Pediatric Orthopedic MCQs (Set 4): Hip, Spine & Trauma | ABOS OITE 2004 Review

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.

Spinal muscular atrophy is caused by an abnormal survival motor neuron gene that prevents apoptosis of the motor nerves. Spinal fusion results in better sitting balance, stabilized or improved pulmonary function, and high parental satisfaction, but it may result in at least temporary loss of upper extremity function. Bentley G, Haddad F, Bull TM, Seingry D: The treatment of scoliosis in muscular dystrophy using modified Luque and Harrington-Luque instrumentation. J Bone Joint Surg Br 2001;83:22-28. Furumasu J, Swank SM, Brown JC, Gilgoff I, Warath S, Zeller J: Functional activities in spinal muscular atrophy patients after spinal fusion. Spine 1989;14:771-775.

The patient has a classic Erb's palsy with weakness of the muscles innervated by the fifth and sixth cervical roots. Horner syndrome, a poor prognostic indicator for recovery, is absent in this infant. All infants with brachial plexus birth palsies initially should be monitored for spontaneous recovery during the first 3 to 6 months of life. During this period of observation, glenohumeral motion, especially external rotation, should be maintained. Many infants will begin to show recovery within the first 6 to 8 weeks after birth and continue on to normal function. The timing of microsurgery is controversial. A recent study found that the outcome of microsurgical repair in patients who had no recovery of biceps function within 3 months after birth was similar compared to those who had recovery of biceps function between 3 and 6 months and no microsurgical repair. The author concluded that microsurgical repair was effective in improving function in those infants who had no evidence of recovery of biceps function within the first 6 months of life. Waters PM: Comparison of the natural history, the outcome of microsurgical repair, and the outcome of operative reconstruction in brachial plexus birth palsy. J Bone Joint Surg Am 1999;81:649-659.

Anterior failure of formation results in a progressive kyphosis that may lead to cord compression and progressive neurologic deficit. Anterior failure of segmentation can also produce progressive kyphosis but usually is not severe enough to cause cord compression. Posterior failure of formation is seen in conditions such as myelomeningocele in which the neurologic deficit is generally stable. Lateral abnormalities and posterior failure of segmentation are rarely associated with progressive neurologic deficit. McMaster MJ, Singh H: Natural history of congenital kyphosis and kyphoscoliosis: A study of one hundred and twelve patients. J Bone Joint Surg Am 1999;81:1367-1383.

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

The iliacus muscle is a frequent site of hemorrhage in patients with severe or moderate hemophilia. In patients with moderate hemophilia, hemorrhage into the iliacus muscle often follows play or sporting events that include forceful contraction of the hip flexor muscles. An expanding iliacus hematoma compresses the adjacent femoral nerve, with one study reporting 60% complete femoral nerve palsy in hemophiliacs with an iliacus or iliopsoas hemorrhage. Femoral nerve compression typically includes paresthesias in the distribution of the terminal saphenous nerve branch. Hip joint hemarthrosis may occur, but this condition is not as frequent in hemophiliacs as muscle hemorrhage into the iliacus muscle. More importantly, a hip joint hemarthrosis is not associated with significant compression of the femoral nerve. Avulsion fractures of the anterior superior iliac spine typically occur during adolescence and are not associated with saphenous nerve paresthesias. Slipped capital femoral epiphysis does not have an increased association with hemophilia and usually occurs during the adolescent years. Greene WB: Diseases related to the hematopoietic system, in Morrissy RT, Weinstein SL (eds): Lovell and Winter's Pediatric Orthopaedics, ed 5. Philadelphia, PA, Lippincott Williams and Wilkins, 2001, pp 379-426.

Brachymetatarsia is a congenital hypoplasia of one or more metatarsals. Shortening of the fourth metatarsal is the most common form of brachymetatarsia and is often bilateral. Taping and manipulative reduction attempts are ineffective, and extensor tenotomy and capsulotomy are not likely to sufficiently correct the deformity. Fusion or metatarsal lengthening result in complications and generally are not indicated. Shoe modifications, such as extra-depth or extra-wide shoes, generally will improve symptoms. If pressure and trauma persist in the older child, metatarsal lengthening or amputation may be indicated. Stevens PM: Toe deformities, in Drennan JC (ed): The Child's Foot and Ankle. New York, NY, Raven Press, 1992, p 195.

Because the radiographs reveal poor regenerate bone, especially anteriorly and laterally, the first step in management is to slow the distraction rate. If this does not solve the problem, temporary reversal of the distraction, or "accordionization," can be used to induce a greater healing response. Maintaining the same distraction rate will further impair regenerate formation and delay healing. Bone grafting should be reserved as an option if decreasing the distraction rate or alternating a week of compression with a week of distraction fails to improve the callus formation. Repeat corticotomy is performed in patients with premature consolidation. Raney EM: Limb-length discrepancy, in Fitzgerald RH, Kaufer H, Malkani AL (eds): Orthopaedics. St Louis, MO, Mosby, 2002, pp 1519-1526.

The patient has juvenile scoliosis. MRI has shown an association between juvenile scoliosis and intraspinal abnormalities, most often syringomyelia and Arnold-Chiari malformations. All juvenile curves greater than 20 degrees should be evaluated with MRI despite the absence of neurologic findings. Weinstein SL (ed): The Pediatric Spine: Principles and Practice, ed 1. New York, NY, Raven Press, 1994, pp 685-705 Nohria V, Oakes WJ: Chiari I malformation: A review of 43 patients. Pediatr Neurosurg 1990-91;16:222-227.

The first priority is to gain control of the airway with intubation. Following intubation, management should consist of ventilation and placement of a chest tube if needed, vascular access and circulatory stabilization, radiographs of the cervical spine and chest, and CT of the brain. American College of Surgeons Committee on Trauma. Advanced Trauma Life Support Course. Instructor's Manual. Chicago, IL, American College of Surgeons, 1984.

Plexiform neurofibromas are lesions found in patients with NF1. Clinical reports show the prevalence of plexiform neurofibroma to be 20% to 30% but increases to 40% when imaging studies are routinely obtained. The lesions are characterized by diffuse hypertrophy of the involved nerves but with preservation of the nerves' fascicular organization. The lesions may involve the dermis or may arise in the deeper structures. Palpation of a dermal lesion provokes an image of a "bag of worms." Plexiform neurofibromas may cause disfigurement and hyperpigmentation of the overlying skin. The lesions also can cause diffuse hypertrophy of the soft tissue and bone, with resultant changes ranging from a relatively minor limb-length discrepancy to gigantism of the entire extremity. Dural ectasia is frequently found in patients with NF1. Therefore, MRI should be obtained prior to planning spinal procedures in these patients; however, dural ectasia is not the cause of limb overgrowth. Lisch nodules are benign hamartomas of the iris. The lesions are uncommon during early childhood but are found in all adults with NF1. Juvenile xanthogranuloma has a low occurrence rate in patients with NF1; its presence is associated with juvenile chronic myeloid leukemia. Malignant peripheral nerve sheath tumors, formally called neurofibrosarcoma, result from malignant degeneration of a plexiform neurofibroma. This condition occurs in up to 4% of patients with NF1. Localized pain, an enlarging mass, or progressive neurologic symptoms suggest a malignant peripheral nerve sheath tumor in a patient with NF1. However, progressive neurologic symptoms also may occur with benign growth of a plexiform neurofibroma. Alman BA, Goldberg MJ: Syndromes of orthopaedic importance, in Morrissy RT, Weinstein SL (eds): Lovell and Winter's Pediatric Orthopaedics, ed 5. Philadelphia, PA, Lippincott Williams and Wilkins, 2001, pp 287-338.

Neural monitoring during scoliosis surgery was initially developed to avoid the devastating effects of spinal cord injury, particularly paraplegia. Monitoring in some form has become standard for this type of surgery. Somatosensory-evoked potentials in the lower extremities will detect many but not all neurologic difficulties with the spinal cord. Anterior spinal cord vascular disruption also can be detected by monitoring motor potentials. Electromyography following stimulation of lumbar pedicle screws can prevent nerve root injury that is the result of misplacement of the screws. This is best documented in the lumbar spine and has not been routinely used in the thoracic spine. The most common neural deficits following spinal surgery, however, are in the upper extremities because of the positioning of the patient in the prone position for long periods. In Schwartz and associates series of 500 patients, impending upper extremity neural injury was detected by somatosensory-evoked potentials in 18 (3.6%) patients. In contrast, lower extremity deficits were detected by combined motor- and sensory-evoked potentials in only 2 (0.4%) out of 500 patients in Padberg and associates series. Neural compression in the upper extremity can be easily detected by somatosensory-evoked potentials, and injury can be prevented by repositioning the patient. Padberg AM, Wilson-Holden TJ, Lenke LG, Bridwell KH: Somatosensory- and motor-evoked potential monitoring without wake-up test during idiopathic scoliosis surgery: An accepted standard of care. Spine 1998;23:1392-1400.

The patient has an obvious slipped capital femoral epiphysis of the left hip for which the recommended treatment is percutaneus pinning in situ. Development of a contralateral slip is less likely at this age; therefore, observation of the right hip is indicated because there is no general agreement regarding prophylactic fixation. Typically, there is no role for spica casting. Physical therapy is not indicated as a primary treatment, and reduction is contraindicated, as it has been associated with osteonecrosis. Loder RT, Aronsson DD, Greenfield ML: The epidemiology of bilateral slipped capital femoral epiphysis: A study of children in Michigan. J Bone Joint Surg Am 1993;75:1141-1147. Aronsson DD, Karol LA: Stable slipped capital femoral epiphysis: Evaluation and management. J Am Acad Orthop Surg 1996;4:173-181. Hurley JM, Betz RR, Loder RT, Davidson RS, Alburger PD, Steel HH: Slipped capital femoral epiphysis: The prevalence of late contralateral slip. J Bone Joint Surg Am 1996;78:226-230.

The posttraumatic lumbar kyphotic deformity will not remodel and is likely to worsen with time because the central line of gravity lies anterior to the deformity and the ligamentous disruption will not heal. The worsening deformity also puts the patient at some risk for future neurologic damage. Ebraheim NA, Savolain ER, Southworth SR, et al: Pediatric lumbar seat belt injuries. Orthopedics 1991;14:1010-1013.

In this age group of patients with arthrogryposis, open reduction through a medial approach is generally recommended. Open reduction through an anterior approach is reserved for patients in which a medial approach has failed or for older patients who require simultaneous femoral shortening and/or pelvic osteotomy. Closed treatment of unilateral hip dislocation in association with arthrogryposis is rarely successful. In bilateral hip dislocation associated with arthrogrypsis, the consensus is that the hips are best left unreduced because of the difficulty in obtaining excellent clinical and radiographic results bilaterally. Staheli LT, Chew DE, Elliot JS, Mosca VS: Management of hip dislocations in children with arthrogryposis. J Pediatr Orthop 1987;7:681-685. Szoke G, Staheli LT, Jaffe K, Hall JG: Medial-approach open reduction of hip dislocation in amyoplasia-type arthrogryposis. J Pediatr Orthop 1996;16:127-130.

The clinical presentation and MRI findings are consistent with an acute infection of the SI joint. Bed rest and nonsteroidal anti-inflammatory drugs alone are insufficient to treat the problem. Staphylococcus aureus is the causative organism in most of these infections; therefore, unless there is an unusual factor in the history such as IV drug use, immune system compromise, or unusual travel, SI joint aspiration is unnecessary. It is often difficult to enter the SI joint, even under radiographic guidance. Management should consist of hospital admission and IV antibiotics. Blood cultures may be positive and should be obtained prior to starting antibiotics. Surgical fusion of the SI joint is not indicated. Morrissey RT: Bone and Joint Sepsis in Pediatric Orthopaedics. Philadelphia, PA, JB Lippincott, 1990. Beaupre A, Carroll N: The three syndromes of iliac osteomyelitis in children. J Bone Joint Surg Am 1979;61:1087-1092.

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

The radiographs show the characteristic features of osteopetrosis. The condition results from defective resorption of immature bone by osteoclasts. There are three distinct clinical forms: (1) infantile-malignant, which is autosomal recessive and fatal in the first few years of life if untreated; (2) intermediate autosomal recessive; and (3) autosomal dominant. These conditions do not follow a malignant course, and patients have normal life expectancy with orthopaedic problems and anemia. In the malignant form, the clinical features include frequent fractures, macrocephaly, progressive deafness and blindness, hepatosplenomegaly, and severe anemia beginning in early infancy or in utero. Deafness and blindness are generally thought to represent effects of pressure on nerves and usually occur later in life. The anemia is caused by encroachment of bone on marrow, resulting in obliteration, and the hepatosplenomegaly is caused by compensatory extramedullary hematopoiesis. Dental caries and abscesses, as well as osteomyelitis of the mandible, are also seen. Most patients have normal intelligence. Treatment of the malignant form includes high dose 1,25 dihydroxy vitamin D with a low-calcium diet to stimulate bone resorption, not because there are vitamin deficiencies. Bone marrow transplant has also been successful. Herring JA: Tachdjian's Pediatric Orthopedics, ed 4. Philadelphia, PA, WB Saunders, 2002, p 1550. Zaleske DJ: Metabolic and endocrine abnormalities, in Morrissy RT, Weinstein SL (eds): Lovell and Winter's Pediatric Orthopaedics, ed 5. Philadelphia, PA, Lippincott Williams and Wilkins, 2001, pp 212-214.

Vascular invasion, histologically similar to granulation tissue, has been noted between the columns in the zone of hypertrophy, leading to the theory of microtrauma as an etiology. SCFE is also associated with conditions that increase the height of the zone of hypertrophy, including the adolescent growth spurt and endocrinopathies. The perichondral ring has been shown to decrease in thickness with age. Normal undulations in the growth plate also decrease during this time, possibly further destabilizing the physis. Abnormal accumulations of proteoglycan have been reported. Chung SM, Batterman SC, Brighton CT: Shear strength of the human femoral capital epiphyseal plate. J Bone Joint Surg Am 1976;58:94-103.

The patient has a projected limb-length discrepancy of 7 cm. This includes the 4 cm she already has, plus 3 cm expected growth of the uninvolved distal femur during the 3 years of growth she has remaining. She also has moderate limb deformity. Femoral lengthening is considered the treatment of choice because it can address both the limb-length discrepancy and the deformity. Epiphyseodesis will not result in limb-length equality at maturity, with only approximately 1.8 cm of equalization expected from this procedure. Use of closed femoral shortening of 7 cm runs the risk of weakening the quadriceps on the normal side and will leave the patient with a remaining residual valgus deformity. Tibial lengthening will leave the knees at different levels. A shoe lift can be prescribed as a temporary measure but is not a good long-term solution. Westh RN, Menelaus MB: A simple calculation for the timing of epiphyseal arrest: A further report. J Bone Joint Surg Br 1981;63:117-119. Sasso RC, Urquhart BA, Cain TE: Closed femoral shortening. J Pediatr Orthop 1993;13:51-56.

The patient has the typical history and presentation of transient synovitis of the hip, a condition that is more common in children age 2 to 5 years but which may affect children up to 12 years. The discomfort typically is noted on awakening, and the child will refuse to walk. Later in the day, the pain commonly improves and the child can walk but will have a limp. Mild to moderate restriction of hip abduction is the most sensitive range-of-motion restriction. The extent of the evaluation for transient synovitis depends on the intensity and duration of symptoms. Because she has been afebrile for the past 24 hours, observation is the management of choice. In the differential diagnosis of suspected transient synovitis, septic arthritis of the hip is the primary disorder to exclude. Osteomyelitis of the proximal femur also should be considered. In most patients, clinical examination will differentiate of these disorders to a reasonable certainty. Plain radiographs are normal in the early stage of an infectious process. Ultrasonography shows increased fluid in the hip joint in both transient synovitis and septic arthritis. MRI can differentiate the two conditions; however, this test would require general anesthesia and is not required in most patients in this age group. If a child with transient synovitis has a concurrent infectious process such as an upper respiratory tract infection or otitis media, the temperature will most likely be elevated. In this situation, a full evaluation for an infectious process and initiation of IV antibiotics should be considered. This would include radiographs, CBC count, erythrocyte sedimentation rate, blood cultures, aspiration of the hip joint, and IV antibiotics. Del Beccaro MA, Champoux AN, Bockers T, Mendelman PM: Septic arthritis versus transient synovitis of the hip: The value of screening laboratory tests. Annals Emerg Med 1992;21:1418-1422.

In a patient with hemophilia, factor replacement followed by assessment of compartment pressures is essential. If the patient has inhibitors, the problem is more difficult. Porcine factor has been helpful in patients with inhibitory antibodies. Recent evidence points to using activated factor VII and bypassing the intrinsic pathway. Desmopressin is an adjunct to therapy but is not as effective as factor VII. Dumontier C, Sautet A, Man M, Bennani M, Apoil A: Entrapment and compartment syndromes of the upper limb in haemophilia. J Hand Surg Br 1994;19:427-429. Carr ME Jr, Loughran TP, Cardea JA, Smith WK, Kuhn JG, Dottore MV: Successful use of recombinant factor VIIa for hemostasis during total knee replacement in a severe hemophiliac with high-titer factor VIII inhibitor. Int J Hematol 2002;75:95-99.

The rectus femoris muscle spans two joints and is active during running, sprinting, and walking at a fast pace during the preswing and early swing phase of gait. In these situations, the muscle helps to generate power to initiate hip flexion while absorbing or controlling the rate of knee flexion during early swing phase. Quadriceps activity, including the rectus femoris, is not normally needed when walking at a routine cadence. However, rectus femoris activity is commonly noted during preswing and the swing phase in patients with cerebral palsy, particularly those with diplegia. In an effort to initiate swing phase, the rectus femoris is "overactive." As a result, the knee flexion that commonly occurs at terminal stance and initial swing is restricted. Instead of achieving the normal 50 to 60 degrees of flexion during early swing, this patient's knee flexion is limited to 15 degrees. The goal of treatment is to retain rectus femoris activity for initiation of hip flexion but to diminish its restraint on knee flexion. Studies have shown that transfer of the distal rectus femoris tendon provides more flexion of the knee during the swing phase of gait than simply releasing the tendon. V-Y lengthening of the quadriceps tendon or a Z lengthening of the patellar tendon causes too much weakening of the quadriceps muscle and worsens the crouch deformity. In addition to transfer of the rectus femoris tendon, other procedures are often done concomitantly to obtain the best balance and realignment of hip-knee-ankle activity. Aiona MD: Guidelines for managing lower extremity problems in cerebral palsy, in Fitzgerald RH, Kaufer H, Malkani AL (eds): Orthopaedics. St Louis, MO, Mosby, 2002, pp 1534-1541. Chambers H, Laure A, Kaufman K, Cardelia M, Sutherland D: Prediction of outcome after rectus femoris surgery in cerebral palsy: The role of cocontraction of the rectus femoris and vastus lateralis. J Pediatr Orthop 1998;18:703-711.

Elbow release and triceps transfer to restore motion can be performed in children who are age 4 years and older. The ability to flex the elbow either actively or passively is of great assistance in activities of daily living. Van Heest A, Waters PM, Simmons BP: Surgical treatment of arthrogrypsosis of the elbow. J Hand Surg Am 1998;23:1063-1070.

Symptoms of activity-related low back pain, physical findings of pain with extension, lateral bending, and resuming an upright position, and relative hamstring tightness are consistent with spondylolysis. While the initial diagnostic work-up should include plain radiographs of the lumbosacral spine, the findings may be negative because it can take weeks or months for the characteristic changes to become apparent. SPECT has been a useful adjunct in the diagnosis of spondylolysis when plain radiographs are negative. Since the patient's pain is activity related and she is otherwise healthy, evaluation for infection is not indicated. Because the neurologic examination is normal, electromyography, nerve conduction velocity studies, and MRI are not indicated. CT can be used in those instances in which SPECT and bone scans are negative. Ciullo JV, Jackson DW: Pars interarticularis stress reaction, spondylolysis, and spondylolisthesis in gymnasts. Clin Sports Med 1985;4:95-110. Collier BD, Johnson RP, Carrera GF, et al: Painful spondylolysis or spondylolisthesis studied by radiography and single photon emission computed tomography. Radiology 1985;154:207-211. Jackson DW, Wiltse LL, Cirincione RT: Spondylolysis in the female gymnast. Clin Orthop 1976;117:68-73.