Orthopedic Surgery Mock Exam - Set 2915AD

- Medial_

Charcot arthropathy is a progressive condition of the musculoskeletal system that is characterized by joint dislocations, pathologic fractures, and debilitating deformities. This disorder results in progressive destruction of bone and soft tissues at weight-bearing joints; in its most severe form, it may cause significant disruption of the bony architecture. In patients with diabetes, the incidence of acute Charcot arthropathy of the foot and ankle ranges from 0.15% to 2.5%. Acute Charcot arthropathy almost always appears with signs of inflammation. Profound unilateral swelling, an increase in local skin temperature (generally, an increase of 3° to 7° above the nonaffected foot’s skin temperature), erythema,joint effusion, and bone resorption in an insensate foot are present. These characteristics, in the presence of intact skin and a loss of protective
sensation, are often pathognomonic of acute Charcot arthropathy.Cellulitis is an infection of the skin and osteomyelitis is an infection of the bone; examination of the limb would remain unchanged after 30 minutes of elevation. Reynaud and Sjogren syndromes are rheumatologic conditions that do not have these symptoms.
CLINICAL SITUATION FOR QUESTIONS 101 THROUGH 103
A 27-year-old woman has had pain in her right ankle for 2 years. Examination reveals a slightly warmjoint, without erythema. Ankle range of motion is limited by pain.
Radiographs are unremarkable.Because management consisting of immobilization, nonsteroidal anti-inflammatory drugs, and physiotherapy has failed to provide relief, MRI scans are obtained and shown in Figures 101a and 101b.An intraoperative image and the histology are shown in Figures 101c and 101d.

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Most clinical venous thromboembolism events occur between the second and sixth weeks after surgery. It is estimated that 10% of patients are readmitted to the hospital within the first 3 months after total hip or knee arthroplasties. Most pulmonary events on the day of surgery are related to fat embolism or cardiac events.

Primary TKA with respect to Knee Society scores and operative complications shows that a primary TKA group scored 88% good to excellent results compared to 63% for the post-HTO group

Early radiographic findings of avascular necrosis (AVN) of the hip include sclerosis and a subchondral lucency. A common presentation of Legg-Calve-Perthes disease (idiopathic pediatric hip AVN) is intermittent pain in the thigh, groin, or knee with an examination localizing to the hip; a Trendelenburg gait or sign; and painful, restricted passive hip range of motion. AVN also may be observed in association with a slipped capital femoral epiphysis (SCFE). AVN risk is highest in the setting of an unstable SCFE (10%-60%); risk is 0% to 1.4% when the SCFE is stable. A multicenter review of the modified Dunn procedure for treatment of unstable SCFE noted an AVN rate of 26%.
The most common deformity associated with SCFE is proximal femoral varus, flexion, and external rotation leading to an abnormal femoral head-neck junction offset. This causes a loss of passive hip flexion and internal rotation and the phenomenon of obligate external
rotation with flexion. The residual deformity frequently results in femoroacetabular impingement. Labral tears also are associated with cam impingement secondary to underlying osseous abnormalities including abnormal femoral head-neck junction offset.
Endocrinopathies potentially are associated with SCFE because of hormone-related physeal changes and subsequent mechanical insufficiency of the proximal femoral physis. With renal osteodystrophy, the physeal widening results from secondary hyperparathyroidism and progressive proximal femoral deformity may develop. Optimal medical management of hyperparathyroidism is essential. Surgical stabilization via in situ fixation of the proximal femur is indicated when SCFE is diagnosed.
The proximal femoral epiphysis secondary ossification center commonly appears between the ages of 4 and 7 months. In the setting of developmental hip dislocation, the appearance of the secondary ossification center is commonly delayed. After closed or open reduction of developmental dysplasia of the hip, failure of the femoral head ossific nucleus to appear within 12 months following the reduction is a sign of proximal femoral growth disturbance and AVN.

Figure 46a

Figure 46b

Figure 46c

Figure 46d

The natural history of cervical myelopathy is one of slow deterioration over time, typically in a stepwise fashion with a variable period of stable neurologic function. More recent studies suggest that surgery should be performed as soon as possible when cervical spondylotic myelopathy has been diagnosed. Both anterior and posterior are effective and there is no statistical difference between their outcomes. Surgical outcome is related to the patient’s age, disease course, the presence of osseous spinal stenosis, preoperative comorbidities, the preoperative spinal cord functional score, and the presence of high-signal abnormalities on T2-weighted images. To improve the operative result, all the influencing factors should be considered. Patients with focal high-intensity intramedullary signal changes on T2-weighted images have better clinical outcomes following surgery than do patients with demonstrable multisegmental high-intensity intramedullary signal changes on T2-weighted sequences. The transverse area and shape of the spinal cord at the involved segment may also be predictive of surgical outcome.
With progressive compression, the cross section of the spinal cord changes from a boomerang shape to a teardrop shape to a triangular shape. In patients with a Nurick grade of I, there are signs of cord involvement, but gait remains normal. With a Nurick grade of II, there are mild gait abnormalities,not affecting the patient’s employment status. With a Nurick grade of III, gait abnormalities prevent employment, but the patient remains able to ambulate without assistance. In Nurick grade IV, the patient is only able to ambulate with assistance. In Nurick grade V, the patient is chair-bound or bedridden. Clearly, it is desirable to operate when the patient is functioning with a Nurick grade of I or II. Whereas many patients presenting with cervical spondylotic myelopathy also report axial neck pain and radicular symptoms in the upper extremities, this is not always the case. Surgical intervention will generally be effective in eliminating this pain; however, the pain is not the determining factor for performing surgery.Surgery is performed to preserve and restore function. Changes in bowel and bladder function can occur
in extremely severe cases of myelopathy, but this is quite rare.

The most specific laboratory finding is an elevated antibody titer to Borrelia burgdorferi. This test is commonly referred to as a
Lyme titer.
All of the mentioned tests are generally seen in Lyme disease, however, elevated erythrocyte sedimentation rate, elevated C - reactive protein, negative antinuclear antibody, and negative rheumatoid factor are all nonspecific.

The contracted Achilles tendon leads to increased forefoot pressure, thus increasing the risk for ulceration in neuropathic patients. Several studies have shown the benefit of Achilles tendon lengthening to heal and prevent forefoot ulceration in these patients. The flexor hallucis longus transfer is used for chronically torn/deficient Achilles tendons, not a contracted Achilles tendon. The Jones procedure works well for the first ray but does not help to alleviate pressure under the second ray. Peripheral bypass surgery is unnecessary because the ulcer healed during the initial treatment, indicating that the patient has adequate circulation. The posterior tibial tendon transfer is used for foot drop or other neuromuscular conditions to correct deformity and increase function. It is not used for forefoot ulcers in patients with diabetes mellitus.
REFERENCES: Armstrong DG, Stacpoole-Shea S, Nguyen H, et al: Lengthening of the Achilles tendon in diabetic patients who are at high risk for ulceration of the foot. J Bone Joint Surg Am 1999;81:535-538.
Meuller MJ, Sinacore DR, Hastings MK, et al: Effect of Achilles tendon lengthening on neuropathic plantar ulcers: A randomized clinical trial. J Bone Joint Surg Am
2003;85:1436-1445.

Nonsurgical management has failed to provide relief; therefore, the treatment of choice is arthrodesis with an intramedullary nail. Amputation may be indicated if the arthrodesis fails. The patient does have adequate circulation for an attempt at salvage. Total ankle arthroplasty is not indicated in a neuropathic patient.
REFERENCES: Pinzur MS, Kelikian A: Charcot ankle fusion with a retrograde locked intramedullary nail. Foot Ankle Int 1997;18:699-704.
Herbst SA: External fixation of Charcot arthropathy. Foot Ankle Clin 2004;9:595-609.

The radiograph and sagittal T2-weighted MRI scan show multilevel degenerative changes and subaxial subluxations with anterolisthesis at C3-C4 and C4-C5 and retrolisthesis at C5-C6. In addition, there is evidence of midcervical kyphosis. Such findings are often seen in patients with rheumatoid arthritis. Patients with osteomyelitis typically show increased signal intensity in the disks and vertebral bodies. Patients with ankylosing spondylitis typically show ankylosis of the disks and vertebral bodies. Age-related degenerative changes typically manifest as degenerative disk disease with occasional single- level spondylolisthesis, but not typically multilevel spondylolisthesis, as seen in this patient. The spinous processes are intact; these changes do not appear to be postoperative.

DISCUSSION: Salter Harris III and IV fractures of the medial malleolus often contain a large cartilaginous portion, larger than the apparent ossified fragment seen on radiographs. Consequently, articular incongruity is common. As such, open reduction and internal fixation is often required. Growth disturbance and angular deformity are also common complications of Salter Harris III and IV fractures of the distal tibia.

REFERENCES: Flynn JM, Skaggs DL, Sponseller PD, et al: The surgical management of pediatric fractures of the lower extremity. Instr Course Lect 2003;52:647-659.
Kay RM, Matthys GA: Pediatric ankle fractures: Evaluation and treatment. J Am Acad Orthop Surg 2001;9:268-278.

Nonoperative treatment will allow the patient to retain maximum mobility of the hips.
Operative treatment carries substantial risk of avascular necrosis, stiffness, and redislocation. These risks are not worth taking in view of the patientâs limited muscle strength about the hips. In addition, the motor level alluded to (L2-L3) means that she will not have sensation of pain from the hips.

The most common reason for a nerve deficit following shoulder arthroplasty is a temporary neuropraxia due to stretch. Correct Answer: Temporary neuropraxia due to stretch

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A stress fracture of the femoral neck or pelvis should be ruled out in this patient. She should be placed on crutches and not allowed to run. The consequences of missing such a diagnosis can be devastating. Superior cortical femoral neck stress fractures are tension injuries and can progress to a complete fracture and avascular necrosis. Surgical fixation may be indicated. Plain radiographic findings often do not appear until late in the clinical course. MRI is more accurate, more specific, and is superior to radionuclide bone scanning for the diagnosis of stress fracture in young endurance athletes. MRI detects early changes in osseous stress injury and allows precise definition of the anatomy and extent of injury. This patient may have the female athletic triad: disordered eating, amenorrhea, and osteoporosis. However, the workup for this condition (including a possible DEXA scan) may be delayed until after the stress fracture is diagnosed and treated.

The most important determining factor for correction of an adult flatfoot without an arthrodesis is the flexibility of the subtalar and transverse tarsal joints. Rigid deformities cannot be corrected with a medial sliding calcaneal osteotomy with FDL transfer or a subtalar arthroereisis. Isolated subtalar or talonavicular arthrodesis does not correct the deformities entirely. If the patient has forefoot supination that can be corrected to less than 7°, an isolated subtalar fusion is a possible alternative.
REFERENCE: Mann RA: Flatfoot in adults, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 6. St Louis, MO, Mosby, 1993, pp 757-784.

The patient has a degenerative collapse of the midfoot through the tarsometatarsal joints with significant forefoot abduction; therefore, a midfoot arthrodesis is required to address the arthritic joints and deformity at the tarsometatarsal articulation. All of the other procedures correct hindfoot deformities and therefore would not be appropriate treatment.
REFERENCES: Brage M: Degenerative joint disease of the midfoot. Foot Ankle Clin 1999;4:355-367.
Mann RA, Prieskorn D, Sobel M: Mid-tarsal and tarsometatarsal arthrodesis for primary degenerative osteoarthrosis or osteoarthrosis after trauma. J Bone Joint Surg Am
1996;78:1376-1385.

In symptomatic partial-thickness rotator cuff tears, a painful arc with active range of motion is common, impingement signs are usually positive, and the lift-off test is normal. Active and passive range of motion measurements are often equal, although active range of motion can be painful. External rotation lag signs are often seen with larger full-thickness tears.
REFERENCES: Hertel R, Ballmer FT, Lambert SM, Gerber C: Lag signs in the diagnosis of rotator cuff rupture. J Shoulder Elbow Surg 1996;5:307-313.
McConville OR, Iannotti JP: Partial thickness tears of the rotator cuff: Evaluation and management. J Am Acad Orthop Surg 1999;7:32-43.
Gerber C, Krushell RJ: Isolated rupture of the tendon of the subscapularis muscle: Clinical features in 16 cases. J Bone Joint Surg Br 1991;73:389-394.
Fukuda H: Partial-thickness rotator cuff tears: A modern view on Codman’s classic. J Shoulder Elbow Surg 2000;9:163-168.

Elderly patients with femoral neck fractures (FNF) undergoing total hip arthroplasty (THA) are less likely to require reoperation than those undergoing internal fixation.
Intracapsular FNF are common in elderly patients after a fall from standing height. Treatment depends on physiological age and displacement (Garden's classification). For displaced fractures, physiologically young patients are treated with internal fixation while physiologically old patients are treated with
either hemiarthroplasty (debilitated, less active patients) or THA (more active patients, those with acetabular disease or preexisting inflammatory arthritis).
Chammout et al. retrospectively compared the long term (17 years) results of THA (cemented both component) and ORIF (2 cannulated screws) in elderly patients (>65 years). They found no difference in mortality. But hip scores were higher and pain was better in the THA group, while reoperation rates were higher in the ORIF group. Walking speed was initially faster in the THA group, but later did not differ between groups. They recommend THA for elderly patients with displaced FNF.
Rogmark et al. prospectively compared closed reduction and internal fixation (CRIF) with arthroplasty (combining hemiarthroplasty and THA) at 2 years in elderly patients (>70 years). Failure rates were higher, pain was worse, and walking was more impaired after CRIF. They recommend arthroplasty for patients >70 with FNF.
Incorrect Answers:
Answer 1: Patients undergoing THA are more likely to have less pain than internal fixation.
Answer 3: Patients undergoing THA have superior functional outcome scores. Answer 4: Patients undergoing THA perform ADL better in the short term. In the long term, there is no difference in ADL between the groups.
Answer 5: Mortality rates are similar after the two procedures.

The patient has a loose acetabular component, which explains her pain and progressive shortening. She has a history of inflammatory arthritis, elevated ESR and C-reactive protein, and has recently been treated for an infection. Thus, the suspicion for infection is high and must be ruled out. A triple phase bone scan can assist in the identification of component loosening but cannot differentiate infection from noninfectious causes. Indium-111 scans have been shown to have limited utility, although a negative scan can be helpful in ruling out infection. The selective preoperative use of aspiration of the hip joint has been shown to be effective and is most likely to identify infection; however, the patient must be off of antibiotics for a minimum of 2 weeks prior to her aspiration to avoid a false negative culture.
REFERENCES: Della Valle CJ, Zuckerman JD, Di Cesare PE: Periprosthetic sepsis. Clin Orthop Relat Res 2004;420:26-31.
Lachiewicz PF, Rogers GD, Thomason HC: Aspiration of the hip joint before revision total hip arthroplasty:
Clinical and laboratory factors influencing attainment of a positive culture. J Bone Joint Surg Am 1996;78:749-754. 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.

Figure 73

styloid fracture were found to increase risk for DRUJ instability. An ulnar styloid base fracture involves the insertion of the radioulnar ligaments and can cause DRUJ instability if displaced. If persistent instability is present after fixation of the ulnar styloid, DRUJ pinning is a reasonable option. Early ROM
The initial radiographs show a comminuted displaced distal radius fracture, along with a displaced fracture of the base of the ulnar styloid. The displacement is best seen on the oblique view. After reduction and fixation of the radius, DRUJ stability should be assessed. The majority of scenarios that involve this injury pattern will not be unstable because of the oblique band of the interosseous ligament. When DRUJ instability is present after fixation of the radius, reduction and fixation of the ulnar styloid fracture is the best option to provide stability of the distal radioulnar joint (DRUJ) (Figure below). A study by Lawton and associates revealed that all distal radius fractures complicated by DRUJ instability were accompanied by an ulnar styloid fracture. A fracture at the ulnar styloid’s base and substantial displacement of an ulnar
with splinting would not allow reduction or healing of the ulnar styloid and would result in persistent instability. Short-arm casting also would not allow stability of the DRUJ and would be a less reliable method with which to achieve healing of the ulnar styloid.

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This patient has an aneurysmal bone cyst of the vertebra. Selective arterial embolization is a minimally invasive treatment that often succeeds in arresting the lesions. Many times it is the only treatment needed. Selective arterial embolization can also be used as part of a strategy to be followed by curettage and reconstruction to decrease operative bleeding.
This lesion will continue to expand and might cause neurologic compromise or mechanical instability. Radiation therapy poses risks of later malignant degeneration. There are other ways of treating this lesion. Radical en bloc resection may unnecessarily injure neurologic structures.
While curettage is often necessary, there is no reason to introduce the risk of radiation therapy.

Acrosyndactyly describes digits that are joined distally but remain separated by a proximal cleft. Acrosyndactylized digits initially develop normal web spaces, but are subsequently joined by secondary events, such as the formation of constriction bands. In contrast to syndactylized fingers, which remain joined due to failure of formation of the web space between contiguous digits, acrosyndactyly may form between non-contiguous digits. C omplex syndactyly involves a confluence of distal osseous and nail elements in addition to soft-tissue bridging. Simple syndactyly describes digits that are joined by soft tissue only. Finally, complete syndactyly refers to digits that are joined along their entire lengths, while incomplete syndactyly describes a web that extends more distally than usual, but not all the way to the finger tips.

The flexed knee and ankle mechanism of injury can result in a PCL and/or posterolateral corner injury. The examination reveals an isolated injury to the posterolateral corner (arcuate, popliteus, posterolateral capsule). This results in increased posterior translation and external rotation, as well as varus that is most notable at 30° of flexion and decreases as the knee is further flexed to 90°. Combined PCL and posterolateral corner injuries are characterized by increasing instability as the knee is flexed to 90° from 30°, while isolated PCL tears show the greatest degree of instability at 90° of flexion. A rupture of the quadriceps tendon would not affect anterior or posterior stability, whereas an isolated rupture of the lateral collateral ligament, which is a rare injury, is characterized by varus instability at 30° of knee flexion without posterior translation.
REFERENCES: Harner CD, Hoher J: Evaluation and treatment of posterior cruciate ligament injuries. Am J Sports Med 1998;26:471-482.
Veltri DM, Warren RF: Isolated and combined posterior cruciate ligament injuries. J Am Acad Orthop Surg 1993;1:67-75.

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This is a prospective comparative study but is not randomized or blinded and
is therefore a Level II therapeutic study. To qualify as Level I, it would need to be a high- quality randomized trial with narrow confidence intervals regardless of a significant difference or no difference in outcomes. Level III would be
case-control studies or retrospective comparisons. Level IV is case series and Level V is expert opinion.

The clinical scenario and radiographs are consistent with a Gustilo and Anderson type 3A open tibia fracture.
Melvin et al review the evidenced-based literature and make recommendations for the initial evaluation and management of open tibial shaft fractures. The time elapsed before antibiotic administration and adequate surgical debridement of all contamination are the only factors definitively shown to reduce infection and improve outcome. Traditional recommendations have suggested surgical debridement of open fractures occur within 6 hours of injury. However, there is no literature to support this time window. Certainly, open fractures should be addressed with urgency, but there is no evidence reporting a definitive time window. There is insufficient data to recommend gram negative coverage with gentamicin for all open fractures although this is a common practice. The addition of antibiotics to the irrigation solution has been shown to decrease bacterial load, but it has also demonstrated host tissue necrosis and delayed wound healing. There is not sufficient data to support its use over a castile soap solution or normal saline. Similarly, high pressure pulsatile lavage decreases bacterial load, but also seeds bacteria deeper within the soft tissues and harms host tissues. There is no evidence to support pulsatile lavage over gravity flow.

The most accurate way to monitor the motor tracts of the spinal cord is to stimulate the motor cortex. Stimulation at the level of the spinal cord conducts mainly antidromically through sensory pathways. Stimulation of the tibial and peroneal nerve is performed for monitoring sensory pathways only; these are an important indicator of spinal cord integrity but do not monitor the motor pathways per se. Stimulation of the gastrocnemius does not have any value for monitoring.

The radiograph reveals a four-part fracture-dislocation of the proximal humerus. Humeral hemiarthroplasty and tuberosity repair is the treatment of choice because the risk of osteonecrosis is high after attempted repair of this injury. Glenoid resurfacing is reserved for acute fractures in which there is significant preexisting glenoid arthrosis, such as in patients with rheumatoid arthritis.
REFERENCES: Neer CS II: Displaced proximal humeral fractures: II. Treatment of three- and four-part displacement. J Bone Joint Surg Am 1970;52:1090-1103.
Robinson CM, Page RS, Hill RM, et al: Primary hemiarthroplasty for treatment of proximal humeral fractures. J Bone Joint Surg Am 2003;85:1215-1223.

With a severe injury to the upper extremity, the best opportunity for achieving a good functional result for a floating elbow is immediate debridement of the open fracture, followed by internal fixation of the fractures. The ability to do this depends on the patient’s physiologic status. In this patient, the procedure is acceptable because she has normal vital signs and no chest or abdominal injuries, and normal physiologic parameters (base excess and lactate) show adequate peripheral perfusion. The surgical approaches will be determined by the associated injury patterns and open wounds. In this patient, the humerus was debrided and stabilized through a posterior approach as was the medial condyle fracture. The ulna was fixed through an extension of the posterior incision and the radius through a separate dorsal approach.
REFERENCES: Solomon HB, Zadnik M, Eglseder WA: A review of outcomes in 18 patients with floating elbow. J Orthop Trauma 2003;17:563-570.
Pape HC, Hildebrand F, Pertschy S, et al: Changes in the management of femoral shaft fractures in polytrauma patients: From early total care to damage control orthopedic surgery. J Trauma 2002;53:452-461.

Autosomal recessive conditions classically show âhorizontalâ inheritance. Ancestors do not display the gene because they would likely have only one copy of the mutant allele. Only when two carriers reproduce is the phenotype manifest in approximately one- fourth of their offspring.
Autosomal dominant inheritance is characterized by vertical transmission. Many generations manifest the trait because it takes only a single copy of a mutant allele to display the phenotype.
Sex-linked conditions are often traced back in a family. Normally the males are affected and the females are carriers. Multifactorial conditions are thought to result from the combination of different genes. Although the risk of recurrence in kindred is somewhat greater than the population as a whole, it is still quite low (only a few percent). It is rare for siblings to be affected.
Anticipation refers to the phenomenon in which successive generations are likely to display more severe forms of a given disorder. Myotonic dystrophy is a classic example of this phenomenon.

DISCUSSION: In vivo fluoroscopic studies have enlightened orthopaedic surgeons as to the actual kinematic performance of the total knee implants. Importantly, many technical factors combine to result in abnormal kinematics after total knee arthroplasty. The typical kinematics of the normal knee are negated by osteoarthritis and the various changes created by the surgeon’s technique. Dennis and associates observed that anterior femoral condylar translation during deep knee flexion was most commonly observed in posterior cruciate-retaining knees.

REFERENCES: Dennis DA, Komistek RD, Mahfouz MR, et al: Multicenter determination of in vivo kinematics after total knee arthroplasty. Clin Orthop Relat Res 2003;416:37-57.
Freeman MA, Pinskerova V: The movement of the normal tibio-femoral joint. J Biomech 2005-38'197- 208.
**42 • American Academy of Orthopaedic Surgeons**

Figure 52

The anterior drawer test is performed with the ankle in 10° of plantar flexion, which results in the greatest amount of translation. The test investigates the integrity of the anterior talofibular ligament with a key distance of translation being 8 to 10 mm. While the patient is sitting and has her knees flexed over the edge of a table or bench, the physician uses one hand to stabilize the distal leg and with the other hand applies an anterior force to the heel in an attempt to gap the talus anteriorly from under the tibia. The anterior talofibular ligament and calcaneofibular ligament are both compromised based on the examination findings. The anterior drawer test result reflects injury to the anterior talofibular ligament and a possible injury to the calcaneofibular ligament. A lateral talar tilt test angle measurement >15° degrees reflects a rupture of both anterior talofibular ligament and calcaneofibular ligaments. The diagnosis is a severe lateral ligament complex sprain. This is optimally managed with early mobilization and a guided rehabilitation program that emphasizes proprioceptive stability.

Lumbricals 1 and 2 are innervated by the median nerve, in addition to the opponens pollicis brevis, abductor pollicis brevis, and flexor pollicis brevis.

Disruption of the posterior ligamentous complex is an important determinant of the stability of a burst fracture. This patient is neurologically intact and his MR images do not reveal posterior ligamentous complex (PLC) disruption. The standing radiograph confirms that overall alignment is acceptably and relatively preserved. Nonsurgical treatment with or without a brace is acceptable in this scenario; however, the patient should not be cleared to resume full activity until fracture healing, which may be as long as 3 months after the date of injury. Anterior or posterior surgery should be reserved for patients with PLC disruption, neurological injury, or, in some cases, multiple trauma.
RECOMMENDED READINGS
[Wood K, Buttermann G, Mehbod A, Garvey T, Jhanjee R, Sechriest V. Operative compared with nonoperative treatment of a thoracolumbar burst fracture without neurological deficit. A prospective, randomized study. J Bone Joint Surg Am. 2003 May;85-A(5):773-81. Erratum in: J Bone Joint Surg Am. 2004 Jun;86-A(6):1283. Butterman, G [corrected to Buttermann, G]. PubMed PMID: 12728024. ](http://www.ncbi.nlm.nih.gov/pubmed/12728024)[View ](http://www.ncbi.nlm.nih.gov/pubmed/12728024)[Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/12728024)
[Vaccaro AR, Lehman RA Jr, Hurlbert RJ, Anderson PA, Harris M, Hedlund R, Harrop J, Dvorak M, Wood K, Fehlings MG, Fisher C, Zeiller SC, Anderson DG, Bono CM, Stock GH, Brown AK, Kuklo T, Oner FC. A new classification of thoracolumbar injuries: the importance of injury morphology, the integrity of the posterior ligamentous complex, and neurologic status. Spine (Phila Pa 1976). 2005 Oct 15;30(20):2325-33. PubMed PMID: 16227897. ](http://www.ncbi.nlm.nih.gov/pubmed/16227897)[View Abstract at](http://www.ncbi.nlm.nih.gov/pubmed/16227897)[ ](http://www.ncbi.nlm.nih.gov/pubmed/16227897)[PubMed](http://www.ncbi.nlm.nih.gov/pubmed/16227897)
[Vaccaro AR, Zeiller SC, Hulbert RJ, Anderson PA, Harris M, Hedlund R, Harrop J, Dvorak M, Wood K, Fehlings MG, Fisher C, Lehman RA Jr, Anderson DG, Bono CM, Kuklo T, Oner FC. The thoracolumbar injury severity score: a proposed treatment algorithm. J Spinal Disord Tech. 2005 Jun;18(3):209-15. PubMed PMID: 15905761.](http://www.ncbi.nlm.nih.gov/pubmed/15905761)[View ](http://www.ncbi.nlm.nih.gov/pubmed/15905761)[Abstract at PubMed](http://www.ncbi.nlm.nih.gov/pubmed/15905761)
RESPONSES FOR QUESTIONS 86 THROUGH 89
1. Proximal junctional kyphosis (PJK)
2. Adjacent segment degeneration
3. Intraoperative neurological injury
4. Postsurgical wound infection
Please select the complication listed above that most commonly is associated with a clinical scenario described below.

For stage III adult-acquired flatfoot deformity characterized by dysfunction of the posterior tibial tendon, rigid valgus deformity of the hindfoot, and arthritic changes of the hindfoot joints,arthrodesis is the favored procedure. In an overweight patient with degenerative changes affecting the subtalar and Chopart joints, triple arthrodesis is the best treatment option. Subtalar arthrodesis only addresses the talocalcaneal joint and continues to render the patient symptomatic in the talonavicular and calcaneocuboid joints. Advanced stage III disease precludes reconstructive procedures involving calcaneal osteotomy and tendon transfer.

- Figure 51d_

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A child with midlumbar myelomeningocele, without other lesions, would be expected to have the ability to ambulate, though delayed. She has a high likelihood of hip dislocations because of lack of function of the abductor muscles. The presence or absence of hip dislocation does not affect ambulatory ability; the child is already walking. The best course of action is education of the family and therapist as to the minimal effect that a hip dislocation has in these patients. A shoe lift or brace buildup can address leg length discrepancy; in a hip without contractures, no other treatment is needed.
Radiographs are unnecessary in the management of the hip dislocation in myelomeningocele. Surgery has been shown to convert supple, painless dislocated hips into stiff, painful hips that have a high likelihood of redislocation. Though the dislocation is not recommended for treatment, this does not preclude the ability to safely ambulate and undergo therapy, which is not harmful to the condition.

3 _AL_. _-M_ E _ad_ m _en_ e _a_ rg _C_ e _o_ n _p_ t _y_
knee arthroscopy

2010 Pediatric Orthopaedic Examination
ook • 43

4. ##### Four-compartment calf fasciotomy
5. ##### Non-weight-bearing, a knee immobilizer, and follow- up in 1 week

PREFERRED RESPONSE: 1
DISCUSSION: The anatomic lesion in this patient is not exactly defined, but she has most likely sustained an injury about the knee. A Salter-Harris type I proximal tibial physeal fracture is likely. The normal radiograph reading can be misleading because these injuries may displace and spontaneously reduce. The child is at risk of compartment syndrome although she is currently not displaying signs of it. Thus, even though this injury may seem trivial by radiographic findings, it should be treated like a knee dislocation with a risk of late developing compartment syndrome. MRI or CT may be necessary to define the injury. She does not require emergent treatment, but merits close observation for possible compartment syndrome. Any of the possible injuries about the knee can be unstable and require internal fixation after reduction.

REFERENCES: McGuigan JA, O’Reilly MJ, Nixon JR: Popliteal arterial thrombosis resulting from disruption of the upper tibial epiphysis. Injury 1984;16:49-50.
Burkhart SS, Peterson HA: Fractures of the proximal tibial epiphysis. J Bone Joint Surg Am
1979;61:996- 1002.

The osteon is a unique arrangement of bone cells and matrix surrounding a blood vessel. The osteon is an irregular branching, anastomosing cylinder composed of a centrally placed neurovascular canal surrounded by cell-permeated layers of bone matrix.
The bone remodeling unit refers to the cutting cone of leading osteoclasts and following osteoblasts.
Plexiform bone is a structural type of bone found in large animals where rapid bone growth occurs. There are alternating layers of lamellar and woven bone.
Volkman canals are the channels connecting different osteons or Haversian units.
Canaliculi are small channels through which the cell processes of the osteocytes connect to each other. Correct Answer: Osteon

The Lisfranc ligament arises from the lateral surface of the first (medial) cuneiform and is directed obliquely outward and slightly downward to insert on the medial surface of the second metatarsal base. It is the strongest of the tarsometatarsal interosseous ligaments.
REFERENCES: Sarrafian SK: Anatomy of the Foot and Ankle: Descriptive, Topographic, Functional, ed 2. Philadelphia, PA, JB Lippincott, 1993.
Solan MC, Moorman CT III, Miyamoto RG, et al: Ligamentous restraints of the second tarsometatarsal joint: A biomechanical evaluation. Foot Ankle Int 2001;22:637-641.

This patient demonstrates several upper extremity issues including possible carpal tunnel syndrome, cervical radiculopathy, and pronator syndrome. The electrodiagnostic testing is equivocal, and a corticosteroid carpal tunnel injection should be performed prior to surgical intervention to assess its effectiveness in eliminating the patient's symptoms. Positive response (meaning improvement in symptoms), after corticosteroid injection at the carpal tunnel correlates well with symptom relief following surgery. Trigger-point injections are not indicated for carpal tunnel syndrome. Ultrasound and carpal tunnel view radiograph can provide diagnostic information but would not be helpful in determining _treatment in this specific case._

Osteofibrous dysplasia occurs exclusively in the tibia. This non-neoplastiCcondition may be related to adamantinoma. The lesion is usually located in the anterior cortex and there is often bowing of the tibia.

Fracture is common in this condition because of osteopenia and the stress concentration due to joint stiffness.
Osteomyelitis is uncommon in the diaphysis and much less common in this scenario than fracture. Septic arthritis of the hip is uncommon in this disease.
Dislocation of the hip would not cause pain and swelling in this setting. Deep vein thrombosis is uncommon at this age.

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Cubitus varus deformity may occur after pediatric supracondylar and lateral condyle fractures. The deformity is a combination of varus, extension, and internal rotation. Although pediatric cubitus varus following a pediatric distal humerus fracture or congenital deformity has traditionally been considered a cosmetic problem, adult orthopaedic literature cites the posterolateral rotatory instability, ulnar neuropathy, snapping triceps, progressive varus of the ulna, elbow joint malalignment and tendency to distal humerus lateral condyle fracture as possible long-term sequela.