changes (Ficat Stage 5), total hip replacement has good to excellent outcomes.
Mont et al. review surgical options for avascular necrosis of the hip. Head preserving procedures are generally reserved for those patients where the femoral head has not collapsed. Collapse and associated arthritis warrant utilization of arthroplasty procedures.
Mont et al. conducted a systematic review to better delineate the symptomatic progression of asymptomatic avascular necrosis of the hip. They found that patients with sickle cell disease have the highest rate of progression to
collapse. Medium sized, laterally located lesions were associated with a higher frequency of collapse and joint preserving procedures are recommended for these.
Figure A shows radiograph of a patient with avascular necrosis; note the femoral head flattening, narrowing of the joint space and acetabular sclerosis.
Incorrect Answers:
OrthoCash 2020
The function of which of the following structures is to resist internal tibial rotation with the knee in full extension?
Anterior cruciate ligament
Iliotibial band
Popliteus tendon
Popliteofibular ligament
Posterior oblique ligament
Corrent answer: 5
The primary function of the posterior oblique ligament is to resist internal tibial rotation with the knee in full extension.
The posterior oblique ligament is a structure within the posteromedial corner of the knee, with attachments proximally to the adductor tubercle of the femur and distally to the tibia/posterior knee capsule. The posterior oblique ligament and posteromedial capsule play a significant role in the prevention of additional posterior tibial translation in the knee in the setting of posterior cruciate ligament injury. They also act to resist internal tibial rotation with the knee in full extension.
Griffith et al. reports that the posterior oblique ligament provides significant resistance to valgus and internal rotation forces with knee extension. They used a cadaver model and demonstrated that the superficial MCL resists valgus and external rotation forces more than the posterior oblique ligament, while the posterior oblique ligament is more involved in resisting internal rotation.
Tibor et al. reviews the anatomy of the posteromedial corner of the knee. They report that failing to recognize injury to these structures may cause failure of cruciate ligament reconstruction surgery, and that reconstruction or repair of the posteromedial corner may be indicated in the face of multiple ligament injuries.
Illustration A shows the posteromedial corner of the knee, including the posterior oblique ligament.
Incorrect answers:
4: These structures are not primary restraints to internal tibial rotation in full extension.
OrthoCash 2020
Increasing the porosity of a cement spacer for an infected total knee arthroplasty leads to which of the following?
Increased strength
Increased elution of antibiotics
Increased cement density
Improved cement-prosthesis bonding
Increased reinfection rate
Corrent answer: 2
Elution of an antibiotic is increased with increased porosity of a cement spacer. This porosity increase can be obtained with hand mixing and avoiding the use of a vacuum-type mixing device.
Joseph et al. reviews antibiotic-impregnated cement in hip arthroplasty. They note that use of this cement in one- or two-stage revisions has lowered reinfection rates, with the spacers acting to reduce dead space while stabilizing the joint.
Cui et al. reviews antibiotic impregnated cement for TKA and THA. They report that use of greater than 2 grams of antibiotic per 40 gram unit of cement weakens the cement and that use of two antibiotics in conjunction may potentially increase elution.
The reference by Stevens et al compared Simplex and Palacos bone cement in regards to elution in a TKA mold model. They found that initial as well as weekly (9 weeks total) elution rates were greater in the Palacos spacers than the Simplex models. They recommend use of the Palacos cement in TKA model to target antimicrobial delivery while limiting the potential for systemic antibiotic-related toxicity.
Illustrations A and B show an antibiotic spacer in a two-stage revision TKA. Illustration C shows a PROSTALAC in a two-stage revision THA.
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OrthoCash 2020
A 65-year-old patient was treated with an open reduction/internal fixation for a left femoral neck fracture sustained 25 years ago. Five years ago he developed hip pain and was converted to a left hip hemiarthroplasty. He presents with complaints of groin pain for the past 6 weeks. A recent radiograph is shown in Figure A. The patient’s physical exam is limited secondary to pain. Serum laboratory values are WBC-8.0, ESR-20, CRP-0.5. A synovial fluid aspirate of the hip demonstrates < 500 cells (60% PMN). What is the most likely cause of this patient's symptoms?
Acetabular protrusio
Infected hip hemiarthroplasty
Lumbar radiculopathy
Impingement of the hip hemiarthroplasty
Iliopsoas tendinitis
Based on the history, radiographs, and laboratory values, the patient has developed failure of his hip hemiarthroplasty. At this point in time he warrants a conversion to a total hip arthroplasty.
Avascular necrosis (AVN) of the femoral head after traumatic injury to the femoral neck occurs at an incidence of 10-45%. Although the risk increases with failure to anatomically reduce the fractue, it can still occur in non displaced settings. Treatment of avascular necrosis in older patients includes hip hemiarthroplasty or a total hip replacement. With the former, development of acetabular protrusio can contribute to groin symptoms. Functional outcomes have been reported to be higher in those receiving total hip replacement for AVN of the femoral head.
Lee et al. prospectively compared the use of bipolar hip hemiarthroplasty versus total hip arthroplasty for advanced stages of AVN of the femoral head (Ficat Stage 3). Total hip scores were most improved in the total hip arthroplasty group. Migration of the outer head in the hemiarthroplasty group was seen in 23% of patients. They recommend use of a total hip arthroplasty in patients with Ficat Stage 3 AVN of the femoral head
Ito et al. evaluated the outcomes of patients who underwent bipolar hemiarthroplasties for femoral head avascular necrosis. They found that proximal migration and acetabular degeneration were risk factors for groin symptoms. They also found that outcomes were inferior to patients who had undergone total hip arthroplasty for AVN of the femoral head. They recommend use of total hip arthroplasty in advanced osteonecrosis of the femoral head
Diwanji et al. evaluated outcomes of patients who underwent a conversion from a bipolar hip arthroplasty to total hip arthroplasty in 25 patients. Thirteen (52%) patients were revised to THA because of acetabular erosions. Follow up was completed for an average of 7.2 years. At final follow-up, they found improvement of the Harris Hip Scores and improvement of the pain portion of the WOMAC index. They recommend use of total hip replacement as an option to salvage failed bipolar hip hemiarthroplasty
Figure A shows the radiograph of a hip hemiarthroplasty where acetabular protrusion has developed.
Incorrect Answers
OrthoCash 2020
A 38-year-old female patient presents to your office three years after a hip resurfacing. She complains of worsening left hip discomfort for the last 6 months. Her ESR is 12 (normal 0-20) and CRP is 1.2 (0-5). A radiograph and axial and coronal MRI scans are shown in Figures A, B, and C. What is the most likely diagnosis?
Infection
Type I Hypersensitivity reaction
Femoral neck fracture
Prosthesis Loosening
Pseudotumor
The clinical presentation is consistent with a young woman who has developed a symptomatic pseudotumor following hip resurfacing. Her hip discomfort is related to a mass that has developed around the left hip.
Pseudotumors, also referred to as Aseptic Lymphocyte-Dominated Vascular-Associated Lesions (ALVAL), are sterile inflammatory lesions that most commonly occur from metal-on-metal articulations. They occur at an incidence of 0-39% with metal-on-metal resurfacing hip components. The exact mechanishm of formation is unclear, however excessive wear is considered the initiating process, leading to the release of microscopic metal particles. These are cytotoxic to macrophages once phagozytised, leading to necrosis within the lesions and the development of semi-solid or fluid-filled masses around the implant. Lymphocytes are thought to be responsible for the tissue reaction.
Patients often do not complain of pain, but present with a mass around the hip that causes discomfort.
Hart et al. performed a case-control study comparing patients with well-functioning metal-on-metal hip resurfacing to those who have painful prostheses. They found no significant difference between the painfree and painful groups with MRI diagnosed pseudtumors (61% vs. 57%). They concluded that the presence of a pseudotumor should not automatically necessitate revision surgery.
Daniel et al. reviewed the current concepts surrounding pseudotumor. Risk factors associated with pseudotumor formation and failure are female gender, age under 40, hip dysplasia, metal hypersensitivity, and small components.
Larger components have been found to decrease the risk of failure.
Figure A is an AP pelvis radiograph of a patient following a left hip resurfacing surgery. Figures B and C are axial and coronal MR images demonstrating a large pseudotumor around the left hip resurfacing. Illustrations A and B identify the large pseudotumor as outlined in red.
Incorrect Answers:
OrthoCash 2020
After total hip arthroplasty (THA) for osteoarthritis a patient is unable to dorsiflex her ankle or extend her great toe. She is treated conservatively with an orthosis and after 3 months on physical therapy she ambulates with a "slapping gait." What is the most appropriate next treatment option?
MRI of her spine
Ankle Fusion
Continue Ankle-Foot Orthosis
Revision total hip arthroplasty
Sural nerve grafting
Corrent answer: 3
The patient has suffered from a peroneal nerve injury most likely from errant retractor placement during the hip replacement resulting in a foot drop. The most appropriate next treatment is an ankle-foot orthosis.
The ankle joint of an ankle-foot orthoses (AFOs) should restrict plantarflexion to prevent foot drop during the swing phase. In a patient who can not actively dorsiflex the foot the AFO keeps the foot in a neutral position during gait allowing for uninterrupted swing during ambulation.
Park et al reviewed common peroneal nerve injury after THA. Only one-half of the patients in the study who developed common peroneal nerve palsy following total hip arthroplasty recovered fully. The mean time to recovery was approximately one year for partial peroneal palsy and one and one-half years for complete palsy. Obesity adversely influenced the nerve recovery. Thus, at 3 months, the nerve should continue to be monitored and the use of an AFO would assist in ambulation.
Yokoyama et al. developed an AFO with an oil damper to adjust the plantarflexion resistive moment as excessive plantarflexion resistance will cause excessive knee flexion during the stance phase. They found the AFO with the oil damper achieved sufficient plantarflexion of the ankle and mild flexion of the knee by adjusting a proper plantarflexion resistive moment during initial stance phase, and provided a more comfortable gait than did the traditional AFOs.
Illustration A shows the location of the sciatic nerve relative to the short external rotators when performing a posterior approach to the hip.
Incorrect Answers:
OrthoCash 2020
Which of the following statements is true about racial disparities in total joint arthroplasty?
The rate of surgical intervention for African American males is lower than white or Hispanic males
The rate of surgical intervention for Hispanics is higher than that for whites
The rate of surgical intervention for white males is lower than for African American males
There is no difference in the rate of surgical intervention between whites, Hispanics, or African Americans
The rate of surgical intervention is equal for Hispanic and white males
Corrent answer: 1
The rate of surgical intervention for African American males is lower than either white or Hispanic males.
Numerous studies have shown clear racial disparities in the utilization of total joint arthroplasty for the treatment of osteoarthritis. African American and Hispanic patients undergo total joint arthroplasty at a rate much lower than
white patients, even in areas where insurance coverage is more equitable. Currently, little is known about the reasons for such disparities.
Skinner et al. reviewed the Medicare claims between 1998 through 2000 to determine any racial or ethnic disparities amongst patients undergoing total knee arthroplasty. Amongst other things, they showed that the arthroplasty rates for black men were consistently lower than white men in nearly every region.
Nelson reviews health disparities in orthopaedic surgery. Amongst other things, they discuss how African American patients and white patients perceive the same pain and functional limitations for similar radiographic disease. Thus, ethnic differences in perception of symptoms cannot explan the racial disparities noted in total joint arthroplasty.
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OrthoCash 2020
A 65-year-old man presents with aseptic loosening 3 years after total knee arthroplasty. The surgeon reviews radiographs of his knee and takes him to the operating room for revision total knee arthroplasty. During surgery, the exposure technique shown in Figure A is used. Which of the following radiographs (Figures B-F) has the greatest likelihood of needing this exposure technique?
Figure A shows a tibial tubercle osteotomy (TTO). Patella baja (Figure D) is an indication for a TTO.
In revision total knee arthroplasty (TKA), surgical exposure should be extensile. Different exposure techniques have been described (see below). Patella baja may indicate that there is patellar tendon contracture. In this instance, a TTO can be used to prevent inadvertent patellar tendon avulsion which is difficult to repair and may lead to loss of function. Further, proximal transfer of the osteotomized tibial tubercle may be used to correct patella baja, bearing in mind that excessive superior translation alters the mechanics of the knee by making the quadriceps less efficient.
Younger et al. reviewed surgical approaches in revision TKA. They include quadriceps snip, patellar turndown, TTO, femoral peel, medial epicondylar osteotomy and quadriceps myocutaneous approach.
Mendes et al. reviewed the results of TTO in revision TKA. They advocate TTO for cases where the patellar cannot be retracted laterally with knee in 90deg of flexion. Complications include nonunion, tubercle fragment fracture and displacement, and tibial metaphyseal fracture (at the level of the distal cut of the osteotomy).
Della Valle et al. reviewed surgical approaches for revision TKA. They advocate TTO because repair is stronger than patellar turndown, there is less tension on the tibial tubercle in flexion than on the quadriceps tendon, and where multiple operations are required (as multiple VY approaches lead to excessive scar, making the approach difficult) or where stemmed tibial components need to be removed.
Illustration A shows tibial tubercle osteotomy hinged on a lateral periosteal flap. Illustration B shows quadriceps snip. Illustration C shows patellar turndown. Illustration D shows medial epicondyle osteotomy.
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situation.
OrthoCash 2020
Which of the following is the most common intraoperative complication in a patient with sickle cell disease undergoing a total hip arthroplasty?
Periprosthetic fracture distal to the implant
Iatrogenic fracture causing pelvic discontinuity
Perforation of the femoral canal
Cardiac arrest from fat embolization to lungs
Injury to the sciatic nerve
Corrent answer: 3
Perforation of the femoral canal during preparation of the femur is not an uncommon complication, with rates ranging from 4.9-18.2%.
While total hip arthroplasty is extremely effective for pain relief in patients with osteonecrosis of the hip secondary to sickle cell disease, the procedure carries a higher rate of complications compared with non-sickle cell disease patients. Particular attention should be given to the preparation of the femur as femoral medullary widening from chronic marrow hyperplasia adjacent to patchy areas of dense sclerosis can make preparation of the canal difficult.
Some surgeons prefer to ream over a guide-wire to avoid perforation.
Jeong et al. reviewed total hip arthroplasty in patients with sickle cell disease. Amongst other things, they discuss the difficulties associated with preparation of the femoral canal, quoting a perforation rate between 4.9-18.2%. They also state there are no prospective studies comparing cementless to cemented THA, but retrospective data has shown promising results with cementless components.
Hernigou et al. retrospectively reviewed 244 patients with sickle cell disease that underwent cemented total hip arthroplasty. They had a 3% infection rate, a relatively low rate of revision for aseptic loosening, and a 27% rate of medical complications. Overall, they viewed their results as favorable.
Illustration A shows a patient with bilateral AVN secondary to sickle cell disease. Note the areas of patchy dense sclerosis in the metaphyseal region of the proximal femur.
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to be more common in this patient population. The rate of post-operative hematoma causing sciatic nerve dysfunction may be higher in this patient population.
OrthoCash 2020
A 63-year-old patient presents with periprosthetic joint infection 3 years after primary total knee arthroplasty. A radiograph of her knee is seen in Figure A. She undergoes 2-stage revision total knee arthroplasty. Radiographs taken at the time of explantation are seen in Figure B. An articulating antibiotic spacer is placed. Two months later, she is deemed to be free of infection and is taken to the operating room for the second stage operation. Intraoperatively, it is noted that the collaterals are intact and the previous tibial tubercle osteotomy had healed. What is the most appropriate surgical strategy at this point?
Address epiphyseal defects with impaction particulate bone grafting
Address metaphyseal defects with structural allograft and uncemented, unstemmed implants
Address metaphyseal defects with uncemented, porous metaphyseal
sleeves and uncemented, stemmed implants
Address diaphyseal defects with porous metal cones and uncemented, stemmed implants
Address diaphyseal defects with cemented stemmed implants
Corrent answer: 3
This patient has massive metaphyseal defects following resection of primary TKA implants. Metaphyseal defects may be addressed with uncemented, porous metaphyseal sleeves and uncemented stemmed implants.
In revision settings, metaphyseal bone is often deficient. The Anderson Orthopaedic Research Institute classification (AORI) is most commonly used to classify defects. Stemmed implants are necessary to divert stress away from deficient metaphyseal defects to structurally sound cortical bone. These may be cemented or uncemented.
Haidukewych et al. reviewed metaphyseal fixation in revision TKA. For large defects, they advocate structural allograft, porous metal cones, and stepped metaphyseal sleeves.
Bush et al. reviewed managing bone loss in TKA. They cautioned that joint line elevation, distal femoral bone loss, and femoral prosthesis downsizing leads to flexion instability. They advocate cement filling for Type I defects, modular augments for Type 2, impaction grafting for Type 1 or 3, structural allograft for Types 2 and 3, metaphyseal filling or megaprosthesis for Type 3, including porous metal implants.
Figure A shows an infected primary TKA with a stemmed tibial component with medial augments. This suggests that the revision implant will require at least a stemmed, augmented component. Figure B shows massive metaphyseal defects (AORI Type 2) at the time of explantation. Illustration A comprises postop images of osseointegrated metaphyseal sleeves and stemmed implants. Illustration B depicts the AORI classification (see Review Topic for detailed description). Images courtesy of Haidukewych et al (Ref 1).
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OrthoCash 2020
During templating for a total hip arthroplasty, placing the femoral head center of rotation directly superior to the center of rotation of the acetabular component will have which of the following effects?
Increase offset
Decrease limb length
Decrease offset
Increase limb length
No change in length or offset
Corrent answer: 4
Placing the femoral head center of rotation directly superior (above) the acetabular center of rotation will lengthen the limb without changing offset.
When templating the femoral component for a total hip arthroplasty, it is imperative to restore limb length and offset. To change limb length, the femoral component center of rotation (COR) can be adjusted in a superior or inferior direction. If the femoral component COR is superior to the acetabular component COR, the limb will be lengthened (as in the example above).
Conversely, if the femoral component COR is inferior to the acetabular component COR, the hip will be shortened. A change in offset will be determined by the medial/lateral relationship between the acetabular and femoral components. In the example above, the COR of the femoral component is directly above the COR of the acetabular component. In this situation, there is no change in offset.
Merle et al. performed a retrospective cohort study to identify differences in femoral offset as measured on an AP pelvis radiograph, AP hip radiograph, and a CT scan. They found that femoral offset is significantly underestimated on AP radiographs of the pelvis. In contrast, AP radiographs of the hip are much more accurate in representing true offset.
Della Valle et al. review the importance of preoperative planning prior to total hip arthroplasty. While they mention that templating can be very accurate, determination of stem and cup size should also be determined by tactile feedback during broaching and reaming.
Illustration A shows the femoral head COR inferior to the acetabular COR. This will result in a decreased limb length.
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OrthoCash 2020
Which of the following intra-operative errors most commonly leads to patellar maltracking during a total knee arthroplasty?
Using the gap balancing technique instead of measured resection technique
Internal rotation of the femoral component
External rotation of the tibial component
Lateralization of the femoral prosthesis
Overresection of the patella
Internal rotation of the femoral component increases the Q-angle and will increase the likelihood of patellar maltracking.
Patellar maltracking is one of the most common complications following a total knee arthroplasty. Any alteration that results in increased lateral retinaculum tension or an increased Q-angle may lead to patellofemoral instability.
Common causes include internal rotation of the femoral or tibial components, medialization of the femoral component, and placement of the patellar prosthesis on the lateral border of the patella. If a patient presents with postoperative maltracking and component rotation is thought to be the cause, a CT scan is the diagnostic study of choice.
Rhoads et al. analyze 7 cadaveric specimens to define the kinematics of the intact knee and to evaluate the effects of prosthetic replacement on those kinematics. Amongst other things, they showed that lateralization of the femoral component improved patellar tracking and prevented dislocation.
Malo et al. review patellar maltracking following a total knee replacement. They discuss the importance of externally rotating the femoral component on the femur relative to the posterior articular condyles to establish a rectangular and balanced flexion gap and to accommodate central patellar tracking.
Illustration A shows how an internally rotated femoral component displaces the patella medially. The blue line is a straight line upwards from the tibial tubercle, and the green line represents a line from the tibial tubercle to the center of the patella. The difference between the blue and green lines in the internally rotated prosthesis is the amount the patella has displaced medially. If you deviate the patella medially, this increases the Q-angle and could lead to patellar maltracking in a total knee replacement.
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OrthoCash 2020
When performing a total knee arthroplasty on a 60-year-old female patient, a surgeon chooses not to resurface the patella. Instead, he performs a patelloplasty by excising the marginal osteophytes and reshaping the patella. All of the following statements comparing the results of patelloplasty to patella resurfacing are true EXCEPT:
There is no difference in relative risk of anterior knee pain.
There is no difference in relative risk for revision surgery involving the tibial and femoral components.
There is an increased risk that she will need secondary resurfacing.
No difference in rates of patellar avascular necrosis or patellar tendon injury.
Total knee arthroplasty improved function regardless of whether the patella was resurfaced.
In TKA with an unresurfaced patella, there is an increased risk of anterior knee pain and secondary resurfacing.
Surgeons can choose to resurface or not resurface all patellae, or selectively resurface patellae. In unresurfaced patellae, they may perform a patelloplasty (excise marginal osteophytes and reshape the patella). Unresurfaced patellae have increased risk of anterior knee pain requiring secondary resurfacing.
Indications for resurfacing include inflammatory arthritis, patella maltracking, patellofemoral osteoarthritis as the main indication for TKA.
Meneghini et al. reviewed the literature on patellar resurfacing. Prospective, randomized studies show conflicting results with regards to satisfaction rates between groups. Meta-analyses show increased risk of re-operation and anterior knee pain in the unresurfaced group.
Parvizi et al. performed meta-analysis on 1519 knees. They found there was
(1) lower relative risk of re-operation (resurfaced group), (2) lower relative risk of anterior knee pain (resurfaced group), (3) increased rate of secondary resurfacing (unresurfaced group), (4) no difference in patient satisfaction, (5) TKA improved function regardless of whether the patella was resurfaced, (6) no difference in complications.
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OrthoCash 2020
A 55-year-old patient returns for followup 2 years after a left ceramic-on-ceramic total hip arthroplasty. He has no pain or symptoms of instability. The video in Figure V shows him ascending stairs. All of the following factors may contribute to this phenomenon EXCEPT
Impingement
Edge-loading
Loss of fluid film lubrication.
Third-body particles
Subclinical infection
The clinical presentation is consistent for prosthesis squeaking following a THA. Squeaking is multifactorial and may include impingement, edge-loading, loss of fluid film lubrication, and third-body particles. Subclinical infection does not play a role in squeaking.
Squeaking is defined as a high-pitched, audible sound occurring during movement of the hip. In ceramic-on-ceramic (COC) hips, the incidence is 0.5-10%. The incidence of revision because of squeaking is 0.5%. Squeaking is less common in metal-on-metal bearing surfaces (4-5%).
Chevilotte et al. reviewed COC bearing surfaces. They found that without lubrication, squeaking occurred with normal gait, high load, stripe wear, material transfer, edge wear and microfractures. In contrast, with lubrication, squeaking only occurred with material transfer.
Finkbone et al. reviewed COC total hip arthroplasty in patients <20-years-old after 52-month (average) follow-up. They found that survival rate was 96% with 1 revision for a loose acetabular component (failure of bone ingrowth). They found no cases of osteolysis, which can theoretically occur because of stripe wear, or femoral neck-on-liner impingement.
Walter et al. reviewed squeaking hips. They found that this phenomenon is associated with (1) walking, bending, rising (cyclical gait movements or extreme flexion), (2) maloriented acetabular components, (3) impingement,
(4) third-body particles, (5) edge loading, (6) loss of fluid film lubrication and
(7) thin, flexible (titanium) stem.
The video shows squeaking of a left total hip arthroplasty during hip extension from a flexed position. This is consistent with edge loading. Illustration A shows superior edge loading in the walking position. The arrow represents the loading force. The superolateral edge of the liner is in contact with the superior surface of the head. The dark area (area of edge loading) is anteverted with respect to a line of latitude (dark line) on the head. Illustration B shows posterior edge loading in the bending position. The arrow represents the loading force. The posterior edge of the liner is in contact with the superior surface of the head. The shaded area represents the area of edge loading and the dark stripe indicates wear on the femoral head.
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OrthoCash 2020
Figure A shows the image of a 72-year-old male who sustained a fall from standing. Past medical history is significant for hypertension. He was a community ambulator without the use of a cane or walker prior to the fall. During the operation, he is noted to have a well-fixed acetabular component without significant wear of his polyethylene liner, but his femoral component is easily extractable. Which of the following correctly pairs his Vancouver classification and appropriate surgical intervention?
Vancouver A, Revision of femoral component to cemented stem with fixation of the fracture
Vancouver B1, Revision of femoral component to cemented stem with fixation of the fracture
Vanvouver B1, Revision of femoral component to a long, porous-coated, cementless stem with fixation of the fracture
Vancouver B2, Fixation of the fracture with a plate and cerclage wires
Vancouver B2, Revision of femoral component to a long, porous-coated, cementless stem with fixation of the fracture
Figure A shows a Vancouver B fracture around the femoral prosthesis. Because the prosthesis is noted to be loose during the operation, it is classified as a Vancouver B2 fracture. The most appropriate operation would be revision of the femoral component to a long, porous-coated, cementless stem in addition to fixation of fracture with a plate and cerclage wires.
According to the Vancouver classification, a type B2 fracture occurs around or just distal to a loose femoral stem with adequate proximal bone. Revision of the femoral component is necessary, with uncemented stems showing superior clinical results to cemented stems in most studies. The revision prosthesis should bypass the distal fracture by 2 cortical widths.
Corten et al. reviewed thirty-one patients with Vancouver B2 fractures that
were treated with a long cemented stem with additional allograft or plate fixation. At 46 months, none of the implants had to be revised, but it should be noted that 43% of the patients died within the first year.
Mulay et al. reviewed 24 patients with Vancouver B2 and B3 fractures managed with a cementless, tapered, fluted, and distally fixed stem. 91% of fractures united uneventfully. Complications included dislocations (5), nonunions (2), and infection (1).
Springer et al. review 116 patients with Vanvouver B fractures treated with revision of the femoral component. The uncemented, extensively porous-coated implants had the highest likelihood of stable fixation and were not associated with any nonunions.
Illustration A reviews the Vancouver classification for periprosthetic femur fractures. Illustration B shows a post-operative radiograph following a Vancouver B2 fracture. In this case, a trochanteric plate with cerclage wires was used to fix the fracture. A long-stemmed, porous-coated, cementless femoral prosthesis was used for the revision.
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OrthoCash 2020
A 56-year-old male undergoes revision of his right hip arthroplasty for acute pain and radiographs suggestive of ceramic femoral head fracture. At the time of the revision, multiple fragments of the ceramic femoral head were seen in the joint and soft tissues. The components were noted to be in good position. He was copiously irrigated and the ceramic head was exchanged with a metallic femoral head. 12 months later, the patient presents with insidious onset right groin pain. Radiographs show no gross abnormalities without signs of loosening. Which of the following is the most likely cause of the patient's pain?
Periprosthetic infection
Massive third body wear
Pseudotumor formation
Soft tissue metallosis
Iliopsoas tendonitis
The most likely cause of the patient's pain is massive third body wear caused by retained ceramic fragments.
Cermamic femoral head fractures create many fragments that are difficult to extract at the time of revision surgery. During the revision surgery, it is imperative to remove all fragments that can be visualized. Despite a thorough debridement, microscopic fragments will still remain. These particles may cause pain through the creation of an inflammatory response in the tissues.
Exchange of the femoral head should be performed with another ceramic head, as opposed to a metal head. If a metal head is used, abrasive wear will ensue as the microscopic fragments will scratch the femoral head due to differences in hardness.
Traina et al. describe their experiences with revision of ceramic components. Most commonly, fractures of ceramic components occur as a result of trauma, dislocation, or errors in operative technique. These include head-neck taper mismatch, impacting the ceramic head with too much force, debris, and intraoperative damage to the metal neck taper.
Hannouche et al. review ceramics in total hip replacement. They state that if the ceramic is properly manufactured, it can be a highly effective, low-wear solution for the young patient in need of a total hip replacement.
Illustration A shows the typical ceramic femoral head used for a total hip arthroplasty. Illustration B shows a fractured ceramic head in many pieces.
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OrthoCash 2020
Figure A and B are radiographs of a 77-year-old patient presenting with right hip and upper thigh pain for the past 3 months. He is an avid golfer and plans to travel south for 6 months on a golf tour. He denies fever, chills or weight loss. His past medical history includes hypertension and a right total hip replacement 15 years ago. Physical examination reveals minimal pain with range of motion. ESR=10 (normal range 0-20) and CRP=4 (normal range 0-10). He does not want any further surgery. The patient is at the highest risk of which complication with non-operative care?
Infection
Pseudotumour formation
Periprosthetic femoral fracture
Periprosthetic acetabular fracture
Dislocation
This patient has presented with significant osteolysis and aseptic loosening of his femoral THA component. If untreated, he is at an increased risk of a periprosthetic femur fracture.
Indications for surgery for periprosthetic osteolysis include: pathological fracture, impending pathological fracture, symptomatic THA with evidence of osteolysis, and extensive osteolysis that would compromise revision surgery in the future. The goal of surgery is to remove the loose component, repair/bypass/replace bone deficiency, and obtain stable component fixation.
Robbins et al. reviewed the causes of pain in THA. They report that hip pain can originate from the implant, soft tissue, or bone. The use of laboratory tests (e.g. ESR/CRP), radiographic and fluoroscopic imaging, hip aspirate, contrast arthrography and local anesthetic injections can help to determine the origin of pain.
Ollivere et al. report that the most frequent cause of failure after total hip replacement in all reported arthroplasty registries is periprosthetic osteolysis. Osteolysis occurs with the activation of macrophages and a complex biological cascade that results in bone loss.
Hirakawa et al. analyzed the circumstances around retrieved failed THA components. They showed that cement mantle defects, noncircumferential porous coatings, and screw holes are risk factors for osteolysis. They conclude by saying that the formation of a granulomatous tissue that ultimately invades the bone-implant interface is the final step in the pathogenesis of aseptic loosening.
Figure A and B show AP and lateral views of a right THA. The femoral stem shows gross loosening in all zones. Subsidence is obvious with a high-riding greater trochanter. The lateral cement mantle is fractured. There is endosteal erosion distally with the tip of the stem showing radiographic toggle.
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osteolysis, but it remains well fixed. Acetabular fractures are less likely when there is minimal osteolysis.
OrthoCash 2020
A 60-year-old woman undergoes a total knee arthroplasty for end-stage osteoarthritis. Preoperative knee range of motion is 5 to 100 degrees. Postoperatively, she experiences reduced range of motion. She is scheduled to undergo manipulation under anesthesia. In which of the following scenarios is this procedure best indicated?
Knee range of motion 0 to 60 degrees at 2 months postoperatively
Knee range of motion 0 to 60 degrees at 8 months postoperatively
Knee range of motion 30 to 120 degrees at 2 months postoperatively
Knee range of motion 30 to 120 degrees at 8 months postoperatively
Knee range of motion 30 to 120 degrees at 2 weeks postoperatively
Manipulation under anesthesia (MUA) can achieve the greatest gains in flexion when performed for patients with less than 90 degrees of flexion within the first three months.
There are many risk factors for postoperative stiffness, the most important being preoperative stiffness. MUA is indicated when flexion is less than 90 degrees. Flexion gains are generally greater when applied early (6-12 weeks postoperatively) rather than late (>12 weeks). In cases with late-presenting stiffness (>12wks), MUA may still be attempted. Failed MUA is addressed with arthroscopic or open adhesiolysis +/- MUA, quadricepsplasty, or component revision.
Namba et al. compared the results of early (<90 days) vs late (>90 days) MUA. They found that: (1) knee flexion improved a mean of 32 deg and 20 deg after early and late MUA respectively, (2) extension improved in the early MUA group, but not the late MUA group, and (3) pain improved after early but not late MUA. Despite early MUA being more desirable, the authors state that patients with limited flexion at 6-12 months may still benefit from late MUA.
Keating et al. assessed the outcomes of MUA in 113 knees at a mean of 10 weeks after surgery. They found that (1) 90% of patients achieved
improvement in knee flexion of 35 degrees at 5 year followup, (2) there was no difference in flexion gains between early (<12 weeks) and late (>12 weeks) MUA and (3) patients treated with MUA had better pain control than those without MUA. They concluded that manipulation can result in significant and lasting improvement in knee flexion.
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OrthoCash 2020
A 62-year-old man is scheduled for a total knee arthroplasty. In his pre-operative office visit, he asks questions about different tibial components. You tell him that compared with the tibial component shown in Figure A, the tibial component shown in Figure B:
Is less expensive
Has greater durability
Has greater instability because of its monobloc nature
Provides improved short-term functional status, but no difference in long term functional status
Is associated with fewer adverse events because of easier implantation
Corrent answer: 1
Figure B shows an all-polyethylene tibia (APT) component, which is $470 to
$1650 less expensive than metal-backed tibia (MBT) designs.
It was traditionally thought that modular MBT may have lower survivorship (compared to APT) because of locking mechanism dysfunction, breakage,
backside wear, and osteolysis. However, many studies now show the two to be comparable, with the only difference being that APT are less expensive.
Voight et al. performed a systematic review comparing APT and MBT. They found that the former was cheaper. There was no difference in adverse events, durability (need for revision or radiographic failure) at 2, 10, and 15 years, and functional status at 2, 8, and 10 years.
Toman et al. compared APT and MBT retrospectively. They found that APT implants perform as well as MBT implants in patients with BMI <37.5. There were 4 tibial implant failures in the MBT group in patients BMI >40.
Dalury et al. examined APT performance in obese patients (125 knees) after a minimum of 7 years. There were no implant failures. There were 5 nonprogressive tibial radiolucencies and 1 case of nonprogressive osteolysis.
Figure A shows a cemented metal-backed tibia component. Figure B shows a cemented all-polyethylene tibia component.
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OrthoCash 2020
Figures A and B show pre- and post-operative radiographs of a sedentary 75-year-old female who underwent surgery on her left hip. Based on the radiographic findings, what was the most likely indication for revision surgery?
Left acetabular fracture
Left acetabular cup osteolysis
Left femoral stem osteolysis
Left hip instability
Left femoral stem valgus malalignment
Corrent answer: 4
Figure A shows a left total hip arthroplasty with eccentric polyethylene wear. Figure B shows that her left hip was revised to a constrained acetabular liner, most likely a result of recurrent instability.
Revision strategies for hip instability are typically directed at correcting the underlying cause of instability. For example, instability most commonly occurs as a result of poor implant design, positioning or loosening, or the loss of soft-tissue function or tensioning. Operative strategies are designed to correct these etiologies by repositioning or exchanging components, integrating modular designs and improving soft tissue tensioning, etc. Constrained acetabular liners are often used in conjunction with these modalities to address the problem of recurrent instability relating to soft tissue deficiency and dysfunction in the affected hip.
Alberton et al. retrospectively reviewed 1548 revision arthroplasties for the incidence of dislocation. They found the overall dislocation rate to be 7.8%. Factors contributing to increased dislocations were found to be trochanteric non-unions, femoral heads <28mm in diameter and extensive soft-tissue dissection. Protective factors were modular acetabular components or liners, larger femoral heads >28mm and re-establishing abductor tensioning.
Paterno et al. retrospectively reviewed 438 primary and 181 revision total hip arthroplasties for patient factors contributing to dislocation. They found an overall dislocation rate of 6%. 23% of patients with a history of excessive intake of alcoholic beverages (more than six ounces a day) had at least one dislocation. There was no relationship between the variables of age, gender, obesity, or preoperative diagnosis and the incidence of dislocation.
Figure A shows bilateral primary cementless, nonconstrained total hip replacements. The left hip shows eccentric femoral head placement within the acetabulum indicative of eccentric polyethylene wear. Figure B shows the conversion to a constrained, dual-mobility, polyethylene liner. The overall metal component position appears satisfactory.
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OrthoCash 2020
A 62-year-old woman is brought to the emergency room after falling down a flight of stairs. Prior to her fall, she had no knee pain and was a community ambulator without assistance. Intraoperatively,
it is determined that the implants are well-fixed. What is the best next treatment step to optimize her quality of life?
Closed reduction and long leg casting at 20 degrees of flexion for 6 weeks, followed by hinged-knee brace for 6 weeks.
Open reduction and internal fixation with a distal femoral locking plate
Open reduction and internal fixation with a condylar buttress plate
Distal femoral replacement arthroplasty
Closed reduction and fixation with an antegrade intramedullary nail
Corrent answer: 2
This patient has a displaced far-distal supracondylar fracture around a stable TKA femoral component. Locked plating is the best option for management of this fracture.
Surgical fixation of periprosthetic fractures around a stable femoral component is challenging. Locked plating allows for multiple angle-stable fixation points around stems and lugs and does not depend on TKA design or quality of distal bone stock for fixation. Su Type I fractures may be treated with retrograde or antegrade intramedullary nailing. Type II fractures require retrograde intramedullary nailing or fixed-angle plating. Type III fractures require fixation with a fixed-angle device or revision arthroplasty when bone stock is poor.
Ricci et al. evaluated indirect reduction and locked lateral plating of Vancouver B1 THA fractures without allograft struts. They found that all fractures healed with satisfactory alignment and without implant loosening at an average of 12 weeks. They recommend this technique for stable Vancouver B1 fractures.
Streubel et al. examined the outcomes of locked plating in treatment of extreme distal periprosthetic supracondylar fractures located proximal to the flange (Su Types I and II) compared with fractures distal to the flange (Su Type III, see Illustration B). They found no difference in delayed union, nonunion, infection and failure rates between the 2 groups.
Figure A shows a Su Type III periprosthetic fracture around a TKA femoral component. Illustration A shows fixation of the same fracture with a distal femur locking plate. Illustration B shows the Su classification of fractures around the femoral component (Type I, proximal to the femoral component; Type II, starting at the anterior flange and extending proximally; Type III, fracture line distal to the anterior flange).
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OrthoCash 2020
Which of the following fractures would most likely require revision arthroplasty with a long-stemmed, uncemented prosthesis?
Figure B shows a Vancouver B2 periprosthetic femur fracture with an unstable femoral stem that requires revision arthroplasty with a long-stemmed prosthesis.
The Vancouver classification for periprosthetic femur fractures can help guide treatment of these challenging problems. Vancouver A fractures involve the greater and lesser trochanter and can be initially managed with non-operative measures. Vancouver B fractures occur around the stem and are broken down into B1 (stable prosthesis), B2 (unstable prosthesis) and B3 (poor proximal bone quality) fractures. B1 fractures may be treated with internal fixation, B2 fractures require a revision arthroplasty, and B3 fractures often require more advanced reconstruction with a proximal femoral replacement versus revision with a distally fixed prosthesis. Vancouver C fractures occur distal to the stem and require internal fixation.
Springer et al. reviewed 118 patients who underwent revision arthroplasty for Vancouver B2 periprosthetic fractures. They had a 90% survival rate at 5-years and a 79.2% survival rate at 10-years. The most common reasons for revision were loosening, infection, and non-union.
Illustration A shows the Vancouver classification of periprosthetic fractures about the femur.
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OrthoCash 2020
A 65-year-old female sustains a periprosthetic supracondylar femur fracture proximal to a well-fixed implant. She undergoes direct reduction and locked plating with a titanium distal femoral locking plate via an extensile lateral approach. At 9 months post-operatively, weightbearing is at 50% and is painful. Examination reveals mild swelling and warmth around the distal incision. Erythrocyte sedimentation rate and C-reactive protein are normal. Radiographs taken 9 months post-operatively are shown in Figure A. Which of the following may have increased the risk of this complication?
Neglecting to add topical rhBMP-2 on a carrier-scaffold
Neglecting to use lag screws and cerclage cables
Locked plating instead of locked antegrade nailing
Use of a titanium plate instead of a stainless steel plate
Use of an extensile lateral approach instead of a submuscular approach
Corrent answer: 5
A submuscular approach has been shown to have less risk of nonunion than an extensile lateral approach. There is less disruption of soft tissue attachments and devitalization of fracture fragments with the submuscular approach.
The risks for periprosthetic fractures include notching, knee stiffness, osteoporosis, poor mobility and falls. The risk is higher in females and after revision surgery. The treatment of periprosthetic supracondylar fractures depends on the location of the fracture, fixation of the implant, and bone stock.
Hoffman et al. retrospectively reviewed 36 periprosthetic supracondylar femur fractures treated with locked plating. They found that submuscular plating had reduced nonunion risk compared to an extensive lateral approach. They recommend indirect reduction and submuscular plating to reduce the incidence of nonunion.
Hou et al. retrospectively reviewed 53 fractures fixed with retrograde nailing
(18) and locked plating (34). They found no difference in blood loss, time to union, operating time and hospital stay. They believe locked plating can
provide the same favorable results as retrograde nailing and recommend this technique for most patients and prosthetic designs.
Figure A shows nonunion and surrounding osteopenia after locked plating of a periprosthetic supracondylar fracture. Illustration A shows management of these fractures according to the Su classification.
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OrthoCash 2020
Immediately following a total hip arthroplasty (THA), a healthy 55-year-old patient is unable to dorsiflex her ankle or extend her great toe. After 4 weeks she continues to ambulate with a "slapping gait." Examination reveals passive ankle joint dorsiflexion to 10 degrees. What is the most appropriate next treatment option?
MRI of her spine and pelvis
Revision total hip arthroplasty
Ankle-foot orthosis
Posterior tibial tendon transfer to navicular bone
Neurology consult
This patient is presenting with foot drop after a THA for hip dysplasia (Crowe 4). The most appropriate treatment at this stage would be providing her with an ankle foot orthosis (AFO) for mobility.
Sciatic nerve injury after THA is an uncommon and difficult situation to manage. Patients with DDH that have undergone a large limb-lengthening procedure are at a greater risk due to the significant stretch of the sciatic nerve. Intra-operative procedures that have been shown to prevent this outcome include good pre-operative planning, limb lengthening <3 cm, subtrochanteric osteotomy, intra-operative wake-up test, and downsizing implant components if presenting with deficits peri-operatively. An ankle-foot orthosis may be used for foot drop when surgery is not warranted or during neurologic recovery.
Prahinski et al. reviewed the Bridle transfer for paresis of the anterior and lateral compartment musculature. Indications for the procedure include no neurological recovery for at least 18 months after injury or 18 months after the most recent attempt at exploration or repair of the nerve.
Electrodiagnostic changes must indicate permanent damage. In addition, there must be good passive range of motion, with at least 90° of dorsiflexion.
Edwards et al. reported on twenty-three peroneal and sciatic nerve palsies that occurred in patients following total hip arthroplasty. They showed that peroneal nerve palsy occurred with an average lengthening of 2.7 cm (1.9 cm-3.7 cm) in comparison with 4.4 cm (4.0 cm-5.1 cm) for sciatic nerve palsies.
Figure A and B show pre- and post-operative images of a patient with severe hip dysplasia treated with primary total hip arthroplasty.
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OrthoCash 2020
A 60-year-old male with history of renal transplantation and previous intravenous drug abuse undergoes total knee arthroplasty. Two years later, he begins to have mild knee pain and low-grade swelling that persists for 10 months before he finally comes to the emergency room. Examination reveals no fever. Range of motion is 5 to 70 degrees. Erythrocyte sedimentation rate is 22mm/h, and C-reactive protein is 0.8mg/L. Knee aspiration reveals 12,000/mm3 nucleated cells with 76% neutrophils. Gram stain is negative and aerobic and anaerobic cultures are negative after 4 days in culture. His symptoms do not resolve after 5 days of empiric intravenous antibiotics and he is taken to the operating room for arthroscopic irrigation and debridement. Operative synovial tissue cultures are shown in Figure A. What is the best next step?
Cessation of immunosuppressant medication, lifelong antimycobacterial suppression
Open irrigation and debridement, implant retention and lifelong antifungal suppression
Open irrigation and debridement, resection arthroplasty, antimycobacterial drugs for 6 to 12 months
Open irrigation and debridement, single-stage exchange, antifungal drugs for 6 to 12 months
Open irrigation and debridement, two-stage exchange, antifungal drugs for 6 to 12 months
This patient has a fungal prosthetic joint infection (PJI) with Candida albicans. Optimal treatment involves resection arthroplasty, delayed reimplantation
arthroplasty, and antifungal drugs for 6-12 months.
Fungal PJI are uncommon. Risk factors include immune suppression and systemic illness e.g. diabetes and chronic renal failure. Candida species is usually the causative organism. The infection is usually indolent and systemic symptoms (e.g. fever) may be absent. ESR and CRP may be only minimally elevated. Two-stage exchange arthroplasty is standard of care.
Phelan et al. described delayed reimplantation in 10 patients with fungal PJI. They found that the median time from resection to reimplantation arthroplasty was 9 and 2 months for total hip and total knee arthroplasty respectively. Two patients had recurrence of infection. They recommend antifungal therapy and delayed reimplantation arthroplasty after confirmation of an infection-free period as the best chance for cure.
Azzam et al. retrospectively reviewed arthroplasty database data to identify 31 fungal PJIs in 6 centers. Delayed implantation was performed in 19 of 29 patients who underwent resection arthroplasty at an average of 7 months.
They recommend two-stage exchange arthroplasty as the treatment of choice, addition of antibacterial drugs to the cement spacer to prevent superinfection, antifungal drugs for 6-12 months, repeat joint aspirations prior to reimplantation, and optimization of host nutritional status prior to reimplantation.
Figure A is a high-powered micrograph showing synovial tissue covered by fibrinopurulent exudates containing fungal colonies of Candida albicans.
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OrthoCash 2020
Which of the following non-operative treatments for osteoarthritis has the best evidence to support its use?
Combination of supervised and home exercise programs
Hyaluronic acid injections
Lateral heel wedge
Acetaminophen
Glucosamine
Of the options listed, a combination of home and supervised exercise has the best supporting evidence for the treatment of osteoarthritis.
The AAOS has recently developed guidelines for the treatment of osteoarthritis. Therapies that are recommended by the AAOS include weight loss, home and supervised exercise programs, and NSAIDs/tramadol.
Therapies that remain inconclusive (lack of supporting evidence) include electrotherapeutic modalities, manual therapy, bracing, acetaminophen/opiods, steroid injections and PRP. Glucosamine, lateral heel wedges and hyaluronic acid injections are not recommended, as current literature has shown them to be ineffective. Keep in mind that these guidelines are subject to change as new literature is published.
Zhang et al. present a systematic review of the literature on arthritis management in the three years following the original OA Research Society International (OARSI) guidelines published in 2006. While weight loss showed an increase in effectiveness with the addition of new studies, electromagnetic therapy, glucosamine, chondroitin sulfate, and hyaluronic acid injections showed a decrease in effectiveness.
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OrthoCash 2020
Figure A shows the 2 bundles of the ACL dissected from a cadaveric knee off their bony attachments. They are labeled Bundle A and Bundle B, respectively. Which of the following is true?
The tibial attachment of Bundle A is anterior to Bundle B. In extension, Bundle B is loose and Bundle A is tight.
The tibial attachment of Bundle A is anterior to Bundle B. In flexion, Bundle B is loose and Bundle A is tight.
The tibial attachment of Bundle B is anterior to Bundle A. In flexion, Bundle B is loose and Bundle A is tight.
The tibial attachment of Bundle B is anterior to Bundle A. In flexion, Bundle A is loose and Bundle B is tight.
The tibial attachment of Bundle B is anterior to Bundle A. In extension, Bundle A is loose and Bundle B is tight.
Bundle A is the anteromedial (AM) bundle, which is longer, and is tight in flexion. Bundle B is the posterolateral (PL) bundle, which is shorter, and is loose in flexion. The AM bundle is attached anterior to the PL bundle on the tibia.
The ACL is comprised of 2 bundles. The AM bundle is longer than the PL bundle. Their names reflect their relative anatomic positions on the tibial insertion site. On the femur, the AM bundle begins at the proximal-anterior aspect of the femoral insertion site, while the PL bundle begins at the posterior-inferior part. In flexion, the AM bundle is tight and the PL bundle is loose. In extension, the AM bundle is loose and the PL bundle is tight.
Bicer et al. reviewed the anatomy of the ACL. They found that the AM bundle was longer (32mm) compared with the PL bundle (18mm). PL bundle carries greater force near full extension, and the AM bundle carries greater force after 15-45° of flexion. Under combined rotatory loads (valgus and internal tibial torque at knee flexion >30°), the AM bundle bore more force than the PL bundle.
Figure A shows the 2 bundles of the ACL. The AM bundle is longer than the PL bundle. The oft referred to length of ACL refers mainly to the length of the AM bundle. Illustrations A and B show the spatial relationships of the AM and PL bundles in a cadaveric knee. Illustration C shows the relative positions of the attachments of each bundle.
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OrthoCash 2020
An 83-year-old man, who had a total hip arthroplasty performed 13 years ago, is referred to your office for evaluation. He reports worsening groin pain over the past year, which has been increasing in frequency. Prior to this past year, he had no other complaints. His current radiograph is shown in Figure A. If he continues to ambulate with this implant, he is at greatest risk for which of the following?
Infection
Acetabular component loosening
Femoral component loosening
Dislocation
Periprosthetic fracture
The patient has eccentric polyethylene wear secondary to component malpositioning. He is at highest risk for dislocation.
Late dislocation following total hip arthroplasty(THA) can occur and has a high recurrence rate, thereafter. Risk factors include eccentric polyethylene, THA at an early age, neurologic decline or associated neurologic conditions (i.e.
Parkinson's disease), or associated trauma.
Parvizi et al. noted in this instructional course lecture that eccentric, excessive polyethylene wear is one of the most common reasons for late, recurrent dislocation. Revision is recommended.
Pulido et al. in this review, reiterated that polyethylene wear can lead to increased inflammation, capsular distention, and instability, increasing risk for dislocation.
von Knoch et al. reviewing over 500 dislocated hips, also noted that eccentric wear was one of major causes linked to late dislocation.
Figure A. exhibits a left total hip arthroplasty with eccentric wear. Incorrect answers:
OrthoCash 2020
Figure A shows a radiograph of a 62-year-old female that underwent a left total hip arthroplasty 5 years ago. She presents to your office with insidious onset of left groin and buttock pain. She denies trauma, fever or chills. On physical examination, her left hip has mild pain with range of motion. She has a normal gait cycle, normal power across the hip and her vitals signs are stable. A left hip aspirate was performed and results are shown in Figure B. What is the most likely cause of her hip pain?
Periprosthetic bacterial hip infection
Periprosthetic hip fracture
Large-particle wear debris disease
Pseudotumor hypersensitivity response
Abductor tendon tear
Corrent answer: 4
This patient is presenting with a metal induced system hypersensitivity response in the setting of a metal-on-metal total hip arthroplasty.
A hip aspiration of a painful THR is a very useful investigation for the work up of infection, having a sensitivity of 75-85% and specificity of 85-100% for
infection. Metal-on-metal THA may mimic infection as aspirate results will often show increased inflammatory infiltrate, with synovial WBC counts in the thousands. However, infected THA are more likely to produce higher percentages of PMNs (>70%) in comparison to hypersensitivity reactions/ adverse reaction to metal debris, which are more likely to produce a higher percentage of lymphocytes (>40%).
Campbell et al. looked at the histological features of pseudotumor-like tissues from metal-on-metal hips. They found that the patients with hip pain and suspected metal sensitivity had fewer metal particles but more aseptic lymphocytic vasculitis-associated lesions compared to patients with evidence of metallic wear. They concluded that pseudotumors occur more because of a hypersensitivity reaction than particle wear.
Kwon et al. examined a small cohort of patients with metal-on-metal hip arthroplasties to investigate the incidence and level of metal-induced systemic hypersensitivity. They found that lymphocyte reactivity to Co, Cr, and Ni did not significantly differ in patients with pseudotumors compared to those patients without pseudotumors. This suggests that systemic hypersensitivity type IV reactions may not be the dominant biological reaction involved in the occurrence of the soft tissue pseudotumors.
Figure A shows a patient with bilateral metal-on-metal total hip arthroplasties. There are no identifiable fractures. The position of the left acetabular cup is slightly vertical, which can increase edge loading and particle wear. Figure B shows the results from the hip aspirate.
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OrthoCash 2020
A 72-year-old patient is scheduled to undergo revision total hip arthroplasty. A 3D-model of the patient's hemipelvis is constructed for pre-operative planning and is shown in Figure A. A custom-designed implant shown in Figure B is created. Which of the following is TRUE of the planned reconstruction?
The implant is a bilobed cup.
The most common complication is dislocation.
The acetabular defect can be classified as AAOS Type V.
Radiation-compromised bone stock is a contraindication.
The winged profile of the implant facilitates insertion through both anterior and anterolateral approaches.
The patient has pelvic discontinuity that will be reconstructed with a custom triflange acetabular component. Dislocation is the most common complication.
Custom triflange acetabular components are indicated for severe acetabular bone loss and pelvic discontinuity that are not amenable to treatment with off-the-shelf implants such as reconstruction plates, jumbo cups and antiprotrusio cages. Dislocation is common and possible etiologies include extensive dissection, less reliable soft tissue repair, deficient abductors/trochanteric nonunion, superior gluteal nerve stretch neuropraxia, and surgeon reluctance to use constrained liners in the face of poor bone stock.
Christie et al. reviewed reconstruction with the triflange cup in 78 hips with AAOS Type III (combined deficiency) or Type IV (pelvic discontinuity) defects. They found improvement in Harris hip scores, limp, need for walking aids.
Dislocation was the most common complication (15.6%, 12 patients), and half of these patients (6/12) needed re-operation for recurrent dislocation. They recommend the triflange cup for difficult reconstructions involving severe bone loss.
Taunton et al. reviewed 57 patients with pelvic discontinuity treated with a custom triflange component. They found that 21% developed instability (10 required revision, and 2 treated nonoperatively). Of note, 51% had preop trochanteric escape (nonunion of the greater trochanter to the femoral component or femur with >1cm of displacement. They recommend the custom triflange implant for discontinuity as it provides predictable midterm fixation and consistent healing.
Figure A is a 3D hemipelvis model generated by stereolithography from a patient’s CT scan. It shows massive bone loss and pelvic discontinuity. Figure B is a custom hydroxyapatite (HA)-coated porous triflange acetabular prosthesis with ilial and ischial screw holes. Illustration A shows a bilobed cup and its appearance on an AP radiograph.
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OrthoCash 2020
All of the following are risk factors for wear-related failure in total knee arthroplasty when using a polyethylene liner that underwent sterilization via gamma irradiation in air EXCEPT?
Increasing shelf age of polyethylene liner
Younger age of patient
Male gender
Posterior cruciate retaining knee design
Use of a rough tibial baseplate
Corrent answer: 4
Increasing shelf age, younger age, male gender, and a rough tibial baseplate are all risk factors for wear-related failure in total knee arthroplasty when using a polyethylene liner. Posterior cruciate retaining knee design is not a documented risk factor.
Fehring et al reviewed 2091 TKA using the Press fit condylar system and noted that the 13-year survivorship for all patients was 82.6% with a 8.3% prevalence of wear-related failure. Cox hazards analysis revealed five variables that were correlated with wear-related failure: patient age, patient gender, polyethylene sheet vendor, polyethylene finishing method, and polyethylene shelf age. They were unable to identify one factor as the defining reason for these wear-related failures. They cautioned that these findings may only be specific to inserts that underwent sterilization via gamma irradiation in air.
Collier et al followed 365 TKA (PCL-retaining) for 5-10 yrs and noted that
factors related to polyethylene insert osteolysis included advanced shelf age, sterilization method, and the material from which it was machined. Osteolysis was identified in 34% with an insert that had been gamma-irradiated in air and affixed to a rough baseplate surface, but only 9% when the insert had been gamma-irradiated in an inert gas or not irradiated at all and joined to a polished surface.
OrthoCash 2020
A 65-year-old healthy patient fell 18 years after a total hip arthroplasty and sustained the fracture shown in Figure A. Which of the following would be the most appropriate treatment?
Percutaneous locked plating
Open reduction internal fixation with a cable plate and allograft strut
Revision to a long femoral stem with allograft bone
Revision to a cemented revision femoral stem that bypasses the fracture site by 5 cm
Three months of non-weight bearing
Corrent answer: 3
The Vancouver classification of periprosthetic femur fractures is based on the fracture site, implant stability, and remaining bone stock. The patient in the question has a type B3 fracture. The cemented stem is loose and there is very poor remaining bone stock. He should be treated with a long, cementless
revision stem with biplanar strut grafts. A tumor prosthesis or allograft-prosthesis composite would be alternate possibilities. Illustrations A and B are a diagram and table of the Vancouver classification of periprosthetic hip fractures.
Springer, et al. looked at the results and complications of revision total hip arthroplasty for the treatment of acute Vancouver type-B periprosthetic femoral fracture. In their series they treated these fractures in multiple ways, including cemented stems, uncemented stems, allograft-prosthetic composite, or tumor prosthesis. They concluded that the best results were with an uncemented, porous coated femoral stem, and the most common cause of revision was loosening.
Parvizi, et al. concluded that due to the poor bone quality and delayed healing of older patients & their periprosthetic fractures that it is imperative that a strong mechanical construct be achieved in the treatment of these fractures. They “advocate the use of numerous screws with purchase of at least ten cortices and reinforcement of fixation with biplanar strut allografts whenever possible. When a revision stem is used, we ensure that adequate diaphyseal fixation is obtained and the fracture is traversed by at least 5 to 8 cm.”
OrthoCash 2020
A 85-year-old man who underwent hemiarthroplasty 5 years ago now complains of thigh pain for the past four months. Laboratory studies show a normal white blood cell count (WBC), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). An aspiration of the hip is performed and is negative for infection. A radiograph is shown in Figure A. Which of the following is the best management option for the femoral implant?
Bone scan to look for loosening
Touch down weight bearing and physical therapy
Revision with a tumor prosthesis
Revision of femoral component with metaphyseal cement fixation of the stem
Revision to a cementless femoral component with diaphyseal press-fit fixation of the stem
The radiograph shows lucency around the femoral stem cement mantle consistent with loosening. There is bone loss in the proximal femur. Diaphyseal fixation is the best option from the choices available. Revision to a cementless femoral stem is the most appropriate management.
Paprosky et al. described their results of revision to cementless femoral components and report 95% survivorship with a minimum of 10 years follow
up.
Haydon et al showed that despite historical literature discouraging the use of cemented femurs for revision, in their experience cemented femoral revision had 91% survivorship when the cause was aseptic loosening. They found early generation cementing techniques, poor cement mantle, poor bone quality, age of less than 60, and male gender to be risk factors for failure in cemented revisions.
OrthoCash 2020
Figure A is a diagram showing the medial side of the knee. During a total knee arthroplasty, proximal tibia resection results in the transection of the ligament in Figure A along the red line. Intraoperative examination reveals coronal plane instability. What are the best next steps?
Use of the implant shown in Figure B, and use of a hinged knee brace postoperatively
Suture repair of the torn ligament, use of the implant shown in Figure C
Use of the implant shown in Figure D, and use of a knee immobilizer postoperatively
Suture repair of the torn ligament, use of the implant shown in Figure D, and use of a hinged knee brace postoperatively
Use of the implant shown in Figure C alone
Corrent answer: 4
This patient has intraoperative midsubstance transection of the MCL. MCL repair, use of either a CR or PS implant, and postoperative knee bracing for 6 weeks is recommended. A possible alternative is the use of an unlinked constrained implant.
The MCL is likely to be compromised by medially placed retractors or during medial subperiosteal elevation (tibial avulsion) or injured by oscillating saw-blade during the tibial or posterior femoral condyle cut. There is no consensus for the treatment of intraoperative rupture. Acceptable salvage options include
(1) direct repair (heavy sutures for midsubstance rupture, and suture anchors for tibial sleeve avusions) and postop knee bracing for 6 weeks with either CR or PS implants, or (2) use of unlinked constrained implants with or without repair.
Lee and Lotke reviewed 37 patients with intraoperative MCL injury out of 1478 patients. They attempted repair in 14 patients, and increased constraint in 30
patients. They found higher failure rates (regardless of MCL repair technique) for cruciate retaining components. They recommend use of an unlinked constrained prosthesis (with or without ligament repair), especially for midsubstance injuries.
Leopold et al. reviewed 16 MCL injuries in 600 knees. They performed suture or suture anchor repair and used a hinged knee brace for 6 weeks postoperatively. All limbs were stable and did not require bracing beyond 6 weeks, demonstrated acceptable alignment, and did not require revision at 45 months. They recommend the use of primary MCL repair or reattachment and postoperative bracing instead of implants with increased constraint.
Figure A shows MCL transection in its midsubstance. Figure B shows a cruciate retaining implant. Figure C shows a hinged knee prosthesis (linked constrained implant). Figure D shows a posterior stabilized implant. Illustration A shows an unlinked constrained implant.
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OrthoCash 2020
A 65-year-old woman complains of intermittent knee pain 12 years after a total knee arthroplasty. She has no history of fever or recent infections. Radiographs are shown in Figures A and B. Examination reveals minimal warmth and a moderate knee effusion. Range of motion is 5 to 100 degrees bilaterally. The C-reactive protein level is 15 mg/L (normal, 0.0-0.8mg/L), and erythrocyte sedimentation rate is 45mm/h (normal, 0-10mm/h). Arthrocentesis reveals 7500 white blood cells and 90% neutrophils. Gram stain is negative. Cultures are negative at 3 days. What is the next best step?
MRI with metal subtraction protocol
Arthroscopic debridement
Open debridement and polyethylene liner exchange
Single-stage revision total knee arthroplasty (TKA)
Explantation of components with two-stage revision TKA
Corrent answer: 5
By the updated 2018 Musculoskeletal Infection Society (MSIS) criteria, this presentation is consistent with a diagnosis of periprosthetic joint infection (PJI). The patient has an elevated CRP (2), ESR (1), synovial WBC >3,000 (3), and >80% PMNs (2), for a total of 8 points. Given the chronicity of the infection, the patietn would be a candidate for two-stage revision.
This patient has clinical signs of PJI such as elevated laboratory values and radiographs suggestive of implant loosening. Even in the absence of positive cultures, the next most supported step in management if two-stage revision with explantation of the prosthesis and insertion of an antibiotic spacer.
Intraoperative cultures should be taken to guide post-operative antibiotic treatment.
Parvizi et al. recently released the updated 2018 MSI crtieria for diagnosis of PJI. The updated criteria (Illustration A) included new diagnostic tests and studies from the seven-year period since the previous criteria were established. Alpha defensin was a new addition. The two major criteria remained, each individually diagnostic of PJI. However the minor crtieria were broken down into pre-operative and intra-operative. The authors showed that a total of 6 points or more had a 97.7% SN and 99.5% SP for PJI.
Huang et al. retrospectively reported the infection control rates in 2-stage exchanges in 55 patients, and compared culture-negative cases with 295 culture-positive cases. They found that infection control in culture-negative cases was 73% at 1-year. Infection control rates were similar in culture-negative and culture-positive cases, and that infection-free survival is highest after 2-stage exchange with postoperative vancomycin. They recommend 2-stage exchange with postoperative vancomycin.
Buller et al. retrospectively assessed traits that would predict the success of debridement and liner exchange for 62 hips and 247 knees. They found that 149 (48.2%) cases failed to eradicate infection. Risks for recurrent infection include longer symptom, higher ESR, previous PJI or infection in the same joint, and an infection by a group 1 (MRSA, VRE, and methicillin-resistant S. epidermidis) or group 2 (MSSA or methicillin-sensitive coagulase-negative Staphylococcus) organism.
Della Valle et al. discuss the AAOS recommendations on diagnosis of periprosthetic hip and knee infections. They recommend repeat hip and knee aspirations when there is discrepancy between probability of PJI and initial aspiration culture result.
Aggarwal et al. prospectively compared the yield of intraoperative tissue and swab cultures in 74 hip, 43 knee, 30 septic and 87 aseptic cases. They found that tissue cultures had higher sensitivity, specificity, positive and negative predictive values for identifying PJI. Swab cultures had higher false positive and negative values. They recommend not using swab cultures, and only using tissue cultures.
Figures A and B are AP and lateral radiographs showing areas of bony erosion suggestive of loosening of the femoral and tibial components.
Illustration A is the 2018 MSIS criteria with point values.
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OrthoCash 2020
What are the affects on limb-length and offset according to the total hip arthroplasty template shown in Figure A?
Limb-length will stay the same, offset will be increased
Limb-length will be decreased, offset will be increased
Limb-length will stay the same, offset will be decreased
Limb-length will be increased, offset will be increased
No change in either limb-length or offset
Corrent answer: 1
In Figure A, the center of rotation of the femoral component lies medial to the center of rotation of the acetabular component. If these components are implanted as shown, the offset will be increased and the leg-lengths will remain equal.
Offset and leg-length changes during templating and insertion of a total hip replacement are determined by the changes in the center of rotation (COR) of the femur relative to the acetabulum. If changes are made in the horizontal plane (x-axis), a change in offset will occur. If changes are made in the vertical plane (y-axis), changes in leg-lengths will occur. If the femoral COR is templated superior to the acetabular COR, the leg will be lengthened. In
contrast, if the femoral COR is templated inferior to the acetabular COR, the leg will be shortened. For offset, the same principles apply. If the femoral COR is templated medial to the acetabular COR, offset will be increased. In contrast, if the femoral COR is templated lateral to the acetabular COR, offset will be decreased. One should aim to restore native offset and leg-lengths in uncomplicated primary total hip arthroplasty.
Merle et al. retrospectively reviewed 152 patients to evaluate femoral offset on an AP pelvis and AP hip radiograph compared to a CT scan of the affected hip. They found that AP pelvis radiograph underestimated femoral offset by 13% when compared to a CT scan. In contrast, the AP hip radiograph showed no difference when compared to the CT scan. They recommend obtaining AP of the hip prior to templating for accurate assessment of femoral offset.
Della Valle et al. review preoperative planning for total hip arthroplasty. While they state that templating has a high predictive value in achieving the desired plan, the surgeon should always be prepared to make intraoperative adjustments based on tactile feedback.
Illustration A shows an example where leg-length will be shortened (femoral COR is inferior to acetabular COR) and offset will stay the same (femoral COR and acetabular COR are in the same horizontal plane). Illustration B is a table which summarizes the points we have discussed.
Incorrect Answers:
OrthoCash 2020
A 65-year-old patient is diagnosed with a periprosthetic joint infection 6 years after total knee arthroplasty. He recalls a history of knee realignment surgery many years prior. Examination reveals lateral patellar tracking and passive flexion to 65 degrees. A recent radiograph is shown in Figure A. During the exposure for explantation, a standard medial parapatellar approach is performed through the previous incision. It is found that adequate knee flexion to allow exposure of the prosthesis cannot be achieved even after release of the lateral gutters and excision of the scar. Which surgical exposure technique (depicted in Figures B through F) would provide the best
surgical exposure for the procedure and preserve the blood supply to the patella?
Fig B
Fig C
Fig D
Fig E
Fig F
A tibial tubercle osteotomy (TTO) would provide the best surgical exposure without compromising patellar blood supply. This patient has patella baja arising from previous high tibial osteotomy, with a scarred, contracted patellar tendon leading to knee stiffness.
A TTO is able to provide good exposure while protecting the extensor mechanism and preventing inadvertent avulsion of a contracted patellar tendon. Further, proximal transfer of the osteotomized tibial tubercle may be used to correct patella baja, bearing in mind that excessive superior translation alters the mechanics of the knee by making the quadriceps less efficient.
Mendes et al. used TTO for surgical exposure in 67 knees undergoing revision TKA. There were good-excellent knee scores at 30 months in 87%. There were no patellofemoral complications, no component malalignments, and no avulsions of the patellar tendon occurred. They advocate TTO for cases where the patellar cannot be retracted laterally with knee in 90deg of flexion.
Whiteside described a series of TTO in 136 TKA. At 2 years, mean range of motion was 94deg. There were 2 tibial tubercle avulsion fractures and 3 tibial fractures (2 in a patient with Charcot arthropathy, and 1 following manipulation after open adhesiolysis. He advises using stemmed tibial components in patients with insensate knees and in cases where manipulation is expected.
Figure A is a lateral radiograph showing severe patella baja. Figure D shows a TTO. See below for Figures B, C, E and F. Illustration A shows the surgical technique for TTO. The distal saw cut angles out of the anterior cortex at a gentle angle to reduce the stress riser effect and risk of postoperative tibial stress fracture.
Incorrect Answers:
sufficient in the presence of severe patellar baja and patellar tendon contracture.
OrthoCash 2020
Figure A show pre- and post-operative radiographs, from left to right respectively, of a 79-year-old male that underwent revision total hip arthroplasty 2 years ago. He presents today for consultation after 4 episodes of right hip dislocation within the past 6 months. Physical examination reveals a trendelenburg gait with no clinical or radiographic limb length discrepancy. An Infection work-up is negative. Results from a CT scan are shown in Figure B. What would be the best treatment option?
Physiotherapy and application of abductor brace
Revision arthroplasty to medialize the cementless cup and surgical repair of the abductor tendon
Revision arthroplasty to a constrained polyethylene liner
Revision arthroplasty to a femoral component with extended offset
Revision arthroplasty to a large ceramic femoral head and offset polyethylene cup
On the left, Figure A shows a metal-on-metal (MOM) bearing hip resurfacing. On the right, Figure A shows a large head, uncemented metal-on-polyethylene (MOP) total hip replacement. In this setting, the most appropriate treatment option would be revision arthroplasty with constrained polyethylene liner.
Constrained liners should be reserved for patients demonstrating recurrent instability despite treatment with a large femoral head. Other indications include elderly patients who do not require implant longevity or have a low functional demand, as well as patients with deficient or non-repairable abductor mechanisms.
Sikes et al. report on the results of a series of 41 patients (52 hips) with recurrent dislocations. They recommend that large femoral heads (LFH) be used as a first-line treatment in high-risk patients (patients of any age with dementia, neuromuscular disability, and inability to comply with precautions). Constrained liners should be reserved for patients demonstrating recurrent
instability despite treatment with an LFH.
Kilampali et al. reviewed late instability of bilateral metal on metal hip resurfacings. They suggest that late instability of hip resurfacing should raise concerns relating to possible local tissue reaction and muscle damage.
Concerning features include steeply-inclined acetabular components a large abduction angle of more than 55 degrees along with a combination of small size component.
Figure A shows an image of a revised socket which was performed to convert the MOM THA to a MOP THA. Figure B shows normal parameters of THA components. The recommendation for acetabular position is anteversion 20° ± 10° and abduction 45° ± 10°. For the femur, recommendations are 10°- 15° of anteversion and 41mm - 45mm of offset.
Incorrect Answers:
OrthoCash 2020
Which of the following has been shown to increase the rate of failure of cemented femoral components in total hip arthroplasty?
Stems that are precoated with polymethylmethacrylate
Calcar contact of the collar
Smoother implant corners
Cement mantle of 2 millimeters
Stem material with a Young's modulus higher than 115 GPa
Corrent answer: 1
Precoating a stem with PMMA adds an additional inferface at risk of failure.
Stiffer stem materials (higher Young's modulus) improve performance. Titanium has a Young's modulus of 115 GPa with alloy and stainless steel
having a higher Young's modulus than titanium. Calcar collar contact adds minimal strength to the construct, but does not lead to premature failure. Smoother corners decrease the rate of failure since they decrease stress risers. The ideal cement mantle is ~2mm. Obtaining less than this would decrease the strength of the construct.
OrthoCash 2020
An 80-year-old male sustains a fall down the stairs and presents with knee swelling. He is a community ambulator who does not use walking aids. Injury radiographs are shown in Figures A and B. What is the next best step?
Intramedullary nailing
Locked plating
Long leg casting
External fixation
Revision total knee arthroplasty
Corrent answer: 5
This patient sustained a periprosthetic femoral fracture around the femoral component which is now loose. Revision of the femoral component is necessary.
Various classifications exist for periprosthetic fractures around TKA. In general, for the femoral component, treatment depends on fracture displacement, fracture location, bone stock, and whether the component is loose. For loose femoral components, revision TKA using distal femoral replacement prosthesis is an option.
Kim et al. proposed a new classification for periprosthetic fractures. Type IA fractures (good bone stock, well fixed, nondisplaced or easily reducible) are managed conservatively. Type IB fractures (good bone stock, well fixed, irreducible closed) are managed with reduction and fixation. Type II fractures (good bone stock, reducible, loose or malpositioned components) are managed with revision. Type III fractures (poor bone stock, loose or malpositioned components) are treated with distal femoral replacement.
Johnston et al. reviewed the options for treating periprosthetic fractures about the knee. They advocate revision of the femoral component when the prosthesis is loose, where there is poor bone stock, or insufficient bone to gain purchase for locked plates or distal locking screws of intramedullary nails.
Nauth et al. review the current concepts in treatment of periprosthetic fractures. They prefer minimally invasive locked plating unless the fracture is significantly proximal to the anterior flange and amenable to retrograde intramedullary nailing. Then they choose nails with options for distal interlocking screws and locking condylar bolts. In extreme osteopenia, they use intramedullary fibular strut allografts (with locked plating). For loose prostheses or poor bone stock, they perform alloprosthetic composite in younger patients and a distal femoral replacement in elderly patients.
Figures A and B are AP and lateral radiographs showing periprosthetic femoral fracture around a loose femoral component. Illustrations A and B are postoperative radiographs showing revision to a hinged prosthesis with long-stemmed components. Illustration C shows Kim' proposed classification of
periprosthetic fractures around the femoral component of a TKA.
Incorrect Answers:
OrthoCash 2020
Utility of the implant seen in Figure A would be best considered in which of the following revision total hip arthroplasty scenarios?
Minimal acetabular deformity, intact rim
Superior acetabular bone lysis with intact superior rim
Localized acetabular destruction of medial wall
Absent superior acetabular rim, superolateral migration
Significant acetabular bone loss, pelvic discontinuity
Corrent answer: 5
Paprosky Type 3B acetabular bone defects describes significant acetabular bone loss, with pelvic discontinuity. Type 3 defects often require reconstruction cages (as seen in Figure A) or acetabular distraction techniques
to treat severe bone loss with an associated pelvic discontinuity.
Deficient acetabular bone stock poses a technical challenge in hip arthroplasty surgery. Paprosky classification for acetabular bone loss to helps guide treatment for revision total hip arthroplasty. The classification is as follows:
Type 1: Minimal deformity, intact rim
Type 2A: Superior bone lysis with intact superior rim Type 2B: Absent superior rim, superolateral migration Type 2C: Localized destruction of medial wall
Type 3A: Significant bone loss, superolateral cup migration Type 3B: Significant bone loss, pelvic discontinuity
Sheth et al. reviewed acetabular bone loss in revision total hip arthroplasty. They state that Paprosky Type 1 and 2 defects can usually be managed with porous-coated hemisphere cup secured with screws. Type 3 defects require reconstruction cages to protect with cups and structural augments or custom triflange implants.
Taunton et al. investigated clinical outcomes and cost-effectiveness of using a custom triflange acetabular component to treat pelvic discontinuity in revision THA. They found satisfactory clinical outcomes (81% had a stable triflange component with healed pelvic discontinuity) and cost equivalence with Trabecular Metal cup-cage constructs.
Figure A shows a lateral image of the pelvis with a reconstruction cage and cup construct. Illustration A shows an illustration of the Paprosky classification. Illustration B shows a table of the Saleh/Gross classification. Illustration C shows a table of the AAOS classification.
Incorrect Answers:
OrthoCash 2020
A 65-year-old male who had a total knee arthroplasty 8 years ago comes into the office with worsening knee pain. The orthopaedic surgeon is concerned about infection and aspirates the knee. Which of the following are the lowest laboratory values from a synovial aspirate suggestive of infection?
WBC of 500 cells/ml and PMN 25%
WBC of 1,000 cells/ml and PMN 25%
WBC of 1,500 cells/ml and PMN 70%
WBC of 5,000 cells/ml and PMN 70%
WBC of 25,000 cells/ml and PMN 70%
WBC of 1,500 cells/ml and PMN 70% indicates the lowest synovial aspirate suggestive of infection.
Mason et al in 2003 reviewed 440 revision TKA's of which 86 had preoperative aspirations. The aspirations yield 55 aseptic failures and 31 septic failures. The mean WBC of the aseptic group was 645 cells/mm(3) compared to 25,951 cells/mm(3) for the septic group (P=<.001). The mean percentage of polymorphonuclear cells (PMNs) was statistically higher in the septic group compared with the aseptic group (72.8% vs 27.3%; P=<.001). With these results, the authors concluded that aspirates with a WBC count greater than 2,500 and 60% PMNs are highly suggestive of infection.
However, in a more recent and larger study, Ghanem et al reviewed 161 infected TKA's vs 268 aseptic failures and concluded that aspiration with WBC of >1100 cells/mm3 and PMN > 64% are suggestive of infection. When both tests yielded results below their cutoff values, the negative predictive value was 98.2% (95% confidence interval, 95.5% to 99.5%), whereas when both tests yielded results greater, infection was confirmed in 98.6% (95% confidence interval, 94.9% to 99.8%) of the cases. Thus, according to the most recent literature, WBC >1100 and PMN > 64% should be considered suggestive of infection in a TKA.
OrthoCash 2020
A 50-year-old man with a past medical history significant for diabetes and end-stage renal disease presents with a chief complaint of instability 6-months following a total knee arthroplasty. Preoperative radiographs are shown in Figures A-C. Physical exam at that time was notable for a large effusion, maltracking patella, extensor lag of 15 degrees, medial instability, and gross laxity to anterior and posterior forces. The procedure was uncomplicated, and was completed using a posterior-stabilized prosthesis with tibial augements and uncemented intramedullary rods in both the femur and tibia. Which of the following surgical techniques should have been implemented to avoid this complication?
Cementing the intramedullary rods in the tibia and femur
Explant with placement of an antibiotic spacer
Taking 5mm of extra bone from the distal femur to elevate the joint line
Use of a hinged total knee arthroplasty
Taking 5mm of extra bone from the tibia to distalize the joint line
Corrent answer: 4
The patient has a neuropathic joint with ligamentous instability and a maltracking patella. The appropriate procedure would have included use of a hinged total knee arthroplasty.
Choosing the appropriate constraint during a total knee arthroplasty ensures the best possible outcome. Hinged total knee arthroplasty prostheses are indicated in the setting of global instability, massive bone loss in a neuropathic joint, oncologic procedures, and hyperextension instability. In a hinged prosthesis, the tibial and femoral components are linked with an axle that restricts varus/valgus and translational stresses. While hinged prostheses are useful in the setting of major revision surgery, they are at increased risk for aseptic loosening due to the high degree of constraint inherent to the device.
Petrou et al. review the results of 100 primary cemented rotating-hinge total knee arthroplasty at 7- to 15-years. At 15 years, survival was 96.1%.
Complications included DVT (n=3), skin necrosis (n=2), subcutaneous hematoma (n=5), intra-operative fracture of either the femur or tibia (n=4), and early infection (n=2).
Figures A-C show a neuropathic joint with considerable lateral bone loss and a frankly dislocated patella. Illustration A shows an example of a hinged total knee arthroplasty. Note how the tibial and femoral components are linked using an axle.
Incorrect Answers:
OrthoCash 2020
A 63-year-old man returns for follow-up 4 years after metal-on-metal left total hip arthroplasty complaining of mild chronic hip pain with ambulation. He is afebrile and ESR and CRP are within normal limits. Radiograph of the left hip is shown in Figure A. What is the best next step?
Anti-inflammatory medication
Serum cobalt and chromium levels
MRI with metal subtraction
Physical therapy
Revision hip arthroplasty
Corrent answer: 2
Metal-on-metal total hip arthroplasties (THA) have been associated with complications presumably due to metal debris and toxicity. Serum cobalt and chromium levels are recommended as part of follow-up evaluation for patients with metal-on-metal hips, even when asymptomatic.
Many patients with metal-on-metal hips have been found to have elevated serum cobalt and chromium levels, for which MR with metal subtraction is recommended to look for pseudotumors and other pathologies. These solid or cystic masses are thought to be related to metal debris and macrophage infiltration and may be associated with pain in some patients.
Lombardi et al summarize and present on behalf of The Hip Society an algorithmic approach to evaluating and treating patients with metal-on-metal THA in follow-up. They state the goals of care as determining the etiology of any pain, managing any intrinsic problems with the arthroplasty, and reassuring/observing when appropriate. They organize the types of patients seen in followup and components of the evaluation.
Chang et al evaluate the correlation between symptoms and MRI findings and report that symptomatic patients tend to have bone marrow edema and tendon tearing on MRI. They report a 69% prevalence of pseudotumors on MRI after metal-on-metal hip arthroplasty, but did not find a correlation between pseudotumor presence and pain.
Hayter et al focus on MRI findings in symptomatic (painful) patients with metal-on-metal THA in a review including 31 hip resurfacing and 29 THA. In the THA group, they report 86% rate of synovitis, 10% extracapsular disease, and 24% osteolysis, with no statistically significant difference in rates between resurfacing and THA.
Figure A is an AP view radiograph of a left hip after metal-on-metal total hip arthroplasty with components well positioned and no osteolysis.
Illustrations A and B from Lombardi et al depict a recommended algorithm for the workup and management of symptomatic and asymptomatic patients, respectively, with metal-on-metal THA.
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OrthoCash 2020
A 72-year-old woman sustains a fall onto her knee three years after an uncomplicated total knee replacement. The fracture pattern is seen in Figure A. The operative note reveals that a cemented patellar component was used. On exam, she has a large effusion and an
inability to straight leg raise. If the patellar component is well fixed, what is the best treatment option?
Patellectomy
Extensor mechanism allograft
Revision of the patellar component with cement and bone grafting of any residual defect
Open reduction and internal fixation of the patella fracture
Non-operative treatment in a knee brace locked in extension for 6 weeks
Corrent answer: 4
Displaced, periprosthetic patella fractures with a deficient extensor mechanism and adequate bone stock are best treated with open reduction and suture or implant fixation.
Periprosthetic patella fractures are a rare, but potentially devastating complication associated with total knee arthroplasty. When evaluating patella fractures, it is important to consider 1) is the extensor mechanism intact, 2) is the patellar component well fixed or loose, and 3) is there sufficient bone stock remaining. Stable implants with an intact extensor mechanism should almost exclusively be treated non-operatively in a brace. In contrast, a deficient
extensor mechanism is an absolute indication for surgical management.
Adigweme et al. review the epidemiology, diagnosis, and treatment of periprosthetic patella fractures. When analyzing patella fractures, they suggest treatment should be based on fracture severity, remaining bone stock, patellar component stability, as well as extensor mechanism function.
Sarmah et al. review periprosthetic fracture around total knee arthroplasty. They provide an algorithm for treatment of periprosthetic patella fractures based on displacement, viability of remaining bone stock, and fracture type.
Figure A is a preoperative lateral radiograph showing a periprosthetic patellar fracture. The distal fragment is comminuted and separated from the proximal fragment by approximately 15 mm. The patellar component appears to be well fixed. Illustration A is intraoperative photograph showing the threads of the suture anchors in the proximal fragment passing through the tunnels in the distal fragment and exiting at the inferior pole of the patella. Illustration B demonstrates anatomical reduction after the knots were tied at the inferior pole of the patella. Illustration C is a lateral x-ray 1 year postoperatively showing fracture union.
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OrthoCash 2020
Knee pain and osteoarthritis are associated with "metabolic syndrome." All of the following are included in the collection of risk factors known as "metabolic syndrome" EXCEPT:
Peripheral vascular disease
Dyslipidemia
Hypertension
Impaired glucose tolerance
Central obesity
Peripheral vascular disease (PVD) may develop in patients with metabolic syndrome. However, no direct relationship between metabolic syndrome and PVD is known, and it is not a part of metabolic syndrome itself. Metabolic syndrome has been shown to be associated with knee pain and development of knee osteoarthritis (OA).
Metabolic syndrome is a collection of medical comorbidities that are known to
be risk factors for developing cardiovascular disease. Metabolic syndrome includes central (abdominal) obesity, dyslipidemia (high triglycerides and low-density lipoproteins), high blood pressure, and elevated fasting glucose levels. There is an increased prevalence of knee pain (and OA) among patients with metabolic syndrome. It is felt that the most important contributing factor to knee pain and OA in metabolic syndrome is obesity. Patients presenting with knee pain or OA and the risk factors included in metabolic syndrome should be counseled on the need to control those risk factors.
Inoue et al. present a study comparing metabolic syndrome and knee OA in a Japanese population. They found that knee OA and metabolic syndrome were highly correlated in females, but not in males.
Engström et al. present a study comparing metabolic syndrome with hip and knee OA. They found no relationship to hip OA, but did find a strong correlation between patients with metabolic syndrome and risk of developing knee arthritis. Patient BMI was the most predictive factor. They also compared prevalence of knee OA to CRP levels, but found no significant relationship.
Incorrect answers:
OrthoCash 2020
A 75-year-old male presents with recurrent dislocations of this left hip. He underwent bilateral total hip arthroplasties 12 and 8 years ago. There were no early post-operative complications with either hip. Despite a total of 5 dislocations in 6 months, he does not have pain or weakness across the left hip. On examination, there is a healthy appearing left lateral scar, equal limb lengths, normal gait and full abductor strength. Radiographs of the pelvis are shown in Figure A. His laboratory results show an erythrocyte sedimentation rate of 8 mm/h (reference range, 0-20 mm/h), and C-reactive protein of 3 mg/L (reference range, 0-5.0 mg/L). A hip aspirate culture is negative. What is the next best management option for this patient?
Magnetic resonance imaging of left hip to exclude an abductor muscle tear
Re-aspiration of left hip to exclude a subclinical infection
Continued observation for trochanteric bursitis
Supervised physiotherapy and gait training for abductor strengthening
Left revision total hip arthroplasty for polyethylene wear
Corrent answer: 5
This patient presents with recurrent late hip instability with radiographic evidence of eccentric polyethylene wear. The best treatment option for this patient would be revision total hip arthroplasty (THA).
The etiology of late instability includes polyethylene wear, component malpositioning or loosening, trauma, infection or deterioration in neurological status of the patient. Identifying the cause of late instability will require a thorough work up. A good history, examination and scrutiny of radiographs can identify most causes. Advanced imaging may be requires when bone or soft-tissue pathology is suspected or radiographic evidence of osteolysis or malpositioning needs further assessment. Blood work to assess for an acute inflammatory response (ESR and CRP) should be ordered routinely as elevated markers may indicate an underlying infection.
Parvizi et al. evaluated the outcome of revision arthroplasty for polyethylene wear presenting as late dislocation. They found that revision surgery restored stability to eighteen of the twenty-two patients. Surgical treatment options may include liner-only exchange (contained or unconstrained) +/- soft-tissue repair, or revision of one or all components.
Berry et al. evaluated the long-term risk of dislocation in 6,623 consecutive primary total hip arthroplasties with a Charnley prosthesis. They found a 7% incidence of late dislocation at 25 years compared to 1% after 5 years.
Patients at highest risk were females, patients with osteonecrosis of the femoral head or an acute fracture, and nonunion of the proximal part of the femur.
Figure A shows an AP pelvis with bilateral, uncemented, total hip arthroplasties. There is eccentric wear of the left acetabular component. No fracture or loosening of the components can be identified. The components appear well-positioned.
Incorrect Answers:
This patient has no pain or weakness in the affected hip. Therefore, soft tissues can be evaluated intra-operatively during the revision THA procedure. Answer 2: A hip aspirate would not be warranted. There are no risk factors for infection in this patient (for example, no pain, no early wound complications or antibiotics, etc). Additionally, his inflammatory markers are normal.
OrthoCash 2020
A 58-year-old woman undergoes a total knee arthroplasty with a posterior stabilized design. Two years later, she returns with recurrent sterile joint effusions, a sensation of instability without giving way and difficulty with ascending and descending stairs. Examination reveals diffuse tenderness around the pes anserinus and peripatellar region, and increased anterior tibial translation most notable at 90° of flexion. Radiographs demonstrate well cemented implants with 5° of posterior tibial slope. Figure A represents a femoral cutting block with lines 1 through 5 corresponding to femoral bone cuts. The most likely cause of her symptoms is over-resection at:
Resection line 1
Resection line 2
Resection line 3
Resection line 4
Resection line 5
Over-resection of the posterior femoral condyles (resection line 2) in posterior-stabilized (PS) TKA leads to flexion instability without frank dislocation.
There are 7 bone cuts in a total knee replacement. The posterior condylar cut determines the flexion gap. Flexion instability in PS knees arises because of an enlarged flexion gap (excessive posterior condylar resection, or increased tibial slope), allowing anterior tibial translation, which is pathognomonic. There will not be posterior subluxation because of the cam-post design. Symptoms include sensation of instability without giving way, especially with stair climbing, recurrent knee effusions, and diffuse knee pain. Signs include anterior tibial translation at 90° flexion, tenderness at multiple sites (including pes anserinus, peripatellar, posterior hamstrings), and effusion. Revision surgery is indicated for symptomatic patients.
Clarke et al. reviewed flexion instability after primary TKA. They caution that most cases arise from failure to create symmetric balanced flexion and extension spaces. Treatment is usually revision TKA using the same principles. If this is not possible, increased constraint is required (constrained condylar prosthesis or hinged prosthesis).
Schwab et al. reviewed flexion instability without dislocation in PS knees in 10 patients. Revision surgery focused on flexion-extension gap balancing and filling the enlarged flexion gaps and successfully relieved pain, and improved stability to anterior tibial translation. Flexion space reconstruction includes using a larger femoral component or posterior augments. Isolated polyethylene exchange is not recommended.
Figure A shows a 5-in-1 cutting block with anterior femoral cut (line 1), posterior femoral cut (line 2), posterior chamfer cut (line 3), anterior chamfer cut (line 4), and distal femoral cut (line 5). Of note, most TKA systems have a 4-in-1 cutting block and the distal femoral cut is made separately. Illustration A shows restoration of the posterior condylar offset (line A) with the femoral component (line B).
Incorrect Answers
OrthoCash 2020
Which of the following is true regarding intra-operative fractures during total knee arthroplasty?
They occur more commonly in cruciate-retaining total knee replacements
Fractures of the medial femoral condyle are the most common fracture type
Fractures of the patella are the most common fracture type
Most can be treated without additional fixation at the time of surgery
Tibial fractures are more common than femoral fractures
Corrent answer: 2
Fractures of the medial femoral condyle are the most common type of intraoperative fracture during a total knee arthroplasty.
Intra-operative fractures during total knee replacement are rare, but usually requiring alterations in surgical technique once they occur. The most common time for fractures to occur is during exposure and bone preparation, with fracture during trialing being the next most common. Fractures occur more commonly in posterior cruciate substituting designs, likely due the box cut.
Osteoporosis, female gender, chronic steroid use, advanced age, rheumatoid arthritis, and neurologic disorders are risk factors for post-operative fracture, but are also thought to be risk factors for intra-operative fractures.
Alden et al. reviewed 17,389 primary TKAs and found an intra-operative fracture rate of 0.39%. Of the 67 fractures, 49 were femur fractures, 18 were tibia fractures, and none were patella fractures. They recommend careful surgical technique in patients at high risk for fracture to avoid such a complication.
Sharkey et al. reviewed 10 intra-operative femoral fractures during primary, cementless total hip arthroplasty. They matched these with 20 patients who did not have this complication. At follow-up, there were no differences found between the two groups.
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OrthoCash 2020
A 68-year-old male complains of increasing medial sided knee pain and buckling. The pain is exacerbated by sharp turns while
running. He undergoes knee arthroscopy. Recent radiographs and an arthroscopic photograph of the medial compartment are shown in Figure A. His pain has worsened since the arthroscopy. Which of the following images (Figures B through F) represents the best treatment recommendation for this patient?
This patient has isolated medial compartment osteoarthritis with Outerbridge IV medial compartment cartilage wear on arthroscopy. The best surgical option is a medial unicompartmental knee arthroplasty (UKA).
Indications for UKA include range of motion >100deg with <5deg flexion contracture, angular deformity <15deg valgus or <5deg varus that is passively correctable to neutral. Relative contra-indications include younger patients (age <60), obesity (BMI >30), and ACL deficiency in medial UKA. Asymptomatic patellofemoral chondromalacia is not a contraindication. In general, a UKA is preferred for older, less active patients with minimal varus, more severe arthritis, and no/little knee instability. A HTO is preferred for younger, active patients, with milder arthritis, more malalignment, and AP instability.
Steadman et al. retrospectively examined outcomes of TKA after arthroscopic treatment of OA in 73 patients. They found that mean survival time (conversion to TKA) after arthroscopy was 6.8 years (5.7 years in patients with Kellgren-Lawrence grade 4, and 7.5 years in those with grade 3). They conclude that in patients who want to avoid TKA, arthroscopy may help postpone TKA.
LaPrade et al. examined the results of proximal tibial opening wedge
osteotomies in 47 patients <55 years old with medial compartment osteoarthritis (OA) and genu varus. They found that there was improvement in knee scores and the mechanical axis at 3.6 years. They recommend this technique for patients with medial compartment OA and malalignment.
Figure A is a composite image showing isolated medial compartment osteoarthritis, and Outerbridge IV cartilage wear with large areas of visible subchondral bone. (See below for Figures B through F). Illustration A is a table comparing the indications of HTO vs UKA.
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OrthoCash 2020
A 58-year-old female, with a BMI of 34 kg/m2, underwent a total knee arthroplasty for osteoarthritis 6 weeks ago. She has been participating in supervised rehabilitation since the procedure. Her preoperative, intra-operative and 6 week post-operative knee flexion are shown in Figure A. Current radiographs are shown in Figure B. What is the best step in management?
Convert to a resurfaced patella
Downsize the polyethylene liner
Arthroscopic lysis of adhesions and release of posterior capsule
Continuous passive motion at home for two weeks
Manipulation under anesthesia
Corrent answer: 5
This patient has early post-operative stiffness after total knee arthroplasty (TKA). The next best step would be manipulation under anesthesia.
Management of stiffness following TKA can be challenging. The standard initial treatment option for post-operative knee stiffness is physical therapy. When this fails to achieve knee range of motion (ROM) greater than or equal to 90°, alternative treatment modalities should be considered, such as knee manipulation under anesthesia (MUA). MUA is a non-invasive treatment shown to achieve dramatic improvement in knee flexion during the early postoperative period (usually considered less than three months). Periprosthetic fracture during manipulation is rare, with an overall incidence less than 1%.
Issa et al. examined a cohort of patients that underwent MUA after TKA. At a mean follow-up of 51 months (range, 24 to 85 months), the mean gain in flexion in the MUA cohort was 33° (range, 5° to 65°). There was one periprosthetic fracture in 134 patients. The authors noted a significant improvement in ROM from pre-manipulation values.
Manrique et al. reviewed stiffness after total knee arthroplasty. MUA may be considered within the first three months after the index TKA if physical therapy fails to improve the ROM. Beyond this point, consideration should be given to surgical intervention such as lysis of adhesions, either arthroscopic or open.
Maniar et al. looked at the effectiveness of continuous passive motion immediately after TKA. A total of 84 patients were allocated to no CPM; 1 day CPM; or 3 day CPM. They found that continuous passive motion immediately after TKA did not improve short or mid-term knee ROM.
Figure B shows a cruciate sacrificing total knee arthroplasty with implants in a good position.
Incorrect Answers:
OrthoCash 2020
Which of the following fracture patterns (Figures A-E) would require revision of the femoral component to a long-stemmed, cementless prosthesis?
Figure C depicts a Vancouver B2 periprosthetic fracture, which is optimally treated with a long-stem, fully porous-coated, revision femoral prosthesis.
The Vancouver classification for total hip periprosthetic femoral fractures takes into account the three most important factors in management of these injuries: the site of the fracture, the stability of the femoral component, and the quality of the surrounding femoral bone stock. Type A fractures include those involving the lesser trochanter or the greater trochanter. Type B fractures occur around the stem or just below it. More specifically, B1 fractures have a well fixed stem, B2 fractures have a loose stem but good proximal bone stock and B3 fractures have a loose stem with proximal bone that is of poor quality or severely comminuted. Type C fractures are well below the tip of the femoral stem.
O'Shea et al. assessed the outcome of patients with Vancouver type B2 and B3 periprosthetic fractures treated with femoral revision using an uncemented extensively porous-coated implant. Union of the fracture was successfully achieved in 20 of the 22 patients. Overall, they found good early survival rates and a low incidence of nonunion using this implant.
Figure A depicts a radiograph of a Vancouver type C periprosthetic femur fracture, occurring distal to the stem of the total hip arthroplasty. Figure B demonstrates a Vancouver type A periprosthetic fracture of the greater trochanter. Figure C is an x-ray of a Vancouver type B2 periprosthetic fracture adjacent to the stem with an unstable implant, but adequate bone stock.
Figure D depicts a radiograph of a Vancouver type C periprosthetic femur fracture, occurring distal to the stem of the total hip arthroplasty. Figure E is a Vancouver type B1 periprosthetic fracture at the level of the stem that is well fixed. Illustration A shows a table summarizing the Vancouver classification of periprosthetic femur fractures and the corresponding management options.
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OrthoCash 2020
Which of the following maneuvers places the obturator artery at greatest risk during a total hip arthroplasty?
Placement of a posterior retractor along the posterior wall
Placement of an acetabular screw in the posterior-superior quadrant
Placement of an inferior retractor under the transverse acetabular ligament
Placement of an acetabular screw in the anterior-superior quadrant
Placement of an anterior retractor along the anterior wall
Corrent answer: 3
Damage to the obturator artery most commonly occurs from placement of an inferior retractor inferior to the transverse acetabular ligament (into the obtrator foramen), and/or placement of an acetabular screw in the anterior-inferior quadrant.
Vascular injury during total hip arthroplasty is a rare but devastating complication with a reported incidence of 0.1%-0.2%. The obturator artery travels along the quadrilateral surface of the acetabulum and exits the pelvis at the superolateral corner of the obturator foramen. If the vessel is severely
damaged and bleeding cannot be controlled, ligation of the internal iliac artery has been reported.
Nachbur et al. report on 15 cases of severe arterial injury during hip reconstructive surgery over a period of 8 years. The most common injury was injury to the external iliac artery, the common femoral artery, or main branches of the lateral and medial circumflex femoral artery. These were thought to be caused by the tip of a narrow-pointed Hohmann retractor used for exposure of the hip joint.
Rue et al. review neurovascular injuries during total hip arthroplasty. Among other things, they recommend against placement of screws in the anterior-superior quadrant, prudent retractor placement, and avoiding excessive tension on the sciatic nerve.
Della Valle and Di Cesare review complications resulting from total hip replacement. They state that injury to the obturator artery can occur with acetabular screw fixation in the antero-inferior quadrant or from retractors placed underneath the transverse acetabular ligament.
Illustration A shows the obturator artery as it exits the pelvis at the superolateral corner of the obturator foramen. Illustration B reviews acetabular screw placement and the structures at risk in each quadrant.
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OrthoCash 2020
A 65-year-old male sustains a fall onto his left hip 3 years after a total hip arthroplasty. A radiograph taken at the emergency room is shown in Figure A. What is the next best step?
Open reduction and internal fixation with locked plates and cables through an extensile approach
Revision with a proximally porous-coated stem
Revision with an extensively porous-coated stem
Nonoperative management
Minimally invasive plate osteosynthesis
Corrent answer: 3
The patient has a Vancouver B2 periprosthetic fracture. There is a loose stem that should be treated with revision to an extensively coated stem that bypasses the fracture site.
Revision of the femoral component is recommended for Vancouver B2 and B3 periprosthetic fractures. Type B1 fractures are treated with ORIF and stem retention, and proximally deficient B3 fractures may be treated with alloprosthetic composites or tumor prostheses.
Springer et al. retrospectively reviewed 118 hips with Vancouver B fractures. Seventy-seven percent of 30 extensively coated stems, 60% of 42 cemented stems, 36% of 28 proximally coated stems, and 61% of 18 tumor prosthesis/allo-prosthetic composite stems were well fixed and demonstrated
fracture union. Nonunion and loosening were the most common complications. They recommend extensively porous-coated stems for better results.
Haidukewych et al. review revision of periprosthetic fractures. They found that most acetabular components are well fixed. When the distal fragment has parallel endosteal cortices with >=5 cm of tubular diaphysis (usually with a diameter of <18 mm), they recommend an extensively coated, uncemented, monoblock long-stemmed prosthesis. If the distal diaphysis is divergent, has
<5 cm of parallel endosteal cortex, or large endosteal diameters, a fluted, grit-blasted, titanium, tapered modular stem can be used.
Figure A shows Vancouver B2 fracture. The stem has subsided relative to the proximal fracture fragment, indicating that it is loose. Illustration A shows revision of the same fracture with an extensively porous-coated stem.
Illustration B shows the endoskeleton technique using an osteotomy to split the proximal fragment coronally for stem removal, followed by insertion of a modular, fluted, tapered stem and cerclage fixation of the proximal fragments.
Incorrect Answers:

Question 71:

The right shoulder exercise seen in Figure A will put the LEAST amount of stretch on which structure? Review Topic

Options:

Inferior glenohumeral ligament
Coracohumeral ligament
Anterior-superior capsule
Superior glenohumeral ligament
Posterior capsule

Correct Answer: Inferior glenohumeral ligament

Explanation:

Question 72:

In recurrent posterior shoulder instability, what is the recommended approach to the posterior capsule? Review Topic

Options:

A teres minor-splitting approach
An infraspinatus-splitting approach
Between the infraspinatus and teres minor
Between the supraspinatus and infraspinatus
In the rotator interval

Correct Answer: An infraspinatus-splitting approach

Explanation:

Question 73:

Which of the following statements is correct regarding Vitamin D?

Options:

1,25-dihydrocholecalciferol is the best laboratory study to determine a Vitamin D deficiency
hydroxycholecalciferol is the active form of Vitamin D
24,25-dihydroxycholecalciferol is an inactive form of Vitamin D
1,25-dihydrocholecalciferol is converted to 25-hydroxycholecalciferol in the kidney
The half-life of 1,25-dihydrocholecalciferol is longer than 25-hydroxycholecalciferol

Correct Answer: The half-life of 1,25-dihydrocholecalciferol is longer than 25-hydroxycholecalciferol

Explanation:

Question 74:

Which of the following types of exercise used to increase flexibility is considered most beneficial in increasing joint range of motion?

Options:

Ballistic stretching
Static stretching
Proprioceptive neuromuscular facilitation (PNF)
Isokinetic
Eccentric

Correct Answer: Proprioceptive neuromuscular facilitation (PNF)

Explanation:

Question 75:

A 16-year-old boy sustains a twisting injury to the left knee while wrestling. MRI scans are shown in Figures 22a through 22c. What is the most likely diagnosis?

Options:

Anterior cruciate ligament rupture
Posterior cruciate ligament rupture
Bucket-handle medial meniscus tear
Lateral meniscus tear
Osteochondral lesion

Correct Answer: Bucket-handle medial meniscus tear

Explanation:

DISCUSSION: The MRI scans show a displaced bucket-handle medial meniscus tear that can be visualized on coronal, sagittal, and axial views. The sagittal view shows the typical “double posterior cruciate ligament sign,” in which the low-signal bucket-handle fragment parallels the normal low-signal posterior cruciate ligament. The coronal and axial images both show the displaced medial meniscus in the notch.
REFERENCES: Sanders TG, Miller MD: A systematic approach to magnetic resonance imaging interpretation of sports medicine injuries of the knee. Am J Sports Med 2005;33:131-148.
Miller TT: Magnetic resonance imaging of the knee, in Insall JN, Scott WN (eds): Surgery of the Knee, ed 4. Philadelphia, PA, Churchill Livingstone, 2006, vol 1, pp 201-224.

Question 76:

When comparing arthroscopic lavage and knee debridement with placebo in patients with chronic symptomatic osteoarthritis, what outcome has been demonstrated?

Options:

Reliable and durable pain relief
No significant benefit for chronic osteoarthritis
Up to 75% pain relief for 2 months, then variable response
Three-month measurable pain relief, followed by recurrence

Correct Answer: No significant benefit for chronic osteoarthritis

Explanation:

Question 77:

Options:

Propionibacterium acnes
Staphylococcus aureus
Group B streptococcus
Neisseria gonorrhea
Enterococcus coli

Correct Answer: Enterococcus coli

Explanation:

This patient has sternoclavicular joint septic arthritis with gram positive organisms. Although there is an increased incidence of Pseudomonas aeruginosa infection in IV drug users, S. aureus is still the most common organism.
Ross et al states "Staphylococcus aureus is now the major cause of
sternoclavicular septic arthritis in intravenous drug users. Pseudomonas aeruginosa infection in injection drug users declined dramatically with the end of an epidemic of pentazocine abuse in the 1980s."
The referenced article by Goldin et al is from the New England Journal of Medicine reports that all of their cases of SC joint septic arthritis were in intravenous drug abusers and that P. aeruginosa grew out of 3 patients and S. aureus grew out of 1 patient.
A more recent article by Abu Arab et al reported that Staph aureus was most common even in IV drug users. The review article by Higginbotham and Kuhn note that risk factors for SC joint septic arthritis include hemodialysis, immunocompromise, alcoholism, and HIV. Neisseria gonorrhoeae, fungal, and candida present in HIV patients.
Treatment is I&D and appropriate antibiotics, although aspiration and abx have shown some success too. CT and MRI are useful in diagnosis, and open biopsy or aspiration is recommended for definitive diagnosis.
A 30-year-old man presents with a distal third tibia fracture that has healed in 25 degrees of varus alignment. The patient is at greatest risk of developing which of the following conditions as a result of this malunion?
Degenerative lumbar spine changes
Ipsilateral ankle pain and stiffness
Ipsilateral hip joint degenerative changes
Contralateral hip joint degenerative changes
Ipsilateral medial knee degenerative changes
Correct answer: 2
A significant malunion of the distal tibia has important consequences for patient outcome, including pain, gait changes, and cosmesis.
The first referenced article by Milner et al looked at long-term outcomes of tibial malunions and noted that varus malunion led to increased ankle/subtalar stiffness and pain regardless of the amount of radiographic degenerative changes.
The second referenced article by Puno et al reinforced the concept of decreased functional outcomes of the ankle with tibial malunions, and noted
that other lower extremity joints (ipsilateral and contralateral) do not have increased rates of degeneration from such a malunion.
A 33-year-old man sustains a femur fracture in a motorcycle accident. AP and lateral radiographs are provided in Figure A. Prior to surgery, a CT scan of the knee is ordered for preoperative planning. Which of the following additional findings is most likely to be discovered?
Tibial eminence fracture
Sagittal plane fracture of the medial femoral condyle
Schatzker I tibia plateau fracture
Coronal plane fracture of the lateral femoral condyle
Axial plane fracture through the medial femoral condyle
Correct answer: 4
The "Hoffa fracture" is a coronal plane fracture of the femoral condyle that is often missed on plain radiographs of supracondylar and intercondylar femur fractures. It involves the lateral condyle more frequently than the medial.
Identification is important as it may impact operative planning and likely require screw fixation in the anteroposterior plane.
Nork et al. reviewed 202 supracondylar-intercondylar distal femoral fractures and found a 38% prevalence of associated coronal plane fractures. The authors recommend CT scan imaging of all supracondylar and intercondylar fractures.
Ostermann et al reported on 24 unicondylar fractures of the distal femur treated with open reduction internal fixation with a screw construct. Twenty-
three patients acheived satisfactory results at 5 year follow-up. Illustrations A and B are another example of a supracondylar femur fracture with an associated Hoffa fracture identified on CT scan.
A 35-year-old woman presents with an elbow injury which includes a coronoid fracture involving more than 50%, a comminuted
radial head fracture, and an elbow dislocation. What is the most appropriate treatment?
closed reduction and early range of motion
radial head resection and lateral collateral ligament reconstruction
radial head resection and coronoid open reduction internal fixation
radial head arthroplasty and coronoid open reduction internal fixation
radial head arthroplasty, coronoid open reduction internal fixation, and lateral collateral ligament repair
A terrible triad of the elbow includes dislocation of the elbow with associated fractures of the radial head and the coronoid process. Ring et al. stressed that these injuries are prone to complications and advised against resection of the radial head due to instability, and instead recommended a radial head replacement if too comminuted for ORIF. Coronoid fractures compromise elbow stability as well and require open reduction and internal fixation as with the lateral collateral ligament. McKee et al. showed stable elbows in 34/36 with mean Mayo elbow score of 88 when the standard protocol of coronoid ORIF, radial head repair/replacement, and LCL repair were employed.
The talocrural angle of an ankle mortise x-ray is formed between a line perpendicular to the tibial plafond and a line drawn:
perpendicular to the medial clear space
parallel to the talar body
between the tips of the malleoli
perpendicular to the shaft of the fibular
parallel to the subtalar joint
Correct answer: 3
The talocrural angle is formed by the intersection of a line perpendicular to the plafond with a line drawn between the malleoli (average = 83+/-4deg). When the lateral malleolus is shortened secondary to fracture, this can lead to increased talocrural angle. This malunion leads to lateral tilt of the talus.
Phillips et al looked at 138 patients with a closed grade-4 supination-external rotation or pronation-external rotation ankle fracture. Although the conclusions were limited due to poor follow up, they found the difference in the talocrural angle between the injured and normal sides was a statistically significant radiographic indicator of a good prognosis.
Pettrone et al looked at a series of 146 displaced ankle fractures, and the effect of open or closed treatment, and internal fixation of one or both malleoli. They found open reduction proved superior to closed reduction, and in bimalleolar fractures open reduction of both malleoli was better than fixing only the medial side.
Illustrations A and B are demonstrations of the talocrural angle.
A 33-year-old male sustains the injury shown in Figure A. He is initially treated with a spanning external fixator followed by definitive open reduction internal fixation of the tibia and fibula. His wounds healed without infection or other complications. Two years following surgery, which of the following parameters will most likely predict a poor clinical outcome and inability to return to work?
Joint line restoration
Degree of fracture displacement
Time before definitive ORIF
Open fracture
Lower level of education
Correct answer: 5
Lower level of education is the parameter that correlated most closely with a poor clinical outcome and inability to return to work.
To determine what fracture- and patient-specific variables affect outcome, Williams et al evaluated 29 patients with 32 tibial plafond fractures at a minimum of 2 years from the time of injury. Outcome was assessed by four independent measures: a radiographic arthrosis score, a subjective ankle score, the Short Form-36 (SF-36), and the patient’s ability to return to work. The four outcome measures did not correlate with each other. Radiographic arthrosis was predicted best by severity of injury and accuracy of reduction. However, these variables did not show any significant relationship to the clinical ankle score, the SF-36, or return to work. These outcome measures were more influenced by patient-specific socioeconomic factors. Higher ankle
scores were seen in patients with college degrees and lower scores were seen in patients with a work-related injury. The ability to return to work was affected by the patient’s level of education.
Pollak et al performed a retrospective cohort analysis of pilon fractures. Patient, injury, and treatment characteristics were recorded. The primary outcomes that were measured included general health, walking ability, limitation of range of motion, pain, and stair-climbing ability. A secondary outcome measure was employment status. Multivariate analyses revealed that presence of two or more comorbidities, being married, having an annual personal income of less than $25,000, not having attained a high-school diploma, and having been treated with external fixation with or without limited internal fixation were significantly related to poorer results as reflected by at least two of the five primary outcome measures.
What is the most appropriate treatment for a 17-year-old boy who sustained a gunshot wound to his forearm from a handgun with a muzzle-velocity of 1000 feet/second if he is neurovascularly intact and radiographs reveal no fracture?
Irrigation and local wound care in the emergency department
Emergent irrigation and debridement in the operating room with vacuum-assisted wound closure
Emergent irrigation and debridement in the operating room with 7 days of intravenous antibiotics
Wound closure in the emergency department with follow-up wound check in 1 week
Exploration and removal of all bullet fragments in the emergency department and 10 day course of oral antibiotics
The question refers to appropriate management of a gunshot wound to the forearm. The first question that must be answered when evaluating gunshot injuries is whether the gunshot is low velocity or high velocity. Low-velocity wounds are less severe, are more common in the civilian population, and are typically attributed to bullets with muzzle velocities below 1,000 to 2,000 feet per second. Tissue damage is usually more substantial with higher-velocity (greater than 2,000 to 3,000 fps) military and hunting weapons. In this question, a muzzle velocity of 1,000 ft/sec is provided. Low velocity injuries with stable, non-operative fractures can be treated with local wound care.
The two referenced articles offer guidance for treating low-velocity gunshot injuries with stable, non-operative fracture patterns. The first article by Geissler et al is a retrospective study comparing 25 patients that prospectively received local irrigation and debridement, tetanus prophylaxis and a long acting cephalosporin intramuscularly to a random retrospective sample of 25 patients with similar ballistic-induced fractures and wounds managed by local debridement and 48h of intravenous antibiotics. One infection occurred in each group, requiring further therapy. It was concluded that patients with low-velocity gunshot induced fractures can be managed without the use of short-term intravenous antibiotics with no increased risk of infection.
In the second study, Dickey et al evaluated the efficacy of an outpatient management protocol for patients with a gunshot-induced fracture with a stable, non-operative configuration. 41 patients with a grade I or II open, nonoperative fracture secondary to a low-velocity bullet were treated with 1gm of cefazolin administered in the emergency room and a 7-day course of oral cephalexin. No patient developed a deep infection. Thus, local I&D, tetanus, and oral antibiotics for 2-3 days is adequate for low velocity gunshot wounds.
Which clinical sign is the most sensitive for the diagnosis of compartment syndrome in a child with a supracondylar humerus fracture?
pulselessness
pallor
paresthesia
paralysis
increasing analgesia requirement
Correct answer: 5
Although pain, pallor, paresthesia, paralysis, and pulselessness are all possible signs and symptoms of compartment syndrome in children with fractures, studies have shown increasing analgesia requirement is more sensitive.
Bae et al reviewed thirty-six cases of compartment syndrome in 33 pediatric patients. Approximately 75% of these patients developed compartment syndrome in the setting of fracture. "They found pain, pallor, paresthesia, paralysis, and pulselessness were relatively unreliable signs and symptoms of compartment syndrome in these children. An increasing analgesia requirement in combination with other clinical signs, was a more sensitive indicator of
compartment syndrome."
Whitesides et al summarizes the diagnosis and treatment of acute compartment syndrome. They emphasize the need for early diagnosis, as "muscles tolerate 4 hours of ischemia well, but by 6 hours the result is uncertain; after 8 hours, the damage is irreversible." They recommend fasciotomy be performed when tissue pressure rises past 20 mm Hg below diastolic pressure.
A 45-year-old man sustains the injury seen in Figures A and B following a motor vehicle accident. Postoperative radiographs are seen in Figures C and D. Which of the following is the most accurate when comparing outcomes between intramedullary nailing (IMN) and open reduction internal fixation (ORIF) for this injury?
Union rates at one year are higher with ORIF
Infection rates are higher with IMN
Functional shoulder outcomes at one year are equivalent with IMN and ORIF
Iatrogenic radial nerve injury rate is higher with ORIF
Shoulder stiffness rates at one year are equivalent with IMN and ORIF
Correct answer: 3
Although shoulder pain and stiffness is increased following IMN compared to ORIF, functional outcome scores at one year have been shown to be equivalent
in both treatment groups.
Diaphyseal humeral shaft fractures outcomes following IMN and ORIF are under further investigation. Diaphyseal humeral shaft fractures have historically been treated with ORIF, however proponents for IMN cite benefits of less periosteal stripping and soft tissue dissection. Recent investigations have shown outcomes with regard to nonunion, infection, re-operation, and nerve palsy appear equivalent between both groups. Rates of shoulder stiffness and shoulder pain have been demonstrated to be higher in IMN compared to ORIF. American Shoulder and Elbow Scores (ASES) have shown no difference at one year post-operatively.
Bhandari et al. performed a meta-anaylsis of 3 prospective randomized trials. They found lower rates of re-operation and shoulder impingement with ORIF of humeral shaft fractures.
Wali et al. performed a prospective randomized study of IMN or ORIF on 50 patients with mid-diaphyseal humeral shaft fractures. They found IMN had shorter operative time, shorter hospital stay, and lower blood loss. They found no difference in union rates, complication, or shoulder functional outcomes scores. They conclude IMN to be an effective option for treating mid-diaphyseal humeral shaft fractures.
Heineman et al. have recently conducted an update on their meta-analysis to include more recent randomized studies. With the inclusion of newer studies the author found a statistically significant increase in total complication rate with the use of IM nailing compared with ORIF. The authors found no significant difference between the two treatment modalities for the secondary outcomes (nonunion, infection, nerve palsy, re-operation).
Figures A and B show a diaphyseal humeral shaft fracture. Figure C and D show postoperative radiographs following intramedullary nailing of a humeral shaft fracture.
Incorrect Answers:
A 25-year-old female presents complaining of progressive anteromedial pain in her left ankle. She underwent operative fixation 5 months prior at an outside hospital. The operative report indicated that, due to anterior fracture blisters, a direct medial incision was utilized, centered over the posterior colliculus of the medial malleolus, without violation of the deltoid ligament. A radiograph and computed tomographic scan of her initial injury are shown in Figures A and B, respectively. On exam, she has well-healed incisions, exhibits no tenderness to palpation over her hardware, but does endorse pain with deep palpation along the anteromedial joint line. Figure C shows an anteroposterior left ankle radiograph taken today. Labs are obtained and reveal a white blood cell count of 9.0 k/uL (reference range 4.5-11.0 k/uL) and a C-reactive protein value of 0.8 mg/dL (<0.9 mg/dL). What is the next best step in managing her problem?
Syndesmotic fixation
Intra-articular corticosteroid injection
Referral to physical therapy
Surgical correction of malunion
Removal of hardware
Correct answer: 4
This patient sustained a supination-adduction (SAD) injury with a vertical shear fracture of her medial malleolus and a fibular avulsion fracture. She sustained a medial plafond articular impaction injury that was not addressed at the time of surgery.
In SAD injuries, supination of the foot is combined with inward rotation at the ankle, adduction of the hindfoot, and inversion of the forefoot. This results in the following sequence of events: 1. Talofibular sprain or distal fibular avulsion (equivalent to Weber A). 2. Vertical medial malleolus fracture as the talus strikes the tibia. Associated injuries may include osteochondral damage to the talus and marginal impaction of the medial plafond. It is important to evaluate the medial plafond for articular impaction. When present, an arthrotomy must be performed, typically utilizing an anteromedial incision, with direct visualization of the articular surface to restore the joint line appropriately.
Weber et al. provided a review article on corrective osteotomies for malleolar fracture malunions. They stress that malunions can lead to ankle instability, abnormal load transfer, and post-traumatic arthritis. They conclude that corrective osteotomies that restore anatomical alignment show good results in long-term follow-up.
Perera et al. provided additional commentary on the surgical reconstruction of malunited ankle fractures. The authors emphasize the link between malunion and poor outcomes. They state that successful salvage procedures involve a clear understanding of the deformity, careful preoperative planning, and a solid understanding of reconstructive techniques. They provide several instructive case examples in their review.
McConnell et al. provided a discussion on SAD ankle fractures at their institution and emphasized the importance of recognizing marginal impaction of the tibial plafond when treating these injuries. Of 800 ankle fractures identified over a 5-year period, 44 were SAD injuries, 19 of the 44 displayed a vertical shear fracture of the medial malleolus, and 8 of the 19 demonstrated marginal impaction of the tibial plafond. These 8 impaction injuries were treated with open reduction internal fixation with elevation of the articular impaction; all had good to excellent outcomes without arthritic changes at last
follow-up.
Figure A is an anteroposterior left ankle radiograph demonstrating a SAD injury with a vertical shear fracture of the medial malleolus, a fibular avulsion fracture, and articular impaction of the medial tibial plafond. Figure B is a coronal CT demonstrating articular impaction of the medial plafond. Illustration A is an intra-operative photograph with the medial malleolus retracted allowing inspection of the articular surface; mild anteromedial plafond impaction is present.
Incorrect Answers:
A 90-year-old female slips and falls at home. She is a community ambulator and has no medical problems. She reports right hip pain at this time. Injury radiographs are shown in Figures A & B. Delay of more than 48 hours may result in:
Increased intraoperative time
Increased 30-day mortality
No impact on the rate of postoperative pneumonia
Higher rates of blood transfusion
Increased risk of post-operative infection
Correct answer: 2
Figures A & B demonstrate a right, unstable intertrochanteric femur fracture. Surgical stabilization within 48 hours improves short-term and 30-day mortality.
Hip fractures are common and mortality rates vary. In the elderly, mortality rates may reach 10% at 1-month, 20% at 4-months, and 30% at 1-year. Time to surgery has found to be a decisive factor. A pre-operative delay may lead to an increase in mortality and adversely influence other clinical outcomes.
Clinical guidelines recommend immediate operative stabilization, given the patient is medically fit for surgery.
Nyholm et al. performed a retrospective study of the Danish Fracture Database to investigate whether a surgical delay increases 30-day and 90-day mortality rates for patients with proximal femoral fractures. The 30-day and 90-day mortalities were 10.8% and 17.4%, respectively. The risk of 30-day mortality increased with increasing time intervals of more than 12 hours, 24 hours, and more than 48 hours. 90-day mortality increased with a surgical delay of more than 24 hours. They conclude that rapid surgical treatment should be performed by attending orthopaedic surgeons.
Moja et al. performed a meta-analysis and meta-regression to assess the relationship between surgical delay and mortality in elderly patients with a hip fracture. They analyzed 35 independent studies with 191,873 patients and 34,448 deaths. The majority of studies had a cut-off of 48 hours. They report that early hip surgery was associated with a lower risk of death and pressure sores. They conclude that early hip fracture surgery appears to provide a survival benefit compared to later intervention.
Rodriguez-Fernandez et al. performed a study examining 2 groups with hip fractures. The first group was studied retrospectively and had an average delay of surgical treatment of more than 1-week while the second group was studied prospectively, and had surgical treatment within 48 hours. They found a larger number of complications in the group with a delay in surgical treatment. They conclude that elderly patients with hip fractures should be treated as soon as their medical condition permits.
Figures A and B are the AP and lateral radiographs demonstrating a right, unstable intertrochanteric femur fracture. Illustration A is an intertrochanteric femur fracture, stabilized with a cephalomedullary nail.
Incorrect Answers:
A 22-year-old healthy left hand dominant male presents to the ED with left shoulder pain after falling from an ATV. Figure A is the radiograph of his left clavicle. He is neurovascularly intact and there is no evidence of skin tenting or open fracture. Which of the following most predisposes this patient to nonunion?
Diaphyseal fracture
Fracture displacement
Age
Male Gender
Injury involving the dominant extremity
Correct answer: 2
Displaced clavicle fractures are associated with higher rates of nonunion.
Nonunion occurs in roughly 5-6% of clavicle fractures and can result in slower functional return, poor cosmesis and muscle fatigability. Clavicle fractures can be sub-classified using the Allman classification into medial, diaphyseal, and lateral injuries (Illustration A). The Neer classification for diaphyseal injuries describes fractures as "nondisplaced" (less than 100% displacement) and "displaced" (greater than 100% displacement).
Robinson et al. performed a prospective cohort study to identify risk factors for nonunion after nonoperative management of clavicle fractures. The overall nonunion rate was 6.2% and was highest in lateral third fractures (11.5%).
Diaphyseal fractures had the lowest nonunion rate (4.5%). Additionally, the authors found that the risk for nonunion was increased by advancing age, female gender, fracture displacement, and comminution.
Jorgensen et al. performed a systemic review of the literature looking for predictors of non-union and malunion in mid shaft clavicle fractures treated non-operatively. They found fracture comminution, displacement, older age, female gender, and the presence of smoking to be his factors for non-union. Of these, displacement was the most likely factor that can be used to predict nonunion.
Figure A demonstrates a displaced left clavicle diaphyseal fracture. Note that the medial fragment is displaced superiorly by the deforming force of the sternocleidomastoid. Illustration A represents the Allman classification.
Illustration B demonstrates the deforming forces acting on the clavicle.
Incorrect Answers:
A 24-year-old male presents with ankle pain after being involved in a motor vehicle accident. His injury radiograph is shown in Figure A. Which of the following has been shown to contribute to the development of post-traumatic arthritis in this injury pattern?
Initial superficial zone cartilage cell death via apoptosis at the fracture margins
Initial superficial zone cartilage cell death via apoptosis remote from the fracture margins
Initial superficial zone cartilage cell death via necrosis remote from the fracture margins
Initial superficial zone cartilage cell death via necrosis at the fracture margins
Delayed superficial zone cartilage cell death via necrosis at the fracture margins
Figure A demonstrates a tibial plafond fracture. Initial superficial zone cartilage cell death via necrosis at the fracture margins has been shown to contribute to post-traumatic arthritis.
Post-traumatic osteoarthritis typically occurs after an intra-articular fracture. Impacted chondrocytes die by either necrosis or apoptosis, which have both been implicated in post-traumatic osteoarthritis. Initial cell death in the superficial cartilage zones at the fracture margins occurs by necrosis. Apoptosis occurs in a delayed fashion and is mitigated by several bioactive agents.
Apoptosis also affects the superficial cartilage zones near the fracture margins. Deep cartilaginous zones and areas away from the fracture margins do not seem to be involved in these processes.
McKinley et al. performed a review of the basic science of intra-articular fractures and posttraumatic osteoarthritis. They report that initial damage to the cartilage in combination with the ensuing pathomechanical and pathobiologic response of the cartilage after a fracture contribute to posttraumatic arthritis. Chronic abnormal joint loading is also thought to contribute to this process as well. They conclude that the relative contribution of each is unknown.
Tochigi et al. performed a study to determine the distribution and progression of chondrocyte damage after intra-articular ankle fractures. They harvested 7 normal human ankles and subjected them to impaction. They found that immediate superficial zone chondrocyte death was greater in fracture-edge regions than on-fracture regions. Subsequent cell death over the next 48 hours was significantly higher in fracture-edge regions as well. They conclude that cartilage damage in intra-articular fractures was characterized by chondrocyte death at fracture margins.
Figure A is an ankle mortise radiograph demonstrating an intra-articular tibial plafond fracture.
Incorrect Answers:
A 35-year-old male presents with left knee pain after sustaining the injury seen in Figure A. He is neurovascularly intact and can perform a straight leg raise, but has pain with passive range of motion. Figures B and C show an anteroposterior and lateral radiograph of the left knee, respectively. 175 cc of saline is injected into the superolateral quadrant with no egress of fluid from the inferolateral
laceration. What percentage of traumatic arthrotomies would be detected with this test?

Question 78:

Options:

Spanning external fixation of the radius
Open reduction and internal fixation of the radius with free fibular flap interposition
Open reduction and internal fixation of the radius with interposed strut allograft
Open reduction and internal fixation of the radius with massive cancellous allografting
Open reduction and internal fixation of the radius with massive cancellous autografting

Correct Answer: Open reduction and internal fixation of the radius with free fibular flap interposition

Explanation:

Question 79:

Options:

Use of an abduction orthosis for 6 weeks
Modular exchange of the femoral head to a 36-mm head and a longer neck
Modular exchange of the polyethylene liner to a constrained acetabular insert
Revision and repositioning of the acetabular component and use of a 36-mm femoral head
A physical therapy program stressing abductor strengthening

Correct Answer: Revision and repositioning of the acetabular component and use of a 36-mm femoral head

Explanation:

Question 80:

A left-handed 23-year-old man who fell 5 feet from a ladder onto his left elbow sustained the closed injury shown in Figure 26. Management should consist of

Options:

percutaneous pin fixation.
a percutaneous 6.5-mm screw.
long arm casting in flexion.
open reduction and internal fixation with a tension band plate.
closed reduction and long arm casting in extension.

Correct Answer: open reduction and internal fixation with a tension band plate.

Explanation:

Question 81:

Which of the following best describes athletic pubalgia?

Options:

A syndrome of lower abdominal and adductor pain
Painful symptoms emanating from the symphysis pubis
Painful symptoms associated with dysfunction of the iliopsoas tendon
Stress fracture of the pubic ramus
Entrapment of the pudendal nerve

Correct Answer: A syndrome of lower abdominal and adductor pain

Explanation:

Question 82:

Options:

Cast for 2 weeks
Initiate mobilization
Radial head excision
Radial head replacement
Open reduction and internal fixation

Correct Answer: Initiate mobilization

Question 83:

Following an acute dislocation of the patella, the risk of a recurrent dislocation is greater if the patient has which of the following findings?

Options:

Bipartite patella
Age greater than 15 years at the time of the initial dislocation
Persistent atrophy of the vastus lateralis
Low-lying position of the patella (patella baja)
Passive lateral hypermobility of the unaffected knee

Correct Answer: Passive lateral hypermobility of the unaffected knee

Explanation:

Question 84:

Options:

wound debridement, anterior corpectomy, spinal cord decompression, dural repair, and anterior fusion with strut graft and anterior plating.
wound debridement, anterior corpectomy, spinal cord decompression, dural repair, anterior fusion with strut graft and anterior plating followed by posterior laminectomy, and spinal cord decompression and dural repair with excision of the bullet fragment.
wound debridement, anterior corpectomy, spinal cord decompression, dural repair, anterior fusion with strut graft and anterior plating followed by laminectomy and posterior fusion, and spinal cord decompression and dural repair with excision of the bullet fragment.
laminectomy and posterior fusion, and spinal cord decompression and dural repair with excision of the bullet fragment.
surgical treatment based on extraspinal pathology with orthotic treatment of the spinal fractures.

Correct Answer: surgical treatment based on extraspinal pathology with orthotic treatment of the spinal fractures.

Explanation:

DISCUSSION: Although the spinal canal has been penetrated, the lateral masses are intact bilaterally with only partial destruction of the vertebral body and penetration of the lamina on one side, thus the cervical spine is not unstable and surgical stabilization is not indicated. Dural repair is not indicated since there is no external cerebrospinal fluid leakage. Surgical treatment should be based on the need to treat extraspinal pathology only.
REFERENCES: Bono CM, Heary RF: Gunshot wounds to the spine. Spine J 2004;4:230-240.
Punjabi MM, Jue JJ, Dvorak J, et al: Cervical spine kinematics and clinical instability, in Clark CR (ed): The Cervical Spine, ed 4. Philadelphia, PA, Lippincott Williams & Wilkins, 2005,
pp 55-87.

Question 85:

Phosphate administration decreases urinary calcium excretion through which of the following actions?

Options:

It inhibits PTH secretion thus enhancing calcium reabsorption.
It creates a complex with calcium in the intestine to decrease available calcium for absorption.
It competes with calcium in the bone and soft tissue, thus increasing the filtered load of calcium.
It has a direct effect on the proximal tubule of the kidney.
It increases ionized calcium through binding to serum proteins.

Correct Answer: It creates a complex with calcium in the intestine to decrease available calcium for absorption.

Explanation:

Question 86:

Options:

Acute reconstruction of all ligamentous structures
Emergency MRI and reconstruction of all ligamentous structures
Emergency arteriogram followed by MRI
Emergency surgery with open reduction and repair of all tom structures with vascular surgery available
Closed reduction in the emergency room and reevaluation of the vascular status

Correct Answer: Closed reduction in the emergency room and reevaluation of the vascular status

Explanation:

Question 87:

Which of the following findings helps to distinguish between stress fractures of the tibia and shin splints? Review Topic

Options:

With shin splints, a bone scan shows the posterior tibial cortex in a diffuse, longitudinal orientation.
With tibial shin splints, the bone scan is more intense.
A more diffuse area of tenderness is seen in tibial stress fractures.
A three-phase bone scan is positive in all phases with shin splints, but only positive in delayed images with tibial stress fractures.
After activity, pain persists longer with tibial stress fractures.

Correct Answer: With shin splints, a bone scan shows the posterior tibial cortex in a diffuse, longitudinal orientation.

Explanation:

Question 88:

Options:

Continued bracing
Direct ligamentous repair
Arthroscopic electrothermal capsular and ligamentous shrinkage
Isolated plication of the capsule and ligaments
Free tendon graft reconstruction with capsuloligamentous plication

Correct Answer: Free tendon graft reconstruction with capsuloligamentous plication

Explanation:

Question 89:

A 60-year-old man has pain at the tip of the index finger. A radiograph and biopsy specimen are shown in Figures 40a and 40b. Management should consist of

Options:

surgical debridement and antibiotics.
curettage and bone graft.
amputation through the distal interphalangeal joint.
amputation of the second ray.
radiation therapy.

Correct Answer: amputation through the distal interphalangeal joint.

Explanation:

Question 90:

Options:

Posterior wall/ posterior column
Transverse
T-Type
Anterior column/ posterior hemitransverse
Both columns

Correct Answer: Posterior wall/ posterior column

Explanation:

Question 91:

- In a fatigue test, the maximum stress under which the material will not fail, regardless of how many loading cycles are applied, is defined as

Options:

Endurance limit
Failure stress
Critical stress
Yield stress
Elastic limit

Correct Answer: Endurance limit

Explanation:

Question 92:

Options:

Hemoglobin
Myoglobin
Melanin
Copper
Hemosiderin

Correct Answer: Hemosiderin

Explanation:

DISCUSSION: Pigmented villonodular synovitis (PVNS) is a synovial proliferative disorder that remains a diagnostic difficulty. The most common clinical features are mechanical pain and limited joint motion. On radiographs, the classic finding is often a large lesion, associated with multiple lucencies. Other findings may include a normal radiographic appearance, loss of joint space, osteonecrosis of the femoral head, or acetabular protrusion. MRI is the imaging modality of choice and will show the characteristic findings of a joint effusion, synovial proliferation, and bulging of the hip. The synovial lining has a low signal on T
1
- and T
2
-weighted images, secondary to hemosiderin deposition. Copper deposition occurs in patients with Wilson’s disease, which mainly affects the liver.
REFERENCES: Bhimani MA, Wenz JF, Frassica FJ: Pigmented villonodular synovitis: Keys to early diagnosis. Clin Orthop 2001;386:197-202.
Cotten A, Flipo RM, Chastanet P, et al: Pigmented villonodular synovitis of the hip: Review of radiographic features in 58 patients. Skeletal Radiol 1995;24:1-6.

Question 93:

Options:

MRI of the affected tibia
Palpation of the affected leg compartments during activity
Compartment pressure monitoring 1 and 5 minutes into the activity
Compartment pressure monitoring continuously during the activity

Correct Answer: Compartment pressure monitoring continuously during the activity

Explanation:

Question 94:

Osteopenia is defined by the World Health Organization (WHO) as a bone mineral density (BMD) that is

Options:

within 1 standard deviation of aged-matched normals.
within 1 and 2.5 standard deviations below aged-matched normals.
within 1 standard deviation of young normals.
within 1 and 2.5 standard deviations below young normals.
more than 2.5 standard deviations below aged-matched normals.

Correct Answer: within 1 and 2.5 standard deviations below young normals.

Explanation:

DISCUSSION: Osteopenia, decreased bone mass without fracture risk as defined by the WHO criteria for diagnosis of osteoporosis, is when a woman’s T-score is within -1 to -2.5 SD.
The T-score represents a comparison to young normals or optimum peak density. The Z-score represents a comparison of BMD to age-matched normals. Measurements of bone mineral density (BMD) at various skeletal sites help in predicting fracture risk. Hip BMD best predicts fracture of the hip, as well as fractures at other sites.
REFERENCE: Kanis JA, Johnell O, Oden A, et al: Risk of hip fracture according to the World Health Organization criteria for osteopenia and osteoporosis. Bone 2000;27:585-590.

Question 95:

Decreased risk of shoulder and elbow injury in a throwing athlete has been demonstrated with which of the following? Review Topic

Options:

Rotator cuff strengthening
Superior labral repair
Posterior capsular stretching
Periscapular muscle strengthening
Repair of partial-thickness rotator cuff tears

Correct Answer: Posterior capsular stretching

Explanation:

Question 96:

Figure 13 shows the radiographs of a 20-year-old intercollegiate basketball player who was injured 6 weeks prior to the start of the season. What is the most appropriate treatment?

Options:

Intramedullary screw fixation
Immobilizing orthotic/boot
Walking cast
Physical therapy
Rest for 2 weeks and return to play

Correct Answer: Intramedullary screw fixation

Explanation:

Question 97:

What structure is 7cm from the acromion and at greatest risk of injury during a deltoid splitting approach for a proximal humerus fracture?

Options:

Radial nerve
Suprascapular nerve
Axillary nerve
Axillary artery
Axillary vein

Correct Answer: Radial nerve

Explanation:

Question 98:

Figure 40 shows the MRI scan of a 23-year-old man with a history of recurrent anterior shoulder instability. What is the most likely diagnosis? Review Topic

Options:

Humeral avulsion of the inferior glenohumeral ligament (HAGL lesion)
Osseous Bankart lesion
Perthes lesion
Anterior labroligamentous periosteal sleeve avulsion (ALPSA lesion)
Glenolabral articular disruption (GLAD lesion)

Correct Answer: Anterior labroligamentous periosteal sleeve avulsion (ALPSA lesion)

Explanation:

Question 99:

Options:

protein C and S.
vitamin K.
von Willebrand factor.
factor VIII.

Correct Answer: factor VIII.

Explanation:

Question 100:

Options:

observation.
a shoe lift.
abduction bracing.
nonsteroidal anti-inflammatory drugs.
capsulorrhaphy and pelvic and femoral osteotomies.

Correct Answer: capsulorrhaphy and pelvic and femoral osteotomies.

Explanation:

DISCUSSION: Ligamentous laxity and muscle hypotonia seen in Down syndrome contribute to the incidence of hip subluxation and dislocation. These factors can be progressive and lead to degenerative arthritis in adults with Down syndrome. Because this patient has a progressive limp and decreased endurance, observation and a shoe lift are not options. Bracing may be an option in the younger child before significant bony changes occur. Surgical intervention is the treatment of choice in this patient; however, all components of the deformity need to be addressed. Because of the increased capsular laxity, there is a high likelihood of recurrence if capsulorrhaphy is not included with the pelvic and femoral osteotomies. Surgery in these patients is associated with a high rate of complications.
REFERENCES: Shaw ED, Beals RK: The hip joint in Down’s syndrome: A study of its structure and associated disease. Clin Orthop 1992;278:101-107.
Aprin H, Zinc WP, Hall JE: Management of dislocation of the hip in Down’s syndrome.
J Pediatr Orthop 1985;5:428-431.
Greene WB: Closed treatment of hip dislocation in Down syndrome. J Pediatr Orthop 1998;18:643-647.

Detailed Chapters & Topics

Dive deeper into specialized chapters regarding orthopedic-board-review-oite-aaos-part-149

50 Chapters

Chapter 1 53 min

Orthopedic Board Review MCQs: Hip & Knee Arthroplasty, Sports Medicine | Part 99

Master your OITE and AAOS exams with Part 99 of our Orthopedic Board Review. Test your knowledge with 50 high-yield hip…

Chapter 2 235 min

Orthopedic Board Exam MCQs: Upper Extremity, Spine & Foot/Ankle | Part 112

Master your OITE and AAOS exams with Part 112 of our Orthopedic Surgery Board Review. Practice 100 verified MCQs on fra…

Chapter 3 287 min

Orthopedic Board Review MCQs: Ankle, Deformity, Fracture & Scoliosis | Part 113

Ace your OITE and AAOS exams with Part 113 of our Orthopedic Board Review. Practice 100 verified, high-yield MCQs on an…

Chapter 4 66 min

OITE & ABOS Orthopedic Board Review MCQs: Trauma, Spine & Sports Medicine | Part 114

Ace your OITE and ABOS exams with Part 114 of our Orthopedic Surgery Board Review. Practice 100 verified MCQs on trauma…

Chapter 5 232 min

Orthopedic Board Review MCQs: Hip, Shoulder & Spine Surgery | Part 115

Ace your OITE and AAOS exams with Part 115 of our Orthopedic Board Review. Practice 100 verified, high-yield MCQs on hi…

Chapter 6 392 min

Orthopedic Board Prep MCQs: Arthroplasty, Fracture, Hip, Knee, Shoulder | Part 116

Ace your OITE and AAOS exams with Part 116 of our Orthopedic Board Review. Practice 100 verified MCQs on arthroplasty, …

Chapter 7 304 min

Orthopedic Board Review MCQs: Shoulder, Trauma & Spine | Part 117

Ace your OITE and AAOS exams with Part 117 of our Orthopedic Board Review. Practice 100 high-yield MCQs on shoulder tra…

Chapter 8 492 min

Orthopedic Board Prep MCQs: Pediatric, Shoulder & Sports Medicine | Part 118

Master your OITE and AAOS exams with 100 verified orthopedic board prep MCQs. Part 118 covers pediatric, shoulder, and …

Chapter 9 246 min

Orthopedic Board Review MCQs: Arthroplasty, Trauma & Elbow | Part 119

Master your OITE and AAOS exams with Part 119 of our Orthopedic Surgery Board Review. Practice 100 verified, high-yield…

Chapter 10 206 min

Orthopedic Board Review MCQs: Upper Extremity & Trauma | Part 120

Ace your OITE and AAOS exams with Part 120 of our Orthopedic Board Review. Test yourself with 100 verified MCQs on uppe…

Chapter 11 219 min

Orthopedic Surgery Board Exam MCQs: Shoulder, Nerve, & Spine | Part 121

Ace your OITE and AAOS exams with Part 121 of our Orthopedic Surgery Board Review. Practice 100 verified MCQs on should…

Chapter 12 317 min

Orthopedic Board Prep MCQs: Joints, Fractures & Arthroscopy | Part 122

Ace the OITE and AAOS exams with Part 122 of our Orthopedic Surgery Board Review. Test yourself with 100 verified MCQs …

Chapter 13 231 min

Orthopedic Board Review MCQs: Spine, Hip, & Shoulder | Part 123

Ace your OITE and AAOS exams with Part 123 of our Orthopedic Surgery Board Review. Practice 100 verified MCQs on hip, s…

Chapter 14 42 min

OITE & ABOS Orthopedic Board Prep MCQs: Trauma & Infection Part 124

Master your OITE and ABOS exams with Part 124 of our Orthopedic Surgery Board Review. Test your knowledge with 50 high-…

Chapter 15 238 min

Orthopedic Board Review MCQs: Elbow & Fracture Management | Part 125

Master OITE & AAOS exams with Dr. Hutaif's Orthopedic Board Review Part 125. Practice 100 verified MCQs on elbow and fr…

Chapter 16 203 min

OITE & ABOS Ortho Board Prep MCQs: Elbow, Knee, Trauma & Tumor | Part 126

Ace your OITE and ABOS exams with Part 126 of our Orthopedic Surgery Board Review. Practice 100 verified, high-yield MC…

Chapter 17 231 min

Orthopedic Board Review MCQs: Elbow, Hip, & Nerve | Part 127

Master your OITE and AAOS exams with Part 127 of our Orthopedic Surgery Board Review. Practice 100 verified MCQs on elb…

Chapter 18 246 min

Orthopedic Board Review MCQs: Arthroplasty, Foot & Ankle, Trauma | Part 128

Ace your OITE and AAOS exams with Part 128 of our Orthopedic Surgery Board Review. Practice 100 verified, high-yield MC…

Chapter 19 223 min

Orthopedic Surgery Board Review MCQs: Foot, Fracture, Hip, Infection, Shoulder | Part 129

Master your OITE and AAOS exams with Part 129 of our Orthopedic Surgery Board Review. Practice 100 high-yield MCQs on f…

Chapter 20 352 min

Orthopedic Board Review MCQs: Trauma, Shoulder & Knee | Part 130

Master the OITE and AAOS exams with Part 130 of our Orthopedic Board Review. Test yourself with 100 verified, high-yiel…

Chapter 21 319 min

Orthopedic Surgery Board Review MCQs: Spine, Deformity & Trauma | Part 131

Master your OITE and AAOS exams with Part 131 of our Orthopedic Surgery Board Review. Practice 100 verified MCQs on spi…

Chapter 22 224 min

Orthopedic Surgery Board Review MCQs: Foot, Fracture, Knee, Shoulder | Part 133

Master AAOS/ABOS Orthopedic Surgery boards. 100 high-yield MCQs on Foot, Knee, Shoulder, & Fracture. Mimics OITE/AAOS.

Chapter 23 421 min

Orthopedic Board Prep MCQs: Spine, Arthroplasty, & Trauma | Part 134

Master OITE and AAOS exams with Part 134 of our Orthopedic Board Review. Practice 100 verified, high-yield MCQs on spin…

Chapter 24 60 min

Orthopedic Board Review MCQs: Trauma & Knee Surgery Part 135

Master your AAOS & OITE Orthopedic Surgery board exams. 100 high-yield, verified MCQs with clinical explanations & flex…

Chapter 25 442 min

Orthopedic Board Review MCQs: Foot & Ankle, Trauma & Sports Medicine | Part 136

OITE & AAOS Orthopedic Board prep: Part 136. 100 high-yield, verified MCQs in exam format. Boost certification readines…

Chapter 26 225 min

Orthopedic Board Review MCQs: Arthroplasty, Fracture & Tumor | Part 137

Master OITE and AAOS exams with Part 137 of our Orthopedic Board Review. Test your skills with 100 verified MCQs on art…

Chapter 27 237 min

Orthopedic Board Prep MCQs: Arthroplasty, Trauma, Hip, Peripheral Nerve & Tendon – Part 138

Ace your OITE and AAOS exams with Part 138 of our orthopedic board review. Test yourself with 100 verified MCQs on arth…

Chapter 28 272 min

Orthopedic Board Review MCQs: Ankle, Foot, Hip & Knee | Part 139

Ace your OITE and AAOS exams with Part 139 of our Orthopedic Board Review. Practice 100 high-yield MCQs covering the an…

Chapter 29 334 min

OITE & ABOS Orthopedic Board Prep: Adult Reconstruction, Trauma & Upper Extremity MCQs Part 140

Master your OITE and ABOS exams with Part 140 of our Orthopedic Surgery Board Review. Practice 100 high-yield MCQs on t…

Chapter 30 212 min

Orthopedic Surgery Board Review MCQs: Arthroplasty, Foot & Ankle, Trauma | Part 141

Ace the OITE and AAOS exams with Part 141 of our Orthopedic Surgery Board Review. Test your knowledge with 100 high-yie…

Chapter 31 214 min

OITE & ABOS Orthopedic Board Exam MCQs: Spine, Trauma, Knee - Part 142

Ace your OITE and ABOS exams with Part 142 of our Orthopedic Board Review. Take the interactive quiz with 100 verified …

Chapter 32 45 min

Orthopedic Board Review MCQs: Deformity, Elbow, Hip & Shoulder | Part 143

Ace your OITE and AAOS exams with Part 143 of our Orthopedic Board Review. Practice 100 high-yield MCQs on deformity, e…

Chapter 33 224 min

Orthopedic Board Review MCQs: Elbow & Fracture Surgery | Part 144

Master elbow and fracture surgery with Part 144 of our Orthopedic Board Review. Practice 100 verified OITE and AAOS MCQ…

Chapter 34 336 min

Orthopedic Surgery Board Review MCQs: Spine, Trauma, Hip & Shoulder | Part 145

Master the OITE and AAOS exams with Part 145 of our Orthopedic Surgery Board Review. Test yourself with 100 high-yield …

Chapter 35 216 min

Orthopedic Board Review MCQs: Arthroplasty, Trauma & Infection | Part 146

Master your OITE and AAOS exams with Part 146 of our Orthopedic Board Review. Practice 100 verified MCQs on arthroplast…

Chapter 36 207 min

Orthopedic Board Review MCQs: Knee Arthroplasty, Revision & Spine - Part 147

Ace your OITE and AAOS exams with Part 147 of our Orthopedic Board Review. Practice 100 verified MCQs on knee arthropla…

Chapter 37 247 min

OITE & ABOS Orthopedic Board Prep MCQs: Hip, Sports Medicine & Oncology | Part 148

Orthopedic surgeons, prepare for OITE & ABOS board exams. This high-yield MCQ quiz offers 100 verified questions on Hip…

Chapter 38 337 min

Orthopedic Board Prep MCQs: Foot & Ankle, Knee Arthroplasty, Nerve | Part 150

Master OITE and AAOS exams with Part 150 of our Orthopedic Surgery Board Review! Practice 100 high-yield MCQs on foot, …

Chapter 39 226 min

Orthopedic Board Review MCQs: Trauma, Adult Reconstruction & Upper Extremity | Part 151

Ace your OITE and AAOS exams with Part 151 of our Orthopedic Board Review. Practice 100 verified, high-yield MCQs on tr…

Chapter 40 221 min

Orthopedic Board Prep MCQs: Arthroplasty & Trauma | Part 152

Ace OITE & AAOS exams with Part 152 of Dr. Hutaif's Orthopedic Board Review. Test yourself with 100 verified, high-yiel…

Chapter 41 318 min

Orthopedic Surgery MCQs: Trauma, Hip Arthroplasty & Elbow | Part 153

Master OITE and AAOS exams with 100 verified orthopedic surgery MCQs. Part 153 covers hip arthroplasty, elbow trauma, a…

Chapter 42 230 min

Orthopedic Board Exam MCQs: Trauma, Shoulder, Elbow, & Hip | Part 154

Master your OITE & ABOS exams with Part 154 of our verified, high-yield orthopedic surgery MCQs. Features clinical scen…

Chapter 43 277 min

Orthopedic Board Review MCQs: Lower Extremity Trauma & Arthroplasty | Part 155

Ace your OITE and AAOS exams with Part 155 of our Orthopedic Board Review. Practice 100 verified lower extremity trauma…

Chapter 44 426 min

Orthopedic Board Exam MCQs: Arthroplasty & Trauma Practice | Part 156

Prepare for OITE and AAOS exams with Part 156 of our Orthopedic Surgery Board Review. Test yourself with 100 verified M…

Chapter 45 246 min

Orthopedic Surgery Board Review MCQs: Spine, Arthroplasty & Trauma | Part 157

Master your OITE and AAOS exams with Part 157 of our Orthopedic Surgery Board Review. Take an interactive quiz with 100…

Chapter 46 239 min

OITE & ABOS Orthopedic Board Prep MCQs: Fracture & Shoulder | Part 158

Ace your OITE & AAOS orthopedic board exams with Part 158! Practice 100 verified, high-yield interactive MCQs on fractu…

Chapter 47 233 min

Orthopedic Board Review MCQs: Knee, Shoulder, Trauma & Infection | Part 159

Ace your OITE and AAOS exams with Part 159 of our Orthopedic Surgery Board Review. Practice 100 verified MCQs on knee, …

Chapter 48 223 min

OITE & ABOS Orthopedic Board Exam MCQs: Spine, Lower Extremity, & Shoulder | Part 160

Master your Orthopedic Surgery boards with Part 160 of Dr. Hutaif's OITE & ABOS review. Practice 100 verified MCQs on t…

Chapter 49 229 min

Orthopedic Surgery Board Review MCQs: Spine, Arthroplasty & Trauma | Part 161

Orthopedic surgeons: Prep AAOS & OITE boards. 100 high-yield MCQs on Arthroplasty, Spine, Hip, Elbow, Fracture. Explana…

Chapter 50 238 min

Orthopedic Board Review MCQs: Spine, Trauma, Shoulder & Knee | Part 162

Ace your OITE and AAOS exams with Part 162 of our Orthopedic Surgery Board Review. Test yourself with 100 verified MCQs…

Back to All Master Guides

Medically Verified Content by

Prof. Dr. Mohammed Hutaif

Consultant Orthopedic & Spine Surgeon

Quick Medical Answer

About This Board Review Set

How to Use the Interactive Quiz

Topics Covered in Part 149

Sample Questions from This Set

Why Active MCQ Practice Works

Detailed Chapters & Topics

Orthopedic Board Review MCQs: Hip & Knee Arthroplasty, Sports Medicine | Part 99

Orthopedic Board Exam MCQs: Upper Extremity, Spine & Foot/Ankle | Part 112

Orthopedic Board Review MCQs: Ankle, Deformity, Fracture & Scoliosis | Part 113

OITE & ABOS Orthopedic Board Review MCQs: Trauma, Spine & Sports Medicine | Part 114

Orthopedic Board Review MCQs: Hip, Shoulder & Spine Surgery | Part 115

Orthopedic Board Prep MCQs: Arthroplasty, Fracture, Hip, Knee, Shoulder | Part 116

Orthopedic Board Review MCQs: Shoulder, Trauma & Spine | Part 117

Orthopedic Board Prep MCQs: Pediatric, Shoulder & Sports Medicine | Part 118

Orthopedic Board Review MCQs: Arthroplasty, Trauma & Elbow | Part 119

Orthopedic Board Review MCQs: Upper Extremity & Trauma | Part 120

Orthopedic Surgery Board Exam MCQs: Shoulder, Nerve, & Spine | Part 121

Orthopedic Board Prep MCQs: Joints, Fractures & Arthroscopy | Part 122

Orthopedic Board Review MCQs: Spine, Hip, & Shoulder | Part 123

OITE & ABOS Orthopedic Board Prep MCQs: Trauma & Infection Part 124

Orthopedic Board Review MCQs: Elbow & Fracture Management | Part 125

OITE & ABOS Ortho Board Prep MCQs: Elbow, Knee, Trauma & Tumor | Part 126

Orthopedic Board Review MCQs: Elbow, Hip, & Nerve | Part 127

Orthopedic Board Review MCQs: Arthroplasty, Foot & Ankle, Trauma | Part 128

Orthopedic Surgery Board Review MCQs: Foot, Fracture, Hip, Infection, Shoulder | Part 129

Orthopedic Board Review MCQs: Trauma, Shoulder & Knee | Part 130

Orthopedic Surgery Board Review MCQs: Spine, Deformity & Trauma | Part 131

Orthopedic Surgery Board Review MCQs: Foot, Fracture, Knee, Shoulder | Part 133

Orthopedic Board Prep MCQs: Spine, Arthroplasty, & Trauma | Part 134

Orthopedic Board Review MCQs: Trauma & Knee Surgery Part 135

Orthopedic Board Review MCQs: Foot & Ankle, Trauma & Sports Medicine | Part 136

Orthopedic Board Review MCQs: Arthroplasty, Fracture & Tumor | Part 137

Orthopedic Board Prep MCQs: Arthroplasty, Trauma, Hip, Peripheral Nerve & Tendon – Part 138

Orthopedic Board Review MCQs: Ankle, Foot, Hip & Knee | Part 139

OITE & ABOS Orthopedic Board Prep: Adult Reconstruction, Trauma & Upper Extremity MCQs Part 140

Orthopedic Surgery Board Review MCQs: Arthroplasty, Foot & Ankle, Trauma | Part 141

OITE & ABOS Orthopedic Board Exam MCQs: Spine, Trauma, Knee - Part 142

Orthopedic Board Review MCQs: Deformity, Elbow, Hip & Shoulder | Part 143

Orthopedic Board Review MCQs: Elbow & Fracture Surgery | Part 144

Orthopedic Surgery Board Review MCQs: Spine, Trauma, Hip & Shoulder | Part 145

Orthopedic Board Review MCQs: Arthroplasty, Trauma & Infection | Part 146

Orthopedic Board Review MCQs: Knee Arthroplasty, Revision & Spine - Part 147

OITE & ABOS Orthopedic Board Prep MCQs: Hip, Sports Medicine & Oncology | Part 148

Orthopedic Board Prep MCQs: Foot & Ankle, Knee Arthroplasty, Nerve | Part 150

Orthopedic Board Review MCQs: Trauma, Adult Reconstruction & Upper Extremity | Part 151

Orthopedic Board Prep MCQs: Arthroplasty & Trauma | Part 152

Orthopedic Surgery MCQs: Trauma, Hip Arthroplasty & Elbow | Part 153

Orthopedic Board Exam MCQs: Trauma, Shoulder, Elbow, & Hip | Part 154

Orthopedic Board Review MCQs: Lower Extremity Trauma & Arthroplasty | Part 155

Orthopedic Board Exam MCQs: Arthroplasty & Trauma Practice | Part 156

Orthopedic Surgery Board Review MCQs: Spine, Arthroplasty & Trauma | Part 157

OITE & ABOS Orthopedic Board Prep MCQs: Fracture & Shoulder | Part 158

Orthopedic Board Review MCQs: Knee, Shoulder, Trauma & Infection | Part 159

OITE & ABOS Orthopedic Board Exam MCQs: Spine, Lower Extremity, & Shoulder | Part 160

Orthopedic Surgery Board Review MCQs: Spine, Arthroplasty & Trauma | Part 161

Orthopedic Board Review MCQs: Spine, Trauma, Shoulder & Knee | Part 162

Guide Overview