100 Orthopedic MCQs: Spine, Trauma, Sports Med & Arthroplasty | Comprehensive ABOS Review

Osteochondral lesions of the talar dome can have a traumatic or nontraumatic etiology. Most authors site a probable traumatic etiology for lateral lesions. Stage I and II lesions, which are composed of compressed subchondral bone or a partial detached osteochondral fragment, can be treated initially in a non-weight-bearing short leg cast for 6 weeks. Stage III medial lesions can also be treated in the same manner. If symptoms persist, the treament of choice is debridement of the fracture, curettage of the lesion, and drilling of the subchondral bone. This treatment also applies to lateral stage III and all stage IV lesions. If the fragment is at least one third of the size of the talar dome, management should consist of open reduction and internal fixation. In patients with more chronic lesions (4 to 6 months of persistent pain), the threshold to proceed with surgery is lower, even in a stage II lesion. Lutter LD, Mizel MS, Pfeffer GB (eds): Orthopaedic Knowledge Update: Foot and Ankle. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 205-226.

The radiograph reveals bilateral severe acetabular protrusio. The bone scan and history confirm involvement of multiple joints, including the knees and the hindfoot. Although the first four choices can all cause the acetabular protrusio, the associated multiple joint involvement suggests the diagnosis of rheumatoid arthritis. Arthrokatadysis, or primary protrusio acetabuli, is often associated with osteomalacia but not other joint disease. Developmental dysplasia is a common cause of bilateral hip pathology but does not have acetabular protrusio. Resnick D: Diagnosis of Bone and Joint Disorders, ed 3. Philadelphia, PA, WB Saunders, 1995, pp 956-957. Wheeless' Textbook of Orthopaedics: Acetabular Protrusio. www.wheelessonline.com/ortho/acetabular_protrusio

The most common location of chondrosarcoma is the pelvis (30%), followed by the proximal femur (20%) and shoulder girdle (15%). Chondrosarcoma rarely affects the spine or hand. Lee FY, Mankin HJ, Fondren G, et al: Chondrosarcoma of bone: An assessment of outcome. J Bone Joint Surg Am 1999;81:326-338.

Osteonecrosis of the femoral head is a known complication from the use of rigid intramedullary nails for femoral fractures in adolescents. When the nails are placed through the piriformis fossa, the lateral ascending vessels of the femoral neck may be injured, resulting in osteonecrosis of the femoral head in 1% to 2% of patients. Rigid reamed nails placed into the piriformis fossa are contraindicated in children with open growth plates because the physis is a barrier to blood supply and the ligamentum teres does not provide sufficient vascularity. Alternative fixation methods for femoral fractures in adolescents include external fixation and open reduction and internal fixation. Nailing through the tip of the trochanter may decrease the incidence of this serious complication. Letts M, Jarvis J, Lawton L, et al: Complications of rigid intramedullary rodding of femoral shaft fractures in children. J Trauma 2002;52:504-516. Stans AA, Morrissy RT, Renwick SE: Femoral shaft fracture treatment in patients age 6 to 16 years. J Pediatr Orthop 1999;19:222-228. Buckley SL: Current trends in the treatment of femoral shaft fractures in children and adolescents. Clin Orthop 1997;338:60-73.

There have been no characteristic gene translocations or rearrangements noted in osteosarcoma, chondrosarcoma, neurofibrosarcoma, or epithelioid sarcoma. In contrast, Ewing's sarcoma has been noted to have a consistent genetic translocation t(11:22). Brockstein BE, Peabody TD, Simon MA: Soft tissue sarcomas, in Vokes EE Golomb HM (eds): Oncologic Therapies. New York, NY, Springer-Verlag, 1999, pp 925-952.

The three primary constraints necessary for elbow stability in all directions are the ulnar part of the lateral collateral ligament (also called the lateral ulnar collateral ligament), the anterior band of the medial collateral ligament, and the coronoid. The radial head and capsule are secondary constraints to elbow instability. Kasser JR (ed): Orthopaedic Knowledge Update 5. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1996, pp 283-294.

The MRI scans reveal a meso os acromiale with edema at the site in a skeletally mature patient. Sher JS: Anatomy, biomechanics, and pathophysiology of rotator cuff disease, in Iannotti JP, Williams GR (eds): Disorders of the Shoulder: Diagnosis and Management. Philadelphia, PA, Lippincott Williams & Wilkins, 1999, p 23.

CMT is characterized by a cavovarus foot position that increases weight-bearing stresses along the lateral border. Removal of the fifth metatarsal head carries the risk of creating a transfer lesion at the fourth metatarsal head, particularly with a cavovarus foot. Claw toes are common in CMT, but the fifth toe would be flail in this situation. Ulceration is unlikely given the lack of underlying bone. Peroneal atrophy is associated with CMT but would not be a complication of this procedure. Charcot arthropathy is a neuropathic process frequently seen in individuals with diabetes mellitus. Kitaoka HB, Holiday AD Jr: Metatarsal head resection for bunionette: Long-term followup. Foot Ankle 1991;11:345-349.

The images demonstrate a L5 selective root block as it exits the L5-S1 foramen. This root block best helps relieve pain or paresthesias in the L5 distribution, which is the dorsal first web space and the great toe. The lateral foot is an S1 distribution and would need to be blocked through the posterior first sacral foramen. The anterior shin and thigh represent the L4 root which exits a level above this at the L4-5 foramen. A stocking distribution is nonanatomic and not indicative of a specific root. Magee D: Principles and concepts, in Orthopaedic Physical Assessment, ed 3. Philadelphia, PA, WB Saunders, 1997, pp 1-18.

The Achilles tendon insertion encompasses a broad area on the posterior area of the calcaneus. A biomechanical study has shown that up to 50% of the Achilles tendon insertion point can be detached before the strength of the attachment point starts to weaken. It is recommended that if more than this amount is detached to remove the posterior superior calcaneal prominence, consideration should be given to either securing the tendon to the bone with suture anchors or performing a tendon transfer. Kolodziej P, Glisson RR, Nunley JA: Risk of avulsion of the Achilles tendon after partial excision for treatment of insertional tendinitis and Haglund's deformity: A biomechanical study. Foot Ankle Int 1999;20:433-437.

The patient's findings are consistent with an intermediate form of spinal muscular atrophy. Children with this condition appear normal at birth but are not able to walk. The disorder affects anterior horn cells. Fasciculations may be present, but deep tendon reflexes are typically absent. The development of scoliosis is almost universal with this type of spinal muscular atrophy. More than 90% of patients with spinal muscular atrophy have deletions in the telomeric survival motor neuron gene. Peripheral myelin protein 22 is abnormal in Charcot-Marie-Tooth type IA. Connexin 32 is abnormal in the X-linked type of Charcot-Marie-Tooth disease. Neurofibromin is affected in neurofibromatosis type 1. Friedreich's ataxia is secondary to a disorder of frataxin. Buckwalter JA, Einhorn TA, Simon SR (eds): Orthopaedic Basic Science, ed 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2000, pp 111-131.

The patient has an abnormal neurologic exam as shown by the abnormal abdominal reflexes. Furthermore, she has a significant curve and is younger than age 10 years. These findings are not consistent with idiopathic scoliosis. MRI will best rule out syringomyelia or an intraspinal tumor. Bracing and surgery are not indicated for this small curvature prior to obtaining an MRI scan. Ginsburg GM, Bassett GS: Back pain in children and adolescents: Evaluation and differential diagnosis. J Am Acad Orthop Surg 1997;5:67-78.

The biopsy specimen is a low-power view of a soft-tissue sarcoma with a biphasic pattern of epithelial cells and fibrous spindle cells that are typical of a synovial sarcoma. A deep, painless soft-tissue mass greater than 5 cm in size is suspicious for a sarcoma. The imaging in this patient is indeterminate and the patient requires a biopsy for an accurate diagnosis. The biopsy reveals a tumor with a biphasic appearance consistent with a synovial sarcoma. These tumors are slow growing, occur primarily in the lower extremities, and are found in a younger demographic population compared to malignant fibrous histiocytoma and liposarcoma. They can occur in a biphasic pattern with clumps of epithelial cells and fibrous spindle cells or in a monophasic pattern. Synovial sarcomas stain positively for keratin. Keratin is positive in nearly all biphasic types and in many tumors of the monophasic fibrous type. Sixty percent of these tumors are found in the lower extremity. The area around the knee is the most common location, followed by the ankle and foot. Epithelioid and clear cell sarcomas are found associated with tendon sheaths of the hand and feet and are generally smaller in size. Epithelioid sarcoma may resemble granulomatous inflammation histologically; clear cell sarcoma is composed of nests of clear cells with occasional multinucleated giant cells. Pigmented villonodular synovitis is found within the synovium and is characterized by a villous histologic appearance with hemosiderin-laden macrophages. Malignant fibrous histiocytoma has a storiform histologic pattern with an abundance of pleomorphic cells. Enzinger FM, Weiss SW: Soft Tissue Tumors, ed 3. St Louis, MO, Mosby, 1995, p 757.

The radiograph reveals an atrophic nonunion of the diaphysis of the clavicle. Electrical or ultrasound stimulation may be an option in diaphyseal nonunions that have shown some healing response with callus formation, but these techniques are not successful in an atrophic nonunion. The preferred technique for achieving union is open reduction and internal fixation with bone graft. Percutaneous fixation has no role in treatment of nonunions of the clavicle. Boyer MI, Axelrod TS: Atrophic nonunion of the clavicle: Treatment by compression plating, lag-screw fixation and bone graft. J Bone Joint Surg Br 1997;79:301-303.

Subtle anterior subluxation in the throwing athlete most frequently results from excessive capsular laxity because of repetitive microtrauma. Avulsion of the inferior glenohumeral ligament from the glenoid, or more rarely from the humerus, occurs with macrotrauma. A large Hill-Sachs lesion and a glenoid rim fracture also may result from a traumatic anterior dislocation. Kvitne RS, Jobe FW: The diagnosis and treatment of anterior instability in the throwing athlete. Clin Orthop 1993;291:107-123.

The recurrence rate of anterior dislocation of the shoulder after the first episode in athletes younger than age 20 years is thought to be as high as 90%, making surgery after the initial episode a consideration. The rate drops from 50% to 75% in the 20- to 25-year age group and down to 15% in patients older than age 40 years. An excellent prospective study of 257 patients in Sweden showed that there was no difference in those who did or did not complete 3 weeks of immobilization. The study also showed variability among different age groups in the importance of athletic participation; athletes in the 12- to 22-year age group had a higher recurrence rate, whereas the more sedentary patients in the 23- to 29-year age group had a higher rate. Hovelius L: The natural history of primary anterior dislocation of the shoulder in the young. J Orthop Sci 1999;4:307-317.

The patient has end-stage shoulder arthritis with posterior glenoid erosion and large humeral osteophyte formation. Since the rotator cuff is likely intact, the reverse total shoulder arthroplasty is unnecessary. All the remaining procedures may provide symptomatic relief in appropriate patients; however, for most patients, total shoulder arthroplasty has been associated with the most predictive pain relief and functional improvements. Bryant D, Litchfield R, Sandow M, et al: A comparison of pain, strength, range of motion, and functional outcomes after hemiarthroplasty and total shoulder arthroplasty in patients with osteoarthritis of the shoulder: A systemic review and meta-analysis. J Bone Joint Surg Am 2005;87:1947-1956. Edwards TB, Kadakia NR, Boulahia A, et al: A comparison of hemiarthroplasty and total shoulder arthroplasty in the treatment of primary glenohumeral osteoarthritis: Results of a multicenter study. J Shoulder Elbow Surg 2003;12:207-213.

In an article in the Journal of Shoulder and Elbow, 431 total shoulder arthroplasties were performed with a cemented all-polyethylene glenoid component between 1990 and 2000. Follow-up averaged 4.2 years. In total, 53 surgical complications occurred in 53 patients (12%). Of these, 32 were major complications (7.4%), with 17 of these requiring reoperation. Index complications in order of frequency included rotator cuff tearing, postoperative glenohumeral instability, and periprosthetic humeral fracture. Notably, glenoid and humeral component loosening requiring reoperation occurred in only one shoulder. Data from the contemporary patient group suggest that there are fewer complications of shoulder arthroplasty and less need for reoperation. Especially striking is the near absence of component revision because of loosening or other mechanical factors. Complications involving the brachial plexus have been reported following total shoulder arthroplasty but are not as common of a cause for failure. Chin PY, Sperling JW, Cofield RH, et al: Complications of total shoulder arthroplasty: Are they fewer or different? J Shoulder Elbow Surg 2006;15:19-22.

The biopsy specimens reveal a high-grade spindle cell lesion adjacent to an area of benign cartilage. This is consistent with a dedifferentiated chondrosarcoma. The radiograph shows a pathologic fracture through a lesion characterized by calcification within the left greater trochanter. Distal to the area of calcification, there is a more osteolytic, destructive appearance. Synovial sarcoma has a biphasic appearance histologically with areas of glandular differentiation that stain positive with keratin. Metastatic prostate cancer, although osteoblastic in appearance, would have a glandular histologic appearance. There is no cartilage in these lesions. Classic low-grade chondrosarcoma does not have an area of high-grade pleomorphic spindle cells within the lesion. A periosteal osteosarcoma is a surface-based lesion with a sunburst radiographic pattern. Although there may be cartilage in the lesion histologically, there are also malignant cells producing osteoid. Dedifferentiated chondrosarcoma is an aggressive, high-grade variant of chondrosarcoma. Wold LE, Adler CP, Sim FH, et al: Atlas of Orthopedic Pathology, ed 2. Philadelphia, PA, WB Saunders, 2003, p 269.

Severe osteoporosis is a contraindication to manipulation under anesthesia in patients with a resistant frozen shoulder because of the higher risk of humeral fracture. Manipulation is considered for frozen shoulder in patients who are symptomatic despite undergoing a reasonable course of appropriate physical therapy. Harryman DT II: Shoulder: Frozen and stiff. Instr Course Lect 1997;42:247-257.

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

Creatine is currently used as a nutritional supplement in an attempt to enhance athletic performance. The physiologic basis for its use is based on its conversion by CK to PCr, which acts as an energy reservoir in muscle cells for the production of ATP. A number of studies that examined the effect of creatine supplementation on performance concluded that while creatine does not increase peak force production, it can increase the amount of work done in the first few anaerobic short duration, maximal effort trials. The mechanism for this enhancement of work is unknown, but it is most likely secondary to the increase in the available PCr pool. Greenhaff PL: Creatine and its application as an ergogenic aid. Int J Sport Nutr 1995;5:S100-S110. Greenhaff PL, Casey A, Short AH, Harris R, Soderlund K, Hultman E: Influence of oral creatine supplementation on muscle torque during repeated bouts of maximal voluntary exercise in man. Clin Sci 1993;84:565-571. Trump ME, Heigenhauser GJ, Putman CT, Spriet LL: Importance of muscle phosphocreatine during intermittent maximal cycling. J Appl Physiol 1996;80:1574-1580.

Absolute toe pressures greater than 40 to 50 mm Hg are a good sign of healing potential. An ABI of greater than 0.45 favors healing, but indices greater than 1 are falsely positive due to calcifications in the vessels. Normal albumin is an overall indication of nutritional status. A transcutaneous oxygen level should be greater than 40 mm Hg for healing. Mizel MS, Miller RA, Scioli MW (eds): Orthopaedic Knowledge Update: Foot and Ankle 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1998, pp 113-122.

Because the patient has failed to respond to appropriate nonsurgical management and imaging studies are normal, the use of arthroscopy not only aids in the diagnosis of chronic ankle pain, but is also helpful in its treatment. In patients with this condition, typical findings include synovitis in the lateral gutter and fibrosis along the talofibular articulation; syndesmosis chondromalacia of the talus and ankle also may be found. In patients with anterior soft-tissue impingement, approximately 84% who have a poor response to nonsurgical management will have a good to excellent response after arthroscopic synovectomy and debridement. Ferkel RD, Fasulo GJ: Arthroscopic treatment of ankle injuries. Orthop Clin North Am 1994;25:17-32.

The lesion is an eccentric lytic bone lesion within the epiphyseal-metaphyseal end of the proximal tibia. There is geographic destruction with a "fading border" extending to the articular cartilage. There is no matrix formation or periosteal reaction. The MRI scan shows cortical destruction with extension into the soft tissue. According to the Enneking staging system, benign lesions are stage 1, 2, or 3; malignant lesions are stage I, II, or III. Benign stage 1 lesions are latent; stage 2 are active; and stage 3 are benign aggressive. The histology shows a benign giant cell tumor. Given the cortical breakthrough shown on the MRI scan, the lesion should be classified as stage 3. Enneking WF: Clinical musculoskeletal pathology, in Enneking WF (ed): Appendix A. Gainesville, FL, Storter Publishing, 1986, pp 451-466.

It has been proposed that an imbalance in the proteolytic cascade involving matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) may play a role in the development or progression of malignancy. TIMP activity has been shown to be weak or nonexistent and MMP activity to be high in patients with soft-tissue sarcoma. The level of vascular endothelial growth factor is shown to be a negative prognostic indicator because the expression of this factor is associated with angiogenesis and aggressive growth of many tumors including Ewing' s sarcoma and chondrosarcoma. Stromelysin is a type of MMP. The biology of cytokines in malignancy is complex. A low level of interleukin-1 is not known to be associated with high-grade tumors.

Wide variations in the anatomy of the anterosuperior portion of the labrum and the middle glenohumeral ligament have been reported and are more common than previously thought. The labrum attached to the glenoid rim and a flat/broad middle glenohumeral ligament is the most common "normal" variation. A cord-like middle glenohumeral ligament is often associated with the presence of a sublabral hole. An anterosuperior labrum confluent with a cord-like middle glenohumeral ligament and no labral attachment to bone is the configuration of the Buford complex. The prevalence of each variation from one recent study is as follows: #1: 86.6%; #2: 3.3%; #3: 8.6%; and #4: 1.5%. Rao AG, Kim TK, Chronopoulos E, et al: Anatomical variants in the anterosuperior aspect of the glenoid labrum. J Bone Joint Surg Am 2003;85:653-659. Ilahi OA, Labbe MR, Cosculluela P: Variants of the anterosuperior glenoid labrum and associated pathology. Arthroscopy 2002;18:882-886.

The relationship between the distal articular surface of the first metatarsal head and the long axis of the first metatarsal is called the distal metatarsal articular angle. This angle has been validated by Richardson and associates to measure and determine the congruence of the first metatarsophalangeal joint. This angle is critical in determining the appropriate surgical procedure to perform on a patient with a bunion deformity because a congruent joint requires a procedure to maintain congruence of the articular surfaces following osteotomy. Therefore, a chevron becomes a biplanar chevron, and a Lapidus procedure adds a second osteotomy of the distal metatarsal to tilt the metatarsal head into a congruent location. Coughlin MJ: Juvenile hallux valgus: Etiology and treatment. Foot Ankle Int 1995;16:682-697. Steel MW III, Johnson KA, DeWitz MA, et al: Radiographic measurements of the normal foot. Foot Ankle 1980;1:151-158.

This deformity is early in the disease process. The foot is still flexible, as evidenced by correction with the Coleman block test. A simple dorsiflexion osteotomy of the first metatarsal should provide a plantigrade foot. More complex osteotomies are required later in the disease process when the foot is not flexible and the deformity does not correct with the Coleman block test. The patient may also require a tibialis anterior transfer later in the disease process but not at the present time. Richardson EG (ed): Orthopaedic Knowledge Upate: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 135-144.

Unilateral sacralization of the fifth lumbar vertebra was first described by Bertolotti in 1917. Bertolotti's syndrome is present in 12% to 21% of the population. The altered biomechanics have been postulated to cause low back pain by placing increased stress on the adjacent cephalad disk, thus contributing to accelerated degenerative disk disease at this level. It has also been found that the neoarticulation between the enlarged transverse process and the sacrum and/or ilium may be a source of neural impingement on the exited L5 nerve root and results in radicular pain syndrome. Brault and associates reported on a case treated surgically at the Mayo Clinic, in which the pain generator was found to be the contralateral facet joint. Brault JS, Smith J, Currier BL: Partial lumbosacral transitional vertebra resection for contralateral facetogenic pain. Spine 2001;26:226-229. Quinlan JF, Duke D, Eustace S: Bertolotti's syndrome: A cause of back pain in young people. J Bone Joint Surg Br 2006;88:1183-1186.

The patient has a cavovarus deformity that has resulted in lateral foot overload and stressing of the lateral ligaments. Further treatment depends on the ability to correct the deformity. The Coleman block test indicates whether a deformity is fixed or supple. A supple deformity will respond to orthotic management or soft-tissue procedures, while a fixed deformity requires corrective osteotomy or fusion. Physical therapy, casting, and injection will not address the underlying pathophysiology. There is no indication that this is a neuropathic problem.

The great medullary artery originates as a direct or indirect branch of the left posterior intercostal artery, usually between T8 and T12. It becomes intradural and crosses over one to three disk spaces before turning to the midline where it anastomoses with the anterior spinal artery. Injury to this artery can result in devastating ischemia of the lower spinal cord. Lu J, Ebraheim NA, Biyani A, Brown JA, Yeasting RA: Vulnerability of great medullary artery. Spine 1996;21:1852-1855.

The sural nerve runs with the small saphenous vein on the posterior leg just lateral to the Achilles tendon. It is formed by contributions from both the tibial and common peroneal nerves and provides sensation on the dorso-lateral aspect of the foot. Aktan Ikiz ZA, Ucerler H, Bilge O: The anatomic features of the sural nerve with an emphasis on its clinical importance. Foot Ankle Int 2005;26:560-567.

The extracellular matrix consists of water, proteoglycans, and collagen. Water makes up the majority (approximately 65% to 80%) of wet weight; 95% of the collage is type II with much smaller amounts of other collagens, including types IV, VI, IX, X, and XI. The exact functions of these other collagens are unknown, but they are believed to be important in matrix attachment and stabilization of the diameter of collagen fibrils. Buckwalter JA, Einhorn TA, Simon SR (eds): Orthopaedic Basic Science: Biology and Biomechanics of the Musculoskeletal System, ed 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2000, pp 444-445.

Muliple neurofibromas result in marked foraminal enlargement as seen on the sagittal MRI scan. Collagen disorders leading to dural ectasia may show similar enlargement, but none of these is listed as a possible answer. Kim HW, Weinstein SL: Spine update: The management of scoliosis in neurofibromatosis. Spine 1997;22:2770-2776.

Impaction grafting technique for femoral revision surgery has become increasingly popular over the past decade. This technique is designed to address cavitary deficiencies of the femur. The femoral stem is inserted with cement fixation. Its clinical efficacy has not been shown to be superior to extensively porous-coated stems. Early subsidence of the stem has been reported in more than 50% of the patients. However, loss of fixation has occurred infrequently (5%) in reported series conducted by experienced surgeons. It has not been shown to have a higher infection rate. Gie GA, Linder L, Ling RS, Simon JP, Slooff TH, Timperley AJ: Impacted cancellous allografts and cement for revision total hip arthroplasty. J Bone Joint Surg Br 1993;75:14-21.

The patient has a scaphoid fracture with cystic resorption of the distal aspect of the midthird of the scaphoid. This fracture is unlikely to heal without intervention. Percutaneous pinning, closed manipulation, and bone grafting will not restore alignment. Treatment requires restoration of scaphoid length, bone grafting, and internal fixation to obtain healing with normal alignment. Cooney WP, Linscheid RL, Dobyns JH, Wood MB: Scaphoid nonunion: Role of anterior interpositional bone grafts. J Hand Surg Am 1988;13:635-650. Fernandez DL: A technique for anterior wedge-shaped grafts for scaphoid nonunions with carpal instability. J Hand Surg Am 1984;9:733-737. Stark HH, Rickard TA, Zemel NP, Ashworth CR: Treatment of ununited fractures of the scaphoid by illiac bone grafts and Kirschner-wire fixation. J Bone Joint Surg Am 1988;70:982-991.

The severe depression of the proximal medial tibial epiphysis is most consistent with the diagnosis of neglected infantile Blount's disease. Blount's disease in adolescents produces a deformity in the metaphyseal region. Septic arthritis and JRA affect both sides of the joint. Hemophilia produces a characteristic widening of the intercondylar notch. Thompson GH, Carter JR: Late-onset tibia vara (Blount's Disease). Clin Orthop 1990;255:24-35.

Immediate spica casting is ideal for younger children with uncomplicated femoral fractures that are the result of relatively low-energy injury. Surgical stabilization of pediatric femoral fractures is most commonly performed in children who are older than age 6 years or in children with other factors associated with their femoral fracture, such as concomitant head injury, open fracture, floating knee, severe comminution, or vascular injury. 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. Sponseller PD: Surgical management of pediatric femoral fractures. Instr Course Lect 2002;51:361-365. Wright JG: The treatment of femoral shaft fractures in children: A systematic overview and critical appraisal of the literature. Can J Surg 2000;43:180-189.

Internal fixation of the clavicle, glenoid, or both has been recommended for fractures of the clavicle and glenoid neck (floating shoulders). Recently, the inherent instability of these dual fractures has been questioned in a biomechanical model without further disruption of the coracoclavicular or acromioclavicular ligamentous structures. Nonsurgical management of the majority of combined scapular/glenoid fractures in patients with less than 10 mm of displacement has resulted in excellent shoulder function and will most likely achieve an excellent result in this patient. Egol KA, Connor PM, Karunakar MA, Sims SH, Bosse MJ, Kellam JF: The floating shoulder: Clinical and functional results. J Bone Joint Surg Am 2001;83:1188-1194. Williams GR Jr, Naranja J, Klimkiewicz J, et al: The floating shoulder: A biomechanical basis for classification and management. J Bone Joint Surg Am 2001;83:1182-1187.

The radiographs reveal a lytic subchondral lesion that has a poorly defined margin and lacks mineralization. The bone scan confirms an active lesion that has central photopenia, producing the characteristic doughnut configuration. The MRI scans confirm the presence of a subchondral lesion that is modestly expansile at the lateral plateau and has low signal intensity on the T1-weighted image and a mixed high signal on the T2-weighted image. These features strongly suggest giant cell tumor of bone, more than 50% of which appear around the knee. Simple cyst is excluded by the MRI characteristics. Fibrous dysplasia is unlikely to be in a subchondral location and typically does not show this intensity of uptake on bone scan. Parsons TW: Benign bone tumors, in Fitzgerald RH, Kaufer H, Malkani AL (eds): Orthopaedics. St Louis, MO, Mosby, 2002, pp 1027-1035.

Paucytopenia is a common problem in patients with metastatic disease. Causes include chemotherapy, external beam radiation, marrow replacement by tumor, and anemia of chronic disease. There is no correlation with decreased calcium and a decrease in hematopoiesis. Supportive care with granulocyte-colony stimulating factor (G-CSF) and neupogen can stimulate hematopoiesis.

The patient has an unstable slipped capital femoral epiphysis (SCFE). According to the classification system based on physeal stability, an unstable SCFE is one in which the patient is unable to walk, even with crutches. Ishemic necrosis, or osteonecrosis, of the femoral head is the most devastating complication of SCFE. One study found a 47% incidence of ischemic necrosis following unstable slips. This complication is most likely the result of vascular injury associated with initial femoral head displacement rather than the result of either tamponade from joint effusion or gentle repositioning prior to stabilization. Chondrolysis is a relatively uncommon complication following treatment of SCFE. This complication has been associated with persistent penetration of the hip joint with screws or pins used to stabilize the femoral head or with spica cast immobilization. There are no reports to suggest that osteochondritis dissecans, nonunion, or coxa magna follows treatment of SCFE. Loder RT, Richards BS, Shapiro PS, et al: Acute slipped capital epiphysis: The importance of physeal stability. J Bone Joint Surg Am 1993;75:1134-1140.

The radiographs reveal phleboliths on the volar side of the forearm consistent with hemangioma. The MRI scan reveals a rather well-circumscribed in size, irregular in shape, intramuscular soft-tissue mass in the volar aspect of the distal right forearm within the flexor group musculature. The mass demonstrates heterogeneous mixed signal intensity in both T1- and T2-weighted sequences with increased signal intensity on the T1, suggesting fat within the tumor, typical of hemangioma. The postgadolinium-enhanced sequences demonstrate heterogeneous enhancement. The MRI findings are consistent with a soft-tissue hemangioma. Garzon M: Hemangiomas: Update on classification, clinical presentation and associate anomalies. Cutis 2000;66:325-328.

The figures show a lesion of the proximal humerus consistent with an enchondroma. The lesion is calcified on the radiographs. There is no cortical destruction, significant endosteal scalloping, or soft-tissue mass. The bone scan shows mild uptake in the area of the proximal humerus, and the T2-weighted MRI scan shows a lesion with high uptake, suggesting a lesion with high water content. A CT scan could also be obtained to rule out bone destruction or periosteal reaction. Pain with overhead activities is likely related to the rotator cuff. A biopsy is unlikely to add information because of inherent difficulties interpreting low-grade cartilaginous lesions. Curettage and grafting and en bloc resection are excessive treatments for a benign lesion that is apparently asymptomatic. Observation with a follow-up radiograph in 3 to 6 months is appropriate. Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 103-111.

The superior cluneal nerves (L1, L2, and L3) are at greatest risk when harvesting iliac crest bone graft during a posterior decompression and fusion. The nerves pierce the lumbodorsal fascia and cross the posterior iliac crest beginning at 8 cm lateral to the posterior superior iliac spine. The ilioinguinal and iliohypogastric nerves innervate anterior structures, and the lateral femoral cutaneous nerve lies in proximity to the anterior superior iliac spine and is at risk with anterior iliac crest bone graft harvesting. The superior gluteal nerve courses through the sciatic notch and supplies motor branches to the gluteus medius, minimus, and tensor fascia lata muscles. An HS: Principles and Techniques of Spine Surgery. Baltimore, MD, Williams and Wilkins, 1998, pp 770-773.

The lateral arm flap is based on the posterior radial collateral artery, a branch of the profunda brachial artery. Katsaros J, Tan E, Zoltie N: The use of the lateral arm flap in upper limb surgery. J Hand Surg 1991;16:598-604.

Manipulative treatment and casting of talipes equinovarus has become popular because of disappointing surgical results and enthusiasm for the Ponseti method of manipulation. In this technique, the primary goal is to rotate the foot laterally around a talus that is held fixed by the manipulating surgeon's hands. While the navicular may be rotated anterolaterally with this technique, the primary focus is on the calcaneus. The calcaneus is rotated laterally and superiorly, not translated. Some dorsiflexion of the calcaneus can be obtained by manipulation, but the primary focus is on the rotational relationship of the talus and calcaneus, not the degree of calcaneal dorsiflexion. Ponseti IV: Common errors in the treatment of congenital clubfoot. Int Orthop 1997;21:137-141.

IGF-I, formerly known as somatomedin-C, possibly acts by both paracrine and endocrine hormone pathways. The products of the GH-IGF-I system induce proliferation without maturation of the growth plate and thus induce linear skeletal growth. The action of the thyroid hormone axis is via an active metabolite that enters target cells and signals a nuclear receptor to stimulate both proliferation and maturation of the growth plate. Increased amounts of the active steroid hormone metabolite promote proliferation and maturation of the growth plate. Calcitonin inhibits bone resorption. Binder G, Grauer ML, Wehner AV, et al: Outcome in tall stature: Final height and psychological aspects in 220 patients with and without treatment. Eur J Pediatr 1997;156:905-910. Wang J, Zhou J, Cheng CM, et al: Evidence supporting dual, IGF-I-independent and IGF-I-dependent, roles for GH in promoting longitudinal bone growth. Endocrinol 2004;180:247-255.

Displaced supracondylar humerus fractures in children may have associated vascular compromise. Decreased blood flow may be due to vessel injury, entrapment within the fracture site, kinking from fracture displacement, or from vessel spasm. Optimal initial treatment in the emergency department includes gentle realignment of the limb and vascular assessment. Angiography is not required in isolated injuries as the level of the vessel compromise is always at the site of the fracture. When blood flow is not restored, the next best step in treatment is to proceed urgently to the operating room. A formal closed reduction and pinning is performed, and then the vascular status is reassessed. Exploration and vascular repair is required if the hand is cool, white, and without pulses. Ay S, Akinci M, Kamiloglu S, et al: Open reduction of displaced pediatric supracondylar humeral fractures through the anterior cubital approach. J Pediatr Orthop 2005;25:149-153. Sabharwal S, Tredwell SJ, Beauchamp RD, et al: Management of pulseless pink hand in pediatric supracondylar fractures of humerus. J Pediatr Orthop 1997;17:303-310.

The patient has a failed Silastic implant. Nonsurgical management will not work at this point. A Keller resection will only exacerbate her metatarsalgia. Implant removal with structural bone grafting and MTP fusion is the most appropriate choice because restoration of length is needed to alleviate the forefoot pain and bone grafting is required to fuse the MTP joint because there is an abundance of osteolysis. Total toe implants do not offer good long-term outcomes and are very difficult to fit into the large exploded-out cavity of the proximal phalanx. Hecht PJ, Gibbons MJ, Wapner KL, et al: Arthrodesis of the first metatarsophalangeal joint to salvage failed silicone implant arthroplasty. Foot Ankle Int 1997;18:383-390.

Numerous reports have documented serious complications including death from migration of intact or broken Kirschner wires or Steinmann pins into hilar structures such as the heart, pulmonary artery, and the aorta. Gilot GJ, Wirth MA, Rockwood CA: Injuries to the sternoclavicular joint, in Bucholz RW, Heckman JD, Court-Brown C (eds): Fractures in Adults. Philadelphia, PA, Lippincott, Williams and Wilkins, 2006, vol 2, pp 1373-1374.

A farm injury is automatically considered a grade III (Gustillo classification) injury regardless of size, energy, or additional soft-tissue injury due to the likelihood of substantial contamination. Antibiotic recommendations for grade III injuries include a first- or second-generation cephalosporin with an aminoglycoside or fluoroquinolone within 3 hours of injury, with penicillin added for farm injuries. Okike K, Bhattacharyya T: Trends in the management of open fractures: A critical analysis. J Bone Joint Surg Am 2006;88:2739-2748.

The reported failure rate is in the range of 15%, which may be the result of incorrect diagnosis, improper web space selection, or formation of a stump neuroma. Therefore, the procedure should be approached with caution, measures should be taken to ensure that the diagnosis is accurate, and nonsurgical options should be exhausted. Mizel MS, Miller RA, Scioli MW (eds): Orthopaedic Knowledge Update: Foot and Ankle 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1998, pp 101-111. Beskin JL: Nerve entrapment syndromes of the foot and ankle. J Am Acad Orthop Surg 1997;5:261-269.

A herniated cervical disk at C5-6 causes a C6 radiculopathy. There are eight cervical nerve roots and seven cervical vertebrae, and C8 exits between the C7 and T1 vertebrae. The C6 nerve root typically innervates the biceps and wrist extensor. The deltoid is predominantly innervated by C5. The wrist flexor and triceps are predominantly innervated by C7. Grip strength is predominantly a function of C8.

Resection of a previously excised soft-tissue sarcoma is recommended. Reoperation is recommended after removal of malignant tumors previously believed to be benign, as approximately one half of the patients will have residual tumor in the re-excised specimen. Observation is not indicated in most patients because local recurrence is likely. Radiation therapy alone may result in long-term local control but is felt to be less effective than reoperation. Chemotherapy and radiation therapy alone are not recommended. Wide excision is the most important factor for local disease control. Radiation therapy after surgical re-excision may also decrease the risk of local recurrence. Peabody TD, Monson D, Montag A, Schell MJ, Finn H, Simon MA: A comparison of the prognoses for deep and subcutaneous sarcomas of the extremities. J Bone Joint Surg Am 1994;76:1167-1173. Giuliano AE, Eilber FR: The rationale for planned reoperation after unplanned total excision of soft-tissue sarcomas. J Clin Oncol 1985;3:1344-1348. Lewis JJ, Leung D, Espat J, Woodruff JM, Brennan MF: Effect of resection in extremity soft tissue sarcoma. Ann Surg 2000;231:655-663.

The etiology of osteochondritis dissecans of the capitellum is somewhat unclear. However, trauma has been implicated in this disease process. Gymnasts who load their upper extremities during tumbling and throwing athletes with repetitive trauma during the throwing motion are common patient subgroups in which osteochondritis dissecans of the elbow is seen. This often occurs in the adolescent age population. Baumgarten TE, Andrews JR, Satterwhite YE: The arthroscopic classification and treatment of osteochondritis dissecans of the capitellum. Am J Sports Med 1998;26:520-523.

The sagittal and axial CT scans show a bilateral spondylolysis at L5. The defect is in the pars interarticularis on the right side but at the base of the pedicle on the left. Having failed a trial of physical therapy with only a 3-month history of pain, the next most appropriate step in management should consist of activity modification and bracing in an antilordotic lumbosacral orthosis. Surgical intervention is reserved for patients who have failed to respond to a trial of bracing and activity restriction. Debnath UK, Freeman BJ, Grevitt MP, et al: Clinical outcome of symptomatic unilateral stress injuries of the lumbar pars interarticularis. Spine 2007;32:995-1000.

In patients with an osteomyelitic infection, radiographic findings at 1 to 5 days usually show soft-tissue swelling only. Seven to 14 days after symptoms begin, radiographs will most likely show the classic signs of acute osteomyelitis. Reactive bone formation would be expected by 6 months. Kasser JR (ed): Orthopaedic Knowledge Update 5. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1996, pp 149-161.

Adult patients with isthmic spondylolisthesis most commonly have neurologic symptoms due to foraminal stenosis at the level of the spondylolisthesis. In this scenario, the patient is most likely to have weakness of the L5 myotome, which would cause weakness of the extensor hallucis longus. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 311-317.

The plantar intrinsic muscles are divided into four layers with respect to depth from the plantar fascia. They are (from superficial to deep): 1) abductor hallucis, flexor digitorum brevis, abductor digiti minimi; 2) quadratus plantae, lumbricals; 3) flexor digiti minimi, flexor hallucis brevis, adductor hallucis brevis; and 4) dorsal and plantar interosseous muscles. The flexor hallucis brevis and adductor hallucis brevis originate from the midtarsal bones, encompass the sesamoids, and insert into the base of the proximal phalanx. The adductor hallucis brevis consists of two muscle bellies forming a conjoined tendon and inserting into the lateral portion of the proximal phalanx and the lateral sesamoid. The adductor hallucis brevis is stronger than the abductor hallucis brevis, which may contribute to hallux valgus. The flexor digitorum minimi travels under the fifth metatarsal, arising at the base and inserting into the lateral base of the fifth proximal phalanx.

All of the answers are possible complications of meniscal repair. There are large volumes of literature evaluating the results of meniscal repair, both for the all-inside technique, as well as the inside-out technique. Failure rates are similar. Intra-articular synovitis occurs with absorbable sutures and absorbable implants. Peroneal nerve injuries are more common with the lateral-sided repairs. Saphenous nerve injuries are more common with medial-sided tears. Because of the incision required and the technique of tying over soft tissue, the risk of a saphenous nerve injury is greater with an inside-out technique than with an all-inside technique. Farng E, Sherman O: Meniscal repair devices: A clinical and biomechanical literature review. Arthroscopy 2004;20:273-286.

It is often difficult to accurately discern between lateral epicondylitis and radial tunnel syndrome. Neither MRI nor a bone scan is likely to reveal abnormalities. Electrodiagnostic studies are often inconclusive, and radial tunnel syndrome often presents without motor weakness. The symptoms of radial tunnel syndrome are expected to improve with an injection of lidocaine into the radial tunnel; therefore, this is the test of choice in this clinical scenario. Radiographs of the wrist will not assist in making the diagnosis. Eversmann WW Jr: Entrapment and compression neuropathies, in Green DP (ed): Operative Hand Surgery, ed 3. New York, NY, Churchill Livingston, 1993, pp 1341-1385.

The lesion is a variation of a type I superior labrum anterior and posterior lesion; therefore, appropriate treatment is simple debridement. Biceps tenodesis or release is not indicated because the biceps tendon and anchor are intact. There is no indication for labral repair or capsulorraphy. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 261-270.

The MRI scans show a popliteal cyst (Baker's cyst) in its most common location. The cyst emerges from the knee joint between the medial head of the gastrocnemius muscle and the tendon of the semimembranosus muscle. These images are diagnostic; therefore, no further work-up is indicated. Since the patient is asymptomatic, no treatment is necessary. Dlabach JA: Nontraumatic soft tissue disorders, in Canale ST (ed): Campbell's Operative Orthopaedics, ed 10. Philidelphia, PA, Mosby, 2003, vol 1, pp 885-969.

The results are statistically significant (at the arbitrary level of P < 0.05). That is, they indicate a probability of only 1/10,000 that the observation that the drug is effective in reducing healing time by 0.3 weeks occurred by chance selection of the study subjects. However, because the statistical power of a study increases with the number of subjects included (sample size), a difference that is trivial clinically can occur with a very high level of statistical significance (a very small P-value) if enough patients are included in the study. Because of this, the P-value alone, no matter how small, does not establish clinical significance or importance. Rather, the clinical significance of the observed difference must be assessed taking into consideration the medical importance of the difference if it is, in fact, true in the general population. In this example, the reduction in healing time of only a few days is probably clinically unimportant, particularly if the use of the new growth factor is expensive, complex, and/or has substantial side effects.

The most significant impact on long-term survival is the presence or absence of identifiable metastatic disease on initial presentation. All of these factors have been shown to be predictive of long-term survival to varying degrees. Enneking WF, Spanier SS, Goodman MA: A system for the surgical staging of musculoskeletal sarcoma. Clin Orthop Relat Res 1980;153:106-120.

Latissimus dorsi tendon transfer is considered a surgical option for treatment in patients with chronic supraspinatus and infraspinatus tendon tears. Preoperative subscapularis function is necessary for good clinical results. Additionally, men with active elevation to shoulder level and active external rotation to 20 degrees have predictably good results. Women with active shoulder elevation limited to below chest level have poor results from this procedure and should not be considered candidates. Postoperatively they lack pain control, active elevation, and active external rotation. Muscular atrophy in the latissimus dorsi does not occur, and glenohumeral arthritic changes frequently develop postoperatively. Gerber C, Maquieira G, Espinosa N: Latissimus dorsi transfer for the treatment of irreparable rotator cuff tears: Factors affecting outcome. J Bone Joint Surg Am 2006;88:113-120.

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

Although pin loosening generally has not been considered a major problem, it has been cited as the most common complication in two published series of halo vest complications. The other possible complications are all significantly less common. Baum JA, Hanley EN Jr, Pullekines J: Comparison of halo complications in adults and children. Spine 1989;14:251-252. Garfin SR, Botte MJ, Waters RL, Nickel VL: Complications in the use of the halo fixation device. J Bone Joint Surg Am 1986;68:320-325.

Sural nerve entrapment is the major risk of percutaneous repair. A small mini-open technique with a suture guide can obviate that issue. Re-rupture rates after surgical repair are approximately 3%. Infection and wound problems are rarely encountered with percutaneous repair; they are issues with open repair. Aracil J, Pina A, Lozano JA, et al: Percutaneous suture of Achilles tendon ruptures. Foot Ankle 1992;13:350-351. Sutherland A, Maffulli N: A modified technique of percutaneous repair of the ruptured Achilles tendon. Oper Orthop Traumatol 1998;10:50-58.

Vascular injury most commonly occurs at L4-L5, followed by L5-S1 and are associated with use of the pituitary rongeur. Hohf reported that 17 of 58 patients died as a result. Early recognition and treatment of this complication is vital; unfortunately, intraoperative bleeding from the disk space may occur in up to 50% of these patients. Some may be first recognized in the recovery room. Common clinical findings include hypotension, tachycardia, and a rigid abdomen. Formation of an arteriovenous fistula is the most common vascular injury resulting from lumbar disk surgery but is usually not recognized until months after surgery. Cardiomegaly and high output cardiac failure are common presenting symptoms. Hohf RP: Arterial injuries occurring during orthopaedic operations. Clin Orthop 1963;28:21-37. Montorsi W, Ghiringhelli C: Genesis, diagnosis and treatment of vascular complications after intervertebral disk surgery. Int Surg 1973;58:233-235.

Significant elevation of the erythrocyte sedimentation rate in a patient with a painful hip arthroplasty mandates a complete work-up for infection prior to considering revision surgery. Reproducibility and reliability of ultrasonography as a diagnostic test still needs clarification. Aspiration is the easiest and most cost-effective test and should be performed prior to nuclear imaging. The latter is most valuable if the results are negative, strongly predicting the absence of infection. Barrack RL, Harris WH: The value of aspiration of the hip joint before revision total hip arthroplasty. J Bone Joint Surg Am 1993;75:66-76.

The findings are most consistent with a rupture of the anterior tibial tendon. The damaged area of tendon should be resected, followed by tendon reconstruction or tenodesis. The histology is not consistent with giant cell tumor of the tendon sheath, gout, or synovial sarcoma. Fibromatosis is characterized by a large number of spindle cells within the collagen background. Otte S, Klinger HM, Loreaz F, Haerer T: Operative treatment in case of closed rupture of the anterior tibial tendon. Arch Orthop Traum Surg 2002;122:188-190.

The most effective way to measure a limb-length discrepancy in a patient with a knee flexion contracture is a lateral CT scanogram. All the other methods listed provide inaccurate results with a knee flexion contracture because the measurements are made in the coronal plane. Aaron A, Weinstein D, Thickman D, et al: Comparison of orthoroentgenography and computed tomography in the measurement of limb-length discrepancy. J Bone Joint Surg Am 1992;74:897-902.

Plasmacytoma is very sensitive to radiation therapy and given the complexity of the resection and complications of surgery in the given location, radiation therapy is preferred. However, the patient has clear loss of bony structural integrity, and resultant instability would persist even with tumor irradiation; therefore, posterior stabilization is warranted. Chemotherapy and bone marrow transplant are reserved for systemic disease with multiple myeloma. Corwin J, Lindberg RD: Solitary plasmacytoma of bone vs. extramedullary plasmacytoma and their relationship to multiple myeloma. Cancer 1979;43:1007-1013.

Complications of thermal capsule shrinkage or accelerated rehabilitation include capsule ablation. Since the original surgery did not include labral reattachment, findings of a Bankart lesion or a glenoid fracture from a nontraumatic injury are unlikely. Subscapularis detachment or biceps subluxation is a postoperative complication of open repairs. Failure of early postoperative instability treatment should not produce loose bodies. Abrams JS: Thermal capsulorrhaphy for instability of the shoulder: Concerns and applications of the heat probe. Instr Course Lect 2001;50:29-36.

The work-up for a patient with an unknown primary lesion that is metastatic to bone includes a search for the primary tumor and other sites of metastasis. This involves conducting a thorough history and physical examination, appropriate laboratory studies, bone scan, chest radiograph, and CT of the chest, abdomen, and pelvis. In women, a mammogram may be indicated. CT of the brain is not necessary in the early stages of a metastatic work-up. Simon MA, Bartucci EJ: The search for the primary tumor in patients with skeletal metastases of unknown origin. Cancer 1986;58:1088-1095.

The primary action of the posterior tibialis tendon is inversion of the foot; secondarily, it plantar flexes the ankle. The anterior tibialis tendon also inverts the foot and only partially antagonizes the posterior tibialis tendon. The primary action of the peroneus longus is plantar flexion of the first ray. It secondarily everts the posterior tibialis tendon. The action of the flexor digitorum longus tendon is synergistic with the posterior tibialis tendon. The primary action of the peroneus brevis tendon is eversion; therefore, it is the primary antagonist of the posterior tibialis tendon. Sarrafian SK: Anatomy of the Foot and Ankle: Descriptive, Topographic, Functional, ed 2. Philadelphia, PA, JB Lippincott, 1993, pp 550-551.

As long as the dissection stays proximal to the annular ligament, the posterior interosseous nerve is not at risk for injury. However, to ensure that the nerve is as far removed from the surgical field as possible, the forearm should be placed in pronation. Forearm supination of any degree will bring the nerve toward the surgical field. A neutral position of the forearm or elbow extension with wrist extension will not protect the posterior interosseous nerve. Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics: The Anatomic Approach, ed 2. Philadelphia, PA, Lippincott-Raven, 1992, p 100.

To define bacteria responsible for dog and cat bite infections, a prospective study yielded a median of five bacterial isolates per culture. Pasteurella is most common from both dog bites (50%) and cat bites (75%). Pasteurella canis was the most frequent pathogen of dog bites, and Pasteurella multocida was the most common isolate of cat bites. Other common aerobes included streptococci, staphylococci, moraxella, and neisseria.

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. Sarrafian SK: Anatomy of the Foot and Ankle: Descriptive, Topographic, Functional, ed 2. Philadelphia, PA, JB Lippincott, 1993.

The patient has lung cancer metastatic to the right proximal femur. The lesion is large, has destroyed a portion of the cortex, and involves the peritrochanteric region. All of these findings put the patient at high risk for pathologic fracture. The lesion is amenable to intramedullary fixation in the form of some type of reconstruction nail. Chemotherapy alone will not restore the bone stock. Given the extent of the lesion, radiation therapy, chemotherapy, or embolization will not prevent fracture. A proximal femoral replacement would be indicated in patients with bone destruction extending into the femoral head and neck. Bisphosphonates may diminish the risk of subsequent lesions but are not sufficient to treat this high-risk lesion. Radiation therapy should be given postoperatively to prevent further bone destruction.

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 possibility of an open joint injury should be considered in any patient who has a small periarticular laceration. Failure to promptly diagnose and treat such injuries may lead to septic arthritis. The diagnosis of an open joint is easily made when there is visible communication of the joint through the traumatic wound, or when intra-articular air is present on a radiograph. In the absence of these findings, the diagnosis of an open joint may be established by the saline load test, in which a volume of saline is injected into the joint under sterile conditions. If fluid extravasates through the traumatic wound, the diagnosis of an open joint is established. Voit and associates used a saline load test in 50 patients with periarticular lacerations suggestive of joint penetration. When they compared the clinical prediction of whether or not the laceration had penetrated the joint and the test results, the authors reported a false-positive clinical result in 39% of patients and a false-negative clinical result in 43%. The authors concluded that the saline load test was valuable in evaluating periarticular lacerations. Voit GA, Irvine G, Beals RK: Saline load test for penetration of periarticular lacerations. J Bone Joint Surg Br 1996;78:732-733.

The patient has a displaced fracture of the apophysis of the olecranon for which most authorities recommend surgical treatment. In older children, stability of the reduction may be achieved by the use of two parallel medullary Kirschner wires and a figure-of-8 tension band loop of either stainless steel wire or absorbable suture. The use of an absorbable suture does not require removal of the implant. Absorbable suture alone is best used in very young patients who have this type of injury. An intramedullary screw would pose an unnecessary risk of future growth disturbance. A displaced, isolated fracture of the apophysis of the olecranon is an unusual injury in a child. It has been suggested by several authors that children who have osteogenesis imperfecta may be especially prone to this injury. One study reported seven of these fractures occurring in five children who had the mild form of osteogenesis imperfecta (Sillence type IA). The authors of this study suggest that the diagnosis of osteogenesis imperfecta be considered in any child who has a displaced fracture of the apophysis of the olecranon, especially when the injury is associated with relatively minor trauma. Stott NS, Zionts LE: Displaced fractures of the apophysis of the olecranon in children who have osteogenesis imperfecta. J Bone Joint Surg Am 1993;75:1026-1033. Gaddy BC, Strecker WB, Schoenecker PL: Surgical treatment of displaced olecranon fractures in children. J Pediatr Orthop 1997;17:321-324.

The radiograph shows the correct tibial tunnel and anterior femoral tunnel; therefore, range of motion will most likely show loss of flexion. Brown CH Jr, Carson EW: Revision anterior cruciate ligament surgery. Clin Sports Med 1999;18:109-171.

The most common inherited neuromuscular disease seen by orthopaedic surgeons is CMT, which is an inherited autosomal-dominant disease. It is more commonly seen in men due to the nature of the inheritance. Identification of cavus deformity in the foot of a child should arouse suspicion. Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 135-143. Charcot-Marie-Tooth Disease (CMT) Penn State Hershey Medical Center. www.hmc.psu.edu/healthinfo/c/cmt.htm

The patient requires an arthrodesis of the first metatarsophalangeal joint because of the abnormal neuromuscular forces. The more traditional bunionectomies such as a distal chevron bunionectomy, a proximal first metatarsal osteotomy, and a double osteotomy have a high failure rate because of the underlying Down syndrome. The Keller procedure is indicated for older, sedentary individuals and has little role in the management of a neuromuscular bunion. Coughlin MJ, Abdo RV: Arthodesis of the first metatarsophalangeal joint with Vitallium plate fixation. Foot Ankle Int 1994;15:18-28.

In the treatment of ankle fractures, the superficial peroneal nerve is most commonly injured by the use of a direct lateral approach to the ankle. The superficial peroneal nerve and its branches exit the fascial hiatus approximately 9 cm to 10 cm proximal to the tip of the distal fibula with a range of 4 cm to 13 cm, and their course is typically anterior to the midlateral plane of the fibula. However, small branches may course across the surgical plane directly laterally. A posterior-lateral approach diminishes the risk of injury to the superficial peroneal nerve and its branches; however, by moving farther posterior, the sural nerve and its branches may be at increased risk. Cast immobilization may injure the cutaneous nerves about the ankle; however, the risks are greater with surgical intervention. A medial or anterior-medial approach to the ankle will not injure the superficial peroneal nerve at the ankle level. Redfern DJ, Sauve PS, Sakellariou A: Investigation of incidence of superficial peroneal nerve injury following ankle fracture. Foot Ankle Int 2003;24:771-774.

It is common for patients with ankylosing spondylitis to sustain extension-type fractures, typically near the cervicothoracic junction. These fractures can be minimally displaced, making them difficult to diagnose. In addition, the vertebral bodies are vascular and their canals are relatively enclosed, making them vulnerable to epidural bleeding. The MRI scan shows an epidural hematoma posteriorly compressing the cord. Bohlman HH: Acute fractures and dislocations of the cervical spine. J Bone Joint Surg Am 1979;61:1119-1142. Weinstein PR, Karpman RR, Gall EP, et al: Spinal cord injury, spine fracture and spinal stenosis in ankylosing spondylitis. J Neurosurg 1982;57:609-616.

Organisms may develop resistance to antibiotics by production of specific enzymes. S aureus develops methicillin resistance by production of penicillin-binding protein 2a (PBP2a). The strains of S aureus that have acquired the mecA gene for PBP2a are designated as methicillin-resistant S aureus (MRSA). The enzyme manifests resistance to covalent modification by beta-lactam antibiotics at the active-site serine residue in two ways. First, the microscopic rate constant for acylation (k2) is attenuated by three to four orders of magnitude over the corresponding determinations for penicillin-sensitive PBPs. Second, the enzyme shows elevated dissociation constants (Kd) for the noncovalent preacylation complexes with the antibiotics, the formation of which ultimately would lead to enzyme acylation. The two factors working in concert effectively prevent enzyme acylation by the antibiotics in vivo, giving rise to drug resistance. Catalase and oxidase are enzymes produced by some bacteria that confer virulence to the organism but do not make the organisms methicillin resistant. Glycocalix is the pericellular layer produced by bacteria that serves many functions including attachment to surfaces. Beta-lactam describes a class of antibiotics. Fuda C, Suvorov M, Vakulenko SB, et al: The basis for resistance to beta-lactam antibiotics by penicillin-binding protein 2a (PBP2a) of methicillin-resistant staphylococcus aureus. J Biol Chem 2004;279:40802-40806. Lim D, Strynadka NC: Structural basis for the beta lactam resistance of PBP2a from methicillin-resistant Staphylococcus aureus. Nat Struct Biol 2002;9:870-876.

Localized PVNS is a variant of the disease process where the synovial proliferation occurs in one area and usually presents as a discrete mass. It has been effectively treated with complete excision. This may be performed arthroscopically or with arthrotomy. Complete synovectomy and radiation therapy are unnecessary to eradicate the localized form of PVNS. Tyler WK, Vidal AF, Williams RJ, et al: Pigmented villonodular synovitis. J Am Acad Orthop Surg 2006;14:376-385.

The typical mechanism of injury is a fall and the patient grasps something to prevent the fall. This maneuver forces the arm into external rotation against resistance. Kreuz PC, Remiger A, Erggelet C, et al: Isolated and combined tears of the subscapularis tendon. Am J Sports Med 2005;33:1831-1837.

A concern in the multiply injured patient who has a pulmonary contusion is the potential for further pulmonary compromise because of embolization of marrow, blood clot, or fat during manipulation of the medullary canal. Recent evidence has shown that the presence of a lung injury is the most important determining factor in future deterioration. However, despite the lung injury and its potential consequences, this patient's femur fracture needs stabilization. Because damage control in the multiply injured patient requires a technique that can be performed rapidly and consistently, the treatment of choice is application of an external fixator. By placing two pins above and below the fracture and with longitudinal traction, the fracture is quickly realigned and stabilized. This allows the patient to be resuscitated and treated at a later date when definitive management of the fracture can be carried out. There is little difference between plate fixation and intramedullary nailing. Bosse MJ, MacKenzie EJ, Riemer BL, et al: Adult respiratory distress syndrome, pneumonia, and mortality following thoracic injury and a femoral fracture treated with either intramedullary nailing with reaming or with a plate: A comparative study. J Bone Joint Surg Am 1997;79:799-809. Scalea TM, Boswell SA, Scott JD, Mitchell KA, Kramer ME, Pollak AN: External fixation as a bridge to intramedullary nailing for patients with multiple injuries and with femur fractures: Damage control orthopedics. J Trauma 2000;48:613-623.

This is a classic C6 nerve injury, and it is most likely the result of a herniated nucleus pulposus at C5-6. The C5 nerve root controls the elbow flexors, shoulder abductors, and external rotators. The C7 nerve root controls the elbow extensors, wrist pronators, and the triceps reflex. Standaert CJ: The patient history and physical examination: Cervical, thoracic and lumbar, in Herkowitz HN, Garfin SR, Eismont FJ, et al (eds): Rothman-Simeone The Spine, ed 5. Philadelphia, PA, Saunders Elsevier, 2006, vol 1, pp 171-186.

When comparing closed reduction and pinning to ligament reconstruction, the reconstruction group had slightly better abduction and pinch strength. The volar oblique ligament usually tears off the first metacarpal in a subperiosteal fashion. In this young patient, motion-sparing procedures are preferred. Simonian PT, Trumble TE: Traumatic dislocation of the thumb carpometacarpal joint: Early ligamentous reconstruction versus closed reduction and pinning. J Hand Surg Am 1996;21;802-806.

While many factors play a role in the outcome of osteochondritis dissecans, ample evidence has shown that the prognosis is most influenced by the growth status of the plates. If the growth plates are open, the chance of a successful outcome is significantly greater than if they are closed. Federico DJ, Lynch JK, Jokl P: Osteochondritis dissecans of the knee: A historical review of etiology and treatment. Arthroscopy 1990;6:190-197.

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 patient has obvious signs of progressive myelopathy. Based on her significant physical examination findings, nonsurgical management will not significantly impact her outcome. Cervical decompression alone is contraindicated in patients with cervical kyphosis such as seen here. Anterior cervical fusion is the best option. Emery SE, Bohlman HH, Bolesta MJ, et al: Anterior cervical decompression and arthrodesis for the treatment of cervical spondylotic myelopathy: Two to seventeen-year follow-up. J Bone Joint Surg Am 1998;80:941-951. Ferguson RJ, Caplan LR: Cervical spondylotic myelopathy. Neurol Clin 1985;3:373-382.