Orthopedic Pediatrics 2026 MCQs: Board Review Part 4

Question 1

Figure 33 shows the oblique radiograph of an 11-year-old boy who has a mild left flatfoot deformity. Examination reveals that subtalar motion is limited and painful. Despite casting for 6 weeks, the patient reports foot pain that limits participation in sport activities. A CT scan shows no subtalar joint abnormalities. Management should now include

Explanation

The radiograph shows an incompletely ossified calcaneonavicular coalition. When symptomatic, a trial of cast immobilization is reasonable. If this fails to provide relief, the preferred treatment is resection of the coalition. Before attempting surgery, a CT scan should be obtained to rule out ipsilateral subtalar coalition. Recurrence of the coalition is usually prevented with interposition of autogenous fat graft or with local interposition of the extensor digitorum brevis muscle. Approximately 80% of patients treated in this manner have decreased pain and improved subtalar motion. When the flatfoot deformity is mild, calcaneal lengthening or medial translation osteotomy is unnecessary. Primary triple arthrodesis may be indicated if degenerative changes are present in the subtalar or midfoot joints. Peroneal lengthening has been described for treatment of the peroneal spastic flatfoot without demonstrable tarsal coalition. Gonzalez P, Kumar SJ: Calcaneonavicular coalition treated by resection and interposition of the extensor digitorum brevis muscle. J Bone Joint Surg Am 1990;72:71-77. Vincent KA: Tarsal coalition and painful flatfoot. J Am Acad Orthop Surg 1998;6:274-281.

Question 2

A nonambulatory verbal 6-year-old child with spastic quadriplegic cerebral palsy has progressive bilateral hip subluxation of more than 50%. There is no pain with range of motion, but abduction is limited to 20 degrees maximum. An AP radiograph is seen in Figure 34. Management should consist of

Explanation

The natural history of the patient's hips, if left untreated, is gradual progression to dislocation. To prevent future pain, prevention of dislocation is often helpful. The patient is too old for soft-tissue releases alone. Therefore, the treatment of choice is medial release of both hips to obtain 45 degrees or better of hip abduction in conjunction with psoas tenotomy and bilateral femoral varus osteotomies. Presedo A, Oh CW, Dabney KY, et al: Soft-tissue releases to treat spastic hip subluxation in children with cerebral palsy. J Bone Joint Surg Am 2005;87:832-841.

Question 3

Figures 35a through 35c show the clinical photograph and radiographs of a 15-year-old boy who stubbed his toe 1 day ago while walking barefoot in the yard. Management should consist of

Explanation

35b 35c The patient has an open fracture of the physis of the distal phalanx with a portion of the nail bed interposed in the physis. Seymour initially described this injury in the distal phalanges of fingers. Optimal treatment consists of removing the interposed tissue, irrigating the fracture, and a short course of antibiotics. The nail should be preserved to provide stability. Kensinger DR, Guille JT, Horn BD, et al: The stubbed great toe: Importance of early recognition and treatment of open fractures of the distal phalanx. J Pediatr Orthop 2001;21:31-34. Pinckney LE, Currarino G, Kennedy LA: The stubbed great toe: A cause of occult compound fracture and infection. Radiology 1981;138:375-377.

Question 4

Figure 36 shows the radiograph of a 14-year-old boy who has been treated in the past for Perthes' disease with an abduction brace. He now has hip pain that limits his activity, and nonsteroidal anti-inflammatory drugs have failed to provide relief. What is the most appropriate treatment?

Explanation

Several authors have reported good success in relieving pain with shelf acetabuloplasty. This patient's Perthes' disease is in the healed phase; therefore, proximal femoral varus and Salter innominate osteotomies aimed at improving containment are not indicated. The medial one half of the patient's femoral head is markedly deformed, and rotating it into a weight-bearing position with proximal femoral valgus osteotomy is unlikely to relieve pain. Hip arthrodesis can always be performed as a salvage procedure if the shelf acetabuloplasty fails. Daly K, Bruce C, Catterall A: Lateral shelf acetabuloplasty in Perthes' disease: A review of the end of growth. J Bone Joint Surg Br 1999;81:380-384.

Question 5

A newborn girl is referred for evaluation of suspected hip instability. What information from her history would place her in the highest risk category?

Explanation

Breech positioning has been noted as the risk factor that most increases the relative risk of developmental dysplasia of the hip in multiple series and meta-analysis. All the other factors also increase the risk but to a lesser magnitude. Lehmann HP, Hinton R, Morello P, et al: Developmental dysplasia of the hip practice guideline: Technical report. Committee on Quality Improvement, and Subcommittee on Developmental Dysplasia of the Hip. Pediatrics 2000;105:E57.

Question 6

A teenager is undergoing a correction of deformity and lengthening of the femur. Distractions are proceeding as expected; however, during his 6-week follow-up examination, the patient reports that the distraction motors have become harder to turn over for the past 2 to 3 days. Figures 37a and 37b show current radiographs. What is the most likely complication being encountered?

Explanation

37b Premature consolidation is a complication that is unique to gradual bone lengthening after corticotomy. Causes include excessive latency period, inadequate distraction rate, exuberant bone formation, patient compliance problems, and mechanical failure of the distraction apparatus. The femur and fibula are most commonly involved. This patient did not have an incomplete corticotomy, as initial distraction occurred before the distraction device was noted to seize up. The radiographs show bowing of the Ilizarov wires and mature regenerate bone, both suggestive of premature consolidation. No wire breakage or joint subluxation is seen on the radiographs. Treatment for premature consolidation includes continuing distraction until the consolidation bridge ruptures, or additional surgery may include closed rotational osteoclasis or repeat corticotomy. Paley D: Problems, obstacles and complications of limb lengthening, in Maiocchi AB, Aronson J (eds): Operative Principles of Ilizarov. Baltimore, MD, Williams & Wilkins, 1991, p 360.

Question 7

A 4-year-old child was born with bilateral congenital radial clubhands. Which of the following associated conditions is a contraindication to centralization of the hands on the ulna?

Explanation

Patients born with bilateral radial clubhands may have difficulty getting their hands to their mouth. The centralization procedure would take away that ability if there is a lack of elbow flexion. Green DP, Hotchkiss RN, Pederson WC: Green's Operative Hand Surgery, ed 4. New York, NY, Churchill Livingstone, 1999, pp 344-349.

Question 8

A 6-year-old Little League pitcher has had pain in the right elbow for the past 2 weeks. Examination reveals mild lateral elbow joint tenderness with full range of motion and no effusion or collateral laxity. A radiograph is shown in Figure 38. Initial management should consist of

Explanation

The radiograph shows osteochondritis dissecans (OCD) of the capitellum, one manifestation of "pitcher's elbow." The lesion is nondisplaced, and healing is possible if the inciting throwing activities are curtailed. Long arm cast treatment may be reasonable for the noncompliant patient but should not exceed 6 weeks duration. Surgical treatment is indicated for loose bodies or cartilage flaps. Elbow OCD lesions are now being seen in younger children as more participate in organized sports, especially baseball and gymnastics. Bauer M, Jonsson K, Josefsson PO, et al: Osteochondritis dissecans of the elbow: A long-term follow-up study. Clin Orthop 1992;284:156-160. Takahara M, Ogino T, Sasaki I, et al: Long term outcome of osteochondritis dissecans of the humeral capitellum. Clin Orthop 1999;363:108-115.

Question 9

The parents of a 10-year-old boy with Down syndrome are seeking sports clearance for participation in the high jump at the Special Olympics. He is asymptomatic, and the neurologic examination is normal. The hips and patellae are clinically stable. Radiographs of the cervical spine in flexion and extension show a maximum atlanto-dens interval (ADI) of 6 mm. Based on these findings, what recommendation should be made?

Explanation

In approximately 15% of children with Down syndrome, atlantoaxial instability develops because of ligament laxity, making them susceptible to spinal cord injury with relatively minor trauma. The American Academy of Pediatrics recommends lateral flexion-extension views of the cervical spine in any patient with Down syndrome who wishes to participate in sports. A normal ADI is up to 4 mm. Patients with Down syndrome with an ADI of more than 5 mm should not participate in contact sports or sports with a high risk for neck injury, such as diving, gymnastics, high jump, or butterfly stroke. Cervical fusion has a very high rate of complications in patients with Down syndrome and is recommended only for patients who have myelopathic signs or symptoms. Atlantoaxial instability in Down syndrome: Subject review. American Academy of Pediatrics Committee on Sports Medicine and Fitness. Pediatrics 1995;96:151-154. Tredwell SJ, Newman DE, Lockitch G: Instability of the upper cervical spine in Down syndrome. J Pediatr Orthop 1990;10:602-606.

Question 10

An 18-month-old infant with myelomeningocele and rigid clubfeet has grade 5 quadriceps and hamstring strength, but no muscles are functioning below the knee. What is the best treatment option for the rigid clubfeet?

Explanation

This child has the potential to walk and therefore should have all the contracted structures in the feet released as necessary to place the feet in a plantigrade position for fitting of ankle-foot orthoses. Physical therapy, manipulation, and casting may provide some benefit in a newborn with flexible feet but are not effective in an older infant with rigid clubfeet. Botulinum injections and tendon transfers are of no use because there are no muscles functioning below the knee. Tendon releases are more effective than tendon transfers in children with myelomeningocele. Mazur JM: Management of foot and ankle deformities in the ambulatory child with myelomeningocele, in Sarwark JR, Lubicky JP (eds): Caring for the Child with Spina Bifida. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2001, pp 155-160.

Question 11

Figures 39a and 39b show the current radiographs of an 8-year-old girl who has had pain in the left thigh for the past 3 months. She was recently diagnosed with hypothyroidism and started treatment 1 week ago. Examination reveals a mild abductor deficiency limp on the left side. She lacks 30 degrees internal rotation on the left hip compared with the right hip. Management should consist of

Explanation

39b The radiographs confirm a slipped capital femoral epiphysis of the left hip, as well as a widened growth plate on the contralateral hip. This is considered a stable slip because the patient is able to walk. Treatment options for stable slips include in situ pinning, bone graft epiphysiodesis, and in some centers severe slips are treated with primary osteotomy and epiphyseal fixation. Percutaneous in situ fixation is the most popular and widely used method of treatment. This juvenile patient has an endocrine condition and a widened growth plate on the right side; therefore, strong consideration should be given to pinning the contralateral hip "pre-slip." Muscle strengthening, hip spica casting, and closed reduction have no place in the primary treatment of a stable slipped capital femoral epiphysis. Loder RT, Richards BS, Shapiro PS, et al: Acute slipped capital femoral epiphysis: The importance of physeal stability. J Bone Joint Surg Am 1993;75:1134-1140. Loder R, Wittenberg B, DeSilva G: Slipped capital femoral epiphysis associated with endocrine disorders. J Pediatr Orthop 1995;15:349-356.

Question 12

A 7-year-old boy with spastic diplegia is a limited community ambulator. He has a moderately severe crouched gait. The parents request a treatment that will result in a permanent decrease in lower extremity muscle tone. This is best accomplished with

Explanation

Posterior rhizotomy provides a permanent reduction in tone of spastic muscles. Potential drawbacks of the procedure include excessive muscle weakness, hip dislocation, and spinal deformity. Intramuscular botulinum-A toxin results in permanent blockade of presynaptic release of acetylcholine across the neuromuscular junction. The clinical effect usually resolves after 3 to 6 months due to neural regeneration. Tone-reduction AFOs have not been shown to reduce tone. A baclofen pump could offer prolonged reduction in tone, but not a single intrathecal injection. Arens LJ, Peacock WJ, Peter J: Selective posterior rhizotomy: A long-term follow-up study. Childs Nerv Syst 1989;5:148-152. Koman LA, Paterson Smith B, Balkrishnan R: Spasticity associated with cerebral palsy in children: Guidelines for the use of botulinum-A toxin. Paediatr Drugs 2003;5:11-23.

Question 13

Figure 40 shows the radiographs of a 2-year-old boy who has a deformed leg. The patient is ambulatory and has no pain. What is the most appropriate management?

Explanation

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.

Question 14

Where is the most common site for tuberculosis (TB) spondylitis in children?

Explanation

In children, the main route of infection in skeletal TB is through hematogenous spread from a primary source. The mycobacterium is deposited in the end arterials in the vertebral body adjacent to the anterior aspect of the vertebral end plate. Thus, the anterior portion of the vertebral body is most commonly involved. The lower thoracic region is the most common segment; next in decreasing order of frequency are the lumbar, upper thoracic, cervical, and sacral regions. Teo HE, Peh WC: Skeletal tuberculosis in children. Pediatric Radiol 2004;34:853-860.

Question 15

Examination of a 13-year-old boy with asymptomatic poor posture reveals increased thoracic kyphosis that is fairly rigid and accentuates during forward bending. The neurologic examination is normal. Spinal radiographs show 10 degrees of scoliosis at Risser stage 2, and there is no evidence of spondylolisthesis. A standing lateral view of the thoracic spine is shown in Figure 41. The kyphosis corrects to 50 degrees. Management should consist of

Explanation

The radiograph shows excessive thoracic kyphosis (normal 20 degrees to 50 degrees) with multiple contiguous vertebral wedging and end plate irregularity, all consistent with the diagnosis of Scheuermann's kyphosis. The patient is skeletally immature; therefore, there is the potential for progression of the kyphotic deformity. Extension bracing has shown efficacy in the treatment of Scheuermann's kyphosis that measures 50 degrees to 74 degrees, and has actually reduced the curvature permanently in some patients. A thoracolumbosacral orthosis may be used if the apex of kyphosis is at T7 or lower. Indications for surgical treatment are controversial, but spinal fusion most likely should not be considered for a painless kyphosis measuring less than 75 degrees. Murray PM, Weinstein SL, Spratt KF: The natural history and long-term follow-up of Scheuermann kyphosis. J Bone Joint Surg Am 1993;75:236-248. Wenger DR, Frick SL: Scheuermann kyphosis. Spine 1999;24:2630-2639.

Question 16

What is the most important sign of impending modulation with rapid progression of a spinal deformity in neurofibromatosis?

Explanation

Rib penciling is the only singular factor; 87% of the curves progressed significantly in patients with three or more penciled ribs. Modulation in neurofibromatosis scoliosis implies the change from an idiopathic type to a dysplastic type of curve with rapid progression and the need for aggressive stabilization by fusion. Crawford AH, Schorry EK: Neurofibromatosis in children: The role of the orthopaedist. J Am Acad Orthop Surg 1999;7:217-230.

Question 17

A 6-year-old child has a fixed flexion deformity of the interphalangeal (IP) joint of the right thumb. The thumb is morphologically normal, with a nontender palpable nodule at the base of the metacarpophalangeal joint. Clinical photographs are shown in Figures 42a and 42b. Based on these findings, what is the treatment of choice?

Explanation

42b The child has a trigger thumb deformity. A trigger thumb is a developmental mechanical problem rather than a congenital deformity. The anomaly generally is not noted at birth. A fixed flexion deformity of the IP joint of the thumb most commonly occurs in children in the first 2 years of life. A stretching and splinting program may correct the deformity in the first year of life, but nonsurgical management after age 3 years results in a success rate of only 50%. Release of the proximal annular pulley of the flexor sheath is recommended at this age. Tan AH, Lam KS, Lee EH: The treatment outcome of trigger thumb in children. J Pediatric Orthop B 2002;11:256-259. Slakey JB, Hennrikus WL: Acquired thumb flexion contracture in children: Congenital trigger thumb. J Bone Joint Surg Br 1996;78:481-483.

Question 18

A 3-year-old boy had been treated with serial casting for a right congenital idiopathic clubfoot deformity. The parents are concerned because the child now walks on the lateral border of the right foot. Examination shows that the foot passively achieves a plantigrade position with neutral heel valgus and ankle dorsiflexion to 15 degrees. The forefoot inverts during active ankle dorsiflexion. Mild residual metatarsus adductus is present. Management should now consist of

Explanation

Dynamic midfoot supination that is the result of peroneal weakness is a common residual problem after cast correction or surgical reconstruction of a congenital idiopathic clubfoot. Dynamic supination is unlikely to resolve spontaneously. Most parents do not want to use brace support forever. Transfer of the posterior tibialis to the dorsum of the foot has shown poor results in clubfeet. Preferred treatments include: 1) transfer of the entire anterior tibialis tendon to the lateral cuneiform, or 2) split transfer of the anterior tibialis tendon to the cuboid or to the peroneus brevis tendon. Kuo KN, Hennigan SP, Hastings ME: Anterior tibial tendon transfer in residual dynamic clubfoot deformity. J Pediatr Orthop 2001;21:35-41. Garceau GJ: Anterior tibial tendon transfer for recurrent clubfoot. Clin Orthop 1972;84:61-65.

Question 19

Figures 43a and 43b show the clinical photographs of a 4-month-old child with bilateral popliteal pterygium. The fixed knee contractures measure 100 degrees bilaterally. What future treatment is most likely to successfully correct this deformity?

Explanation

43b Congenital popliteal webbing with contractures of 60 degrees is a difficult deformity to correct. The anatomy of the web is of considerable importance. MRI can delineate the extent of the posterior fibrous band that often stretches from the ischium to the calcaneus. The sciatic nerve, usually shortened, most often runs just anterior to this fibrous band. For mild contractures of less than 20 degrees, nonsurgical management is usually adequate. Hamstring lengthening and postoperative splinting are usually sufficient for contractures of 20 degrees to 40 degrees. Moderate contractures of up to 60 degrees usually require Z-plasties in the popliteal fossa and postoperative serial casting to avoid undue tension on neurovascular structures. Contractures of more than 60 degrees require a femoral shortening osteotomy or gradual correction with an external fixator. However, rapid recurrence following fixator removal is common if formal soft-tissue procedures and postoperative splinting are not performed. Parikh SN, Crawford AH, Do TT, et al: Popliteal pterygium syndrome: Implications for orthopaedic management. J Pediatr Orthop B 2004;13:197-201.

Question 20

A 15-year-old boy reports a 2-day history of progressive left buttock pain and severe limping. He denies any history of trauma or radiation of the pain. He has an oral temperature of 100.4 degrees F (38 degrees C). Examination reveals that the lumbar spine and left hip have unguarded motion. The abdomen is nontender. There is moderate tenderness of the left sacroiliac region with no palpable swelling. Pain is elicited when the left lower extremity is placed in the figure-4 position (FABER test). Laboratory studies show a peripheral WBC count of 11,500/mm3 (normal to 10,500/mm3) and an erythrocyte sedimentation rate of 38 mm/h (normal up to 20 mm/h). Radiographs of the pelvis, hips, and lumbar spine are normal. A nucleotide bone scan (posterior view) is shown in Figure 44. Initial management should consist of

Explanation

The symptoms, physical findings, and laboratory studies are most consistent with a diagnosis of infectious sacroiliitis, usually caused by Staphylococcus aureus. Initial radiographs will be normal, and the diagnosis of sacroiliitis is often delayed. A technetium Tc 99m bone scan will localize the problem in 90% of patients but may occasionally give a false-negative result in early cases. If suspicion is high, a gallium scan or MRI scan may help confirm the diagnosis of sacroiliitis. Needle aspiration of the sacroiliac joint is difficult; therefore, antibiotic selection is usually empiric or based on blood cultures. Sacroiliitis that is the result of connective tissue inflammatory disease is usually bilateral and without fever or leukocytosis. The lack of hip irritability, spinal rigidity, and abdominal tenderness helps to rule out other causes of limping with fever, such as psoas abscess, diskitis, and septic hip. Aprin H, Turen C: Pyogenic sacroiliitis in children. Clin Orthop 1993;287:98-106.

Question 21

A 12-month-old boy has right congenital fibular intercalary hemimelia with a normal contralateral limb. A radiograph of the lower extremities shows a limb-length discrepancy of 2 cm. All of the shortening is in the right tibia. Assuming that no treatment is rendered prior to skeletal maturity, the limb-length discrepancy will most likely

Explanation

Many congenital limb deficiencies and bowing deformities result in growth retardation. If unilateral, a gradually progressive limb-length discrepancy will result; however, the proportional lengths of the lower extremities will remain at a relatively constant ratio. For example, if the right foot is at the level of the left knee at birth, this will still be true at maturity. This concept can be useful for early prediction of limb-length discrepancy by using a "multiplier method," as described by Paley and associates. This method can facilitate early treatment decisions, such as the need for amputation, without having to wait for serial scanography measurements. Paley D, Bhave A, Herzenberg JE, et al: Multiplier method for predicting limb-length discrepancy. J Bone Joint Surg Am 2000;82:1432-1446.

Question 22

What is the preferred treatment of a symptomatic curly toe deformity in a 6-year-old child?

Explanation

While some curly toe deformities spontaneously improve in younger children, the deformity is likely to persist in a 6-year-old child. Taping techniques result in no change or only a temporary decrease in deformity. Studies have shown that simple flexor tenotomy is as effective as flexor tendon transfer. Arthrodesis is rarely indicated. Hamer A, Stanley D, Smith TW: Surgery for curly toe deformity: A double-blind, randomized, prospective trial. J Bone Joint Surg Br 1993;75:662-663.

Question 23

A 12-year-old girl who is Risser stage 3 has had intermittent mild midback pain for the past 4 weeks. The pain is worse after prolonged sitting and after carrying a heavy backpack at school. She occasionally takes acetaminophen, but the pain does not limit sport activities. Examination reveals a mild right rib prominence during forward bending. Neurologic examination is normal. Radiographs show a 20-degree right thoracic scoliosis with no congenital anomalies or lytic lesions. Management should consist of

Explanation

Mild scoliosis is not a painful condition, but it usually presents during adolescence. Intermittent back pain is reported by 25% to 30% of adolescents whether or not scoliosis is present. Such pain is often attributed to muscle strain from tight muscles, poor posture, or heavy school backpacks. The clinician must distinguish typical pain (mild, intermittent, nonlimiting) from atypical pain. The latter requires more careful examination and imaging studies (bone scan or MRI) to determine the source of pain. The patient's age and right thoracic curve pattern are typical for idiopathic scoliosis; therefore, imaging of the neuroaxis is not necessary to look for cord syrinx, tethering, or tumor. Brace treatment is not required for this small curve unless future progression is demonstrated. Ramirez N, Johnston CE, Browne RH: The prevalence of back pain in children who have idiopathic scoliosis. J Bone Joint Surg Am 1997;79:364-368. Hollingworth P: Back pain in children. Br J Rheum 1996;35:1022-1028.

Question 24

What zone of the physis is widened in rickets?

Explanation

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

Question 25

A 7-year-old boy has had low back pain for the past 3 weeks. Radiographs reveal apparent disk space narrowing at L4-5. The patient is afebrile. Laboratory studies show a WBC count of 9,000/mm3 and a C-reactive protein level of 10 mg/L. A lumbar MRI scan confirms the loss of disk height at L4-5 and reveals a small perivertebral abscess at that level. To achieve the most rapid improvement and to lessen the chances of recurrence, management should consist of

Explanation

The patient has diskitis. Administration of IV antibiotics speeds resolution and minimizes recurrence. Bed rest and cast immobilization have been successfully used to treat this disorder but can be associated with prolonged recovery and frequent recurrence, even when oral antibiotics are administered. A perivertebral abscess seen in association with this condition usually resolves without surgery. Ring D, Johnston CE II, Wenger DR: Pyogenic infectious spondylitis in children: The convergence of discitis and vertebral osteomyelitis. J Pediatr Orthop 1995;15:652-660.

Question 26

A 12-year-old boy with a BMI of 35 presents with a 3-week history of left groin pain and a limp. He is diagnosed with a stable left slipped capital femoral epiphysis (SCFE). Which of the following factors is the strongest indication for prophylactic pinning of the contralateral right hip?

Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial but is generally recommended in patients with endocrine disorders (such as hypothyroidism, renal osteodystrophy, or growth hormone deficiency), previous pelvic radiation, or highly delayed bone age (Modified Oxford bone age score of 16 or less). A score of 22 indicates older bone maturity.

Question 27

A 6-year-old girl sustains a severely displaced, extension-type supracondylar humerus fracture. On arrival, the hand is pink and well-perfused but the radial pulse is absent. She is taken to the operating room for closed reduction and percutaneous pinning. Following anatomic reduction and pinning, the radial pulse remains absent, but the hand remains pink with brisk capillary refill. What is the most appropriate next step in management?

Explanation

In a pediatric supracondylar humerus fracture, a 'pulseless, pink hand' after anatomic reduction and stabilization should be observed closely. Capillary refill and skin color indicate adequate collateral perfusion. Open exploration of the brachial artery is indicated if the hand becomes or remains pulseless and pale/ischemic after reduction.

Question 28

A 6-week-old female infant is treated with a Pavlik harness for a dislocated left hip (Graf type IV). At her 2-week follow-up, the mother reports that the infant is not moving her left leg as much as the right. On examination, the infant lacks active knee extension on the left, but hip and ankle movements are intact. What is the most likely cause of this finding?

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment, typically caused by hyperflexion of the hip. It presents with decreased or absent active knee extension. The harness should be adjusted to reduce hip flexion or temporarily discontinued if the palsy occurs. Excessive abduction is associated with a risk of avascular necrosis.

Question 29

An 8-year-old boy presents with a 2-month history of a painless limp. Radiographs demonstrate sclerosis and fragmentation of the right capital femoral epiphysis. Which of the following radiographic findings at presentation is the most significant indicator of a poor prognosis in Legg-Calvé-Perthes disease?

Explanation

Lateral subluxation (extrusion) of the femoral head is one of the 'head-at-risk' signs described by Catterall and is the most significant radiographic indicator of a poor prognosis. It leads to loss of containment, hinge abduction, and severe deformity if not addressed.

Question 30

In the Ponseti method for the treatment of idiopathic clubfoot, what is the correct sequence of deformity correction?

Explanation

The Ponseti method sequentially corrects the deformities of clubfoot in the order of the acronym CAVE: Cavus (by elevating the first ray), Adductus, Varus, and finally Equinus (which often requires a percutaneous Achilles tenotomy).

Question 31

A 10-year-old boy complains of a clunking sensation and pain in his lateral right knee. He has no history of trauma. MRI confirms the diagnosis of a symptomatic complete discoid lateral meniscus. There is no meniscal tear. What is the most appropriate surgical treatment?

Explanation

The standard surgical treatment for a symptomatic complete discoid lateral meniscus without an unstable tear or peripheral detachment is arthroscopic saucerization. The goal is to reshape the meniscus to a more normal, crescentic configuration while preserving a stable peripheral rim (about 6-8 mm) to maintain its shock-absorbing function. Total meniscectomy is avoided due to the high risk of early osteoarthritis.

Question 32

A 9-year-old boy sustains a type III tibial spine eminence fracture after a bicycle accident. Radiographs show complete displacement of the avulsed fragment. What is the primary risk of nonoperative management (casting without reduction) for this specific fracture pattern?

Explanation

A Meyers and McKeever type III tibial spine fracture is completely displaced. Failure to anatomically reduce and stabilize the fragment can result in nonunion or malunion, leading to anterior cruciate ligament (ACL) laxity, anterior knee instability, and a potential block to knee extension. Operative reduction and internal fixation is indicated for type III fractures.

Question 33

A 3-year-old girl is brought to the emergency department after falling from a slide. Radiographs reveal a closed, isolated, spiral fracture of the middle third of the left femoral shaft. She has no neurovascular deficits and no other injuries. What is the most appropriate definitive management for this patient?

Explanation

Early spica casting is the treatment of choice for isolated, closed femoral shaft fractures in young children aged 6 months to 5 years (with less than 2 cm of shortening). ESIN is generally indicated for children aged 5 to 11 years (or younger children with multiple trauma/open fractures). Rigid nailing is contraindicated in this age group due to the risk of avascular necrosis and physeal injury.

Question 34

A 2-year-old girl presents with progressive bilateral bowing of the legs. Radiographs show an abrupt, sharp varus angulation at the proximal tibial metaphysis with a Drennan metaphyseal-diaphyseal angle of 18 degrees. What is the most appropriate initial management?

Explanation

Infantile Blount disease typically presents between 2 and 3 years of age. A metaphyseal-diaphyseal angle (MDA) > 16 degrees suggests a high risk of progression to true Blount disease rather than physiologic bowing. The initial treatment for infantile Blount disease in a child under 3 years with early-stage disease (Langenskiöld stage I or II) is bracing with knee-ankle-foot orthoses (KAFOs) during weight-bearing. Surgical intervention is considered if bracing fails or in older children.

Question 35

A 13-year-old boy presents with recurrent right ankle sprains and a rigid, painful flatfoot. Clinical examination reveals a lack of subtalar motion and peroneal spasticity. Computed tomography confirms a large, osseous talocalcaneal coalition involving the middle facet. The coalition involves approximately 60% of the posterior subtalar joint surface area, and there are moderate osteoarthritic changes in the posterior facet. What is the most appropriate surgical management?

Explanation

The surgical management of a talocalcaneal coalition depends on the size of the coalition and the presence of degenerative changes. Resection is generally indicated for coalitions involving <50% of the joint surface area without significant degenerative changes. Since this patient has a large osseous coalition (>50%) and osteoarthritic changes in the posterior facet, resection is contraindicated. Subtalar arthrodesis (or triple arthrodesis if other joints are involved) is the treatment of choice to relieve pain and stabilize the hindfoot.

Question 36

A 4-year-old girl is brought in by her parents for an abnormal gait and limb length discrepancy. She has no prior orthopedic history. Radiographs show a high dislocated left hip with a false acetabulum and severe acetabular dysplasia.

What is the most appropriate surgical management?

Explanation

In children older than 3 years with neglected or untreated developmental dysplasia of the hip (DDH), open reduction alone is associated with an unacceptably high rate of avascular necrosis (AVN) and redislocation due to soft tissue contractures and bony deformity. A concomitant femoral shortening osteotomy is necessary to relieve soft tissue tension and decrease the risk of AVN. A pelvic osteotomy (e.g., Dega, Salter, or Pemberton) is required to address the underlying acetabular dysplasia and provide adequate anterolateral coverage for the reduced femoral head.

Question 37

A 6-year-old boy falls from the monkey bars and sustains a widely displaced Gartland type III supracondylar humerus fracture. On arrival at the emergency department, his hand is pink but the radial pulse is not palpable. Closed reduction and percutaneous pinning are performed. After pinning, the hand remains well-perfused and pink, but the radial pulse is still absent on palpation and Doppler. What is the most appropriate next step in management?

Explanation

The management of a 'pink, pulseless' hand following an acceptable reduction and pinning of a supracondylar humerus fracture is observation. Collateral circulation in the pediatric elbow is robust, providing adequate perfusion to the hand even if the brachial artery is in spasm or sustains a localized intimal injury. Current AAOS guidelines support observation; the pulse typically returns within 24 to 48 hours. Vascular exploration is strictly indicated if the hand is white, cold, and poorly perfused (ischemic) after reduction.

Question 38

A 12-year-old obese boy presents with a left chronic stable slipped capital femoral epiphysis (SCFE) and undergoes uncomplicated in situ pinning. Which of the following is the most significant risk factor indicating the need for prophylactic pinning of the contralateral asymptomatic hip?

Explanation

The status of the triradiate cartilage and the modified Oxford bone age are the strongest predictors for the development of a contralateral slip in SCFE. An open triradiate cartilage or a chronologic age of less than 10 years (or less than 12 years in boys) indicates significant remaining growth and a high risk of subsequent contralateral SCFE. In these patients, prophylactic pinning of the contralateral hip is strongly recommended.

Question 39

An 8-year-old boy with a chronic limp is diagnosed with Legg-Calvé-Perthes disease. Which of the following radiographic findings is considered a 'head at risk' sign according to Catterall, indicating a poor prognosis and a higher risk of femoral head deformation?

Explanation

Catterall identified several 'head at risk' signs in Legg-Calvé-Perthes disease that correlate with a poor prognosis and progressive deformity. These include Gage's sign (a V-shaped radiolucency in the lateral portion of the epiphysis and adjacent metaphysis), calcification lateral to the epiphysis, lateral subluxation of the femoral head, a horizontal growth plate, and metaphyseal cysts. The Waldenström sign is widening of the medial joint space, and the crescent sign indicates subchondral fracture, which are standard findings rather than specific Catterall risk factors.

Question 40

An infant is undergoing serial casting for idiopathic clubfoot using the Ponseti method. After the fifth cast, the midfoot cavus, forefoot adductus, and hindfoot varus have been fully corrected. However, evaluation reveals only 0 degrees of ankle dorsiflexion. What is the most appropriate next step in management?

Explanation

In the Ponseti method for clubfoot, the deformities are corrected in a specific order: cavus, adductus, varus, and finally equinus. Once the midfoot and hindfoot are corrected (abducted to about 60 degrees), equinus often persists. If there is less than 15 degrees of ankle dorsiflexion, a percutaneous Achilles tenotomy is indicated. Attempting to forcefully cast out the equinus without a tenotomy risks creating a iatrogenic rocker-bottom foot deformity.

Question 41

A 13-year-old boy presents with severe groin pain after a minor fall. He is completely unable to bear weight, even with crutches. Radiographs confirm a severe slipped capital femoral epiphysis (SCFE).

What is the most devastating complication specific to this type of presentation, and what surgical technique is frequently utilized to minimize its risk?

Explanation

The patient's inability to bear weight even with crutches defines an unstable SCFE. Unstable SCFE carries a significantly high risk of avascular necrosis (AVN), historically reported to be up to 50%. To minimize this risk, surgeons often employ an anterior capsulotomy (to decompress the intracapsular hematoma and reduce tamponade effect on the epiphyseal vessels) and perform gentle, incidental reduction or fix the slip in situ without forceful manipulation.

Question 42

A 2-year-old boy with a history of anterolateral bowing of the tibia presents with a new diaphyseal fracture that fails to heal after 3 months of immobilization. Physical examination reveals multiple café-au-lait spots on his trunk.

What is the most likely underlying diagnosis and the optimal surgical strategy for achieving union?

Explanation

Anterolateral bowing of the tibia progressing to a non-healing fracture is classic for congenital pseudarthrosis of the tibia (CPT), which is highly associated with Neurofibromatosis type 1 (NF1). The presence of café-au-lait spots strongly supports this diagnosis. Achieving union in CPT is notoriously difficult; the standard surgical strategy involves radical excision of the hamartomatous pseudarthrosis tissue, robust autologous bone grafting, and rigid intramedullary fixation (e.g., Williams rod, Fassier-Duval rod), often augmented with an external fixator.

Question 43

A 14-year-old girl sustains an ankle injury while playing soccer. Radiographs and a CT scan reveal a Salter-Harris III fracture of the anterolateral distal tibial epiphysis with 4 mm of displacement.

What is the specific pathomechanics of this fracture pattern?

Explanation

This is a juvenile Tillaux fracture, a Salter-Harris III fracture of the anterolateral distal tibia. It occurs during the transitional period of physeal closure (typically ages 12-14). The distal tibial physis closes from central, to medial, to lateral. Because the anterolateral physis is the last to close, an external rotation force on the foot causes the anterior inferior tibiofibular ligament (AITFL) to avulse the anterolateral epiphyseal fragment. Operative reduction and internal fixation are indicated for displacement >2 mm.

Question 44

A 4-year-old girl is evaluated for severe and worsening bilateral bowlegs. Her BMI is in the 98th percentile. Standing radiographs reveal bilateral genu varum with sharp varus angulation at the proximal tibial metaphysis and significant medial metaphyseal beaking (Langenskiöld stage III).

Which of the following is the most definitively appropriate initial management for this patient?

Explanation

This child has progressed infantile Blount's disease (tibia vara). Orthotic management (KAFOs) may be effective in children under 3 years old with early-stage disease (Langenskiöld stages I-II). However, in a 4-year-old with advanced deformity (stage III) and high BMI, bracing is ineffective. Surgical intervention with a proximal tibial valgus osteotomy (often with derotation and fibular osteotomy) is the standard of care to restore the mechanical axis and offload the sick medial physis before permanent physeal arrest occurs.

Question 45

A 5-year-old boy with spastic quadriplegic cerebral palsy (Gross Motor Function Classification System [GMFCS] level V) is evaluated in the clinic. He is nonambulatory and nonverbal. His mother reports difficulty with perineal care, but there is no apparent pain with passive range of motion.

According to established international hip surveillance guidelines, how frequently should this patient undergo screening AP pelvis radiographs?

Explanation

Children with Cerebral Palsy are at high risk for progressive hip displacement, which correlates directly with their GMFCS level. Children at GMFCS level V have the highest risk, approaching 90%. Consensus guidelines (e.g., AACPDM Hip Surveillance Guidelines) mandate that children at GMFCS levels IV and V undergo an AP pelvis radiograph every 6 months until age 7, and then annually until skeletal maturity, to monitor the Reimers migration percentage and intervene before painful, irreversible dislocation occurs.

Question 46

A 6-year-old boy sustains a completely displaced extension-type supracondylar humerus fracture. Upon initial presentation, he has a pink, pulseless hand. Urgent closed reduction and percutaneous pinning is performed. In the recovery room, the hand remains pink and pulseless with a capillary refill time of less than 2 seconds. What is the most appropriate next step in management?

Explanation

A pink, pulseless hand after closed reduction and percutaneous pinning (CRPP) of a supracondylar humerus fracture typically indicates adequate collateral perfusion. Current pediatric orthopedic guidelines recommend observation and close clinical monitoring if the hand remains well-perfused (pink, warm, brisk capillary refill). Immediate vascular exploration is indicated for a persistently 'white and pulseless' hand following reduction.

Question 47

A 6-month-old girl presents for follow-up of a dislocated left hip. She had been treated with a Pavlik harness for 6 weeks starting at 1 month of age, which failed to reduce the hip.

What is the next most appropriate step in management?

Explanation

In an infant older than 6 months or one who has failed a proper trial of a Pavlik harness, the standard next step in management of developmental dysplasia of the hip (DDH) is closed reduction and spica casting under general anesthesia, typically accompanied by an arthrogram. Open reduction is indicated if a stable, concentric closed reduction cannot be achieved.

Question 48

An 8-year-old boy presents with a 2-month history of right hip pain and a limp. Radiographs demonstrate fragmentation of the capital femoral epiphysis with lateral subluxation consistent with Legg-Calvé-Perthes disease. Which of the following is considered the most significant prognostic factor for long-term hip outcome in this patient?

Explanation

The most significant prognostic factor in Legg-Calvé-Perthes disease is the age at clinical presentation. Children who present before 6 to 8 years of age have a significantly better prognosis because they have more remaining growth potential, allowing for better remodeling of the femoral head into a spherical shape.

Question 49

A 12-year-old boy with a BMI of 32 presents with severe left hip pain and inability to bear weight after a minor fall. Radiographs show an acute-on-chronic slipped capital femoral epiphysis (SCFE). During discussion of treatment, prophylactic pinning of the contralateral hip is considered. In which of the following scenarios is prophylactic pinning of the contralateral hip most strongly indicated?

Explanation

Prophylactic pinning of the contralateral hip is strongly indicated in patients with a high risk of developing a bilateral SCFE. Risk factors for bilaterality include endocrine disorders (such as hypothyroidism, panhypopituitarism, or growth hormone deficiency), prior pelvic radiation, and age younger than 10 years.

Question 50

An 8-year-old boy with spastic quadriplegic cerebral palsy (GMFCS Level V) is evaluated for hip surveillance. His migration percentage on an AP pelvis radiograph is 45% bilaterally. He has no pain, but hip abduction is limited to 20 degrees bilaterally. What is the most appropriate management?

Explanation

In an older child (>8 years old) with cerebral palsy and a hip migration percentage greater than 40%, soft tissue release alone (e.g., adductor tenotomies) is insufficient to halt or reverse the progression of hip subluxation. Bony reconstruction, typically consisting of a femoral varus derotational osteotomy (VDRO) and frequently combined with a pelvic osteotomy, is required to properly restore joint congruency.

Question 51

A 2.5-year-old obese boy presents with progressive left-sided genu varum.

Radiographs demonstrate a metaphyseal-diaphyseal angle (MDA) of 18 degrees with early medial metaphyseal beaking. What is the most appropriate initial management?

Explanation

An MDA greater than 16 degrees in a child younger than 3 years old with progressive varus is highly indicative of infantile Blount's disease (Langenskiöld stage I or II). The initial treatment of choice for infantile Blount's disease in children under age 3 is bracing with a knee-ankle-foot orthosis (KAFO) during weight-bearing activities. Surgery is indicated if bracing fails or for older children.

Question 52

A 2-year-old boy who was successfully treated for idiopathic right clubfoot with the Ponseti method presents with a recurrent deformity. Examination shows dynamic supination of the foot during the swing phase of gait and fixed equinus of 10 degrees. The parents report poor compliance with the abduction brace. What is the most appropriate surgical management?

Explanation

Recurrent clubfoot following Ponseti management often presents with dynamic supination and equinus. The correct protocol is to first perform serial casting to correct any recurrent cavus, adductus, and varus deformities, followed by an anterior tibial tendon transfer (ATTT) to balance the foot and a repeat Achilles tenotomy to correct the residual fixed equinus.

Question 53

A 6-year-old boy presents with a 6-month history of a painless snapping sound in his right knee. Examination reveals a palpable clunk at 20 degrees of flexion during extension of the knee. MRI confirms a complete discoid lateral meniscus with no evidence of a meniscal tear. What is the most appropriate management?

Explanation

An incidental or completely asymptomatic discoid meniscus, or one that presents solely with a painless snap ('snapping knee syndrome'), requires observation. Surgical intervention (such as saucerization and/or repair) is reserved for patients who are symptomatic with pain, locking, mechanical symptoms, or MRI evidence of a tear.

Question 54

A 14-year-old boy sustains an ankle injury while playing soccer.

Radiographs and a CT scan reveal a displaced Salter-Harris III fracture of the anterolateral distal tibia with a 3 mm articular step-off. Which of the following best describes the pathomechanics of this specific fracture pattern?

Explanation

The patient has a Tillaux fracture, which is a Salter-Harris III fracture of the anterolateral distal tibia. It occurs during early adolescence when the central and medial portions of the distal tibial physis have closed, but the anterolateral portion remains open. An external rotation force leads to an avulsion fracture of this anterolateral epiphysis by the anterior inferior tibiofibular ligament (AITFL).

Question 55

A 13-year-old girl presents with progressive knee pain for 3 months. Radiographs demonstrate a mixed sclerotic and lytic lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction. Biopsy confirms high-grade osteosarcoma. What is the current standard treatment protocol for this condition?

Explanation

The standard of care for high-grade conventional osteosarcoma includes neoadjuvant (preoperative) chemotherapy, followed by wide surgical resection (either limb salvage or amputation), and then adjuvant (postoperative) chemotherapy. Radiation therapy has a limited role as osteosarcoma is generally radioresistant, though it may be used in unresectable cases.

Question 56

A 13-year-old girl presents with left ankle pain and swelling following a twisting injury while playing soccer.

Radiographs reveal a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis. What is the primary deforming force and associated anatomical structure responsible for this specific fracture pattern?

Explanation

The clinical scenario describes a juvenile Tillaux fracture, which is a Salter-Harris type III fracture of the anterolateral distal tibial epiphysis. This occurs in adolescents because the distal tibial physis closes in a specific pattern: central, then anteromedial, then posteromedial, and finally the lateral aspect. An external rotation injury of the foot causes the anterior inferior tibiofibular ligament (AITFL) to pull on the unfused anterolateral epiphysis, resulting in an avulsion fracture.

Question 57

A 6-year-old boy sustains a severe extension-type supracondylar humerus fracture. On initial presentation, his hand is pale and pulseless.

He is immediately taken to the operating room. After successful closed reduction and percutaneous pinning, the hand remains pale and pulseless. A warming blanket is applied and the arm is slightly lowered, but there is no improvement after 15 minutes. What is the most appropriate next step in management?

Explanation

In the management of pediatric supracondylar humerus fractures, a 'pulseless and pale' hand after closed reduction and pinning is a surgical emergency indicating persistent arterial occlusion (kinking, intimal tear, or entrapment of the brachial artery). Open exploration via an anterior approach is indicated to inspect and free the brachial artery. A 'pulseless but pink' hand with good capillary refill after reduction can generally be observed, but a 'pale' hand requires immediate vascular intervention. Delaying for CT angiography is unnecessary and prolongs ischemia.

Question 58

An 8-year-old boy presents with a painless limp that has progressively worsened over the past 3 months.

Radiographs confirm Legg-Calvé-Perthes disease in the fragmentation stage. The surgeon classifies the hip using the Herring Lateral Pillar classification. According to this system, which of the following radiographic criteria defines a Lateral Pillar Type B?

Explanation

The Herring Lateral Pillar classification is evaluated on the AP pelvis radiograph during the fragmentation stage of Legg-Calvé-Perthes disease. Type A: 100% of the lateral pillar height is maintained. Type B: >50% of the lateral pillar height is maintained. Type C: <50% of the lateral pillar height is maintained. Type B/C border involves exactly 50% loss or a very thin lateral pillar. Lateral pillar height is strongly prognostic for long-term hip deformity and outcomes.

Question 59

A 12-year-old boy with a BMI in the 99th percentile presents to the emergency department with acute severe left groin pain after a minor slip.

He refuses to bear weight on the left leg, even with the assistance of crutches. Radiographs demonstrate a slipped capital femoral epiphysis (SCFE). According to the Loder classification, this clinical presentation is associated with a significantly increased risk of which of the following complications?

Explanation

The Loder classification divides SCFE into stable and unstable based on the patient's ability to bear weight (with or without crutches). An unstable SCFE (patient unable to bear weight) carries a high risk of avascular necrosis (AVN) of the femoral head, historically reported as high as 47-50%, compared to nearly 0% in stable slips. Prompt recognition and careful treatment (such as urgent gentle reduction and pinning or modified Dunn procedure, often with capsular decompression) are critical in managing unstable SCFE.

Question 60

A 4-year-old boy presents for follow-up of a right idiopathic clubfoot that was treated in infancy with the Ponseti method.

His parents report he walks with a persistent inward turn of the foot. Examination reveals correctable forefoot adductus, a neutral hindfoot, and dynamic supination of the foot during the swing phase of gait. What is the most appropriate next step in management?

Explanation

Dynamic supination during the swing phase of gait in a relapsed clubfoot treated via the Ponseti method is classically managed with a split anterior tibial tendon transfer (SPLATT) or full tibialis anterior tendon transfer to the lateral cuneiform (often after a brief period of serial casting to correct residual passive deformity). It addresses the muscle imbalance caused by an overactive tibialis anterior and weak peroneal muscles. Bony procedures like triple arthrodesis are salvage procedures for older children.

Question 61

A 2-year-old girl is undergoing an open reduction for developmental dysplasia of the hip (DDH) via a medial approach.

The surgeon encounters several obstacles preventing concentric reduction of the femoral head into the true acetabulum. Which of the following structures is considered an extracapsular obstacle to reduction?

Explanation

In DDH, obstacles to closed or open reduction are divided into extracapsular and intracapsular structures. The iliopsoas tendon is an extracapsular obstacle that causes an hourglass constriction of the joint capsule. Intracapsular obstacles include the hypertrophied ligamentum teres, fibrofatty pulvinar, inverted labrum (neolimbus), and a contracted transverse acetabular ligament. A medial approach allows direct visualization and release of the iliopsoas tendon and transverse acetabular ligament.

Question 62

A 32-month-old, obese boy presents with progressive bilateral bowing of the lower extremities.

Standing radiographs reveal bilateral genu varum, metaphyseal beaking, and an exact metaphyseal-diaphyseal angle of 20 degrees. He is diagnosed with Langenskiöld Stage II infantile Blount disease. What is the most appropriate initial management?

Explanation

The patient has infantile Blount disease (tibia vara), distinguished from physiologic bowing by an age >2 years, progressive deformity, metaphyseal beaking, and a metaphyseal-diaphyseal angle >16 degrees. For children between ages 2 and 3 with early-stage disease (Langenskiöld Stage I or II), a trial of bracing with Knee-Ankle-Foot Orthoses (KAFOs) is the standard initial treatment and can be corrective. Surgery (proximal tibial osteotomy) is indicated for older children (usually >4 years), failure of bracing, or advanced stages (Langenskiöld Stage III and above).

Question 63

An 11-year-old boy weighing 65 kg (143 lbs) sustains a length-unstable spiral fracture of the femoral shaft following a fall from a tree.

Which of the following surgical interventions is most appropriate for this patient, optimizing biomechanical stability while minimizing the risk of iatrogenic avascular necrosis (AVN) of the femoral head?

Explanation

In older and heavier pediatric patients (typically >11 years old or weighing >50 kg/110 lbs), Titanium Elastic Nails (TENs) have unacceptably high rates of failure, malunion, and loss of reduction, particularly in length-unstable fractures. Rigid locked intramedullary nailing is the standard of care. To prevent iatrogenic avascular necrosis of the femoral head due to injury of the medial femoral circumflex artery branches, a lateral greater trochanteric entry point is strictly utilized in the pediatric population, completely avoiding the piriformis fossa.

Question 64

A 14-year-old male athlete presents with a rigid left flatfoot and a history of frequent ankle sprains. Examination shows marked restriction of subtalar motion and peroneal spasm.

A lateral weight-bearing radiograph displays an unbroken halo of sclerosis corresponding to the C-sign. Which anatomical region is primarily affected by the underlying pathology?

Explanation

The clinical scenario and the radiographic 'C-sign' (formed by the medial outline of the talar dome and the posteroinferior outline of the sustentaculum tali) are pathognomonic for a talocalcaneal coalition. Tarsal coalitions most frequently involve the calcaneonavicular joint or the talocalcaneal joint. Talocalcaneal coalitions most commonly involve the middle facet of the subtalar joint. Patients typically present in adolescence as the coalition ossifies, causing a rigid flatfoot, peroneal spasm, and recurrent ankle sprains due to loss of subtalar shock absorption.

Question 65

A 7-year-old child with a known mutation in the COL1A1 gene presents with worsening anterolateral bowing of both femurs and a history of four prior low-energy femoral fractures.

The family requests a durable surgical solution to prevent future fractures and correct the deformity. Which of the following is considered the gold-standard surgical technique for this patient?

Explanation

The patient has Osteogenesis Imperfecta (Type I collagen defect). The classic and gold-standard surgical management for severe, progressively bowing long bones with recurrent fractures in OI is the Sofield-Millar procedure. This involves subperiosteal exposure, multiple corrective osteotomies (often described as 'shish kebab' technique), and stabilization with an intramedullary device. In a growing child, telescoping intramedullary rods (e.g., Fassier-Duval rods) are preferred because they elongate with the growing bone, providing continuous internal splintage and reducing the risk of re-fracture or hardware migration.

Question 66

A 15-year-old boy presents with progressive bowing of his left lower extremity, a waddling gait, and medial knee pain. His body mass index is 38. Standing full-length radiographs reveal a severe varus deformity of the proximal tibia, internal tibial torsion, and a procurvatum deformity. The mechanical axis falls medial to the medial compartment of the knee. What is the most appropriate definitive management for this patient?

Explanation

This patient has severe adolescent Blount disease with a multiplanar deformity (varus, internal rotation, procurvatum). In a 15-year-old nearing skeletal maturity, guided growth (hemi-epiphysiodesis) is unlikely to provide sufficient correction due to limited remaining growth. Acute correction of severe multiplanar deformities carries a high risk of compartment syndrome and common peroneal nerve palsy. Therefore, a proximal tibial osteotomy with gradual correction using a fine-wire circular external fixator (e.g., Ilizarov or Taylor Spatial Frame) is the gold standard for definitive, safe correction.

Question 67

A 12-year-old boy is brought to the emergency department unable to bear weight on his right leg after a minor slip. He reports a 4-week history of dull, intermittent right thigh pain prior to the fall. Anteroposterior and frog-leg lateral radiographs demonstrate a severe right slipped capital femoral epiphysis (SCFE). Which of the following approaches is most strongly supported by recent literature to minimize the risk of avascular necrosis (AVN) in this unstable slip?

Explanation

The patient has an unstable SCFE, defined clinically by the inability to bear weight even with crutches. Unstable SCFE has a much higher risk of avascular necrosis (AVN) compared to stable SCFE. Literature supports urgent intervention (typically within 24 hours) utilizing intracapsular decompression (via capsulotomy) to release the tamponade effect of the fracture hematoma, followed by gentle, incidental reduction and stable internal fixation to decrease the risk of AVN.

Question 68

A 6-week-old female infant is undergoing treatment with a Pavlik harness for developmental dysplasia of the left hip (DDH). At the routine two-week follow-up, the mother notes that the infant is no longer actively kicking her left leg. On examination, the infant cries with passive movement, lacks active extension of the left knee, but retains normal toe and ankle movements. The patellar reflex is absent on the left. What is the most appropriate next step in management?

Explanation

The infant has developed a femoral nerve palsy, a known complication of Pavlik harness treatment occurring in approximately 2% of patients. It is typically caused by hyperflexion of the hip, which compresses the femoral nerve against the inguinal ligament. The required management is to immediately discontinue the harness or significantly loosen the anterior straps. Normal function typically returns within a few days to weeks. Continuing the harness or switching to a rigid orthosis without allowing neurologic recovery risks permanent damage and failure of DDH treatment.

Question 69

A 6-year-old boy sustains a completely displaced, extension-type supracondylar fracture of the humerus. On initial evaluation, the hand is pink but the radial pulse is absent. He is taken emergently to the operating room, where a closed reduction and percutaneous pinning are successfully performed. Postoperatively, the fracture alignment is excellent, the hand remains warm with a capillary refill of less than 2 seconds, and oxygen saturation on the index finger is 99%; however, the radial pulse remains non-palpable. What is the most appropriate next step in management?

Explanation

The patient has a 'pink, pulseless' hand after reduction and stabilization of a supracondylar humerus fracture. This indicates that while the radial artery may be in spasm or occluded, the collateral circulation is adequate to perfuse the hand. Current pediatric orthopedic guidelines recommend close observation for 24 to 48 hours for a well-perfused, pink, pulseless hand. Routine exploration or advanced imaging is not indicated unless the hand becomes cool, pale, or ischemic.

Question 70

A 3-year-old boy presents with a relapsed right idiopathic clubfoot. He was initially treated successfully with the Ponseti method, including an Achilles tenotomy. He now walks with a dynamic supination of the foot during the swing phase of gait and has a fixed varus deformity of the hindfoot. Passive correction of the hindfoot is not possible. What is the most appropriate next step in management?

Explanation

Relapses in clubfoot treated with the Ponseti method are relatively common and usually present with dynamic supination and recurrent equinovarus. The anterior tibial tendon transfer (ATTT) is the treatment of choice for dynamic supination. However, an ATTT should never be performed on a foot with a fixed deformity. The fixed deformity (varus/equinus) must first be corrected with a brief period of repeat serial long-leg Ponseti casting. Once the foot is passively correctable, the ATTT can be performed to maintain the correction.

Question 71

A 4-year-old girl with spastic quadriplegic cerebral palsy is evaluated in the orthopedic clinic. She is entirely dependent for mobility and utilizes a custom manual wheelchair for transport. She is classified as Gross Motor Function Classification System (GMFCS) Level V. Based on current hip surveillance guidelines, what is her approximate lifetime risk of developing hip displacement (migration percentage >30%), and what is the recommended frequency for radiographic screening?

Explanation

Hip displacement in cerebral palsy is directly correlated with the patient's GMFCS level. Children who are GMFCS Level V (most severely involved, non-ambulatory) have the highest risk of hip displacement, which approaches 90%. According to cerebral palsy hip surveillance guidelines, these high-risk children should have an anteroposterior pelvis radiograph every 6 to 12 months once the diagnosis is established, to monitor the migration percentage and allow for timely soft-tissue or bony intervention.

Question 72

An 8-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs reveal that he is in the fragmentation stage. According to the Herring Lateral Pillar classification, which of the following radiographic findings places this patient in Lateral Pillar Group C, portending a poorer prognosis?

Explanation

The Herring Lateral Pillar classification assesses the height of the lateral portion of the capital femoral epiphysis on an AP radiograph during the fragmentation stage of Legg-Calvé-Perthes disease. Group A: no loss of height in the lateral pillar. Group B: maintenance of >50% of lateral pillar height. Group C: maintenance of <50% of lateral pillar height. Group C has the poorest prognosis and often goes on to develop an aspherical femoral head and early osteoarthritis.

Question 73

A 14-year-old boy presents with vague, deep medial hindfoot pain and a history of multiple ankle sprains. Physical examination reveals a rigid flatfoot with marked limitation of subtalar motion and peroneal spasticity. A lateral radiograph of the ankle demonstrates a continuous bony bridge extending from the posterior aspect of the talus to the calcaneus, creating a continuous 'C-sign'. What is the most likely diagnosis, and what is the best advanced imaging modality to define the pathoa-natomy?

Explanation

The patient's clinical presentation is classic for a tarsal coalition. The 'C-sign' on a lateral ankle radiograph is a continuous radiodense line formed by the medial outline of the talar dome and the posterior outline of the sustentaculum tali, strongly indicating a talocalcaneal coalition (specifically involving the middle facet). Calcaneonavicular coalitions are best seen on an oblique radiograph (the 'anteater nose' sign). The gold standard advanced imaging modality to accurately map the bony anatomy and size of a coalition for preoperative planning is a CT scan.

Question 74

A 2-year-old girl is referred for anterolateral bowing of her left lower leg. The mother reports a recent minor fall, after which the child refused to bear weight. Radiographs show a fracture through a dysplastic, sclerotic mid-diaphyseal segment of the tibia that has failed to heal after 4 months of casting. This presentation of congenital pseudarthrosis of the tibia (CPT) is most strongly associated with which of the following underlying conditions?

Explanation

Congenital pseudarthrosis of the tibia (CPT) classically presents with anterolateral bowing of the tibia that eventually fractures and fails to unite due to an abnormal periosteal environment (fibromatosis). CPT is highly associated with Neurofibromatosis Type 1 (NF1), with up to 50% of patients with CPT having NF1. Conversely, about 5% of patients with NF1 will develop CPT. Anteromedial bowing is associated with fibular hemimelia, and posteromedial bowing is associated with a calcaneovalgus foot and leg-length discrepancy.

Question 75

An 8-year-old boy complains of a painless snapping sensation and intermittent lateral pain in his right knee. Radiographs reveal widening of the lateral joint space, squaring of the lateral femoral condyle, and a cupped appearance of the lateral tibial plateau. MRI demonstrates a complete, intact discoid lateral meniscus with no evidence of a tear. Given his symptomatic presentation, what is the recommended surgical management?

Explanation

The patient has a symptomatic complete discoid lateral meniscus. While asymptomatic discoid menisci should be observed, symptomatic ones (snapping, pain, locking) warrant surgical intervention. The modern standard of care is subtotal meniscectomy (saucerization) to reshape the meniscus into a normal crescent, while preserving a stable 6 to 8 mm peripheral rim to maintain meniscal function and prevent early osteoarthritis. Total meniscectomy is avoided due to the high risk of rapid, severe degenerative joint disease.

Question 76

A 13-year-old boy undergoes in situ pinning of a stable slipped capital femoral epiphysis (SCFE) of the right hip. Six months postoperatively, he presents with worsening right hip pain, a significant limp, and severely restricted range of motion in flexion and abduction. Radiographs demonstrate severe diffuse joint space narrowing, generalized osteopenia around the joint, but no evidence of segmental collapse or sclerosis of the femoral head. What is the most likely diagnosis?

Explanation

Chondrolysis is a known complication of SCFE, particularly associated with unrecognized intra-articular pin penetration, though it can occur idiopathically. It presents with progressive pain, severe global stiffness, and diffuse joint space narrowing on radiographs. Avascular necrosis (AVN) would typically present with sclerosis, subchondral radiolucency (crescent sign), and eventual segmental collapse of the femoral head, rather than isolated uniform joint space narrowing.

Question 77

A 5-year-old boy with spastic quadriplegic cerebral palsy (GMFCS level IV) presents for routine hip surveillance.

His parents report no pain, but the physical examination reveals hip abduction of 20 degrees bilaterally. An AP pelvis radiograph demonstrates a Reimers migration percentage of 45% bilaterally with early acetabular dysplasia. What is the most appropriate management?

Explanation

In a child older than 4 years with cerebral palsy and a Reimers migration percentage greater than 40%, soft tissue releases alone (such as adductor/psoas tenotomies) are insufficient and carry a high failure rate. Bony reconstruction with a varus derotational osteotomy (VDRO) of the proximal femur, combined with a pelvic osteotomy (e.g., Dega or San Diego) to address acetabular dysplasia, is the standard of care to restore hip biomechanics and prevent progressive dislocation.

Question 78

A 12-year-old boy presents with a 6-month history of frequent lateral ankle sprains and deep hindfoot pain exacerbated by sports. Examination reveals a rigid flatfoot with absent subtalar motion and peroneal spasticity.

Lateral radiographs of the foot reveal a distinct 'C-sign'. What is the most likely anatomical location of the primary pathology?

Explanation

The 'C-sign' on a lateral radiograph of the foot is highly indicative of a talocalcaneal coalition. It is a continuous radiopaque line formed by the medial outline of the talar dome and the posteroinferior outline of the sustentaculum tali. The most common site for a talocalcaneal coalition is the middle facet. Calcaneonavicular coalitions are best seen on an oblique radiograph and typically present with the 'anteater nose' sign.

Question 79

A 6-year-old girl falls from monkey bars and sustains a completely displaced, extension-type supracondylar fracture of the distal humerus.

During the preoperative evaluation, the hand is pink with palpable pulses, but she is unable to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which nerve is most likely injured, and what is the typical prognosis?

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar humerus fractures (often with posterolateral displacement). It is a purely motor branch of the median nerve, innervating the flexor pollicis longus and the flexor digitorum profundus to the index and long fingers. The injury is typically a neuropraxia, and spontaneous recovery usually occurs within 2 to 3 months. Acute exploration is not indicated.

Question 80

A 2-year-old girl is evaluated for a painless limp. Examination demonstrates a positive Galeazzi sign and asymmetric thigh folds. Radiographs reveal a dislocated right hip with a false acetabulum. The surgeon is considering closed reduction and spica casting versus open reduction. Which of the following is an absolute contraindication to closed reduction in this clinical scenario?

Explanation

An inverted limbus (or any dense fibrofatty tissue that interposes and prevents concentric seating of the femoral head) acts as a mechanical block. Forcing a closed reduction against this block will dramatically increase joint contact pressures and the risk of avascular necrosis (AVN). This is an absolute contraindication to closed reduction; an open reduction is required to excise or evert the limbus and clear the joint.

Question 81

A 3-year-old boy, initially treated with the Ponseti method for idiopathic right clubfoot, presents with a relapse.

His parents report that he walks on the outside border of his right foot. Gait analysis shows dynamic supination of the foot during the swing phase. Passive range of motion indicates the deformity is fully correctable. What is the most appropriate next step in management?

Explanation

Dynamic supination during the swing phase in a toddler who has previously undergone successful Ponseti casting is caused by an overactive tibialis anterior pulling against weakened evertors. If the foot is passively correctable, the treatment of choice is the transfer of the entire tibialis anterior tendon (TATT) to the lateral cuneiform. This procedure rebalances the foot and prevents further recurrence.

Question 82

A 14-year-old boy presents to the emergency department after a twisting injury to his ankle while playing soccer.

Radiographs and a CT scan reveal a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis, displaced by 3 mm. What is the pathomechanical etiology of this specific fracture pattern?

Explanation

The scenario describes a juvenile Tillaux fracture. This occurs in adolescents (usually 12-14 years old) because the distal tibial physis closes in a specific pattern: central, then anteromedial, then posteromedial, and finally anterolateral. Because the anterolateral physis remains open last, an external rotation force causes the strong anterior inferior tibiofibular ligament (AITFL) to avulse the anterolateral epiphyseal fragment.

Question 83

A 4-year-old boy is brought to the clinic for progressive, severe bilateral leg bowing. Standing radiographs reveal a metaphyseal-diaphyseal angle (MDA) of 20 degrees bilaterally with profound medial physeal beaking (Langenskiöld stage III). He has previously worn KAFO braces for 1 year without improvement. What is the most appropriate management?

Explanation

This child has infantile Blount disease that has failed conservative management. In children older than 3 to 4 years of age with advanced Langenskiöld stages (II or higher) and high MDAs (>16 degrees), bracing is ineffective. Proximal tibial valgus osteotomy (along with fibular osteotomy or release) is indicated to restore mechanical alignment and decompress the medial physis before permanent physeal arrest occurs. Plateau elevation is reserved for older children with severe joint depression (Langenskiöld stage V/VI).

Question 84

An 8-year-old boy is diagnosed with Legg-Calvé-Perthes disease.

Which of the following radiographic findings is considered one of Catterall's 'head at risk' signs, indicating a potentially poorer prognosis and an increased likelihood of epiphyseal extrusion?

Explanation

Catterall identified several 'head at risk' signs that correlate with a poorer prognosis and impending lateral extrusion of the femoral head in Legg-Calvé-Perthes disease. These include: lateral (not medial) subluxation of the femoral head, Gage's sign (a V-shaped radiolucency in the lateral portion of the epiphysis and metaphysis), calcification lateral to the epiphysis, diffuse metaphyseal radiolucencies, and a horizontal (not vertical) orientation of the growth plate.

Question 85

A 5-year-old boy sustains a severe, completely displaced extension-type supracondylar fracture of the humerus. On presentation, the hand is pink and warm, but the radial pulse is absent. He has normal capillary refill and intact median, ulnar, and radial nerve motor and sensory function. Following an urgent closed reduction and percutaneous pinning, the hand remains pink and warm, and the radial pulse remains absent. What is the most appropriate next step in management?

Explanation

The management of the 'pulseless, pink hand' after adequate reduction and stabilization of a pediatric supracondylar humerus fracture is observation. The well-perfused hand (pink, warm, brisk capillary refill) indicates adequate collateral circulation. Routine surgical exploration or arteriography is not indicated, as the brachial artery often spasms or is tethered but collateral flow is sufficient. The patient must be admitted and closely monitored for compartment syndrome or loss of perfusion.

Question 86

A 3-year-old child who was successfully treated with the Ponseti method for idiopathic clubfoot now presents with dynamic supination of the foot during the swing phase of gait. On examination, the foot is fully correctable passively with no fixed structural deformity. What is the most appropriate next step in management?

Explanation

In young children treated with the Ponseti method, dynamic supination during walking is a classic sign of relapse. The tibialis anterior acts as a strong supinator, and transferring the whole tendon to the lateral cuneiform balances the foot. Whole tendon transfer is preferred over SPLATT in pediatric clubfoot to avoid excessively weakening dorsiflexion power and because SPLATT acts primarily as a tenodesis.

Question 87

A 6-month-old infant with developmental dysplasia of the hip (DDH) was treated with a Pavlik harness starting at age 4 weeks. After 4 weeks of harness wear, the hip remained dislocated, and the harness was discontinued. Currently, ultrasound confirms persistent dislocation. What is the most appropriate next step in management?

Explanation

Pavlik harness failure occurs in about 10% of cases. Continuing the harness past 3-4 weeks if the hip remains dislocated increases the risk of 'Pavlik harness disease' (damage to the posterior acetabular wall) and avascular necrosis. The next appropriate step is closed reduction and spica casting, often preceded by an arthrogram or an adductor tenotomy.

Question 88

A 14-year-old boy with spastic diplegic cerebral palsy presents with severe crouch gait. Physical examination reveals a popliteal angle of 80 degrees, knee flexion contractures of 15 degrees bilaterally, and severe planovalgus foot deformities. Radiographs demonstrate patella alta. Which of the following combinations of surgical procedures is most appropriate to address his knee pathology?

Explanation

Crouch gait in CP is characterized by excessive hip and knee flexion and ankle dorsiflexion during the stance phase. The treatment of fixed knee flexion contractures (>10-15 degrees) typically requires a distal femoral extension osteotomy (DFEO) combined with patellar advancement to treat secondary patella alta, and hamstring lengthening to address underlying spasticity or contracture.

Question 89

A 6-year-old boy sustains a completely displaced extension-type supracondylar humerus fracture. On initial examination, the hand is pink, but the radial pulse is absent. He is taken to the operating room for closed reduction and percutaneous pinning. Post-reduction, the hand remains pink and warm with a capillary refill of less than 2 seconds, but the radial pulse remains unpalpable. Doppler ultrasound confirms flow in the palmar arch. What is the most appropriate next step?

Explanation

The 'pulseless, pink hand' is a well-known entity in pediatric supracondylar humerus fractures. If the hand remains pink and well-perfused (capillary refill <2 seconds, confirmed Doppler signals in the palmar arch) after adequate reduction and pinning, the current standard of care is observation. Vascular exploration is indicated for a white, pulseless hand that does not improve after reduction.

Question 90

A 2.5-year-old girl is evaluated for bilateral bowlegs. Her BMI is in the 95th percentile. Radiographs reveal a metaphyseal-diaphyseal angle (Drennan's angle) of 18 degrees on the right and 19 degrees on the left. There is prominent medial metaphyseal beaking. What is the most appropriate initial management?

Explanation

Infantile Blount disease presents in children <3 years old. A metaphyseal-diaphyseal angle (Drennan's angle) >16 degrees is highly predictive of progressive disease. Initial management for symptomatic children under age 3 is nonoperative with knee-ankle-foot orthoses (KAFOs) worn during weight-bearing. Surgery is indicated if bracing fails or if the child presents at an older age.

Question 91

A 12-year-old boy with a BMI of 32 presents with knee pain. He walks with a limp and his foot is externally rotated. Examination shows obligatory external rotation with hip flexion. AP and frog-leg lateral radiographs of the pelvis show a mild left slipped capital femoral epiphysis (SCFE) and a normal right hip. What is the most appropriate management?

Explanation

Unilateral idiopathic SCFE is typically treated with unilateral in situ percutaneous pinning using a single central screw. Prophylactic pinning of the contralateral hip is generally reserved for patients with endocrine or metabolic disorders, radiation therapy, or those who cannot reliably follow up, given the surgical risks (AVN, chondrolysis, fracture) outweighing the benefits in healthy patients.

Question 92

A 7-year-old girl with Down syndrome wishes to participate in Special Olympics gymnastics. She is completely asymptomatic, has no history of neck pain or weakness, and her neurologic examination is normal. Based on the American Academy of Pediatrics (AAP) guidelines, what is the recommendation regarding pre-participation cervical spine screening?

Explanation

The American Academy of Pediatrics (AAP) revised its guidelines, stating that routine cervical spine radiographs in asymptomatic children with Down syndrome are not indicated prior to sports participation, as they have poor predictive value for catastrophic spinal cord injury. Targeted radiographic screening is recommended only for patients with symptomatic neck pain, radiculopathy, or myelopathy.

Question 93

A 14-year-old girl sustains an ankle injury. Radiographs show a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis. Which structure is responsible for the avulsion of this fracture fragment?

Explanation

A juvenile Tillaux fracture is a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis. It occurs due to an avulsion force from the anterior inferior tibiofibular ligament (AITFL). This happens because the distal tibial physis closes in a characteristic pattern: central, then anteromedial, then posteromedial, and finally lateral, leaving the anterolateral portion vulnerable to avulsion.

Question 94

A 6-month-old infant is evaluated for frequent fractures and is found to have blue sclerae and dentinogenesis imperfecta. A diagnosis of osteogenesis imperfecta is made. This condition is primarily associated with a defect in the synthesis of which of the following?

Explanation

Osteogenesis imperfecta (OI) is a genetic connective tissue disorder primarily caused by autosomal dominant mutations in the COL1A1 or COL1A2 genes, which encode the alpha-1 and alpha-2 chains of Type I collagen. Type I collagen is a major structural component of bone, sclera, and dentin, leading to the classic triad of fragile bones, blue sclerae, and dentinogenesis imperfecta.

Question 95

An 8-year-old boy presents with a limp. Radiographs confirm Legg-Calvé-Perthes disease with fragmentation of the femoral head and more than 50% collapse of the lateral pillar. According to the Herring lateral pillar classification, which of the following best describes his prognosis and indicated management?

Explanation

The Herring lateral pillar classification determines the prognosis in Legg-Calvé-Perthes disease based on the height of the lateral pillar on AP radiographs during the fragmentation stage. Group C indicates >50% loss of lateral pillar height. In children over 8 years of age, Group C hips have a poor prognosis, and studies show that surgical containment does not significantly improve outcomes compared to nonoperative treatment in this specific older cohort.

Question 96

An 11-year-old obese boy presents with right hip pain and a limp. Radiographs confirm a unilateral right slipped capital femoral epiphysis (SCFE), which is treated with in situ single-screw fixation. The parents ask about the risk of the left hip developing the same condition. Which of the following radiographic findings is the strongest predictor for a subsequent contralateral slip and most justifies prophylactic pinning of the asymptomatic left hip?

Explanation

The status of the triradiate cartilage is a crucial indicator of skeletal maturity and the strongest predictor for the development of a contralateral SCFE. An open triradiate cartilage indicates significant remaining skeletal growth, placing the patient at high risk (up to 60-80% in some series, especially in younger or obese patients) for a subsequent contralateral slip. The modified Oxford Bone Age scoring system, which assesses the iliac crest, triradiate cartilage, and proximal femoral epiphysis, is often utilized to quantify this risk. A high Southwick angle describes the severity of the current slip but does not predict the contralateral side. Klein's line intersection is a normal finding; failure to intersect would indicate an already existing slip.

Question 97

A 6-year-old girl is brought to the emergency department after falling from monkey bars. She sustains a severely displaced Gartland type III supracondylar humerus fracture. On initial examination, her hand is pink and well-perfused, but the radial pulse is absent. She is taken to the operating room for urgent closed reduction and percutaneous pinning. Following stable anatomic reduction and pinning, the hand remains pink with brisk capillary refill (< 2 seconds), but the radial pulse remains nonpalpable by Doppler. What is the most appropriate next step in management?

Explanation

The management of the "pink, pulseless hand" following adequate reduction and percutaneous pinning of a pediatric supracondylar humerus fracture is observation. Studies have consistently shown that if the hand remains well-perfused (warm, pink, capillary refill < 2 seconds) despite an absent palpable or Dopplerable pulse, collateral circulation is adequate. Routine vascular exploration or advanced imaging (CTA) is not indicated in this scenario, as the pulse often returns within a few days to weeks, and long-term functional outcomes are excellent. If the hand were "white and pulseless" post-reduction, immediate exploration of the brachial artery would be warranted.

Question 98

A 5-week-old infant is being treated with a Pavlik harness for developmental dysplasia of the left hip. During the 2-week follow-up visit, the parents report that the infant has stopped kicking the left leg. On physical examination, the infant exhibits an absence of active knee extension on the left side, though hip flexion and ankle movements are preserved. Ultrasound confirms the hip is well-reduced. What is the most appropriate management of this complication?

Explanation

The infant has developed a femoral nerve palsy, a known complication of Pavlik harness treatment occurring in approximately 2.5% of cases. It is typically caused by excessive hip flexion (anterior straps too tight) compressing the femoral nerve. The classic presentation is a loss of active knee extension. The standard of care is to discontinue the harness (or significantly loosen it, though most prefer brief discontinuation) to allow the nerve palsy to resolve, which usually occurs within 1 to 2 weeks. Continuing the harness or switching to a rigid orthosis immediately without allowing nerve recovery is contraindicated.

Question 99

A 17-year-old non-ambulatory male (GMFCS Level V) with spastic quadriplegic cerebral palsy presents with severe right hip pain that interferes with seating, perineal care, and sleep. Radiographs demonstrate a chronically dislocated right hip with severe degenerative changes and a deformed femoral head. He has failed extensive non-operative management, including optimizing medical therapy and seating modifications. Which of the following surgical interventions is most appropriate to alleviate his pain and improve nursing care?

Explanation

In severe, non-ambulatory cerebral palsy patients (GMFCS Level V) with a painful, chronically dislocated hip demonstrating severe femoral head deformity and secondary osteoarthritis, reconstructive procedures (such as VDRO and pelvic osteotomies) have unacceptably high failure and complication rates. Salvage procedures are indicated to relieve pain and facilitate perineal hygiene. Proximal femoral resection arthroplasty (e.g., Castle procedure) or proximal femoral valgus osteotomy (e.g., McHale procedure) are the procedures of choice. Total hip arthroplasty is generally contraindicated in GMFCS V patients due to extremely high rates of dislocation and infection. Adductor tenotomy alone is insufficient for a degenerated, dislocated hip.

Question 100

An 9-year-old boy presents with a 5-month history of a painless limp and right hip stiffness. Radiographs demonstrate Legg-Calvé-Perthes disease in the fragmentation stage.

Which of the following factors is the most reliable predictor of a poor long-term radiographic and clinical outcome, often necessitating surgical containment?

Explanation

Age at disease onset is one of the most critical prognostic factors in Legg-Calvé-Perthes disease. Children who develop the disease after the age of 8 years have less potential for remodeling and typically experience worse long-term outcomes (higher risk of severe residual deformity and early-onset osteoarthritis). According to the multicenter prospective studies by Herring et al., patients older than 8 years at onset who have Lateral Pillar B or B/C border hips benefit significantly from surgical containment (e.g., proximal femoral varus osteotomy or pelvic osteotomy) compared to non-operative treatment. Lateral Pillar Class A has a universally good prognosis regardless of age.

AAOS Pediatric Orthopedic MCQs (Set 2): DDH, SCFE & Spinal Deformities | Board Review

Orthopedic Pediatrics 2026 MCQs: Board Review Questions & Answers (Part 4)

Key Takeaway

Orthopedic Pediatrics 2026 MCQs: Board Review Questions & Answers (Part 4)

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