Orthopedic Pediatrics 2026 MCQs: Board Review Q&A

Question 1

A pediatric orthopaedic surgeon refers a child to a neurologist. The neurologist's office requests the office records of the pediatric orthopaedic surgeon. To maintain Health Insurance Portability and Accountability Act (HIPAA) compliance, what must the surgeon obtain from the parent(s) prior to sending records?

Explanation

The privacy rules do not require an individual's written authorization for certain permitted or required uses and disclosures of the medical records. Patient or parental authorization is not required for disclosures for certain purposes related to treatment, payment, or health care operations. Specifically, HIPAA does not require a covered entity to obtain patient authorization for many of the health care industry's most fundamental activities such as providing care. Carroll R: Risk Management Handbook for Health Care Organizations, ed 4. Hoboken, NJ, Jossey-Bass, 2003, p 1142.

Question 2

A 13-year-old boy injured his knee playing basketball and is now unable to bear weight. Examination reveals tenderness and swelling at the proximal anterior tibia, with a normal neurologic examination. AP and lateral radiographs are shown in Figures 1a and 1b. Management should consist of

Explanation

1b The patient has a displaced intra-articular tibial tuberosity fracture; therefore, the treatment of choice is open reduction and internal fixation. Periosteum is often interposed between the fracture fragments and prevents satisfactory closed reduction. Fortunately, most patients with this injury are close to skeletal maturity and therefore, growth arrest and recurvatum are unusual. Nondisplaced fractures can be treated with a cast, but displaced fractures are best treated with open reduction and internal fixation. Intra-articular fractures can disrupt the joint surface and are sometimes associated with a meniscal tear; therefore, arthroscopy may be needed at the time of open reduction and internal fixation. McKoy BE, Stanitski CL: Acute tibial tubercle avulsion fractures. Orthop Clin North Am 2003;34:397-403.

Question 3

A 12-year-old boy sustained a grade III open tibial fracture 1 week ago and underwent multiple debridements and fracture fixation. He now has a soft-tissue defect that measures 6 cm x 6 cm, with an area of exposed bone and muscle on the distal medial leg that is a few centimeters proximal to the ankle. Management of the soft-tissue defect should now consist of

Explanation

The soft-tissue defect is in a very difficult position - the distal tibia. The defect is too distal for a gastrocnemius flap, and the exposed bone precludes an immediate skin graft. A free flap and skin graft would be required for closure. VAC is very effective in soft-tissue defects such as this one. Healthy granulation tissues form quickly. VAC can be the definitive treatment, or it can be used before skin grafting. Wet-to-dry dressings could promote granulation, but the process is hastened substantially by VAC. Amputation is not a consideration because there are no signs of infection or fracture healing problems at this time. Mooney JF III, Argenta LC, Marks MW, et al: Treatment of soft tissue defects in pediatric patients using the V.A.C. system. Clin Orthop 2000;376:26-31.

Question 4

A 6-year-old child sustained a closed nondisplaced proximal tibial metaphyseal fracture 1 year ago. She was treated with a long leg cast with a varus mold, and the fracture healed uneventfully. She now has a 15-degree valgus deformity. What is the next step in management?

Explanation

The tibia has grown into valgus secondary to the proximal fracture. This occurs in about one half of these injuries, and maximal deformity occurs at 18 months postinjury. The deformity gradually improves over several years, with minimal residual deformity. Therefore, treatment at this age is unnecessary as there is a high rate of recurrence and complications regardless of technique. The valgus deformity is not a result of physeal injury or growth arrest. Medial proximal tibial hemiepiphysiodesis is an excellent method of correcting the residual deformity but is best reserved until close to the end of growth. Brougham DI, Nicol RO: Valgus deformity after proximal tibial fractures in children. J Bone Joint Surg Br 1987;69:482. McCarthy JJ, Kim DH, Eilert RE: Posttraumatic genu valgum: Operative versus nonoperative treatment. J Pediatr Orthop 1998;18:518-521.

Question 5

To control most spontaneous bleeding into the knee in children with hemophilia, factor VIII must be replaced to what percentage of normal?

Explanation

The knee is the most common location of spontaneous bleeding in children with hemophilia. Treatment generally requires replacement to 40% to 50% of normal. For surgery, the replacement should be to 100%. The plasma level generally rises 2% for every unit (per kg body weight) of factor VIII administered. Rodriquez-Merchan EC: Management of the orthopaedic complications of hemophilia. J Bone Joint Surg Br 1998;80:191-196.

Question 6

A 6-year-old girl is referred for the elbow injury seen in Figure 2. What is the most appropriate treatment?

Explanation

The patient has a displaced lateral condyle fracture; therefore, simple immobilization for 3 to 8 weeks is likely to result in malunion or nonunion. Closed reduction of such injuries is rarely successful. The fracture is unstable, so fixation is required after open reduction. Because the fixation must cross the physis, smooth pins are indicated for the skeletally immature elbow. Open reduction with fixation has been shown to reduce the risk of delayed union and malunion. Beaty JH, Kasser JR: The elbow: Physeal fractures, apophyseal injuries of the distal humerus, avascular necrosis of the trochlea, and T-condylar fractures, in Beaty JH, Kasser JR (eds): Fractures in Children, ed 5. Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 625-703. Rutherford A: Fractures of the lateral humeral condyle in children. J Bone Joint Surg Am 1985;67:851-856.

Question 7

A patient who underwent closed reduction of the hips as an infant now reports pain. An abduction internal rotation view shows an incongruous joint. Based on the findings shown in Figure 3, what is the most appropriate type of pelvic osteotomy for the right hip?

Explanation

Pelvic osteotomies that redirect hyaline cartilage over the femoral head offer the potential for long-term preservation of the hip; however, salvage procedures such as the Chiari osteotomy are indicated in patients without a concentrically reducible hip. Ito and associates reported that moderate dysplasia and moderate subluxation without complete obliteration of the joint space and a preoperative center-edge angle of at least minus 10 degrees are desirable selection criteria. Ohashi H, Hirohashi K, Yamano Y: Factors influencing the outcome of Chiari pelvic osteotomy: A long-term follow-up. J Bone Joint Surg Br 2000;82:517-525.

Question 8

An 18-year-old girl with quadriplegic cerebral palsy underwent posterior spinal fusion from T2 to the pelvis 3 weeks ago. She now has a low-grade fever and mild midline erythema in a 1-cm area from which there is slight clear yellowish drainage. What is the next most appropriate step in management?

Explanation

The presence of drainage 3 weeks after surgery is a sign of wound infection. This infection most likely involves deep tissues until proven otherwise. Oral or IV antibiotics, in the absence of debridement, are not sufficient. Removal of the hardware would lead to rapid progression of the scoliosis in a spine that has been surgically destabilized by removal of the facet joints. The appropriate treatment is debridement with wound culture, IV antibiotics, and retention of hardware. The wound should be closed over drains. Theiss SM, Lonstein JE, Winter RB: Wound infections in reconstructive spine surgery. Orthop Clin North Am 1996;27:105-110.

Question 9

A 13-year-old girl is referred for a painful progressive valgus deformity of the right knee. Examination reveals an antalgic gait with an obvious valgus deformity. The right distal femur has a palpable, tender mass with erythema and warmth. Figures 4a and 4b show a clinical photograph and a radiograph. Management should consist of

Explanation

4b The radiograph shows a pathologic fracture through a destructive lesion of the distal femur metaphysis with osteolytic and osteoblastic features. The lateral cortex is destroyed, and there is periosteal new bone formation. These findings are consistent with malignancy, most likely an osteogenic sarcoma. Patients with suspected malignant tumors are best managed by surgeons with specific expertise in orthopaedic oncology. The biopsy of a malignant lesion should be deferred to the surgeon who is capable of definitive management of the patient. Enneking W: Principles of musculoskeletal oncologic surgery, in Evarts C (ed): Surgery of the Musculoskeletal System. New York, NY, Churchill Livingston, 1990.

Question 10

An 18-month-old boy with obstetric brachial plexus palsy is being evaluated for limited right shoulder motion. Physical therapy for the past 6 months has failed to result in improvement of the contracture. Which of the following studies is necessary prior to any shoulder reconstruction?

Explanation

The child sustained a brachial plexus injury at birth, and internal rotation/adduction contractures frequently develop at the shoulder. Initial treatment should consist of physical therapy to increase the range of motion. If this fails, as in this patient, MRI is used to evaluate the glenohumeral joint. Commonly, there is joint deformity with increased retroversion of the glenoid and even posterior shoulder subluxation. If the deformity is mild, an anterior release, coupled with teres major and latissimus transfers, is very effective. If the deformity is severe and the shoulder is unreconstructable, then humeral derotation osteotomy is the procedure of choice. MRI of the brain, a radiograph of the elbow, and aspiration of the shoulder would not be helpful. Waters PM: Update on management of pediatric brachial plexus palsy. J Pediatr Orthop B 2005;14:233-244. Waters PM, Bae DS: Effect of tendon transfers and extra-articular soft-tissue balancing on glenohumeral development in brachial plexus birth palsy. J Bone Joint Surg Am 2005;87:320-325.

Question 11

Where is the underlying defect in a rhizomelic dwarf with the findings shown in Figure 5?

Explanation

The radiograph shows the typical findings of achondroplasia. The defect is in fibroblast growth factor receptor 3. The pedicles narrow distally in the lumbar spine. The pelvis is low and broad with narrow sciatic notches and ping-pong paddle-shaped iliac wings. This is often called a champagne glass pelvis. Type I collagen abnormalities are typically found in osteogenesis imperfecta, and type II collagen defects are found in spondyloepiphyseal dysplasia and Kneist syndrome. COMP is defective in multiple epiphyseal dysplasia. Sulfate transport defects are seen in diastrophic dysplasia. Johnson TR, Steinbach LS: Essentials of Musculoskeletal Imaging. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2004, pp 809-812.

Question 12

A 2-year-old boy has complete absence of the sacrum and lower lumbar spine. What is the most likely long-term outcome if no spinal pelvic stabilization is performed?

Explanation

Without stabilization, progressive kyphosis will develop between the spine and pelvis. The kyphosis progresses to the point that the child must use his or her hands to support the trunk, and therefore is unable to use his or her hands for other activities. Neck extension contracture does not usually develop. Neurologic deficit, including sexual dysfunction, is generally present at birth and static. Tachdjian MO: The spine: Congenital absence of the sacrum and lumbosacral vertebrae (lumbosacral agenesis), in Wickland EH Jr (ed): Pediatric Orthopaedics, ed 2. Philadelphia, PA, WB Saunders, 1990, vol 3, p 2228.

Question 13

Which of the following findings is most prognostic for the ability of a young child with cerebral palsy to walk?

Explanation

Several studies have shown that sitting ability by age 2 years is highly prognostic of walking. Molnar and Gordon reported that children not sitting independently by age 2 years had a poor prognosis for walking. Wu and associates reported that children sitting without support by age 2 years had an odds ratio of 26:1 of walking compared with those unable to sit. This was far higher than the odds ratios for cerebral palsy location, motor dysfunction, crawling, creeping, scooting, or rolling. Molnar GE, Gordon SU: Cerebral palsy: Predictive value of selected clinical signs for early prognostication of motor function. Arch Phys Med Rehabil 1976;57:153-158.

Question 14

A 2-year-old girl has had a 2-day history of fever and refuses to move her left shoulder following varicella. Laboratory studies show an erythrocyte sedimentation rate of 75 mm/h and a peripheral WBC count of 18,000/mm3. What is the most common organism in this scenario?

Explanation

The most common bacterial etiologic agent following varicella is group A beta-hemolytic streptococcus. The other organisms are much less common. Staphylococcus aureus is the most common bone infection organism. Staphylococcus epidermidis is increasingly a bone infection organism. Group B streptococcus occurs more commonly in newborns. Kingella kingae is a common joint pathogen but is not as common following varicella. Schreck P, Schreck P, Bradley J, et al: Musculoskeletal complications of varicella. J Bone Joint Surg Am 1996;78:1713-1719.

Question 15

Which of the following is considered the best method to measure limb-length discrepancy in a patient with a knee flexion contracture?

Explanation

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

Question 16

A 5-year-old boy sustained an elbow injury. Examination in the emergency department reveals that he is unable to flex the interphalangeal joint of his thumb and the distal interphalangeal joint of his index finger. The radial pulse is palpable at the wrist, and sensation is normal throughout the hand. Radiographs are shown in Figures 6a and 6b. In addition to reduction and pinning of the fracture, initial treatment should include

Explanation

6b The findings are consistent with a neurapraxia of the anterior interosseous branch of the median nerve. This is the most common nerve palsy seen with supracondylar humerus fractures, followed closely by radial nerve palsy. Nearly all cases of neurapraxia following supracondylar humerus fractures resolve spontaneously, and therefore, further diagnostic studies and surgery are not indicated. Cramer KE, Green NE, Devito DP: Incidence of anterior interosseous nerve palsy in supracondylar humerus fractures in children. J Pediatr Orthop 1993;13:502-505.

Question 17

An 11-year-old basketball player reports that he felt a painful pop in the left knee when he stumbled while running. He is unable to bear weight on the extremity and cannot actively extend the knee against gravity. Examination reveals a large knee effusion. A lateral radiograph is shown in Figure 7. Management should consist of

Explanation

The radiograph shows an avulsion fracture, or "sleeve fracture," of the distal pole of the patella. The distal fragment is much larger than it appears on the radiograph because it largely consists of cartilage; therefore, excision of the fragment is contraindicated. The treatment of choice is open reduction and tension band fixation to correct patella alta and restore the extensor mechanism. Maguire JK, Canale ST: Fractures of the patella in children and adolescents. J Pediatr Orthop 1993;13:567-571.

Question 18

Figures 8a and 8b show the clinical photograph and radiograph of a 4-month-old infant who has a left foot deformity. Examination reveals that the foot deformity is an isolated entity, and the infant has no known neuromuscular conditions or genetic syndromes. Which of the following studies will best confirm the diagnosis?

Explanation

8b The clinical photograph shows a rocker-bottom deformity, and the lateral radiograph suggests a congenital vertical talus deformity. A lateral radiograph of the foot in maximum plantar flexion is needed to demonstrate the fixed position of the deformity with malalignment of the talar-metatarsal axis. A fixed dislocation of the navicular on the talus differentiates a congenital vertical talus from the oblique talus with talonavicular subluxation. Kumar SJ, Cowell HR, Ramsey PL: Vertical and oblique talus. Instr Course Lect 1982;31:235-251. Kodros SA, Dias LS: Single-stage correction of congenital vertical talus. J Pediatr Orthop 1999;19:42-48.

Question 19

An 8-year-old girl was treated for a Salter-Harris type I fracture of the right distal femur 2 years ago. Examination reveals symmetric knee flexion, extension, and frontal alignment compared to the contralateral knee. She has 1-cm of shortening of the right femur. History reveals that she has always been in the 50th percentile for height, and her skeletal age matches her chronologic age. Radiographs are shown in Figure 9. What is the expected consequence at maturity?

Explanation

The child has a near complete central physeal arrest of the distal femur and worsening limb-length discrepancy will develop. She is growing at the average rate for the population. The distal femoral physis grows at a rate of roughly 9 mm per year. Girls finish their growth at approximately age 14 years. Thus, at maturity the left leg will be 6.4 cm longer than the right. An angular deformity has not developed at this point and her arrest is central; therefore, angular deformity is unlikely to develop in any plane. Little DG, Nigo L, Aiona MD: Deficiencies of current methods for the timing of epiphysiodesis. J Pediatr Orthop 1996;16:173-179.

Question 20

Examination of an obese 3-year-old girl reveals 30 degrees of unilateral genu varum. A radiograph of the involved leg with the patella forward is shown in Figure 10. Management should consist of

Explanation

The clinical scenario describes infantile tibia vara (Blount's disease). The radiograph shows severe deformity with the characteristic Langenskiold stage 3 changes of the medial proximal tibial metaphysis that distinguish it from physiologic bowing. The preferred treatment is proximal tibiofibular osteotomy with acute correction into slight valgus to unload the damaged area of the physis. This method provides the best results in patients younger than age 4 years. Continued observation would result in progressive deformity. Bracing is most effective in younger children with less severe deformity. Lateral proximal tibial hemiepiphysiodesis relies on growth of the injured medial physis for correction and would result in severe tibial shortening in this young child. Complete epiphysiodesis also produces severe shortening and requires multiple lengthening procedures. Johnston CE II: Infantile tibia vara. Clin Orthop 1990;255:13-23.

Question 21

What is the most important consideration in the preoperative evaluation of a child with polyarticular or systemic juvenile rheumatoid arthritis (JRA)?

Explanation

The cervical spine may be involved in a child with polyarticular or systemic JRA; fusion or instability can occur. Radiographic assessment of the cervical spine should include lateral flexion-extension views. The potential exists for spinal cord injury during intubation or positioning in the presence of an unstable cervical spine. Limitations of the TMJ and micrognathia may affect ease of intubation and administration of anesthesia via a mask. If the TMJ and jaw are involved, some patients may have dental findings such as dental caries and even abscesses which can affect surgery. Some children, particularly those with systemic arthritis, may be taking corticosteroids long-term and may need stress dosing with complex surgeries. Although it is important to routinely check for uveitis and iritis in children with JRA, this usually is not needed preoperatively. Uveitis and iritis are less likely in a child with systemic JRA. Cassity JT, Petty RE (eds): Textbook of Pediatric Rheumatology, ed 5. Philadelphia, PA, WB Saunders, 2005. Ilowite N: Current treatment of juvenile rheumatoid arthritis. Pediatrics 2002;109:109-115. Ruddy S, Harris ED, Sledge CB (eds): Kelley's Textbook of Rheumatology, ed 6. Philadelphia, PA, WB Saunders, 2001.

Question 22

A 15-year-old boy has a mass at the knee. Radiographs show an aggressive tumor involving the proximal tibia, and biopsy findings reveal a high-grade osteosarcoma. Staging studies show that the tumor impinges on the neurovascular bundle. The tumor enlarges during preoperative chemotherapy. Management should now consist of

Explanation

Limb salvage procedures have become the usual treatment for even high-grade osteosarcomas. However, tumors associated with pathologic fracture, tumors encasing the neurovascular bundle, and tumors that enlarged during preoperative therapy and are adjacent to the neurovascular bundle require amputation.

Question 23

Figure 11 shows the radiograph of a 2-year-old child with marked genu varum and tibial bowing. Based on these findings, what is the best initial course of action?

Explanation

The radiograph shows multiple wide physes, consistent with a diagnosis of rickets. A low serum phosphorous level and an elevated alkaline phosphatase level are the hallmarks in diagnosing familial hypophosphatemic Vitamin D-resistant rickets. Serum calcium is usually normal or low normal. This disease is inherited as an X-linked dominant trait and usually presents at age 18 to 24 months. The disease results from a poorly defined problem with renal phosphate transport in which normal dietary intake of vitamin D is insufficient to achieve normal bone mineralization. Renal tubular dysfunction is associated with urinary phosphate wasting. Treatment involves oral phosphate supplementation, which can cause hypocalcemia and secondary hyperparathyroidism. To prevent associated problems, high doses of Vitamin D are administered. While obtaining a scanogram may be clinically indicated in an associated limb-length discrepancy, and subsequent corrective surgery may be indicated, either of these choices would not be the first course of action. An orthosis may slow the progression of genu varum in this disorder but is less important than establishing the correct diagnosis to begin pharmacologic treatment. This amount of varum and tibial bowing far exceeds the normal limits of physiologic genu varum. Skeletal dysplasias usually are not associated with abnormal laboratory values. Herring JA: Metabolic and endocrine bone diseases, in Tachdjian's Pediatric Orthopaedics, ed 3. New York, NY, WB Saunders, 2002, pp 1685-1743.

Question 24

Figure 12 shows the radiograph of a 15-year-old boy with cerebral palsy who has pain at the first metatarsophalangeal joints. He is a community ambulator. Management consisting of accommodative shoes has failed to provide relief. What is the treatment of choice?

Explanation

While other surgeries have provided some success, first metatarsophalangeal joint arthrodesis has the highest overall success rate compared to other surgeries in ambulatory and nonambulatory children with cerebral palsy. The recurrence rate is unacceptably high with the other procedures listed above. In contrast, neurologically normal children are amenable to osteotomies and soft-tissue procedures. Davids JR, Mason TA, Danko A, et al: Surgical management of hallux valgus deformity in children with cerebral palsy. J Pediatr Orthop 2001;21:89-94.

Question 25

What risk factor is most associated with progression of idiopathic scoliosis to a curve requiring surgery?

Explanation

The magnitude of the curve at the time of the peak height velocity is the most prognostic sign in relationship to surgery. More than 70% of curves that measure more than 30 degrees at this time are likely to reach surgical range. Little DG, Song KM, Katz D, et al: Relationship of peak height velocity to other maturity indicators in idiopathic scoliosis in girls. J Bone Joint Surg Am 2000;82:685-693.

Question 26

A 6-week-old female is treated with a Pavlik harness for developmental dysplasia of the hip. At the 2-week follow-up, the parents report the infant is no longer kicking her right leg. Examination reveals decreased active knee extension on the right, but normal sensation. What is the most appropriate next step in management?

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically resulting from hyperflexion of the hip due to overly tight anterior straps. The harness should be temporarily removed or adjusted; the palsy almost always resolves spontaneously.

Question 27

In the Ponseti method for the treatment of idiopathic congenital talipes equinovarus (clubfoot), what is the correct sequential order of deformity correction?

Explanation

The Ponseti method dictates correction in the mnemonic sequence CAVE: Cavus, Adductus, Varus, and finally Equinus. Correcting the cavus first by elevating the first ray provides a solid foundation to correct the remaining deformities.

Question 28

A 6-year-old boy presents with a completely displaced, extension-type supracondylar humerus fracture. On examination, the hand is pink and warm, but the radial pulse is absent. After urgent closed reduction and percutaneous pinning, the hand remains pink and warm, but the pulse remains absent. What is the most appropriate next step?

Explanation

A "pulseless, pink" hand after reduction and pinning of a supracondylar fracture indicates adequate collateral circulation. Observation is the standard of care, as most radial pulses return within 24 to 48 hours without needing surgical exploration.

Question 29

A 13-year-old obese boy presents with acute-on-chronic hip pain and an inability to bear weight. Radiographs confirm a Slipped Capital Femoral Epiphysis (SCFE). He undergoes urgent in situ percutaneous pinning. Which of the following complications is most highly associated with this specific preoperative presentation?

Explanation

The inability to bear weight defines an unstable SCFE, which carries a significantly higher risk of avascular necrosis (AVN) of the femoral head compared to stable SCFE. Urgent decompression and fixation are often advocated to mitigate this risk.

Question 30

A 14-year-old boy sustains a twisting ankle injury resulting in a Salter-Harris III fracture of the anterolateral distal tibia. Which of the following best describes the anatomical basis for this specific fracture pattern?

Explanation

A Tillaux fracture occurs because the distal tibial physis closes in a predictable sequence: central, medial, then lateral. The anterolateral portion remains open longest, making it susceptible to avulsion by the anterior inferior tibiofibular ligament (AITFL).

Question 31

A 5-year-old child with spastic quadriplegic cerebral palsy (GMFCS level V) undergoes routine hip surveillance. An AP pelvis radiograph demonstrates a Reimers migration percentage of 45% bilaterally. What is the most appropriate definitive management?

Explanation

In children with cerebral palsy, a Reimers migration percentage greater than 40% indicates significant subluxation with high risk of dislocation. Bony reconstruction with a VDRO is necessary, as soft tissue releases alone are no longer sufficient.

Question 32

A 4-year-old boy presents with a diaphyseal femur fracture after a minor fall. He has a history of multiple fractures, blue sclerae, and dentinogenesis imperfecta. This condition is most commonly caused by a mutation in genes coding for which of the following proteins?

Explanation

Osteogenesis imperfecta is most commonly an autosomal dominant disorder caused by mutations in the COL1A1 or COL1A2 genes, which encode Type I collagen. This defect leads to brittle bones, blue sclerae, and associated dental anomalies.

Question 33

A 13-year-old boy presents with recurrent ankle sprains and rigid, painful flatfeet. Radiographs reveal a prominent "C-sign" on the lateral view of the ankle. What is the most likely diagnosis?

Explanation

The "C-sign" on a lateral radiograph is formed by the continuous outline of the medial talar dome and the sustentaculum tali. It is a classic radiographic indicator of a talocalcaneal coalition.

Question 34

In the management of Legg-Calvé-Perthes disease, the Herring Lateral Pillar Classification is most accurately assessed and clinically useful during which stage of the disease?

Explanation

The Herring Lateral Pillar Classification evaluates the height of the lateral pillar of the femoral head and is the most reliable prognostic indicator. It is most accurately applied during the early to late fragmentation stage of the disease.

Question 35

A 4-year-old boy sustains a closed, isolated midshaft femur fracture with 1 cm of shortening. He weighs 18 kg (40 lbs). What is the most appropriate definitive management?

Explanation

For children aged 6 months to 5 years weighing less than 20 kg with isolated, length-stable femur fractures, early spica casting is the standard of care. Flexible nails are generally reserved for older, heavier children.

Question 36

A 7-year-old girl presents with a painless "snapping" sensation in her lateral knee when extending her leg. MRI confirms a discoid lateral meniscus. If the meniscus completely lacks its normal posterior meniscotibial attachments, what specific variant is this?

Explanation

The Wrisberg variant of a discoid meniscus lacks normal posterior capsular and meniscotibial attachments, relying entirely on the meniscofemoral ligament of Wrisberg. This hypermobility leads to the classic snapping knee presentation.

Question 37

Prophylactic in situ pinning of the contralateral, asymptomatic hip in a patient with a unilateral Slipped Capital Femoral Epiphysis (SCFE) is most strongly indicated if the patient has a history of which of the following underlying conditions?

Explanation

Prophylactic pinning of the contralateral hip is highly recommended for patients with endocrine disorders such as hypothyroidism or panhypopituitarism. These underlying systemic conditions dramatically increase the risk of a subsequent bilateral SCFE.

Question 38

A 14-year-old female gymnast presents with persistent lower back pain. Radiographs reveal an isthmic spondylolisthesis at L5-S1 with a slip of 60% (Meyerding Grade III). She has failed 6 months of nonoperative management. What is the most appropriate surgical intervention?

Explanation

For symptomatic high-grade (>50% slip) isthmic spondylolisthesis that fails conservative care, L5-S1 in situ posterolateral fusion (typically with instrumentation) is the standard treatment to prevent further progression.

Question 39

An infant is born with idiopathic clubfoot. The treating surgeon begins Ponseti casting. What specific technical maneuver dictates the correct treatment of the cavus deformity in the application of the first cast?

Explanation

The first step in the Ponseti method (CAVE) corrects the cavus by elevating (dorsiflexing) the first ray to align the forefoot with the hindfoot, effectively supinating the forefoot. This unlocks the transverse tarsal joint allowing subsequent abduction.

Question 40

A 6-week-old infant is placed in a Pavlik harness for Developmental Dysplasia of the Hip (DDH). At the 2-week follow-up, the mother reports the infant is not extending the knee on the affected side. On examination, the quadriceps muscle is flaccid. What is the most appropriate next step in management?

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by hyperflexion of the hip. The appropriate management is to remove the harness temporarily or significantly decrease hip flexion until clinical resolution of the nerve palsy occurs.

Question 41

A 12-year-old boy presents with left hip pain and an obligatory external rotation of the hip during active flexion. He is diagnosed with a stable slipped capital femoral epiphysis (SCFE). Which of the following is the strongest indication for prophylactic in situ pinning of the contralateral asymptomatic hip?

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended in patients with endocrine disorders (e.g., hypothyroidism, growth hormone deficiency, renal osteodystrophy) due to the substantially increased risk of bilateral involvement.

Question 42

An 8-year-old boy presents with a painful limp of insidious onset. Radiographs demonstrate changes consistent with Legg-Calvé-Perthes disease. According to the Herring lateral pillar classification, what specific radiographic finding characterizes a Group B hip?

Explanation

In the Herring lateral pillar classification, Group A has no lateral pillar involvement, Group B maintains >50% of the original lateral pillar height, and Group C has <50% of the height maintained. This classification is heavily used for determining prognosis.

Question 43

An infant with a severe, rigid, idiopathic clubfoot is treated with the Ponseti casting method. To prevent recurrence and effectively correct the deformity, what is the correct anatomical sequence of deformity correction?

Explanation

The Ponseti method sequentially corrects clubfoot deformities in the specific order of Cavus, Adductus, Varus, and finally Equinus (remembered by the acronym CAVE). Equinus is corrected last, typically requiring a percutaneous Achilles tenotomy.

Question 44

A 6-year-old girl sustains a Gartland type III supracondylar humerus fracture. On emergency department presentation, she has a 'pink, pulseless' hand with a normal neurologic examination. Capillary refill is less than 2 seconds. What is the most appropriate initial management?

Explanation

For a 'pink, pulseless' hand in a displaced pediatric supracondylar humerus fracture, the initial step is prompt closed reduction and percutaneous pinning. Vascular exploration is indicated only if the hand becomes poorly perfused (white/cool) after reduction.

Question 45

A 6-week-old female infant is diagnosed with a dislocated left hip that is reducible on Ortolani maneuver. A Pavlik harness is initiated. At the 4-week follow-up, ultrasound reveals the left hip remains persistently dislocated in the harness. What is the most appropriate next step in management?

Explanation

If a dislocated hip fails to reduce after 3 to 4 weeks in a Pavlik harness, it must be discontinued to prevent "Pavlik harness disease" (erosion of the posterior acetabulum). Transitioning to a rigid abduction orthosis (e.g., Ilfeld brace) or proceeding with closed reduction and spica casting are the standard next steps.

Question 46

A 6-year-old boy falls from the monkey bars and sustains a completely displaced posteromedial supracondylar humerus fracture. On examination, the hand is pink and warm, but the radial pulse is absent. After closed reduction and percutaneous pinning, the hand remains pink and warm, and the radial pulse remains nonpalpable. What is the most appropriate next step?

Explanation

In a "pink, pulseless" hand following adequate reduction and stabilization of a supracondylar humerus fracture, collateral circulation is sufficient for distal perfusion. Close observation is recommended, as the pulse typically returns within several days without the need for urgent arterial exploration.

Question 47

In the Ponseti method for the nonoperative treatment of idiopathic clubfoot, which of the following represents the correct sequence of deformity correction?

Explanation

The correct sequence of correction in the Ponseti method is Cavus, Adductus, Varus, and finally Equinus (acronym CAVE). The cavus is corrected first by supinating the forefoot to align it with the hindfoot.

Question 48

A 4-year-old boy presents with right hip pain, a limp, and a refusal to bear weight. He has a temperature of 38.6°C (101.5°F), an erythrocyte sedimentation rate (ESR) of 45 mm/hr, and a white blood cell (WBC) count of 13,000/mm³. According to the Kocher criteria, what is the approximate probability that this child has septic arthritis of the hip?

Explanation

The Kocher criteria for differentiating septic arthritis from transient synovitis include non-weight-bearing, temperature >38.5°C, ESR >40 mm/hr, and WBC >12,000/mm³. The presence of all four predictors yields a 99% probability of septic arthritis.

Question 49

A 13-year-old obese boy presents with acute-on-chronic right groin pain and an inability to bear weight after a minor trip. Radiographs show a severe slipped capital femoral epiphysis (SCFE). Which of the following factors represents the most significant risk for the development of avascular necrosis (AVN) in this patient?

Explanation

The inability to bear weight defines an unstable SCFE according to the Loder classification. Unstable slips have a dramatically higher risk of developing avascular necrosis (up to 47%) compared to stable slips, regardless of the slip angle severity.

Question 50

A 7-year-old girl with spastic quadriplegic cerebral palsy (GMFCS level IV) presents for routine surveillance. An anteroposterior pelvis radiograph demonstrates a Reimers migration percentage of 45% in the left hip, with intact joint cartilage. What is the most appropriate management?

Explanation

For a migration percentage between 40% and 50% in a child with cerebral palsy, bony reconstructive surgery (VDRO and pelvic osteotomy) is indicated to prevent frank dislocation. Soft-tissue releases alone are insufficient at this degree of subluxation.

Question 51

A 14-year-old adolescent boy sustains an ankle injury. Radiographs and a CT scan reveal a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis, displaced by 3 mm. Which ligament is primarily responsible for the avulsion of this fracture fragment?

Explanation

A juvenile Tillaux fracture is a Salter-Harris III fracture of the anterolateral distal tibial epiphysis. It is caused by an avulsion force from the anterior inferior tibiofibular ligament (AITFL) resulting from an external rotation mechanism.

Question 52

A 12-year-old boy presents with frequent ankle sprains and rigid, painful flatfeet. On examination, he has markedly decreased subtalar motion and peroneal spasticity. Radiographs demonstrate a "C sign" on the lateral view. This radiographic finding indicates a coalition primarily in which location?

Explanation

The "C sign" on a lateral ankle radiograph represents a continuous bony outline of the medial talar dome and sustentaculum tali. This finding is highly indicative of a talocalcaneal (subtalar) coalition.

Question 53

A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs reveal greater than 50% loss of height in the lateral portion of the capital femoral epiphysis. According to the Herring lateral pillar classification, which group does this represent, and what is the typical prognosis?

Explanation

Herring Group C is defined by >50% collapse of the lateral pillar height. Patients in Group C generally have poor outcomes, and surgical containment often does not significantly alter the natural history of the severe disease.

Question 54

An 18-month-old boy presents with an anterolateral bow of the right tibia. Radiographs demonstrate a sclerotic medullary canal with a pending fracture. This condition is most strongly associated with a genetic mutation affecting the production of which of the following?

Explanation

Anterolateral bowing of the tibia is highly associated with congenital pseudarthrosis of the tibia (CPT) and Neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant disorder caused by a mutation in the NF1 gene, which encodes the tumor-suppressor protein neurofibromin.

Question 55

A 3-year-old girl is evaluated for severe bilateral genu varum. Standing radiographs reveal a metaphyseal-diaphyseal angle (Drennan's angle) of 18 degrees and early fragmentation of the medial proximal tibial metaphysis. What is the most appropriate initial management for this condition?

Explanation

The metaphyseal-diaphyseal angle >16 degrees and medial metaphyseal fragmentation indicate infantile Blount's disease. For children under or around age 3 with early Langenskiöld stages, a trial of KAFOs during weight-bearing is the recommended initial management.

Question 56

A 6-year-old boy with blue sclerae, dentinogenesis imperfecta, and a history of multiple low-energy fractures is being treated with intravenous pamidronate. What is the primary cellular mechanism of action of this medication in managing his condition?

Explanation

Pamidronate is a bisphosphonate used as the gold-standard medical therapy for osteogenesis imperfecta. It functions by inhibiting osteoclast-mediated bone resorption, thereby increasing bone mineral density and reducing fracture frequency.

Question 57

A 2-year-old girl is brought to the emergency department after her father swung her by her hands. She refuses to use her left arm, holding it in slight flexion and pronation. Radiographs of the elbow are normal. What anatomic structure is primarily involved in this pathology?

Explanation

Nursemaid's elbow (radial head subluxation) occurs when longitudinal traction is applied to an extended, pronated arm. This force causes the annular ligament to slip distally over the radial head and become interposed in the radiocapitellar joint.

Question 58

A 6-month-old infant is brought to the clinic for swelling and decreased spontaneous movement of the right leg. Radiographs reveal a displaced spiral fracture of the right femoral shaft. The parents deny any history of trauma. Which of the following is the most crucial next step in management?

Explanation

A diaphyseal femur fracture in a non-ambulatory infant is highly suspicious for non-accidental trauma (NAT). A complete skeletal survey and child protective services evaluation are mandatory to ensure the child's safety before definitive orthopedic treatment.

Question 59

A 12-year-old boy with obesity presents with a stable slipped capital femoral epiphysis (SCFE). He undergoes in situ single-screw fixation. Which of the following is the most significant predictor of avascular necrosis (AVN) in this patient?

Explanation

The most significant risk factor for AVN in SCFE is the stability of the slip at presentation. Unstable SCFEs (inability to bear weight) have an AVN rate of up to 47%, compared to nearly 0% in stable SCFEs.

Question 60

A 4-year-old boy treated successfully for idiopathic clubfoot with the Ponseti method during infancy presents with a relapsed dynamic supination deformity during the swing phase of gait. His ankle dorsiflexes to 15 degrees past neutral. What is the most appropriate management?

Explanation

Dynamic supination in a previously treated clubfoot is best managed with a complete anterior tibial tendon transfer to the lateral cuneiform (often without Achilles lengthening if dorsiflexion is >10 degrees). SPLATT is generally reserved for spastic conditions like cerebral palsy.

Question 61

A 6-year-old girl sustains a Gartland type III extension-type supracondylar humerus fracture. On examination, she has a pulseless but pink, well-perfused hand. After closed reduction and percutaneous pinning, the hand remains pink and warm, but the radial pulse remains unpalpable. What is the most appropriate next step?

Explanation

A pulseless, pink, well-perfused hand after anatomical reduction and pinning of a supracondylar humerus fracture can be observed. Collateral circulation is adequate, and the radial pulse often returns within a few days due to relief of vasospasm.

Question 62

A 14-year-old boy presents with progressive hand clumsiness and clawing of the ring and small fingers. He reports sustaining an elbow fracture at age 4 that was treated in a cast. Radiographs reveal a nonunion of the lateral humeral condyle and cubitus valgus. Which nerve is most likely compromised?

Explanation

Nonunion of a pediatric lateral condyle fracture frequently leads to progressive cubitus valgus. This deformity stretches the ulnar nerve over time, resulting in tardy ulnar nerve palsy characterized by intrinsic hand weakness and clawing.

Question 63

A 6-week-old female infant with a completely dislocated, irreducible left hip (developmental dysplasia of the hip) has been treated in a Pavlik harness for 4 weeks. Ultrasound shows no improvement, and the hip remains dislocated. What is the most appropriate next step?

Explanation

If a Pavlik harness fails to reduce a dislocated hip after 3 to 4 weeks, it should be discontinued to prevent Pavlik harness disease (posterior acetabular wear). The next step is a trial of a rigid abduction orthosis (e.g., Ilfeld or von Rosen splint) or closed reduction and spica casting.

Question 64

A 13-year-old boy sustains an ankle injury. Radiographs show a fracture that appears as a Salter-Harris type III on the AP view and a Salter-Harris type IV on the lateral view. Which of the following best describes the typical sequence of distal tibial physeal closure that explains this fracture pattern?

Explanation

The distal tibial physis closes in a characteristic sequence: central, then posteromedial, then anteromedial, and finally lateral. This sequence creates a structurally vulnerable lateral physis, leading to transitional fractures like triplane and Tillaux fractures.

Question 65

A 7-year-old boy with spastic quadriplegic cerebral palsy is evaluated during a routine surveillance visit. His AP pelvis radiograph demonstrates a Reimers migration percentage (MP) of 45% in the right hip. He has 30 degrees of hip abduction. What is the recommended management?

Explanation

In cerebral palsy, a migration percentage >40-50% indicates significant hip subluxation requiring bony reconstruction. Soft tissue release (adductor tenotomy) is typically reserved for an MP between 30-40% in younger children without bony deformity.

Question 66

A 2-year-old child with achondroplasia presents with hypotonia, developmental delay, and central sleep apnea. Which of the following is the most critical screening study to obtain to determine the cause of these symptoms?

Explanation

Children with achondroplasia are at high risk for foramen magnum stenosis, which can cause cervicomedullary compression leading to central sleep apnea, hypotonia, and sudden death. MRI of the craniovertebral junction is the imaging modality of choice to assess this.

Question 67

An 8-year-old boy is diagnosed with Legg-Calve-Perthes disease. According to the lateral pillar (Herring) classification, his radiograph demonstrates >50% loss of height in the lateral third of the capital femoral epiphysis. Which of the following describes his classification and prognosis?

Explanation

A lateral pillar height loss of >50% corresponds to Herring Lateral Pillar Group C. In children >8 years old, Group C hips have historically poor outcomes (stiff, non-spherical) regardless of conservative or surgical containment efforts.

Question 68

A 4-year-old girl presents with a 2-day history of right hip pain and a limp. Her temperature is 38.6 degrees Celsius (101.5 degrees Fahrenheit), ESR is 45 mm/hr, WBC is 13.5 x 10^9/L, and she is unable to bear weight. Based on the Kocher criteria, what is the approximate probability she has septic arthritis?

Explanation

The Kocher criteria for septic arthritis of the hip include non-weight-bearing, ESR >40, fever >38.5C, and WBC >12,000. Having all 4 criteria predicts a 99% probability of septic arthritis.

Question 69

A 13-year-old obese male presents with acute-on-chronic slipped capital femoral epiphysis (SCFE) and undergoes urgent in situ pinning. Which of the following factors is most strongly associated with the development of avascular necrosis (AVN) in this patient?

Explanation

The stability of the slip (the patient's ability to bear weight) is the most critical prognostic factor for AVN in SCFE. Unstable slips have a significantly higher rate of AVN compared to stable slips.

Question 70

A 4-week-old female is placed in a Pavlik harness for developmental dysplasia of the hip (DDH). Two weeks later, the parents report she has stopped kicking her leg on the affected side. Exam reveals decreased quadriceps activity. What is the most appropriate next step in management?

Explanation

Femoral nerve palsy in a Pavlik harness is typically caused by excessive hip flexion. Management involves decreasing flexion by loosening the anterior straps or temporarily removing the harness until quadriceps function returns.

Question 71

In the treatment of idiopathic congenital talipes equinovarus (clubfoot) using the Ponseti method, what is the correct sequence of deformity correction?

Explanation

The Ponseti method corrects clubfoot deformities in a specific sequence: Cavus, Adductus, Varus, and finally Equinus (CAVE). The equinus is typically corrected last, often requiring a percutaneous Achilles tenotomy.

Question 72

A 6-year-old boy sustains a Gartland type III extension supracondylar humerus fracture. On examination, the hand is pink and warm, but the radial pulse is not palpable. What is the most appropriate initial management?

Explanation

For a pink, pulseless hand associated with a supracondylar humerus fracture, the initial treatment is urgent closed reduction and percutaneous pinning. Vascular exploration is reserved for a persistently white, pulseless hand post-reduction.

Question 73

A 13-year-old boy presents with a history of recurrent ankle sprains and foot pain. Examination reveals a rigid flatfoot and peroneal spasticity. Radiographs show an "anteater nose" sign. What is the most likely diagnosis?

Explanation

The "anteater nose" sign on an oblique radiograph of the foot is pathognomonic for a calcaneonavicular coalition. By contrast, talocalcaneal coalitions often display a "C-sign" on the lateral radiograph.

Question 74

A 4-year-old girl presents with a 2-day history of right hip pain and refusal to bear weight. Which of the following sets of findings represents the classic Kocher criteria used to differentiate septic arthritis from transient synovitis?

Explanation

The original Kocher criteria include fever > 38.5 C, non-weight-bearing status, ESR > 40 mm/hr, and serum WBC > 12,000/mm3. The presence of all four yields a 99% probability of septic arthritis.

Question 75

A 5-year-old boy sustains a Gartland type III extension supracondylar humerus fracture. On initial presentation, his hand is pale, pulseless, and cool. Urgent closed reduction and percutaneous pinning are performed. Post-operatively, the hand becomes pink with brisk capillary refill, but the radial pulse remains non-palpable. What is the most appropriate next step in management?

Explanation

A pulseless, pink hand following reduction of a pediatric supracondylar humerus fracture indicates adequate collateral circulation. Close observation with continuous pulse oximetry is the standard of care. Surgical exploration is only indicated if the hand remains pale, pulseless, and poorly perfused after anatomical reduction.

Question 76

A 4-year-old girl presents with a painless limp and a positive Trendelenburg sign on the right. Radiographs reveal a high developmental dislocation of the right hip (DDH) with a false acetabulum and an acetabular index of 42 degrees. What is the most appropriate surgical management for this patient?

Explanation

In children older than 3 years with neglected DDH, the soft tissues are contracted and the acetabulum is highly dysplastic. Open reduction combined with a femoral shortening osteotomy is required to safely decompress the joint and reduce the risk of avascular necrosis. A concomitant pelvic osteotomy is necessary to adequately cover the femoral head and correct the dysplasia.

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

Orthopedic Pediatrics 2026 MCQs: Board Review Questions & Answers (Part 1)

Key Takeaway

Orthopedic Pediatrics 2026 MCQs: Board Review Questions & Answers (Part 1)

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