100 Orthopedic MCQs: Adult Reconstruction, Trauma, Spine & Sports Medicine | Comprehensive ABOS Review

Based on the radiographic findings, the patient has melorheostosis, a rare, benign connective tissue disorder that is characterized by a cortical thickening of bone. It produces a "dripping candle wax" appearance with dense hyperostosis that flows along the cortex. Ectopic bone formation is a consideration but is associated with injuries or burns. Bone infarcts produce intraosseous sclerosis typically affecting the distal femur with the "smoke up chimney" appearance. Infection is always a consideration but typically does not have the linear osteitis seen in melorheostosis. Juxacortical chondroma is a benign cartilage growth that arises from the capsule and may involve the underlying cortical bone but rarely the medullary canal. Campbell CJ, Papademetriou T, Bonfiglio M: Melorheostosis: A report of the clinical, roentgenographic, and pathological findings in fourteen cases. J Bone Joint Surg Am 1968;50:1281-1304.

The histologic features of multiple myeloma are distinctive for this lesion. The plasma cells are round or oval and have an eccentric nucleus and prominent nucleolus. These characteristics and a clear area next to the eccentric nucleus representing the prominent Golgi center are pathognomonic for plasma cells. Lymphoma is in the differential diagnosis; the most frequent types that occur in bone are large cell or mixed small and large cell types. The histologic appearance of the specimen is not consistent with the other choices.

Nonsurgical management of a symptomatic accessory navicular should be attempted prior to surgery. Good relief is often obtained with a semi-rigid orthosis with a medial arch support. Myerson MS: Foot and Ankle Disorders. Philadelphia, PA, WB Saunders, 2000, p 655.

The proposed mechanisms by which steroids such as methylprednisolone are thought to prevent neurologic deterioration by limiting secondary insult, include: decreasing the area of ischemia in the cord, reducing TNF-alpha expression and NF-kB binding activity, decreasing free radical oxidation and thus stabilizing cell and lysosomal membranes, and checking the influx of calcium into the injured cells, thus reducing cord edema. Slucky AV: Pathomechanics of spinal cord injury. Spine: State Art Rev 1999;13:409-417.

While all of the answers may be appropriate, radiating pain from hip pathology must be excluded. At this age, a slipped capital femoral epiphysis is likely. Therefore, the hip must be examined. Kocher MS, Bishop JA, Weed B, et al: Delay in diagnosis of slipped capital femoral epiphysis. Pediatrics 2004;113:322-325.

Tension pneumothorax occurs when air trapped in the pleural space between the lung and chest wall achieves sufficient pressure to compress the lungs and shift the mediastinum. Urgent needle decompression of the pleural space air followed by definitive chest tube placement is the treatment of choice.

A flexion contracture of the elbow is commonly seen in hemiplegic patients following cerebrovascular accidents. Spasticity and myostatic contracture of the joint are both causative factors. In patients with a flexion deformity of less than 90 degrees, musculocutaneous neurectomy is recommended, followed by serial casting to treat any residual deformity. At 9 months after injury, physical therapy will not significantly improve motion. Nerve blocks may be used in the early stages of recovery to facilitate therapy and serial casting.

Synovial sarcomas have a number of features that differentiate them from other soft-tissue sarcomas. They often have small areas of calcifications within the lesion. They occur in a younger patient population than most soft-tissue sarcomas. A subset of patients with synovial sarcoma tend to be chemosensitive. They often contain the SYT-SSX translocation. Although they can occur intra-articular, this is rare, despite their name. Campanacci M: Bone and Soft Tissue Tumors, ed 2. New York, NY, Springer-Verlag, 1999, pp 1109-1126.

The radiograph shows the development of a rocker-bottom foot deformity. A rocker-bottom foot occurs in the treatment of clubfoot when casting is continued in the presence of a very tight gastrocnemius-soleus complex and an uncorrected hindfoot. While there are some preliminary reports on using Botox injection and continued casting for the equinus deformity, most authors recommend posterior or posterior medial release. Percutaneous tenotomy has been recently recommended with the resurgence of the Ponsetti technique. Lehman WB, Atar D: Complications in the management of talipes equinovarus, in Drennan JC (ed): The Child's Foot and Ankle. New York, NY, Raven Press, 1992, pp 135-136. Herring JA: Tachdjian's Pediatric Orthopedics, ed 4. Philadelphia, PA, WB Saunders, 2002, pp 927-935.

Tarsal coalitions commonly present in the preadolescent age group as a rigid, planovalgus foot. Small coalitions of the calcaneonavicular joint or the middle facet of the talocalcaneal joint can be excised with interposition of fat or muscle tissue. Isolated calcaneocuboid joint coalitions are very rare. This patient has an associated large talocalcaneal coalition; therefore, resection is contraindicated. Surgery is warranted after failure of nonsurgical management, and because of the involvement of two joints, the only viable option for the severely symptomatic foot is triple arthrodesis. Vincent KA: Tarsal coalition and painful flatfoot. J Am Acad Orthop Surg 1998;6:274-281.

A flexor digitorum longus transfer, while not as strong as the peroneals, improves the tendon balance and maintains hindfoot mobility. Subtalar fusion is a salvage procedure. Posterior tibial tendon transfer compromises inversion strength and arch height. Functional absence of the peroneals results in an imbalance that could lead to forefoot varus. Redfern D, Myerson M: The management of concomitant tears of the peroneus longus and brevis tendons. Foot Ankle Int 2004;25:695-707.

The arrow is pointing to the ulnar nerve within Guyon's canal. Guyon's canal is approximately 4 cm long, beginning at the proximal extent of the transverse carpal ligament and ending at the aponeurotic arch of the hypothenar muscles. Many structures comprise the boundaries of Guyon's canal. The floor, for example, consists of the transverse carpal ligament, the pisohamate and pisometacarpal ligaments, and the opponens digiti minimi. Within Guyon's canal, the ulnar nerve bifurcates into the superficial and deep branches, with the deep branch of the ulnar nerve persisting distal to the canal. The ulnar artery is immediately adjacent and radial to the ulnar nerve. The median nerve is visualized within the carpal tunnel. The radial artery is on the radial side of the wrist. The hook of the hamate is clearly seen in the figure, orienting the observer to the ulnar side of the wrist. Goss MS, Gelberman RH: The anatomy of the distal ulnar tunnel. Clin Orthop 1985;196:238-247.

The differential diagnosis includes septic hip and transient synovitis. Both disorders may present with a joint effusion. The increased teardrop distance and loss of range of motion implies that there is excess fluid in the joint. While the other tests can confirm this, only aspiration can characterize the fluid further, thereby indicating the etiology of the effusion. Provided there is enough fluid obtained at aspiration, the joint fluid should be sent for Gram stain, culture, cell count, glucose, and protein studies.

The patient has a medial subtalar dislocation. These injuries should be reduced as soon as possible to minimize risk to the skin. Most often, this can be done easily, and further radiographic evaluation then can be performed as necessary. On rare occasions, closed reduction is not possible because of fractures of the articular surface of the talus, navicular, interposed extensor digitorum brevis, or transverse fibers of the cruciate crural ligament. The posterior tibial tendon is the most common obstruction to closed reduction in lateral subtalar dislocations, which are less common than medial dislocations. The majority of both injuries can be managed by closed reduction and immobilization. Mulroy RD: The tibialis posterior tendon as an obstacle to reduction of a lateral anterior subtalar dislocation. J Bone Joint Surg Am 1953;37:859-863. Heckman JD: Fractures and dislocations of the foot, in Rockwood CA, Green DP, Bucholz RW (eds): Fractures in Adults. Philadelphia, PA, JB Lippincott, 1991, pp 2093-2100.

The meniscal cartilage, like articular cartilage, possesses viscoelastic properties. The extracellular matrix is a biphasic structure composed of a solid phase (collagen, proteoglycan) that acts as a fiber-reinforced porous-permeable composite, and a fluid phase that may be forced through the solid matrix by a hydraulic pressure gradient. Although these properties are shared with articular cartilage, the meniscus is more elastic and less permeable than articular cartilage. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 3-23.

The patient has a prefractured stage of congenital pseudarthrosis of the tibia and is at risk for fracture. The PTB orthosis may prevent or delay the fracture. Osteotomy is frequently complicated by nonunion. When established nonunion does not respond to intramedullary nailing and bone grafting, vascularized grafting may succeed. Amputation is a salvage procedure. Murray HH, Lovell WW: Congenital pseudarthrosis of the tibia: A long-term follow-up study. Clin Orthop 1982;166:14-20.

The incidence of undetected intraoperative surgical glove perforation has been demonstrated at approximately 8.5%, occurring most frequently on the index finger or left hand of the assistant surgeon. The frequency of glove perforation is higher in surgeries lasting longer than 3 hours. Al-Habdan I, Sadat-Ali M: Glove perforation in pediatric orthopaedic practice. J Pediatr Orthop 2003;23:791-793.

The obturator artery lies closest to the transverse acetabular ligament. The femoral artery is closest to the anterior rim of the acetabulum. No named vessel lies within the substance of the gluteus minimus or superior to the piriformis tendon. The medial femoral circumflex artery lies medial or deep to the quadratus femoris muscle. Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics: The Anatomic Approach, ed 1. Philadelphia, PA, JB Lippincott, 1984, Figure 7-53, p 346.

There is a spectrum of heat-related conditions. Heat cramps are the mildest form of heat illness. In heat exhaustion, cramps are associated with headache and weakness, and the skin is pale and moist. Treatment of heat cramps or heat exhaustion consists of removing and loosening excess clothing, applying ice to the axilla and groin, ingestion of cool water, and cool water sprays. This patient demonstrates symptoms of heat stroke which is a medical emergency. The core body temperature may be as high as 106 to 110 degrees F (41.1 to 43.3 degrees C). In heat stroke, the patient may no longer be sweating, and the skin may be hot and red. The athlete is usually confused, weak, nauseated, and may have seizure activity. Central nervous system depression has been called the most important marker of heat stroke, and progresses from confusion and bizarre behavior to collapse, delirium, and coma. Bizarre behavior is often the first sign of heat stroke. The patient needs to be treated and moved to a medical facility rapidly. During transfer, IV fluids and cooling of the athlete should be initiated. The best treatment of heat-related illness appears to be prevention with adequate hydration and monitoring of conditions (temperature and humidity), with cancellation of competition when conditions do not comply with guidelines. Griffin LY: Emergency preparedness: Things to consider before the game starts. J Bone Joint Surg Am 2005;87:894-902. Barker TA, Motz HA, Gersoff WK: Environmental factors in athletic performance, in Fu FH, Stone DA (eds): Sports Injuries, ed 2. Philadelphia, PA, Lippincott, 2001, pp 67-68.

With documented use of a competent interpreter, informed consent should not be an issue. In Hispanic families, the husband often makes the ultimate decision regarding proceeding with surgery; however, he would not be expected to withhold recommended treatment. Hispanics may have a higher risk of comorbidities, but you do not expect this to be a significant concern with this patient. Claustrophobia and some fear of the unfamiliar may make additional imaging studies more difficult to arrange, but not impossible. The real concern is that with no extended family and three small children, the postoperative demand on the patient could significantly jeopardize her ability to comply with weight-bearing restrictions and overall ambulatory demands. Discharge planning and appropriate help may be paramount for a good outcome.

The patient has classic radioulnar synostosis. Patients with this disorder frequently have duplication of sex chromosomes. Synostosis is often seen in females with 48-XXXX or 49-XXXXX in association with delayed development and mental retardation. In males, it can be associated with 48-XXXY or 49-XXXXY. Radioulnar synostosis is not usually associated with muscle disorders, congenital heart disease, or renal anomalies. MRI of the forearm can reveal other soft-tissue anomalies, but this information is not particularly helpful in planning therapy. Osteotomy is sometimes indicated to improve rotational position of the wrist, but this patient's rotation is quite functional for everyday tasks, and rotational osteotomy is not indicated.

Articular cartilage is a highly organized viscoelastic material, and load transmission depends on the specific composition of the extracellular matrix. Articular cartilage is devoid of neural, lymphatic, and blood vessel tissue. The extracellular matrix consists of water, proteoglycans, and collagen. Water comprises most of the wet weight (65% to 80%). Type II collagen comprises 95% of the collagen. The collagen and proteoglycan (keratan sulfate and chondroitin sulfate) matrix and its high water content are responsible for the mechanical properties of the articular cartilage. Buckwalter JA, Mankin HJ: Articular cartilage: Degeneration and osteoarthritis, repair, regeneration, and transplantation. Inst Course Lect 1998;47:487-504.

In a multivariate analysis, the strongest factor for the development of compartment syndrome is fracture of the proximal third of the forearm. However, compartment syndrome can still occur without a fracture. Therefore, these patients should be followed with a high level of suspicion for the development of compartment syndrome. Moed BR, Fakhouri AJ: Compartment syndrome after low-velocity gunshot wounds to the forearm. J Orthop Trauma 1991;5:134-137.

C-reactive protein declines rapidly as the clinical picture improves. Failure of the C-reactive protein to decline after 48 to 72 hours of treatment should indicate that treatment may need to be altered. Blood culture is positive only 50% of the time and will be negative soon after antibiotics are administered, even if treatment is not progressing satisfactorily. WBC count is highly variable and poorly correlated with treatment. The ESR rises rapidly but declines too slowly to guide treatment. Radiographic findings may not change but can take up to 2 weeks to show changes.

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.

The radiographs reveal small ossified masses around the femoral neck. The CT scans also show these masses and suggest that they are separate from the underlying cortex of the femoral neck, although they abut it. The MRI scan does not reveal significant marrow changes in the proximal femur apart from some mild reactive changes immediately adjacent to the nodules. These findings suggest a synovial or joint-based disorder as opposed to a primary bone tumor. The most likely diagnosis is synovial osteochondromatosis, which is consistent with the patient's mechanical symptoms. Crotty JM, Monu JU, Pope TL Jr: Synovial osteochondromatosis. Radiol Clin North Am 1996;34:327-342.

The lesion has the typical "blown out" lytic radiographic appearance that is most commonly found in thyroid or renal cell metastases. Given the history of hematuria and histology findings, the most likely diagnosis is metastatic renal cell carcinoma. This tumor is relatively resistant to chemotherapy. Radiation therapy is used as a postoperative adjuvant treatment with varying response rates. Surgery should be performed after preoperative embolization to decrease the risk of intraoperative bleeding, as no tourniquet can be used in this location. Patients with metastatic renal cell carcinomas may survive for years, resulting in a higher likelihood of local tumor progression with ineffective adjuvant therapy. Intramedullary fixation combined with curettage and cementation will provide the best chance of local control while maintaining the patient's native shoulder and elbow joints. A total humeral resection is an extensive surgery with considerable morbidity and is not indicated for this patient because less extensive surgery is likely to be effective. Harrington KD, Sim FH, Enis JE, Johnston JO, Diok HM, Gristina AG: Methylmethacrylate as an adjunct in internal fixation of pathological fractures: Experience with three hundred and seventy-five cases. J Bone Joint Surg Am 1976;58:1047-1054. Sun S, Lang EV: Bone metastases from renal cell carcinoma: Preoperative embolization. J Vasc Interv Radiol 1998;9:263-269.

The elbow dislocates by a three-dimensional movement of supination and valgus during flexion. Additional trauma during reduction is minimized by recreating the deformity and reducing the elbow in supination. The actual maneuver includes full supination (actually hypersupination) of the elbow in a valgus position. This is followed by pushing the olecranon distally in line with the long axis of the ulna while swinging the elbow into varus, and then relaxing the supination torque. Postreduction stability is enhanced in pronation, except when the soft-tissue disruption is extensive. O'Driscoll SW: Elbow dislocations, in Morrey BF (ed): The Elbow and Its Disorders, ed 2. Philadelphia, PA, WB Saunders, 1993, p 414.

The anterior cruciate ligament can be visualized on an axial MRI scan as a low-signal structure lying in the lateral aspect of the intercondylar notch. Visualization in multiple planes increases the accuracy of MRI to view the anterior cruciate ligament. The posterior cruciate ligament and ligament of Wrisberg are located on the medial wall of the notch. The ligamentum mucosum is anterior to the notch, and the popliteus tendon is posterior to the lateral femoral condyle. Resnick D, Kang HS (eds): Internal Derangements of Joints: Emphasis on MR Imaging. Philadelphia, PA, WB Saunders, 1997, pp 675-699.

Polyethylene wear has been identified as a major contributor to failure of total knee implants, of which thickness is an important factor. Several studies have shown that the minimum thickness should be 6 to 8 mm. While Wright and Bartel have shown that 6 to 8 mm has been recommended as the minimum thickness of an ultra-high molecular weight polyethylene insert for a tibial component in total knee arthroplasty, more recent work by Meding and associates and Worland and associates has verified the clinical efficacy of 4 mm of polyethylene in compression-molded anatomic graduated nonmodular components. Bartel DL, Bicknell VL, Wright TM: The effect of conformity, thickness, and material on stresses in ultra-high molecular weight components for total joint replacement. J Bone Joint Surg Am 1986;68:1041-1051. Wright TM, Bartel DL: The problem of surface damage in polyethylene total knee components. Clin Orthop 1991;273:261-263. Meding JB, Ritter MA, Faris PM: Total knee arthroplasty with 4.4 mm of tibial polyethylene: 10-year followup. Clin Orthop 2001;388:112-117.

Patients with brachial neuritis or Parsonage-Turner syndrome usually report the sudden onset of intense pain that subsides in 1 to 2 weeks, followed by weakness for a period of up to 1 year in the muscle that is supplied by the involved nerve. Calcific tendinitis usually can be diagnosed radiographically, with calcium deposits seen in the rotator cuff. Bursitis and rotator cuff tendinosis usually are seen after an increase in activity, and both decrease with rest and medication. Glenohumeral arthritis is a slow, progressive problem that results in a loss of range of motion. Misamore GW, Lehman DE: Parsonage-Turner syndrome (acute brachial neuritis). J Bone Joint Surg Am 1996;78:1405-1408.

Calcitonin is a hormone that binds to osteoclasts and acts to decrease both osteoclast activity and number. Calcitonin is most effective in reducing vertebral compression fractures in high-turnover osteoporosis. It is also effective in treating regional osteoporosis. Because of its analgesic effect, it is helpful in treating painful acute compression fractures associated with osteoporosis.

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 histologic appearance of the soft-tissue lesion reveals compact nests of cells with a clear cytoplasm surrounded by a delicate border of fibrocollagenous tissue. There can be scattered multinucleated giant cells. This is consistent with a clear cell sarcoma, also called malignant melanoma of soft parts. This tumor is usually positive for S-100 and HMB45 (a melanoma-associated antigen). These tumors are frequently found around the foot and ankle. Similar to epithelioid sarcoma, it is usually intimately bound to tendons or tendon sheaths. Often the tumors are present for many years. The classic histologic appearance of this lesion differentiates it from the other choices. Enzinger FM, Weiss SW: Soft Tissue Tumors, ed 3. St Louis, MO, Mosby, 1995, p 913.

The patient sustained an incomplete spinal cord injury known as central cord syndrome. Central cord syndrome characteristically has disproportionate involvement of the upper extremities with the lower extremities being relatively spared. It is most commonly seen after cervical injuries in elderly patients with spondylosis and spinal stenosis, often without fracture. Penrod and associates noted that 23 of 59 patients with central cord syndrome (ASIA C and D) ultimately walked. The poorest prognosis, however, was in ASIA C patients older than age 50, in which only 40% walked. Penrod LE, Hegde SK, Ditunno JF Jr: Age effect on prognosis for functional recovery in acute, traumatic central cord syndrome. Arch Phys Med Rehab 1990;71:963-968.

Despite the relatively few problems with porous-coated cementless stems, stress shielding and thigh pain do occur. One design feature of proximally coated stems that has been associated with a higher incidence of distal osteolysis is the presence of noncircumferential proximal porous coating. Tapered, modular with sleeve, and hydroxyapatite proximally porous-coated stems have all performed well. Fully porous-coated straight stems have a high survivorship rate as well. Pellicci PM, Tria AJ Jr, Garvin KL (eds): Orthopaedic Knowledge Update: Hip and Knee Reconstruction 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2000, pp 175-180. Koval KJ (ed): Orthopaedic Knowledge Update 7. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 417-451.

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 superior ulnar collateral, inferior ulnar collateral, and posterior ulnar recurrent arteries provide consistent vascular supply to the ulnar nerve. This supply is segmental in nature. No identifiable direct anastomosis is seen between the superior ulnar collateral and the posterior ulnar recurrent arteries. The inferior ulnar collateral artery provides the only direct vascularization to the nerve and is located in the region just proximal to the cubital tunnel. The segmental nature of the blood supply to the ulnar nerve underscores the importance of its preservation during transposition.

Bilateral joint replacement, chronic disease, and preoperative autologous donation all increase the risk of needing blood. Young patients and a high hemoglobin level (greater than 15 g/dL) are considered clinical parameters that decrease the risk for requiring allogenic blood. Bierbaum BE, Callaghan JJ, Galante JO, Rubash HE, Tooms RE, Welch RB: An analysis of blood management in patients having a total hip or knee arthroplasty. J Bone Joint Surg Am 1999;81:2-10.

The appropriate staging studies should consist of MRI and a radiograph of the primary lesion and CT of the chest. MRI is superior to CT for soft-tissue imaging. CT may be useful for evaluating the cortex of bone for invasion by tumor. Bone scans are not commonly used because soft-tissue sarcomas rarely metastasize to bone. CT of the abdomen and pelvis is not typically ordered except for possible liposarcoma. With liposarcoma, there may be a synchronous or metastatic retroperitoneal liposarcoma. Demetri GD, Pollock R, Baker L, et al: NCCN sarcoma practice guidelines: National Comprehensive Cancer Network. Oncology (Huntingt) 1998;12:183-218.

The initial stages of posterior tibial tendon insufficiency, where the deformity remains supple, may be treated with bracing or an orthotic for pain relief. The Arizona brace was introduced in 1988, and assists in pain relief and deformity correction by minimizing hindfoot valgus alignment, lateral calcaneal displacement, and medial ankle collapse. It is particularly helpful in those patients with advanced disease that cannot tolerate an ankle-foot orthosis. All other choices are incorrect because of the addition of lateral posting, which is not advantageous in valgus deformities. The addition of medial posting to any of the above choices would render them correct alternatives. A heel lift is applicable in Achilles tendon disorders, not posterior tibial tendon disorders. Chao W, Wapner KL, Lee TH, et al: Nonoperative management of posterior tibial tendon dysfunction. Foot Ankle Int 1996;17:736-741.

A significant bunionette deformity that fails to respond to conservative management is best addressed surgically, in this case with the bunion deformity. The radiograph reveals a prominent lateral condyle at the fifth metatarsal head without a significant increase in the intermetatarsal angle. Simple exostectomy is preferred with less risk of complications. Complete excision would risk transfer lesions to the medial metatarsals. Mann RA, Coughlin MJ: Adult hallux valgus, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, pp 415-435.

Results have been satisfactory in many patients; however, at long-term follow-up, examination of the affected shoulder often shows some decrease in range of motion compared with the contralateral side. Although range of motion often improves over time, it does not return to normal in 60% of patients. Pain improves but is often increased compared with the contralateral side. Griggs SM, Ahn A, Green A: Idiopathic adhesive capsulitis: A prospective functional outcome study of nonoperative treatment. J Bone Joint Surg Am 2000;82:1398-1407.

Fractures with a posterior wall fragment that makes up less than one third of the surface generally are stable. Conversely, fractures with a fragment making up more than 50% of the surface are unstable. Patients with an intermediate fracture fragment should undergo a fluoroscopic examination under sedation or anesthesia to determine if the fragment is truly stable. If so, the patient can be treated nonoperatively and safely mobilized. Tornetta P III: Non-operative management of acetabular fractures: The use of dynamic stress views. J Bone Joint Surg Br 1999;81:67-70.

Fatigue from repetitive loading of the stem with the distal aspect well-fixed resulted in stem failure. If the stem had loosened, it would not have broken. Crevice corrosion occurs at a taper interface; galvanic corrosion occurs at the junction of two metals of differing electrochemical potentials, not along a uniform portion of the implant. Simon SR (ed): Orthopaedic Basic Science. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 449-486.

Pelvic osteolysis in the presence of a well-fixed porous-coated socket is a recognized complication in total hip arthroplasty. The radiograph shows large lytic lesions superiorly adjacent to an acetabular screw and inferiorly extending into the ischium. It also reveals eccentricity of the femoral head with respect to the acetabular component, consistent with polyethylene wear. Koval KJ (ed): Orthopaedic Knowledge Update 7. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, p 440.

Flexor digitorum profundus rupture or "rugger jersey finger" often occurs in the ring finger after the player misses a tackle and catches the digit on the shirt of the opposing player. Surgical repair is required for zone I-type injuries. Moiemen NS, Elliot D: Primary flexor tendon repair in zone I. J Hand Surg Br 2000;25:78-84.

According to the MSTS staging system, soft-tissue sarcomas are staged according to the following factors: grade, site, and metastasis. Roman numerals are used to designate malignant tumors, and Arabic numerals are used for benign tumors. Low-grade malignant tumors are staged as I while intermediate- and high-grade tumors are staged as II. Site is defined as intracompartmental (A) or extracompartmental (B). Any metastasis is staged as III. This patient has a high-grade tumor (II), and the MRI scans show that it is confined to a single compartment; therefore, it is staged as IIA. There is no evidence of metastatic disease. Enneking WF, Spanier SS, Goodman MA: A system for the surgical staging of musculoskeletal sarcoma. Clin Orthop 1980;153:106-120. 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. Pisters PW, Leung DH, Woodruff J, Shi W, Brennan MF: Analysis of prognostic factors in 1,041 patients with localized soft tissue sarcomas of the extremities. J Clin Oncol 1996;14:1679-1689.

Ewing's sarcoma is the second most common primary tumor of bone in children. Depending on the site and extent of disease, chemotherapy, radiation therapy, and surgery are all treatment options. In this patient with extensive pelvic and metastatic disease, chemotherapy and radiation therapy offer the best oncologic control while preserving functional outcome. Gibbs CP Jr, Weber K, Scarborough MT: Malignant bone tumors. Instr Course Lect 2002;51:413-428. Thacker MM, Temple HT, Scully SP: Current treatment for Ewing's sarcoma. Expert Rev Anticancer Ther 2005;5:319-331.

In a review of the practical applications of antibiotic-loaded bone cement for the treatment of the infected total joint arthroplasties, Hanssen and Spangehl described commercially available antibiotic-loaded bone cement as low-dose antibiotic cements. These cements generally contained 0.5 g of either tobramycin or gentamicin per 40 g of cement. They are indicated for use in prophylaxis and not for treatment of infected total joint arthroplasties. High-dose antibiotic-loaded bone cements are described as those containing greater than 1.0 g of antibiotic per 40 g of cement. Effective elution levels have been documented with 3.6 g tobramycin and 1.0 g vancomycin per 40 g of bone cement. This was documented by Penner and associates. Furthermore, it was shown that the combination of the two antibiotics in the bone cement improved the elution of both antibiotics. Hanssen AD, Spangehl MJ: Practical applications of antibiotic-loaded bone cement for treatment of infected joint replacements. Clin Orthop 2004;427:79-85.

According to a recent study, cemented pegged glenoid components had fewer radiolucent lines initially and at 2-year follow-up when compared to a cemented keeled design. Curve-backed designs have also shown fewer radiolucent lines when compared to flat-backed designs. Oversizing the glenoid can lead to impaired rotator cuff function and decreased range of motion. An off-centered glenoid can lead to early loosening. Gartsman GM, Elkousy HA, Warnock KM, et al: Radiographic comparison of pegged and keeled glenoid components. J Shoulder Elbow Surg 2005;14:252-257. Szabo I, Buscayret F, Edwards TB, et al: Radiographic comparison of flat-back and convex-back glenoid components in total shoulder arthroplasty. J Shoulder Elbow Surg 2005;14:636-642.

The patient has symptoms and examination findings of acute brachial neuritis which is often a diagnosis of exclusion. The recent viral flu-like symptoms have shown a correlation with the development of this disorder. The acute, severe shoulder weakness excludes calcific tendinitis, impingement, and poliomyelitis. A normal cervical spine examination makes cervical disk disease unlikely. Turner JW, Parsonage MJ: Neuralgic amyotrophy (paralytic brachial neuritis). Lancet 1957;2:209-212.

Although fractures of the proximal tibial metaphysis in young children appear innocuous, development of a progressive valgus deformity is possible despite adequate and appropriate treatment. When treating a child with this injury, it is prudent to warn the parents that a valgus deformity of the tibia may develop. The most likely cause is asymmetric growth of the proximal tibial physis. Because spontaneous angular improvement can be expected in most patients, surgery to correct these deformities should be delayed at least 2 to 3 years and should be limited to patients who have symptoms. There are no studies that document the efficacy of bracing for this deformity. Tuten HR, Keeler KA, Gabos PG, et al: Posttraumatic tibia valga in children: A long-term follow-up note. J Bone Joint Surg Am 1999;81:799-810.

When a study yields a negative result between treatment groups, the next step is to perform a power analysis. The power, by definition, is the probability of rejecting the null hypothesis: in this example the null hypothesis would be that children treated with bisphosphonates would have fewer fractures than the untreated control population. The power analysis helps answer the question as to whether the null hypothesis should be rejected and the finding is real, or whether the sample size was too small or the effect of treatment too subtle to demonstrate a difference between the treatment and control groups. 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, p 7.

This is a very large near circumferential defect with posterior as well as anterior skin and muscle injury. Bone is exposed. The posterior muscles cannot be rotated since they are part of the zone of injury. The bone and other poorly vascularized areas of this wound would not accept a skin graft. The best chance for limb salvage will be to obtain soft-tissue coverage with a free tissue transfer using the latissimus dorsi. Mathes SJ, Nahai F: Vascular anatomy of muscle: Classification and applications, in Mathes SJ, Nahai F (eds): Clinical Application for Muscle and Musculocutaneous Flaps. St Louis, MO, CV Mosby, 1982, p 20.

Osteopenia, decreased bone mass without fracture risk as defined by the WHO criteria for diagnosis of osteoporosis, is when a woman's T-score is within -1 to -2.5 SD. The T-score represents a comparison to young normals or optimum peak density. The Z-score represents a comparison of BMD to age-matched normals. Measurements of bone mineral density (BMD) at various skeletal sites help in predicting fracture risk. Hip BMD best predicts fracture of the hip, as well as fractures at other sites.

Burks and Schaffer described an approach to the tibial insertion of the posterior cruciate ligament that uses the interval between the semimembranosus and the medial gastrocnemius. The medial gastrocnemius muscle is retracted laterally and protects the neurovascular bundle. This approach is used to repair an avulsion of the posterior cruciate ligament tibial attachment or for performing a posterior cruciate ligament tibial inlay reconstruction. Berg EE: Posterior cruciate ligament tibial inlay reconstruction. Arthroscopy 1995;8:95-99.

Synovial sarcoma should always be considered in the differential diagnosis of a foot mass; however, the histopathology shows a typical example of PVNS, with hemosiderin, giant cells, and synovium. Synovial chondromatosis would have metaplastic cartilage in the synovium. The radiograph shows subtle erosion of the lateral cortex of the cuboid, and the MRI scan shows a soft-tissue mass. Ghert MA, Scully SP, Harrelson JM: Pigmented villonodular synovitis of the foot and ankle: A review of six cases. Foot Ankle Int 1999;20:326-330. Jones BC, Sundaram M, Kransdorf MJ: Synovial sarcoma: MR imaging findings in 34 patients. Am J Roentgenol 1993;161:827-830. Sartoris DJ, Resnick D: Magnetic resonance imaging of pediatric foot and ankle disorders. J Foot Surg 1990;29:489-494.

Conus medullaris syndrome describes isolated loss of bowel and bladder function, usually at T12-L1 but can include T11-L2. In central cord syndrome, lower extremity motor function is better than upper extremity function. Cauda equina syndrome generally involves injury at the lumbar levels, with some degree of lower extremity motor loss. Posterior cord syndrome is characterized by preservation of motor function below the level of injury and position/vibratory sensory loss. In anterior cord syndrome, the lower extremity findings include loss of light touch, sharp/dull, and temperature sensations below the level of injury, as well as motor function. Apple DF Jr: Spinal cord injury rehabilitation, in Rothman RH, Simeone FA (eds): The Spine, ed 3. Philadelphia, PA, WB Saunders, 1992, Chapter 31.

In a recent analysis of 200 patients with tibial fractures, Bhandari and associates attempted to identify variables that were predictive of reoperation. The variables in the study were type of injury (fracture pattern), degree of open injury, mechanism of injury, cortical bone contact, postoperative complications, polytrauma, anti-inflammatory drug use, nail insertion technique (reamed versus nonreamed), smoking history, alcohol use, diabetes mellitus, peripheral vascular disease, age, disability status pre-injury, gender, surgeon, time to surgery, steroid use, phenytoin use, antibiotic use, anticoagulant use, and type of fixation used. Three variables were statistically significant predictors of reoperation to achieve bone union in the first postinjury year: transverse fracture pattern, open fracture, and cortical contact of 50% or less. Using these three variables, four reoperation risk groups were identified based on the number of these three variables present: 0, 1, 2, or 3. The risk for reoperation was 0%, 18%, 47%, and 94%, respectively. The authors concluded that these statistics can provide prognostic information to patients and help identify those high-risk patients where early intervention to achieve union is indicated. In addition, the data highlights the significance of achieving cortical contact at the time of initial fixation.

The central one third has been established as the watershed zone by angiographic studies, and has been borne out in clinical conditions involving the navicular, such as stress fractures and osteonecrosis. These findings account for the susceptibility to injury at this level. Nunley JA, Pfeffer GB, Sanders RW, et al (eds): Advanced Reconstruction: Foot and Ankle. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 239-242.

The amount of deformation resulting in response to an applied load depends on the stress distribution that the load creates in the structure and the stress versus strain behavior of the material that makes up the structure. Axial and bending loads create stress distributions that involve normal stresses and normal strains. Although all five responses are indeed material properties, only one, elastic modulus, relates normal stresses to normal strains. In fact, axial and bending stiffness are directly proportional to modulus, so that a nail made from stainless steel will have nearly twice the stiffness of a nail made from titanium alloy (because their respective elastic moduli differ by about a factor of two). Hayes WC, Bouxsein ML: Analysis of muscle and joint loads, in Mow VC, Hayes WC (eds): Basic Orthopaedic Biomechanics, ed 2. New York, NY, Lippincott-Raven, 1997, pp 74-82. 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 159-165.

The history is consistent with a stress fracture. Findings on the plain radiograph are marginal, but the MRI scan shows evidence of stress reaction in the medial neck of the femur (compression side). A lesion on the compression side is not normally at risk for displacement and usually can be managed nonsurgically. A bone scan would further identify the lesion but is not necessary. A skeletal survey and chest radiograph are used in staging a tumor. Radioisotope injection and guided biopsy are sometimes used for osteoid osteomas. Boden BP, Osbahr DC: High-risk stress fractures: Evaluation and treatment. J Am Acad Orthop Surg 2000;8:344-353.

Because the patient has chronic pain, a possible lateral recess stenosis of the C7 root, and no neurologic deficits, keyhole foraminotomy is the treatment of choice for decompressing the exiting nerve root and offering an early return to play, especially when using a muscle-splitting posterior approach. Henderson and associates reported excellent results with posterolateral foraminotomy in patients with radicular symptoms. Although anterior cervical diskectomy and fusion is equally effective in the long term, a period of 6 to 12 weeks is required to allow the anterior fusion to heal prior to a return to play. Chen and associates reported that keyhole foraminotomy maintains cervical motion segment dynamics better than compared to anterior limited diskectomy and foraminotomy or anterior diskectomy with fusion. Henderson, CM, Hennessy RG, Shuey HM Jr, Shackelford EG: Posterior-lateral foraminotomy as an exclusive operative technique for cervical radiculopathy: A review of 846 consecutively operated cases. Neurosurgery 1983;13:504-512. Dillin W, Booth R, Cuckler J, Balderston R, Simeone F, Rothman R: Cervical radiculopathy: A review. Spine 1986;11:988-991.

Because the left paracentral L5-S1 disk herniation is compressing the left S1 nerve root, the patient will have numbness along the lateral border and plantar surface of the foot. Numbness along the anterior thigh stopping at the knee is consistent with an L3 radiculopathy. Sensory changes at the dorsum of the foot and great toe normally signify an L5 distribution; the medial leg signifies an L4 distribution. Perianal numbness involves the S2-S5 nerve roots. Wisneski RJ, Garfin SR, Rothman RH, Lutz GE: Lumbar disk disease, in Herkowitz HN, Garfin SR, Balderston RA, Eismont FJ, Bell GR, Wiesel SW (eds): Rothman and Simeone The Spine, ed 4. Philadelphia, PA, WB Saunders, 1999, vol 1, pp 629-634.

The structure labeled "A" is a peroneus quartus, a supernumary muscle arising most commonly from the peroneus brevis. The presence of peroneus quartus is not uncommon, with an incidence of up to 21%, and is associated with lateral ankle pain and peroneal tendon symptoms, theoretically as a result of mass effect within the peroneal tendon sheath. Zammit J, Singh D: The peroneus quartus muscle: Anatomy and clinical relevance. J Bone Joint Surg Br 2003;85:1134-1137.

Factor V Leiden is a disease caused by an abnormality of factor V in which a single amino acid substitution of glutamine for arginine in the protein C cleavage region leads to decreased inactivation of factor V and thus a greater tendency to form clots. More than half of all individuals with Factor V Leiden will develop deep venous thrombosis in the presence of a single additional risk factor such as long bone fracture or total joint arthroplasty.

Bisphosphonates are indicated in the treatment of osteoporosis. They have been shown to reduce the incidence of vertebral and extremity fractures in patients with a T-score of less than -1.

Based on the available literature, the probability of development of glenoid dysplasia in the setting of a significant limitation of external rotation is close to 70%. Humeral dysplasia is also likely and can be managed surgically. Efforts are being made to identify procedures that will prevent glenoid dysplasia and help maintain function. Pearl ML, Edgerton BW: Glenoid deformity secondary to brachial plexus birth palsy. J Bone Joint Surg Am 1998;80:659-667. Waters PM, Smith GR, Jaramillo D: Glenohumeral deformity secondary to brachial plexus birth palsy. J Bone Joint Surg Am 1998;80:668-677.

Complications of elbow arthroscopy are usually minor or temporary. However, serious complications include nerve injuries. The deep radial nerve is the closest to any of the portals, resting as close as 1 mm away from the scope inserted in the anterolateral portal. The capsule can be displaced anteriorly by distending the joint with about 25 mL of saline solution, thus moving the deep radial nerve approximately 1 cm anteriorly and decreasing the risk of injuring it while establishing the anterolateral portal. Keeping plastic cannulae in the portals may help to diminish fluid extravasation and swelling, which is more of an impediment than a serious complication. The image intensifier has no documented role in guiding loose body removal. While the proximal anteromedial portal is probably the safest anterior portal to establish, it is actually easier to remove a large loose body from this portal while viewing it from an anterolateral position. There is less tendon and muscle bulk to pass through at the site of the proximal anteromedial portal than at the anterolateral portal, making it less likely for the loose body to get stuck in the soft tissues. Techniques have been developed to permit removal of loose bodies as large as 2 cm in diameter without breaking them up into pieces. If it is possible to remove a large loose body intact, doing so greatly simplifies and shortens the procedure. Lynch GJ, Meyers JF, Whipple TL, Caspari RB: Neurovascular anatomy and elbow arthroscopy: Inherent risks. Arthroscopy 1986;2:190-197.

The arrow identifies a transverse dark line that represents primary trabeculae of the physeal scar. A similar finding is seen in the proximal tibia. These lines may persist indefinitely. They do not represent ongoing growth, an abnormally open physeal plate, a stress fracture, or Looser's line (fatigue fracture in osteomalacia).

BMPs signal through the activation of a transmembrane serine/threonine kinase receptor that leads to the activation of intracellular signaling molecules called SMADs. There are currently eight known SMADs, and the activation of different SMADs within a cell leads to different cellular responses. The other mediators are not believed to be directly involved with BMP signaling. Lieberman J, Daluiski A, Einhorn TA: The role of growth factors in the repair of bone: Biology and clinical applications. J Bone Joint Surg Am 2002;84:1032-1044. Li J, Sandell LJ: Transcriptional regulation of cartilage-specific genes, in Rosier RN, Evans C (eds): Molecular Biology in Orthoapedics, Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 21-24.

The 5-year overall survival rate for deep, high-grade soft-tissue sarcomas is around 50%. The overall survival and disease-free survival rates chiefly depend on the tumor stage, but for all stages combined, most cancer treatment centers report a 5-year overall survival rate of around 70% and a disease-free survival rate of 65%. Fleming ID, et al: Manual for Staging of Cancer/American Joint Committee on Cancer, ed 5. Philadelphia, PA, Lippincott Raven, 1997, pp 149-156.

The rate of symptomatic degeneration at an adjacent segment warranting either decompression or arthrodesis was predicted to be 16.5% at 5 years and 36.1% at 10 years based on a Kaplan-Meier analysis.

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

Most closed simple dislocations are best managed with early range of motion. Posterior dislocation typically occurs through a posterolateral rotatory mechanism. When placed in pronation, the elbow has greater stability when the medial ligamentous structures are intact. In traumatic dislocations, MRI rarely provides additional information that will affect treatment. In elbows that remain unstable, primary repair is preferred over ligament reconstruction. Cast immobilization increases the risk of arthrofibrosis.

The patient has posttraumatic arthritis of the elbow; therefore, the treatment of choice is hardware removal and soft-tissue releases with splinting to avoid recurrence of contractures. The combination of pain and stiffness in an elbow that has sustained significant joint surface damage renders it unresponsive to simple soft-tissue releases and heterotopic bone excision. Joint distraction and interposition arthroplasty offer the possibility of maintaining motion and relieving pain as a later salvage procedure. Joint replacement should not be performed in young, active, strong individuals because the prosthesis will fail quickly and complications will develop. Synovectomy and radial head excision are not indicated. Morrey BF: Distraction arthroplasty: Clinical applications. Clin Orthop 1993;293:46-54.

The lesion is an osteochondroma. This is demonstrated by a pedunculated bone-forming lesion where the medullary space of the lesion communicates with the medullary space of the host bone. The cortex of the exostosis is in continuity with the cortex of the underlying bone. The MRI scan reveals that there is no significant cartilage cap, alleviating concern for malignant conversion to a chondrosarcoma. Osteoblastoma and osteosarcoma typically have mixed areas of bone formation and bone destruction. Malignant fibrous histiocytoma of bone is usually purely lytic. Vaccaro AR (ed): Orthopaedic Knowledge Update 8. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 197-215.

Tension forces in the healthy, as well as the reconstructed, anterior cruciate ligament were measured and found to be highest with the knee in full extension and decreased as the flexion increased. Markolf KL, Burchfield DM, Shapiro MM, et al: Biomechanical consequences of replacement of the anterior cruciate ligament with a patellar ligament allograft. Part II: Forces in the graft compared with forces in the intact ligament. J Bone Joint Surg Am 1996;78:1728-1734.

The child has an up-to-date tetanus; therefore, a booster is not recommended. Pseudomonas coverage is most likely not needed because the child was barefoot. It is too early to evaluate for abscess or osteomyelitis with MRI, and a formal debridement is rarely indicated without signs of an abscess or a retained foreign body. Radiographs with soft-tissue penetration should be obtained to check for a retained foreign body. Richardson EG (ed): Orthopaedic Knowledge Update: Foot and Ankle 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 199-205.

The popliteal artery lies just posterior to the posterior cruciate ligament tibial insertion, separated only by the posterior capsule of the knee. When performing a posterior cruciate ligament reconstruction, this artery is at risk for injury during creation of the tibial tunnel. Jackson DW, Proctor CS, Simon TM: Arthroscopic assisted PCL reconstruction: A technical note on potential neurovascular injury related to drill bit configuration. J Arthroscopy 1993;9:224-227.

Cutaneous sensation to the buttock is provided by the superior, middle, and inferior cluneal nerves. The superior cluneal nerves are the lateral branches of the dorsal rami of the upper three lumbar nerves and penetrate deep fascia just proximal to the iliac crest. They pass distally to the skin of the buttock and will be injured if the exposure extends more than 8 cm anterolateral to the posterior superior iliac spine. The lateral femoral cutaneous nerve can be injured in an anterior ilium bone graft. The superior gluteal nerve or even the sciatic nerve can be injured if bone is removed from the sciatic notch or dissection is not kept subperiosteal; however, the rate of injury is far less than cluneal nerve injury. The L5 and S1 nerve roots are anterior and can be injured if the inner table bone is harvested and the dissection is not kept subperiosteal or is too medial; however, the rate of injury still is far less than cluneal nerve injury. Hoppenfeld S, deBoer P: Surgical Exposures in Orthopaedics: The Anatomic Approach. Philadelphia, PA, JB Lippincott, 1984, pp 295-297. Hollinshead WH: Textbook of Anatomy, ed 3. Hagerstown, MD, Harper and Row, 1974, p 379. Last RJ: Anatomy: Regional and Applied, ed 6. London, England, Churchill Livingstone, 1978, p 23.

The patient has a bunionette with a large 4-5 intermetatarsal angle. This requires not only ostectomy of the lateral prominence but metatarsal osteotomy to decrease the intermetatarsal angle. Excising the head results in a flail joint and creates the possibility of a transfer lesion. Condylectomy can reduce plantar pressures but does not address the bunionette. The joint surface is well maintained, thus there are no indications for resection. Coughlin MJ: Treatment of bunionette deformity with longitudinal diaphyseal osteotomy with distal soft tissue repair. Foot Ankle 1991;11:195-203.

The development of a valgus deformity after this type of fracture is a well-known occurrence, and the patient's parents should be informed about this risk. In a patient who is age 4 years, the natural history is one of gradual correction by the development of a physiologic varus deformity at the distal tibial physis; therefore, no active intervention is needed at this time. Bracing has no effect on the deformity, and the child is too young for any procedure on the growth plate. Proximal tibial osteotomy is reserved until the patient nears skeletal maturity because of the risk of recurrence of the deformity. Lateral stapling can be done near skeletal maturity if the deformity persists, but this is unlikely to be necessary. Zionts LE, MacEwen GD: Spontaneous improvement of posttraumatic tibia valga. J Bone Joint Surg Am 1986;68:680-687.

Poor survivorship of cemented sockets in young patients has lead to the development of a variety of cementless designs. Of these, smooth metal-backed sockets have not performed as well as porous-coated designs. Threaded metal-backed sockets showed a 6% to 25% revision rate secondary to aseptic loosening at a mean follow-up of 4.5 to 6 years. Despite some early failed designs, cementless porous-coated metal-backed sockets have shown the best survivorship in long-term studies. Smith SE, Harris WH: Total hip arthroplasty performed with insertion of the femoral component with cement and the acetabular component without cement: Ten to thirteen-year study. J Bone Joint Surg Am 1997;79:1827-1833.

Rheumatoid arthritis is sometimes associated with radiographic evidence of instability of the cervical spine. In a study by Grauer and associates, radiographs of the cervical spine of patients with rheumatoid arthritis who had undergone total joint arthroplasty over a 5-year period were retrospectively reviewed. Nearly one half of the patients had radiographic evidence of cervical instability on the basis of traditional measurements. While radiographic evidence of cervical instability was not infrequent in this population of patients who underwent total joint arthroplasty for rheumatoid arthritis, radiographic predictors of paralysis were much less common. MRI prior to surgery may also be a consideration if the radiographic appearance of the rotator cuff alters the consideration of surgical treatment. In a series of patients undergoing prosthetic arthroplasty for a variety of shoulder disorders, the presence of a rotator cuff tear has been shown to be associated with a less favorable outcome. Most often, the presence of a rotator cuff tear was associated with a diagnosis of rheumatoid or other inflammatory arthritis and the tears were large and generally irreparable. Some case series demonstrated a higher prevalence of loosening of the glenoid component in patients with a large rotator cuff tear associated with superior migration of the humeral head. However, obtaining an MRI scan of the shoulder is not considered the best response since failure to determine cervical instability may result in anesthetic death. Whereas MRI may be helpful in planning reconstruction, it would be a less important priority. Grauer JN, Tingstad EM, Rand N, et al: Predictors of paralysis in the rheumatoid cervical spine in patients undergoing total joint arthroplasty. J Bone Joint Surg Am 2004;86:1420-1424.

The radioscaphocapitate ligament is the prime stabilizer between the radius and capitate, preventing ulnar translocation of the carpus. Its oblique orientation prevents the carpus from drifting ulnarly. This stout ligament must be protected when excising the scaphoid. Stern PJ, Agabegi SS, Kiefhaber TR, et al: Proximal row carpectomy. J Bone Joint Surg Am 2005;87:166-174.

Tillaux and triplane fractures occur in adolescents as the result of an external rotation injury of the ankle. As seen on the CT scan, the growth plate starts to close during adolescence; therefore, growth arrest resulting in limb-length discrepancy or angulation is less of a concern in this age group than achieving joint congruity. The joint should be surgically reduced if displacement is greater than 2 mm to minimize the chances of late arthrosis. Kay RM, Matthys GA: Pediatric ankle fractures: Evaluation and treatment. J Am Acad Orthop Surg 2001;9:268-278. Kling TF Jr: Operative treatment of ankle fractures in children. Orthop Clin North Am 1990;21:381-392.

Anterolateral bowing of the tibia is normally associated with congenital pseudarthrosis of the tibia. This, in turn, is associated with neurofibromatosis. Posterior bowing is more benign and usually corrects spontaneously. However, anterolateral bowing also corrects spontaneously, and the limb-length discrepancy may be the only remaining sequela when associated with duplication of the great toe. Lisch nodules and axillary freckling are pathognomonic findings in neurofibromatosis but would not be expected in this patient because this type of tibial deformity is not associated with neurofibromatosis.

Several studies have shown that ultra-high molecular weight polyethylene liners used in total hip arthroplasties wear at a rate of 0.1 to 0.2 mm/yr. The orthopaedic surgeon performing total hip arthroplasties should be aware of the average wear rate so that potential problems can be identified when following patients postoperatively. Callaghan JJ, Albright JC, Goetz DD, Olejniczak JP, Johnston RC: Charnley total hip arthroplasty with cement: Minimum twenty-five year follow-up. J Bone Joint Surg Am 2000;82:487-497.

The diagnosis of neurofibromatosis may be based on the presence of at least six cafe-au-lait spots larger than 5 mm in diameter and the osseous lesion shown in Figure 18c. Neurofibromatosis occurs in 50% of patients who have an anterolateral bowing deformity of the tibia, and this bowing may be the first clinical manifestation of this disorder. The patient has anterolateral bowing of the tibia and fibula that warrants concern for a possible fracture and pseudarthrosis; therefore, the limb should be protected in a total contact orthosis to prevent fracture. In contradistinction to posteromedial bowing of the tibia and fibula, spontaneous remodeling of an anterolateral bowing deformity is not expected. Intramedullary nailing or the use of a vascularized fibula is reserved for the treatment of a congenital pseudarthrosis of the tibia. Crawford AH Jr, Bagamery N: Osseous manifestations of neurofibromatosis in childhood. J Pediatr Orthop 1986;6:72-88.

Multiple hereditary exostosis and enchondroma commonly present as multiple lesions in the hand. Multiple hereditary exostosis consists of cartilage capped bony exostoses arising from the metaphyseal end of rapidly growing bones. Osteosarcoma and chondrosarcoma rarely appear as multiple lesions. Fracture callus can exhibit enchondral ossification that is usually circumferential, but the radiographic findings are not consistent with fracture. Porter DE, Emerton ME, Villanueva-Lopez F, Simpson AH: Clinical and radiographic analysis of osteochondromas and growth disturbance in hereditary multiple exostoses. J Pediatr Orthop 2000;20:246-250.

The stretched peroneus brevis muscle and tendon follow anterior to the fibula and are most likely incarcerated with reduction. The anterior talofibular ligament is too small to prevent reduction of the ankle joint itself. The extensor digitorum brevis originates from the talus; therefore, it is not involved in the tibiotalar joint. The posterior tibial tendon lies medially and would not be interposed into the ankle joint. Similarly, the anterior tibialis tendon also would not be involved. Pehlivan O, Akmaz I, Solakoglu C, et al: Medial peritalar dislocation. Arch Orthop Trauma Surg 2002;122:541-543.

Arthroscopic capsular release is an effective means of treating stiffness that is the result of capsular contractures, such as in the case of a tight Bankart repair. Open release allows lengthening of a surgically shortened subscapularis, such as after a tight Putti-Platt repair. Additional physical therapy is unlikely to be effective because 8 months of treatment has failed to result in improvement. Accepting this degree of asymptomatic limited motion is not advisable because of the functional limitations for the patient and the increased risk of postoperative degenerative arthritis. Warner JJ, Allen AA, Marks PH, Wong P: Arthroscopic release of postoperative capsular contracture of the shoulder. J Bone Joint Surg Am 1997;79:1151-1158.

Titanium implants are commonly used in spinal surgery, especially when MRI may be needed after implantation. Titanium implants have a lower modulus of elasticity when compared with cobalt-chromium and stainless steel implants. This is felt to allow less stress shielding for these types of implants. The other properties do not apply to titanium implants.

Based on findings of a sudden increase in pain with associated swelling, the most likely diagnosis is a stress fracture. The initial radiographic findings usually will be negative. Morton's neuroma and transfer metatarsalgia are not associated with swelling. Metatarsophalangeal synovitis usually involves the second metatarsophalangeal joint. Freiberg's infraction is seen clearly on a radiograph.

Fractures of the distal one third of the clavicle have a high incidence of delayed union (45% to 67%) and nonunion (22% to 33%) with nonsurgical management. Surgical stabilization with tension band techniques or a combination of plate and screw techniques is indicated, especially in young, active patients. In this patient, significant displacement of the fracture implies injury to the coracoclavicular ligaments with a higher risk of delayed union or nonunion. Various surgical treatments have been recommended, but the use of smooth wires is not indicated because of the potential for hardware migration. Jupiter JB, Ring D: Fractures of the clavicle, in Ianotti JP, Williams GR (eds): Disorders of the Shoulder: Diagnosis and Management, ed 1. Philadelphia, PA, Lippincott, Williams and Wilkins, 1999, pp 709-736.

The obturator vessels and nerve pass along the lateral pelvic wall along the true pelvic brim (nerve lies anterior to the vessels and lies on the obturator internus muscle) and descend into the obturator groove at the upper portion of the obturator foramen. Higuchi T: Normal anatomy and magnetic resonance appearance of the pelvis, in Takahashi HE, Morita T, Hotta T, et al (eds): Operative Treatment of Pelvic Tumors. Tokyo, Japan, Springer-Verlag, 2003, pp 4-21.

Triplane fractures generally occur in children who are near skeletal maturity. The injury is generally caused by a supination external rotation mechanism. The number of fracture fragments present (two or three) depends on what part of the physes is closed at the time of injury. Articular congruity is the major concern in the management of these injuries since the patient has almost reached skeletal maturity. The goal is to restore articular congruity to minimize the development of posttraumatic arthritis. Vaccaro A (ed): Orthopaedic Knowledge Update 8. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 757-765. Kling TF Jr, Bright RW, Hensinger RN: Distal tibial physeal fractures in children that may require open reduction. J Bone Joint Surg Am 1984;66:647-657.

The patient has iliac apophysitis. The radiographic findings are easily overlooked but usually reveal slight asymmetric widening of the iliac crest apophysis. The apophysis is the most vulnerable structure, as it is three to five times weaker than the tendon. This is not an epiphyseal site, and injury to the muscle or the tendinous insertion to bone (enthesis) is unlikely. Clancy WG Jr, Foltz AS: Iliac apophysitis and stress fractures in adolescent runners. Am J Sports Med 1976;4:214-218. Waters PM, Millis MB: Hip and pelvic injuries in the young athlete, in Stanitski CL, DeLee JC, Drez D Jr (eds): Pediatric and Adolescent Sports Medicine. Philadelphia, PA, WB Saunders, 1994, pp 279-293. Lombardo SJ, Retting AC, Kerlan RK: Radiographic abnormalities of the iliac apophysis in adolescent athletes. J Bone Joint Surg Am 1983;65:444-446.