AAOS & ABOS Orthopedics MCQs (Set 9): General Principles & Trauma | 2026 Board Prep

The clinical photograph and radiograph show gout, which is the result of urate deposition in the joint and soft tissues. Radiographs frequently reveal periarticular erosions. The crystals are intracellular and negatively birefringent under the polarized microscope. Treatment for acute flares include colchicines, indomethacin, and corticosteroids (including injections). Medications such as allopurinol help prevent recurrent flares. Tophi such as that seen in this patient are often confused with and associated with infection. Wortmann RL, Kelley WM: Crystal-induced inflammation: Gout and hyperuricemia, in Harris ED, Budd RC, Firestein GS, et al (eds): Kelley's Textbook of Rheumatology, ed 7. New York, NY, Elsevier Science, 2005, pp 1402-1429. Trumble TE (ed): Hand Surgery Update 3: Hand, Elbow, & Shoulder. Rosemont, IL, American Society for Surgery of the Hand, 2003, pp 433-457.

Avulsion fractures of the medial epicondyle are caused by a valgus stress applied to the immature elbow and usually occur in children between the ages of 9 and 14 years. Long-term studies have shown that isolated fractures of the medial epicondyle with between 5 to 15 mm of displacement heal well. Brief immobilization (1 to 2 weeks) in a long arm cast or splint yields results similar to open reduction and internal fixation. Fibrous union of the fragment is not associated with significant symptoms or diminished function. Surgical excision of the fragment yielded the worst results in one study and should be avoided. Open reduction is best reserved for those injuries in which the medial epicondylar fragment becomes entrapped in the elbow joint during reduction and cannot be extracted by closed manipulation. Farsetti P, Potenza V, Caterini R, Ippolito E: Long-term results of treatment of fractures of the medial humeral epicondyle in children. J Bone Joint Surg Am 2001;83:1299-1305.

Very large corrections of tibial deformity can be achieved at or just below the tibial tubercle. This level of osteotomy maintains the relationship between the tubercle and the rest of the joint, does not alter patellofemoral mechanics, and avoids complicating possible future conversion to total knee arthroplasty. High tibial osteotomy is contraindicated for large corrections because of excessive elevation of the tibial tubercle and overhang of the lateral plateau. Correction in the tibial diaphysis creates a zig zag pattern in the tibia by correcting below the deformity and risks nonunion in cortical bone. There is no evidence that the femur is deformed; therefore, femoral osteotomy is not indicated.

The patient has spinal muscular atrophy, type 2. This type is intermediate in severity between the Werdnig-Hoffmann type (type 1) and the Kugelberg-Welander type (type 3). It normally manifests itself between the ages of 3 and 15 months. Survival until adolescence is common. All three types of spinal muscular atrophy have been linked to the SMN gene at the 5q12.2-13.3 locus. DNA testing is available and is preferred to muscle biopsy because it is less invasive and more definitive. Biros I, Forrest S: Spinal muscular atrophy: Untangling the knot? J Med Genet 1999;36:1-8.

The patient sustained a growth plate fracture of the distal radius and ulna. Although treated with closed reduction and casting, the follow-up radiographs demonstrate shortening of the radius in comparison to the ulna, and the MRI scan confirms thinning of the distal radius growth plate and bony bars consistent with a growth arrest. At this time, the discrepancy in length is too minor to consider lengthening of the radius; in addition, excision of a physeal bar with minimal growth potential is not likely to restore the gross discrepancy. Ulnar styloid fractures are rarely symptomatic and do not require treatment in the asymptomatic patient. Closure of the distal ulna growth plate will prevent further discrepancy between the radius and ulna. Vanheest A: Wrist deformities after fracture. Hand Clin 2006;22:113-120.

Patients with an above-the-knee amputation have a 65% increase in energy expenditure. A patient with a transtibial amputation requires 25% more energy above baseline values; however, bilateral transtibial amputations are associated with a 40% increase in energy expenditure. Otis JC, Lane JM, Kroll MA: Energy cost during gait in osteosarcoma patients after resection and knee replacement and after above-the-knee amputation. J Bone Joint Surg Am 1985;67:606-611.

Unwitnessed spiral fractures should raise the possibility of child abuse, especially prior to walking age. With nonaccidental trauma being considered in the differential diagnosis, a skeletal survey is indicated to determine if there are other fractures in various stages of healing. Kempe CH, Silverman FN, Steele BF, et al: The battered-child syndrome. JAMA 1962;181:17-24.

By convention when determining the motor level, the key muscle must be at least 3/5. The next most rostral level must be 4/5. Therefore, this patient's functional level is C6.

Coleman block testing, performed by placing an elevation under the lateral border of the foot, is used to determine if the forefoot and/or plantar flexed first ray is causing a compensatory varus in the hindfoot. The block is placed under the lateral border of the foot, and therefore does not have any relation to the Achilles tendon and suppleness of the hindfoot. Holmes JR, Hansen ST Jr: Foot and ankle manifestations of Charcot-Marie-Tooth disease. Foot Ankle 1993;14:476-486.

Osteochondritis of the capitellum is characterized by pain, swelling, and limited motion. Catching, clicking, and giving way also can occur. It commonly affects athletes who participate in competitive sports with high stresses, such as pitching or gymnastics. Krijnen MR, Lim L, Willems WJ: Arthoscopic treatment of osteochondritis dissecans of the capitellum: Report of 5 female athletes. Arthroscopy 2003;19:210-214.

The recommended position for a hip fusion is flexion of 20 degrees to 30 degrees, slight adduction (5 degrees) or neutral, and 10 degrees of external rotation. In long-term follow-up, patients who underwent fusion in abduction had more ipsilateral knee and low back pain than patients who were positioned in adduction. Internal rotation should be avoided to prevent interference with the opposite foot during gait. External rotation facilitates the application of shoe wear. Callaghan JJ, Brand RA, Pederson DR: Hip arthrodesis: A long-term follow-up. J Bone Joint Surg Am 1985;67:1328-1335.

Achieving stability in chronic locked posterior dislocations of the shoulder remains a difficult challenge. Intraoperative measures include decreased humeral retroversion, anterior releases, and posterior capsular tightening. Postoperative rehabilitation is of equal importance. Immobilization in an external rotation brace (10 degrees to 15 degrees) with the arm at the side for 4 to 6 weeks is recommended to decrease tension in the posterior capsule. When passive range-of-motion exercises are instituted, they should be performed in the plane of the scapula to avoid stress posteriorly. Internal rotation and supine elevation should be avoided for similar reasons. Hawkins RJ, Neer CS II, Pianta RM, Mendoza FX: Locked posterior dislocation of the shoulder. J Bone Joint Surg Am 1987;69:9-18.

The Canale view, which visualizes the talar neck, is taken with the ankle in maximum plantar flexion and the foot pronated 15 degrees. The radiograph is directed at a 75 degree angle from the horizontal plane in the anteroposterior plane. The Broden view, which is different from the Canale view, is best for imaging the posterior facet of the subtalar joint. Canale ST, Kelly FB Jr: Fractures of the neck of the talus: Long-term evaluation of seventy-one cases. J Bone Joint Surg Am 1978;60:143-156.

Malunion of the talus is a devastating complication that leads to malpositioning of the foot and subsequent arthrosis of the subtalar joint complex. This is considered an avoidable complication in that accurate surgical reduction will minimize its development. Posttraumatic arthritis of the subtalar joint, osteonecrosis of the talus, posttraumatic arthritis of the ankle joint, and complex regional pain syndrome all may develop as a result of the initial traumatic event and may not be avoidable despite anatomic reduction. Rockwood and Green's Fractures in Adults, ed 5. Philadelphia, PA, Lippincott, Williams and Wilkins, 2001, pp 2091-2132.

Elastofibroma is a rare tumor that most commonly occurs in adults who are older than age 55 years. The lesions usually grow between the chest wall and the scapula, and 10% are bilateral. Histologic analysis shows that they are composed of equal amounts of elastin and collagen with occasional fibroblasts. Briccoli A, Casadei R, Di Renzo M, Favale L, Bacchini P, Bertoni F: Elastofibroma dorsi. Surg Today 2000;30:147-152.

The five most common primary carcinomas that metastasize to bone are breast, prostate, lung, renal, and thyroid in decreasing order of incidence. Frassica FJ, Gitelis S, Sim FH: Metastatic bone disease: General principles, pathophysiology, evaluation, and biopsy. Instr Course Lect 1992;41:293-300.

Because the patient's shoulders are overtensioned anteriorly, premature osteoarthritis may develop. This may create obligate translation posteriorly and increase the interarticular pressure of the humeral head against the glenoid. Patients should achieve 20 degrees to 30 degrees of external rotation with the elbow at the side. Late degenerative arthritis following a Putti-Platt procedure is associated with significant restriction of external rotation. This patient's shoulder has a reduced risk of anterior instability, rotator cuff tear, and internal impingement because of the limitation of motion. Hawkins RJ, Angelo RL: Glenohumeral osteoarthritis: A late complication of the Putti-Platt repair. J Bone Joint Surg Am 1990;72:1193-1197.

The athlete has symptoms referable to the axillary, musculocutaneous, and suprascapular nerves resulting from an injury to the upper trunk of the brachial plexus. This portion of the plexus is formed by contributions of the fourth through sixth cervical nerve roots. This area is often contused or stretched following a tackling maneuver that results in either depression of the shoulder from contact at Erb's point or traction of the upper plexus from forced stretching of the neck to the contralateral side. Schenck CD: Anatomy of the innervation of the upper extremity, in Torg JS (ed): Athletic Injuries to the Head, Neck, and Face, ed 2. St Louis, MO, Mosby-Year Book, 1991.

In a midterm (7 to 11 years) follow-up study of lumbar total disk arthroplasty, 5 of 55 patients had transient radicular leg pain without evidence of nerve root compression. Implant migration is rare. Deep venous thrombosis, incisional hernia, and retrograde ejaculation are less common complications of disk arthroplasty.

The radiographs and history are consistent with an acute unstable slipped capital femoral epiphysis. Aronson and Loder documented an increased rate of osteonecrosis associated with manipulative reduction. They recommended bed rest with skin traction to allow the synovitis to resolve, followed by in situ pinning. They noted, however, that many of these slips reduced with anesthesia and positioning on a fracture table. Biomechanic studies have shown a slight increased resistance to shear stress when two screws are used, but it is unknown if this is significant in the clinical setting. Open epiphyseodesis does not provide postoperative stability; therefore, adjunctive fixation or immobilization is required. Numerous studies have noted the inadvisability of using multiple screws. Casting has a high rate of complications, including chondrolysis and progression of the slip. Aronson DD, Loder RT: Treatment of the unstable (acute) slipped capital femoral epiphysis. Clin Orthop 1996;322:99-110. Karol LA, Doane RM, Cornicelli SF, Zak PA, Haut RC, Manoli A II: Single versus double screw fixation for treatment of slipped capital femoral epiphysis: A biomechanical analysis. J Pediatr Orthop 1992;12:741-745.

In patients with infected implants, treatment usually involves debridement and exchange of the infected components. In rare cases, when there is severe comorbidity and immune system compromise, as there is with this patient, a form of chronic suppression is indicated. This patient's function is quite satisfactory and, even though there is only a 21% to 38% chance of success (Hirawaka as quoted by Mulvey and Thornhill), an attempt at suppression therapy is indicated. The patient must be followed closely to monitor the potential complications of long-term antifungal therapy and to monitor the integrity of the joint, looking for bone or soft-tissue destruction. Because the patient has satisfactory motion and quadriceps strength, no bracing or other assistive device (except for the walker he is now using) is indicated.

Based on the epiphyseal location and sharp, well-defined borders, the radiograph suggests chondroblastoma. Histologically, multinucleated giant cells are scattered among mononuclear cells. The nuclei are homogenous and contain a characteristic longitudinal groove. Although not seen here, "chicken-wire calcification" with a bland giant cell-rich matrix is also typical for chondroblastoma. Clear cell chondrosarcoma occurs in epiphyseal locations but has a more aggressive histologic pattern and occurs in an older age group. Giant cell tumors occur in the epiphysis but have a more uniform giant cell population histologically. Aneurysmal bone cyst often results in bone remodeling and has a different pathologic appearance. Osteonecrosis has a typical histologic pattern of empty lacunae and necrotic bone. Springfield DS, Capanna R, Gherlinzoni F, et al: Chondroblastoma: A review of seventy cases. J Bone Joint Surg Am 1985;67:748-755. Simon M, Springfield D, et al: Chrondroblastoma: Surgery for Bone and Soft Tissue Tumors. Philadelphia, PA, Lippincott Raven, 1998, p 190.

The radiographs reveal a hindfoot deformity that developed following a severe, comminuted, intra-articular fracture of the calcaneus. There is deformity of the calcaneal body and collapse of the talus into the calcaneus, leading to dorsiflexion of the talus and anterior ankle joint impingement. Distraction bone block subtalar joint arthrodesis will assist with correction of the calcaneal height and will allow for an improved talar declination angle. With this procedure, care must be taken to avoid placing the hindfoot into further varus. A similar reconstruction option not listed would be a calcaneal osteotomy and arthrodesis as described by Romash. Talectomy and tibiocalcaneal arthrodesis are not warranted because the primary structure of the talus and ankle joint is well preserved. In situ subtalar joint arthrodesis will not correct the deformity, and symptoms about the ankle and hindfoot would most likely persist. Lateral wall calcaneal exostectomy may decrease pain from subfibular impingement but will not deal directly with subtalar joint arthrosis and deformity. Carr JB, Hansen ST , Benirschke SK: Subtalar distraction bone block fusion for late complications of os calcis fractures. Foot Ankle 1988;9:81-86. Juliano TJ, Myerson MS: Fractures of the hindfoot, in Myerson MS (ed): Foot and Ankle Disorders. Philadelphia, PA, WB Saunders, 2000, pp 1297-1340.

The arrow is pointing to a cystic-appearing structure with high signal intensity on T2-weighted image sequencing. It appears to be contiguous with the hypertrophied right facet joint, which appears to also have high signal intensity. The mass significantly narrows the right lateral recess. The high signal intensity suggests that this is a fluid-filled mass. In addition, the facet joints are degenerative and there is a very mild degree of anterolisthesis on the sagittal image. These findings make a lumbar synovial cyst the most likely diagnosis. Most lumbar juxtafacet cysts are observed at the L4-5 level, extradurally and adjacent to the degenerative facet joint. They may contain synovial fluid and/or extruded synovium. Presentation is indistinguishable from that of a herniated disk. The etiology of spinal cysts remains unclear, but there appears to be a strong association between their formation and worsening spinal instability. They occasionally regress spontaneously and may respond to aspiration and injection of corticosteroids, though there is a high recurrence rate with nonsurgical management. Synovial cysts resistant to nonsurgical management should be treated surgically. If the patient's symptoms can be attributable to radicular findings, a microsurgical decompression that limits further destabilization should suffice. However, if there is significant low back pain attributable to spinal instability, decompression and fusion remains an appropriate option. Banning CS, Thorell WE, Leibrock LG: Patient outcome after resection of lumbar juxtafacet cysts. Spine 2001;26:969-972. Deinsberger R, Kinn E, Ungersbock K: Microsurgical treatment of juxta facet cysts of the lumbar spine. J Spinal Disord Tech 2006;19:155-160.

The paravertebral musculature, the intervertebral disks, and the normal lordotic curvature of the cervical spine can absorb much of the imparted energy of collision. However, when the neck is flexed approximately 30 degrees, the normal lordotic curvature is flattened and the forces applied to the vertex of the head are directed at a straight segmented column. In this situation, the cervical spine is less able to absorb the applied force. With mounting axial load, compressive deformation occurs within the intervertebral disks, causing angular deformation and buckling. The spine will fail in flexion, with resultant fracture, subluxation, or dislocation. A rotatory component added to axial compression can cause concomitant extension, rotation, and shear injury patterns. The National Football Head and Neck Injury Registry has made two recommendations to the NCAA Football Rules Committee to minimize the risk of such injuries: (1) No player should intentionally strike an opponent with the crown or top of the helmet; and (2) No player should deliberately use his helmet to butt or ram an opponent. Thomas BE, McCullen GM, Yuan HA: Cervical spine injuries in football players. J Am Acad Orthop Surg 1999;7:338-347.

Many clinical studies to date show that the extent of arthritis is the most common variable that has the greatest influence on outcome. The success rate of allograft transplantation is significantly diminished in patients who have grade IV chondromalacia of the knee or notable flattening and general joint incongruity. Carter TR: Meniscal allograft transplantation. Sports Med Arthroscopy Rev 1999;7:51-63. Garrett JC: Meniscal transplantation: A review of 43 cases with two- to seven-year follow-up. Sports Med Arthroscopy Rev 1993;2:164-167.

Chondrosarcomas associated with diffuse bone lesions (enchondromas) are characteristic of Ollier's disease. When accompanied by subcutaneous masses (hemangiomas), the condition is called Maffucci's syndrome. Multiple hereditary exostosis is characterized by diffuse osteochondromas. McCune-Albright syndrome is characterized by polyostotic fibrous dysplasia with cafe-au-lait spots and precocious puberty. Neurofibromatosis can have associated bone lesions but is not associated with chondrosarcomas. Sun TC, Swee TC: Chondrosarcoma in Maffucci's syndrome. J Bone Joint Surg Am 1985;67:1214-1219. Schwartz HS, Zimmerman NB, Simon MA, et al: The malignant potential of enchondromatosis. J Bone Joint Surg Am 1987;69:269-274.

Radiographs reveal malunion of a Monteggia fracture-dislocation. Dislocation of the posterior radial head is caused by the malunited ulnar fracture. The deformity includes shortening with an apex posterior angulation. In the acute setting, open reduction of the radial head rarely is necessary; however, in chronic dislocations, open reduction is required. Without ulnar osteotomy, recurrent radial head dislocation is likely.

Informed consent is generally considered to be a process of mutual decision making between the physician and patient. The physician is required to provide to the patient all material information that is needed for the patient to make an informed decision. The courts have held that a patient's choice of surgeon is as important to the consent as the procedure itself. Assistance by a surgical trainee with adequate supervision is permissible when there has been adequate disclosure. Adequate supervision may be defined as active participation by the attending during the essential parts of the procedure. Allowing a substitute surgeon to operate on a patient without the patient's knowledge "ghost surgery" may result in charges of battery against the substitute surgeon and malpractice against the surgeon to whom the patient gave consent. Kocher MS: Ghost surgery: The ethical and legal implications of who does the operation. J Bone Joint Surg Am 2002;84:148-150.

The arrow is pointing to the posterior columns of the spinal cord that transmit position sense, vibratory sense, and proprioception. There are no motor tracts in the posterior columns. Bohlman H, Ducker T, Levine A: Spine trauma in adults, in Herkowitz HH (ed): The Spine, ed 4. Philadelphia, PA, WB Saunders, 1992, p 911.

The deep fascia of the abductor hallucis muscle is released to relieve pressure on the first branch of the lateral plantar nerve. The tibial nerve lies more proximal to this area. The medial plantar nerve has already passed dorsally and medially, while the sural nerve lies on the lateral side of the foot. The flexor hallucis brevis muscle lies deep to the plantar fascia, not the abductor fascia. Baxter DE, Pfeffer GB: Treatment of chronic heel pain by surgical release of the first branch of the lateral plantar nerve. Clin Orthop 1992;279:229-236.

Because of the long disease-free interval, it cannot be assumed that this is breast cancer. The lesion could represent metastasis from a new primary tumor or could itself be a primary tumor. CT-guided biopsy will most effectively identify the lesion and guide treatment options. Depending on the specific diagnosis, any of the other options may be appropriate.

Prophylactic stabilization of impending fractures does not directly affect the overall survival rate, but it does improve factors related to intraoperative and postoperative complications and decreased recovery time. Mirels H: Metastatic disease in long bones: A proposed scoring system for diagnosing impending pathologic fractures. Clin Orthop 1989;249:256-264.

The abductor hallucis muscle inserts together with the medial tendon of the flexor hallucis brevis into the medial base of the proximal phalanx of the great toe. When the hallux assumes a valgus position, the action of the abductor becomes one of flexion and pronation of the first metatarsal. Resch S: Functional anatomy and topography of the foot and ankle, in Myerson M (ed): Foot and Ankle Disorders. Philadelphia, PA, WB Saunders, 2000, vol 1, pp 25-49.

There are a number of important technical details in performing a biopsy. Incisions should always be longitudinal in the extremity. Good hemostasis is important in avoiding contamination from hematoma. The approach should avoid neurovascular structures, and go through a single muscle belly when possible. Although a frozen section should be obtained to ensure adequate viable tissue has been obtained, definitive diagnosis is not necessary at the time of the frozen section. Vaccaro AR (ed): Orthopaedic Knowledge Update 8. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 197-215.

Maloney and associates reported a 35% increased risk of pelvic osteolysis after total hip arthroplasty with a porous-coated acetabular component without cement. All components were stable at the time of revision. Only liners were exchanged and debridement of the granuloma with or without bone graft was performed. No defects progressed and one third of the lesions were no longer visible on radiographs, regardless of bone grafting. Unfortunately, despite the technical ease of many of these types of revisions, the dislocation rate for these cases is significant. Precautions should be taken postoperatively, and patients should be educated about this risk preoperatively. Vaccaro AR (ed): Orthopaedic Knowledge Update 8. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 411-424. Boucher HR, Lynch C, Young AM, et al: Dislocation after polyethylene liner exchange in total hip arthroplasty. J Arthroplasty 2003;18:654-657.

The patient has a perilunate dislocation. A volar dislocation of the lunate is often associated with median nerve dysfunction. This injury to the wrist is often overlooked because of its benign clinical appearance and the presence of other injuries, as it is caused by high-energy mechanisms. Ruby LK, Cassidy C: Fractures and dislocations of the carpus, in Browner BD (ed): Skeletal Trauma, ed 3. Philadelphia, PA, WB Saunders, 2003, pp 1297-1300.

Because the patient is critically ill and requires expeditious care, stabilization of the long bone fracture is required, but definitive care of the fracture should be postponed. The treatment of choice at this time is irrigation with 12 L of saline solution, followed by debridement and nondefinitive stabilization with a simple four-pin external frame to regain axial and rotational alignment. When the patient's condition is more stable, more definitive care can be performed. Bosse MJ, Kellam JF: Orthopaedic management decisions in the multiple trauma patient, in Browner BD, Jupiter JP, Levine AM, Trafton P (eds): Skeletal Trauma, ed 2. Philadelphia, PA, WB Saunders, 1998, pp 151-164. Weresh MJ, Stover MD, Bosse MJ, Jeray K, Kellam JF: Pulmonary gas exchange during intramedullary fixation of femoral shaft fractures. J Trauma 1999;46:863-868.

Children with spastic diplegic cerebral palsy often have contractures of multiple joints. Because the gait abnormalities can be complex, isolated surgery is rarely indicated. To avoid compensatory deformities at other joints, it is preferable to correct all deformities in a single operation. Isolated heel cord lengthening in the presence of tight hamstrings and hip flexors will lead to progressive flexion at the hips and knees, thus worsening a crouched gait. Split posterior tibial tendon transfer is used for patients with hindfoot varus, which is not present in this patient. Gage JR: Distal hamstring lengthening/release and rectus femoris transfer, in Sussman MD (ed): The Diplegic Child. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1992, pp 324-326.

Rickets causes widening of the hypertrophic layer of the physis because of the failure of mineralization and vascular invasion. The other zones of the physis may be altered in other disease conditions but remain relatively unchanged in rickets. Hunziker EB, Schenk RK, Cruz-Orive LM: Quantitation of chondrocyte performance in growth-plate cartilage during longitudinal bone growth. J Bone Joint Surg Am 1987;69:162-173.

The radiographs show tunnel enlargement, which is seen after ACL reconstruction, particularly with allografts. Occasionally, there will be formation of an associated subcutaneous pretibial cyst. It has been proposed that the tunnel enlargement and cyst are the result of incomplete incorporation of allograft tissues within the bone tunnels. There may be residual graft necrosis, allowing synovial fluid to be transmitted through the tunnel to collect in the pretibial area, manifesting as a synovial cyst. In the absence of cyst formation, the presence of tunnel enlargement does not appear to adversely affect the clinical outcome. Based on studies by Fahey and associates, continued tunnel expansion does not occur. Victoroff and associates report good results with curettage and bone grafting of the tibial tunnel if a pretibial cyst is present. Because this patient does not have a pretibial cyst, observation with activity modification is the preferred treatment. Fahey M, Indelicato PA: Bone tunnel enlargement after anterior cruciate ligament replacement. Am J Sports Med 1994;22:410-414.

The MRI scans reveal advanced degenerative disk disease at L5-S1. Nonsurgical management has failed to provide relief and the patient is quite debilitated as a result of her back pain. Fritzell and associates demonstrated that in a well-informed and selected group of patients with severe low back pain, lumbar fusion can diminish pain and decrease disability more efficiently than commonly used nonsurgical treatments. In a recent updated Cochrane Review of surgery for degenerative lumbar spondylosis, it was noted that while Fritzell and associates appeared to provide strong evidence in favor of fusion, a more recent trial by Brox and associates demonstrated no difference between those patients undergoing lumbar fusion compared to those receiving cognitive intervention and exercise. The Cochrane Review suggests that this may reflect a difference between the control groups. Fritzell and associates compared lumbar fusion to standard 1990s "usual care," whereas Brox and associates compared lumbar fusion to a "modern rehabilitation program." Bear in mind that this patient is a certified athletic trainer and runs a hospital health fitness department; therefore, at least for purposes of this question, it can be assumed that she has participated in a "modern rehabilitation program." The Cochrane Review goes on to state that preliminary results of three small trials of intradiskal electrotherapy suggest that it is ineffective and that preliminary data from three trials of disk arthroplasty do not permit firm conclusions. Gibson JN, Waddell G: Surgery for degenerative lumbar spondylosis: Updated Cochrane Review. Spine 2005;30:2312-2320. Fritzell P, Hagg O, Wessberg P, et al: 2001 Volvo Award Winner in Clinical Studies: Lumbar fusion versus nonsurgical treatment for chronic low back pain: A multicenter randomized controlled trial from the Swedish Lumbar Spine Study Group. Spine 2001;26:2521-2532.

The radiograph shows widening between the scaphoid and lunate. The normal variance is up to 5 mm. Although several ligaments may be torn, the scapholunate interosseous ligament must be torn for this widening to occur. Cooney WP, Linscheid RL, Dobyns JH: The Wrist: Diagnosis and Operative Treatment. St Louis, MO, Mosby-Year Book, 1998, vol 1, pp 503-506.

The clinical photograph and radiograph show an iatrogenic flatback deformity with loss of the normal lumbar lordosis. The safest correction for this malalignment typically is performed away from the spinal cord in the midlumbar spine, most commonly at L2 or L3. The more distal the correction is performed, the more sagittal plane translation of the C7 plumb line with respect to the posterior sacrum. Performing the osteotomy too distally, however, makes it difficult to obtain adequate distal fixation. Shufflebarger HL, Clark CE: Thoracolumbar osteotomy for postsurgical sagittal imbalance. Spine 1992;17:S287-S290.

In this age group, bayonet apposition can produce very good results. Healing occurs rapidly, and remodeling usually is complete in less than 1 year. All of the other methods have significant risks of complications and are unnecessary for this fracture. Martin RF: Fractures of the proximal humerus and humeral shaft, in Letts RM (ed): Management of Pediatric Fractures. New York, NY, Churchill Livingstone, 1994, pp 144-148.

The complications of femoral neck fractures in children include osteonecrosis, malunion, nonunion, and premature physeal closure. It is presumed that the risk of osteonecrosis is directly related to the amount of displacement at the time of injury and is not affected by the type of treatment. The risk of the other complications can be decreased depending on the type of treatment. Anatomic reduction by either closed or open methods can reduce the risk of malunion. The addition of internal fixation allows for maintenance of the reduction. In young children who cannot comply with a partial or non-weight-bearing status, the addition of a spica cast gives added protection. Canale ST: Fractures of the hip in children and adolescents. Orthop Clin North Am 1990;21:341-352.

When attempting a revision anterior cervical approach from the side opposite the original approach, it is important to evaluate the function of the vocal cords. If this evaluation reveals dysfunction of the vocal cord on the side of the original approach, then an approach on the contralateral side should not be attempted. Injury to the stellate ganglion, which causes a Horner's syndrome, should not preclude an approach on the contralateral side. While the side of the symptomatology can influence the surgeon's choice as to the side of an anterior approach, it does not preclude a certain approach. When approaching the lower cervical spine from the right side, the recurrent laryngeal nerve can cross the surgical field and should be preserved. Excessive intraoperative pressure on the esophagus can increase the incidence of dysphagia, but its incidence is no different with either approach. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 387-394.

The superior glenohumeral ligament (SGHL) and coracohumeral ligament serve as primary static restraints against inferior translation of the arm when the shoulder is in 0 degrees of abduction. Of these, the coracohumeral ligament has been shown to have a greater cross-sectional area, greater stiffness, and greater ultimate load than the SGHL. The inferior glenohumeral ligament plays a greater stabilizing role with increasing abduction of the arm. The coracoacromial ligament may help provide superior stability, especially when the rotator cuff is deficient. The coracoclavicular ligaments stabilize the acromioclavicular joint. Boardman ND, Debski RE, Warner JJ, et al: Tensile properties of the superior glenohumeral and coracohumeral ligaments. J Shoulder Elbow Surg 1996;5:249-254.

Fractures of the long bones are common in patients with myelodysplasia, and the frequency of fracture increases with higher level defects. Fractures also occur following surgery and immobilization secondary to disuse osteoporosis. The response to the fracture (swelling, fever, warmth, erythema) is often confused with infection, osteomyelitis, or cellulitis. Management should consist of a short period of immobilization in a well-padded splint. Long-term casting results in further osteopenia and repeated fractures. Lock TR, Aronson DD: Fractures in patients who have myelomeningocele. J Bone Joint Surg Am 1989;71:1153-1157.

The radiographs show well-fixed components of a posterior cruciate-retaining total knee replacement. The relative position of the femoral component is anteriorly subluxated relative to the tibial component. The AP radiograph shows that the articular space is markedly asymmetric, indicating either failure or fracture of the polyethylene or subluxation of the femur relative to the tibia. The patient's symptoms suggest a failure of the posterior cruciate ligament that is consistent with the radiographic findings; therefore, the treatment of choice is revision to a posterior cruciate-substituting implant.

Patellar clunk syndrome is associated with certain types of posterior stabilized knee arthroplasties. Arthroscopic resection of the band of inflammatory tissue inferior to the patellar component is effective in treating this condition. Arthroscopic lavage of infected knee arthroplasties is not associated with an acceptable success rate. Diagnostic arthroscopy for nonspecific pain following arthroplasty is not uniformly successful. Patellar component maltracking is frequently associated with component malposition and is not alleviated by an arthroscopic lateral release. Synovitis secondary to polyethylene wear is best treated by exchange of the polyethylene spacer and not arthroscopic synovectomy. Lucas TS, DeLuca PF, Nazarian DG, et al: Arthroscopic treatment of patellar clunk. Clin Orthop 1999;367:226-229.

The patient has the preliminary diagnosis of an infected shoulder arthroplasty; therefore, shoulder radiographs and joint aspiration for organism identification should be the first steps in the work-up. The patient is at risk for hematogenous spread given the recent history of pneumonia and her history of diabetes mellitus. Although she has stiffness, a stretching program is not indicated with the possibility of infection. Scheduling for revision arthroplasty, or irrigation and debridement will depend on multiple factors including identification of the infecting organism, the organism's susceptibility to antibiotics, and implant stability. An MRI scan to evaluate for a rotator cuff tear is not indicated at this time. Matsen FA III, Rockwood CA Jr, Wirth MA, et al: Glenohumeral arthritis and its management, in Rockwood CA Jr, Matsen FA III (eds): Rockwood and Matsen The Shoulder, ed 2. Philadelphia, PA, WB Saunders, 1998, pp 953-954.

Nondisplaced distal radial fractures have a higher rate of spontaneous rupture of the extensor pollicis longus tendon. The extensor mechanism is felt to impinge on the tendon following a nondisplaced fracture and causes either a mechanical attrition of the tendon or a local area of ischemia in the tendon. Helal B, Chen SC, Iwegbu G: Rupture of the extensor pollicis longus tendon in undisplaced Colles' type of fracture. Hand 1982;14:41-47.

Users of anabolic steroids often display increased feelings of hostility and aggression. Although reports of psychotic, depressive, and manic behavior have been reported with the use of steroids, they are rare. Drug dependence, such as seen with narcotics, is not a feature of steroid use. Hartgens F, Kuipers H: Effects of androgenic-anabolic steroids in athletes. Sports Med 2004;34:513-554.

Repetitive overhead slams and serves may produce a traction injury to the distal branch of the suprascapular nerve. Bankart, biceps, and superior labrum anterior and posterior injuries can occur but usually do not produce visible atrophy. Muscle avulsion is uncommon. Ferretti A, Cerullo G, Russo G: Suprascapular neuropathy in volleyball players. J Bone Joint Surg Am 1987;69:260-263.

Patients with diabetes mellitus should be screened for the presence of protective foot sensation. In the absence of protective foot sensation, patients are at increased risk for the development of neuropathic ulcerations and neuropathic arthropathy. The most reliable screening tool for the presence of protective sensation is the ability to feel the 5.07 Semmes-Weinstein monofilament. Pinzur MS, Shields N, Trepman E, Dawson P, Evans A: Current practice patterns in the treatment of Charcot foot. Foot Ankle Int 2000;21:916-920.

The diagnosis of an interdigital neuroma is best made by a thorough history and careful physical examination. Radiographs are helpful in excluding other pathologic processes such as a metatarsal stress fracture. MRI and ultrasound have both been reported to aid in the diagnosis of an interdigital neuroma. Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2003, pp 145-151.

The TcPO2 measures the O2 delivering capacity of the local vasculature. Values above 40 mm Hg have been shown to correlate with positive healing potential. The hemoglobin A1c is a good indicator of long-term glucose levels; however, it has no direct correlation with wound healing potential. Serum albumin is an indirect measure of nutritional status, and deficiencies in nutrition must be addressed before any surgery. Adequate hemoglobin levels are also necessary to promote adequate oxygenation to the amputation site. The ankle-brachial index may be falsely elevated as a result of calcified vessels in patients with diabetes mellitus. Wyss CR, Harrington RM, Burgess EM, et al: Transcutaneous oxygen tension as a predictor of success after amputation. J Bone Joint Surg Am 1988;70:203-207.

The superficial portion of the MCL contributes 57% and 78% of medial stability at 5 degrees and 25 degrees of knee flexion, respectively. The deep MCL and posteromedial capsule act as secondary restraints at full knee extension. The anterior cruciate ligament and PCL also provide secondary resistance to valgus loads.

The radiograph shows a comminuted proximal ulnar fracture. The most reliable fixation is a posterior plate, acting as a tension band plate. The fracture involves the proximal shaft of the ulna; therefore, a 3.5-mm compression plate or one of similar size should be used to provide adequate stability. Kirschner wires and tension band wires do not provide axial stability of the comminution of the ulna. Compression screws alone will most likely fail and will not provide axial rotational stability to the construct. A medial plate will not resist the distraction forces across this fracture. McKee MD, Seiler JG, Jupiter JB: The application of the limited contact dynamic compression plate in the upper extremity: An analysis of 114 consecutive cases. Injury 1995;26:661-666.

An infection of the shoulder is considered a surgical emergency unless there are medical reasons that a patient cannot be taken to the operating room. If cultures of wound drainage are in question, then an aspiration should be done emergently, not several days later. The hallmark of infection in any major joint is increasing pain out of proportion to what is expected. Drainage occurring 1 to 2 days after an arthroscopic procedure is not normal, and it should be aggressively treated. Delay in diagnosis can result in sepsis and on a delayed basis, postinfectious arthritis. Both the glenohumeral joint and the subacromial space require debridement and irrigation, followed by antibiotics after both areas are cultured. Mansat P, Cofield RH, Kersten TE, Rowland CM: Complications of rotator cuff repair. Orthop Clin North Am 1997;28:205-213. Settecerri JJ, Pitner MA, Rock MG, Hanssen AD, Cofield RH: Infection after rotator cuff repair. J Shoulder Elbow Surg 1999;8:1-5. Ward WG, Eckardt JJ: Subacromial/subdeltoid bursa abscesses: An overlooked diagnosis. Clin Orthop 1993;288:189-194.

Aneurysmal bone cysts typically present as radiolucent lesions with an expansile remodeled cortex. The histologic appearance consists of blood-filled lakes surrounded by a benign lining that contains fibroblasts, giant cells, and hemosiderin. Although the other lesions are in the radiographic differential diagnosis, these histologic findings indicate an aneurysmal bone cyst. Bieselker JL, Marcove RC, Huvos AG, Mike V: Aneurysmal bone cyst: A Clinico-pathologic study of 66 cases. Cancer 1973;26:615.

In most series, elbow stiffness is the most common complication and can be overcome by achieving stable fixation and initiating early motion after surgery. All of the other complications are seen but to a lesser degree than elbow stiffness. Sanders RA, Raney EM, Pipkin S: Operative treatment of bicondylar intra-articular fractures of the distal humerus. Orthopedics 1992;15:159-163.

Commotio cordis is a rare but catastrophic condition that is caused by blunt chest trauma. It results in cardiac fibrillation and is universally fatal unless immediate defibrillation is performed. Although case reports of successful use of the chest thump maneuver exist, the best method of treatment is cardiac defibrillation. IV fluids, epinephrine, and albuterol inhalers are used to treat dehydration, anaphylactic shock, and bronchospasm respectively, and are not effective in the treatment of commotio cordis. McCrory P: Commotio cordis. Br J Sports Med 2002;36:236-237.

In the absence of vascular compromise, there has been no proven value to proceeding immediately to surgery, especially when the patient has a full stomach and runs a significant risk of perioperative aspiration. It would be more prudent to wait until the next morning with a surgical plan of closed reduction and pinning. Open reduction should be reserved for the unusual case of where closed treatment has not been successful. The implication that there may be a radial nerve injury associated with this fracture does not alter the treatment plan, and with a high level of certainty would be expected to resolve. Attempting closed reduction in the emergency department creates the opportunity for uncertain results and is not tolerated well by most patients. Skeletal traction, with its associated lengthy hospitalization and the technical difficulties associated with both the traction and radiographic evaluations, has fallen into disfavor for typical clinical situations. Iyengar SR, Hoffinger SA, Townsend DR: Early versus delayed reduction and pinning of type III displaced supracondylar fractures of the humerus in children: A comparative study. J Orthop Trauma 1999;13:51-55.

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. McAfee PC: Interbody fusion cages in reconstructive operations on the spine. J Bone Joint Surg Am 1999;81:859-880.

New onset pain and stiffness in the young arthritic shoulder is a difficult problem to treat. Initial management should be aimed at reducing pain and improving motion in all planes. This patient's activities and age preclude a shoulder arthroplasty at this time. If nonsurgical management fails to provide relief, then arthroscopic debridement and capsular release may be beneficial. Norris TR (ed): Orthopaedic Knowledge Update: Shoulder and Elbow 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 257-266.

This intra-articular distal humerus fracture with displacement at the joint surface is best treated with surgical fixation. The most biomechanically sound construct is two plates applied to either column 180 degrees from one another. Elbow arthroplasty is most appropriate for low demand elderly patients. Schemitsch EH, Tencer AF, Henley MB: Biomechanical evaluation of methods of internal fixation of the distal humerus. J Orthop Trauma 1994;8:468-475. McCarty LP, Ring D, Jupiter JB: Management of distal humerus fractures. Am J Orthop 2005;34:430-438.

This is a typical presentation of the patellar clunk syndrome. The syndrome usually follows implantation of a posterior stabilized prosthesis. It is thought to be the result of femoral component design and altered extensor mechanics. The condition usually resolves with arthroscopic debridement of the suprapatellar fibrous nodule. Arthrotomy or revision is seldom warranted. Beight JL, Yao B, Hozack WJ, Hearn SL, Booth RE Jr: The patellar "clunk" syndrome after posterior stabilized total knee arthroplasty. Clin Orthop 1994;299:139-142.

The floating elbow is best managed with early open reduction and internal fixation of the humeral and forearm fractures, followed by early range of motion. These fractures predispose the elbow to stiffness, and early range of motion is recommended. Solomon HB, Zadnik M, Eglseder WA: A review of outcomes in 18 patients with floating elbow. J Orthop Trauma 2003;17:563-570.

Growth hormone is the most abundant substance produced by the pituitary gland. Growth hormone has a direct anabolic effect by accelerating the incorporation of amino acids into proteins. It is becoming an increasingly popular anabolic steroid substitute; however, it is expensive and difficult to obtain. Androstenedione is an androgen produced by the adrenal glands and gonads. It acts as a potent anabolic steroid and is converted in the liver directly to testosterone with a resultant increase in levels after administration. DHEA is a naturally occurring hormone made by the adrenal cortex. It is converted to androstenedione, which in turn is converted to testosterone. The beneficial and adverse effects of DHEA can be correlated directly with those of testosterone. Nandrolone is also a potent anabolic steroid. It is commonly taken as 19-norandrostenedione and may be more favored because of its potent anabolic effects with less androgenic effects (no conversion to estrogen compounds). Creatine sales have skyrocketed, and it is a popular nutritional supplement. There is an expectation that creatine can increase strength and power performance; however, direct anabolic effects have not been demonstrated. Creatine serves as a substrate for hydrogen ions and contributes to the resynthesis of ATP (adenosine triphosphate) during maximal exercise. By enhancing ATP production and buffering local pH in muscle, there may be improved tolerance of anaerobic activities. Increases in muscle mass may be related to increased perception of improved training ability or an increase in muscle water content. Silver M: Use of ergogenic aids by athletes. J Am Acad Orthop Surg 2001;9:61-70.

Enchondromas are the most common benign skeletal lesions identified in the bones of the hand. Most are incidentally found or initially become clinically evident after a pathologic fracture. If the patient has a fracture, the hand is immobilized until union. If the lesion is large and further pathologic fractures are expected, then an intralesional curettage and grafting procedure may be warranted. In this patient, the lesion has not significantly altered the size, shape, or morphology of the involved metacarpal head and recurrent fracture is unlikely. Observation with follow-up radiographs is considered appropriate management. Campanacci M: Bone and Soft Tissue Tumors, ed 2. New York, NY, Springer-Verlag, 1999, pp 213-228.

Assessment of the acutely injured patient follows the Advanced Trauma Life Support protocol. Cervical cord injury is often associated with a disruption in sympathetic outflow. Absent sympathetic input to the lower extremities leads to vasodilatation, decreased venous return to the heart, and subsequent hypotension. With hypotension, the physiologic response of tachycardia is not possible because of the unopposed vagal tone. This results in bradycardia. Patient positioning, fluid support, pressor agents, and atropine are used to treat neurogenic shock.

The lateral femoral cutaneous nerve pierces the fascia between the tensor fascia lata and the sartorius approximately 2.5 cm distal to the anterosuperior iliac spine and is at risk when the interval is defined. The superior gluteal and femoral nerves define the internervous plane between the tensor fascia lata and the sartorius and are not at risk for injury. Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics: The Anatomic Approach. Philadelphia, PA, JB Lippincott, 1984, pp 302-316.

The most common bone tumor in the hand is an enchondroma. Forty-two percent of these lesions occur in the small tubular bones. They frequently present with a fracture in these locations. Fractures are usually treated nonsurgically. Indications for surgery include patients with symptomatic lesions or those who are considered high risk for recurrent fracture. The histologic appearance of an enchondroma in the hand is more cellular than enchondromas found in the long bones. Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, p 103.

The findings are consistent with an aneurysmal bone cyst. The MRI scan demonstrates a lesion involving the posterior elements of the vertebrae with fluid-fluid levels and neural compression. Fibrovascular tissue with multinucleated giant cells surrounding a vascular lake is seen on the histology. The most appropriate treatment is a marginal resection of the involved posterior elements. Although the recurrence rate can be as high as 25% to 30%, wide surgical resection could result in permanent neurologic injury and is not necessary. Aspiration and steroid injection have been advocated but would not relieve the nerve compression in this patient. Radiation therapy and chemotherapy are not indicated. Mankin HJ, Hornicek FJ, Ortiz-Cruz E, et al: Aneurysmal bone cyst: A review of 150 patients. J Clin Oncol 2005;23:6756-6762.

Most closed humeral shaft fractures and fractures caused by a low-velocity hand gun can be managed nonsurgically with closed reduction and application of a coaptation splint followed by a functional brace. Contraindications to use of the functional brace include: 1) massive soft-tissue or bone loss; 2) an unreliable or noncompliant patient; and 3) an inability to maintain acceptable fracture alignment of up to 20 degrees of anterior or posterior angulation, 30 degrees of varus or valgus angulation, and greater than 3 cm of shortening. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 271-286. Pollock FH, Drake D, Bovill EG, Day L, Trafton PG: Treatment of radial neuropathy associated with fractures of the humerus. J Bone Joint Surg Am 1981;63:239-243.

The anterior cruciate ligament consists of two functional bundles: anteromedial and posterolateral. During extension of the knee, the posterolateral bundle becomes taut. In flexion, the anteromedial bundle is tight and the posterolateral bundle relaxes. Traditionally, anterior cruciate ligament reconstruction primarily recreates the anteromedial bundle. Recently, techniques for double bundle reconstruction have been described to recreate the normal anatomic relationship of the two bundles. Girgis FG, Marshall JL, Monajem AS: The cruciate ligaments of the knee joint: Anatomical, functional and experimental analysis. Clin Orthop Relat Res 1975;106:216-231. Cha PS, Brucker PU, West RV, et al: Arthroscopic double-bundle anterior cruciate ligament reconstruction: An anatomic approach. Arthroscopy 2005;21:1275.

The postoperative incidence of C5 root palsy after laminoplasty ranges from 5% to 12%. Other roots also may be affected. The palsies tend to be motor dominant, although sensory dysfunction and radicular pain are also possible. The palsy may arise during the immediate postoperative period or up to 20 days later. C5 may be preferentially involved because it is at the apex of the cervical lordosis. Recovery usually occurs over weeks to months. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 235-249.

Axial pain can be difficult to manage. Pain management is not always successful, and surgical approaches may provide disappointing results unless there is discrete pathology. Whereas planning of a surgical approach should consider prior approaches and preexisting laryngeal dysfunction, no compelling case for surgical intervention can be made for this patient. Therefore, management should consist of patient education, exercise, and nonnarcotic medication. Ahn NU, Ahn UM, Andersson GB, et al: Operative treatment of the patient with neck pain. Phys Med Rehabil Clin N Am 2003;14:675-692. Algers G, Pettersson K, Hildingsson C, et al: Surgery for chronic symptoms after whiplash injury: Follow-up of 20 cases. Acta Orthop Scand 1993;64:654-656.

Thromboembolic disease can occur in up to 58% of unprotected patients and up to 20% of protected patients depending on the type of prophylaxis used, even though most thrombi are small and have little clinical consequence. The primary goal of prophylaxis is to prevent symptomatic deep venous thrombosis and fatal pulmonary emboli. Dislocation has been reported in up to 10% of primary cases, but generally acceptable rates of less than 5% are the norm. Component loosening following primary total hip arthroplasty is rare prior to a 10-year follow-up, and 90% to 95% of patients should reach the 10-year follow-up without the need for revision for any reason. Metal hypersensitivity is unusual, and nickel found in cobalt-chromium alloys is the most common offending agent. Infection of primary total hip arthroplasty is less than 1%. Eftekhar N: Total Hip Arthroplasty. St Louis, MO, Mosby,1993, pp 1445-1676.

This patient has shoulder laxity without apprehension. Because there is a wide range of normal laxity in asymptomatic shoulders, the physician should inform the student of these findings, recommend shoulder strengthening exercises, and allow unrestricted sports participation unless symptoms develop. Harryman DT, Sidles JA, Harris SL, Matsen FA III: Laxity of the normal glenohumeral joint: A quantitative in vivo assessment. J Shoulder Elbow Surg 1992;1:66-76. Hawkins RJ, Bokor RJ: Clinical evaluation of shoulder problems, in Rockwood CA Jr, Matsen FA III (eds): The Shoulder. Philadelphia, PA, WB Saunders, 1998, vol 1, p 186. McFarland EG, Campbell G, McDowell J: Posterior shoulder laxity in asymptomatic athletes. Am J Sports Med 1996;24:468-471.

The blood supply to the adult capitellum and lateral trochlea comes from posterior vessels arising from the radial recurrent, radial collateral, and interosseous recurrent arteries. These arteries penetrate the distal humerus posterior and superior to the capitellum.

The main function of collagen in articular cartilage is to provide the tissue's tensile strength. It also immobilizes proteoglycans within the extracellular matrix. Compressive properties are maintained by proteoglycans. Cartilage metabolism is maintained by the indwelling chondrocytes. The flow of water through the tissue promotes transport of nutrients and provides a source of lubricant for the joint. Simon SR (ed): Orthopaedic Basic Science. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 3-44.

Histologic studies have shown that increased bone turnover is the rule in OI. Pamidronate (and all bisphosphonates) reduce osteoclast-mediated bone resorption. Osteoblastic new bone formation on the periosteal surface of long bones is minimally impaired. With inhibition of osteoclastic bone resorption on the endosteal surface, the cortex of the bone can begin to thicken as it does with normal growth in individuals unaffected by OI. Mineralization and collagen matrix organization are not directly affected by pamidronate. Zeitlin L, Fassier F, Glorieux FH: Modern approach to children with osteogenesis imperfecta. J Pediatr Orthop B 2003;12:77-87. Falk MJ, Heeger S, Lynch KA, et al: Intravenous bisphosphonate therapy in children with osteogenesis imperfecta. Pediatrics 2003;111:573-578.

The diagnosis of tuberculous osteomyelitis in children is often delayed. In one series of 23 children, the average interval between the onset of symptoms and definite diagnosis was 4.3 months. In these patients, the presenting signs and symptoms were found to be mild, with the most common signs being localized swelling (69.6%) and a painful disability of the involved limbs (65.2%). A mild elevation of the erythrocyte sedimentation rate may be present, but the C-reactive protein level is usually normal. In patients who have osteoarticular tuberculosis, an MRI scan generally shows large intra-articular effusions, periarticular osteoporosis, and gross thickening of the synovial membrane. Differential diagnosis between tuberculosis and pyogenic arthritis is difficult, and an accurate diagnosis usually requires biopsy of synovial tissue. Aspiration of synovial fluid often results in insufficient information to make a diagnosis. Treatment generally consists of surgical debridement and combined antituberculous chemotherapy with isoniazid, ethambutol, and rifampin. Wang MN, Chen WM, Lee KS, Chin LS, Lo WH: Tuberculous osteomyelitis in young children. J Pediatr Orthop 1999;19:151-155.

Bone bruises are often noted on MRI after anterior cruciate and medial collateral ligament injuries. The significance of these injuries awaits long-term follow-up studies. The areas of increased signal on T2-weighted images represent areas of acute hemorrhage and are secondary to microfractures of the adjacent medullary trabeculae. Wright RW, Phaneuf MA, Limbird TJ, et al: Clinical outcome of isolated subcortical trabecular fractures (bone bruise) detected on magnetic resonance imaging in knees. Am J Sports Med 2000;28:663-667.

The omohyoid muscle crosses the surgical field from inferior lateral to anterior superior traveling from the scapula to the hyoid bone and may need to be transected. The posterior digastric crosses the field as well but higher near C3-4. The other muscles run longitudinally. Chang U, Lee MC, Kim DH: Anterior approach to the midcervical spine, in Kim DH, Henn JS, Vaccaro AR, et al (eds): Surgical Anatomy and Techniques to the Spine. Philadelphia, PA, Saunders Elsevier, 2006, pp 45-56.

Synovial tissue is composed of vascularized connective tissue that lacks a basement membrane. Two cell types (type A and type B) are present: type B cells produce synovial fluid. Synovial fluid is made of hyaluronic acid and lubricin, proteinases,and collagenases. It is an ultrafiltrate of blood plasma added to fluid produced by the synovial membrane. It does not contain erythrocytes, clotting factors, or hemoglobin. It lubricates articular cartilage and provides nourishment via diffusion. Synovial fluid exhibits non-Newtonian flow characteristics. The viscosity coefficient is not a constant, the fluid is not linearly viscous, and its viscosity increases as the shear rate decreases.

The patient has a cervical myelopathy with more than 10 mm of space available for the cord; therefore, she has a reasonable chance of improved neurologic function following surgery. If not treated with surgery, however, her neurologic condition likely will worsen and she will die earlier than if she had surgery. Matsunaga S, Sakou T, Onishi T, et al: Prognosis of patients with upper cervical lesions caused by rheumatoid arthritis: Comparison of occipitocervical fusion between C1 laminectomy and nonsurgical management. Spine 2003;28:1581-1587.

The radiograph shows a type V acromioclavicular joint injury. Type V injuries involve disruption of the acromioclavicular and coracoclavicular ligaments. Type I injuries involve a sprain of the acromioclavicular joint ligaments. Type II injuries involve disruption of the acromioclavicular joint ligaments; the coracoclavicular ligaments are partially injured. Sternoclavicular ligaments stabilize the medial clavicle and the sternum; they are not damaged with acromioclavicular joint dislocations. Fukuda K, Craig EV, An KN, et al: Biomechanical study of the ligamentous system of the acromioclavicular joint. J Bone Joint Surg Am 1986;68:434-439.

The flexor hallucis longus tendon provides the best, most direct route of transfer for filling Achilles tendon gaps. The tendon lies lateral to the neurovascular structures, making it safe for harvest and providing a direct route for transfer into the calcaneus without crossing these important structures. The flexor hallucis longus tendon also has muscle belly that extends distal on the tendon itself, often beyond the actual tibiotalar joint. When the tendon is transferred, this muscle belly brings excellent blood supply to the anterior portion of the reconstruction. Wilcox DK, Bohay DR, Anderson JG: Treatment of chronic achilles tendon disorders with flexor hallucis longus tendon transfer/augmentation. Foot Ankle Int 2000;21:1004-1010.

The patient has a pronounced deformity with pain and degenerative arthritis; therefore, triple arthrodesis is the treatment of choice. Gastrocnemius or Achilles tendon lengthening may be a necessary adjunct to the triple arthrodesis, but alone is inadequate to allow for correction. Because the ankle-foot orthosis has failed to provide relief, a UCBL is not likely to help. Osteotomy procedures are designed for lesser deformities and well-preserved joints. Nunley JA, Pfeffer GB, Sanders RW, et al (eds): Advanced Reconstruction: Foot and Ankle. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 115-120.

Massive bone loss encountered in revision total knee arthroplasty remains a significant challenge. Recent reports have shown high success rates using structural allograft to reconstruct large structural bone defects. A hinged prosthesis is not required in this setting. In this patient, a large amount of posterior cortex has been lost, making the area too large to fill with cement or iliac crest bone graft. Because of her age, the treatment of choice is a revision tibial implant and metal augments. Structural allograft would be suitable in a younger patient. Mow CS, Wiedel JD: Structural allografting in revision total knee arthroplasty. J Arthroplasty 1996;11:235-241. Engh GA, Herzwurm PJ, Parks NL: Treatment of major defects of bone with bulk allografts and stemmed components during total knee arthroplasty. J Bone Joint Surg Am 1997;79:1030-1039.

Embolization of fat and bone marrow elements during total hip arthroplasty has been studied intraoperatively using transesophageal echocardiography. These studies showed the occurrence of a large number of embolic events during the insertion of a cemented femoral stem. Embolic events were rare during insertion of a cementless stem. Femoral broaching caused some embolic events, but they were not nearly as significant as those that occurred following insertion of a cemented stem. Additionally, relocation of the cemented hip was accompanied by significant embolic events. This may be related to the untwisting of blood vessels, with the subsequent release of emboli that were most likely generated during insertion of a cemented femoral stem. Pitto RP, Koessler M, Kuehle JW: Comparison of fixation of the femoral component without cement and fixation with use of a bone-vacuum cementing technique for the prevention of fat embolism during total hip arthroplasty. J Bone Joint Surg Am 1999;81:831-843.

Most leaders in orthopaedic surgery support Jacqueline Perry's theory that the postpolio syndrome is an attritional degenerative process that is the result of overuse of muscles and joints that are unable to adequately tolerate overload, and have little functional reserve. For that reason, aerobic conditioning and exercise are important. Overload and exhaustion of involved muscles should be avoided.

The radiograph shows a type V acromioclavicular separation with greater than 100% superior elevation of the clavicle. This finding implies detachment of the deltoid and trapezius from the distal clavicle. Because of severe compromise of function and potential compromise to the overlying skin, surgery is the treatment of choice for type V acromioclavicular separations. During reduction and repair, meticulous repair of the deltotrapezial fascia will also aid in securing the repair. Nuber GW, Bowen MK: Acromioclavicular joint injuries and distal clavicle fractures. J Am Acad Orthop Surg 1997;5:11-18.

The patient has a displaced radial neck fracture. Displaced radial neck fractures with angulation of more than 30 to 45 degrees require reduction. Methods of attempted closed reduction include wrapping the arm with an Esmarch's bandage and applying direct pressure over the maximum deformity of the radial head. More aggressive methods include a Kirschner wire used as a joystick or intramedullary reduction as described by the Metaizeau technique. Open reduction should be avoided because of complications such as stiffness or osteonecrosis. Indications for open reduction are irreducible displacement of more than 45 degrees with severe restriction of forearm rotation. Leung AG, Peterson HA: Fractures of the proximal radial head and neck in children with emphasis on those that involve the articular cartilage. J Pediatr Orthop 2000;20:7-14. Radomisli TE, Rosen AL: Controversies regarding radial neck fractures in children. Clin Orthop 1998;353:30-39. Skaggs DL, Mirzayan R: The posterior fat pad sign in association with occult fracture of the elbow in children. J Bone Joint Surg Am 1999;81:1429-1433.

The findings are characteristic of hemangioma. When the hemangioma is large enough, vertical striations may be visible on plain radiographs. Axial CT scans commonly reveal a speckled appearance. Metastatic lesions are typically hypointense on T1-weighted images because they replace the fatty marrow. Bony islands, like cortical bone, are dark on T1- and T2-weighted images. Intravertebral disk herniation would have characteristics similar to the disk and be in continuity with the disk. Osteoporosis is more diffuse. Ross JS, Masaryk TJ, Modic MT, Carter JR, Mapstone T, Dengel FH: Vertebral hemangiomas: MR imaging. Radiology 1987;165:165-169.

The term turf toe includes a range of injuries of the capsuloligamentous complex of the first metatarsophalangeal joint with or without osteochondral fracture of the first metatarsal head or one of the sesamoids. The mechanism of injury is hyperextension. Clanton TO, Butler JE, Eggert A: Injuries to the metatarsophalangeal joints in athletes. Foot Ankle 1986;7:162-176.