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Pediatric Hip MCQs

Practice Set 61 of 104

This practice set contains high-yield board review questions covering key concepts in Pediatric Hip. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1201

Topic: Pediatric Hip

A 5-month-old girl with developmental dysplasia of the hip (DDH) has been treated with a Pavlik harness for 4 weeks. Repeat ultrasound reveals an alpha angle of 45 degrees, and the hip remains persistently subluxated. What is the next most appropriate step in management?

. Observation
. Continue the Pavlik harness for 4 more weeks
. Transition to a rigid abduction orthosis or attempt closed reduction
. Open reduction and capsulorrhaphy
. Varus derotational osteotomy

Correct Answer & Explanation

. Transition to a rigid abduction orthosis or attempt closed reduction

Explanation

Continuing a Pavlik harness in an persistently dislocated or subluxated hip beyond 3 to 4 weeks risks 'Pavlik harness disease' (posterior acetabular wear). Transitioning to a rigid abduction orthosis (e.g., Rhino cruiser) or proceeding to closed reduction and spica casting is the standard next step.

Question 1202

Topic: Pediatric Hip
An 8-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs classify the hip as Lateral Pillar B/C. According to current evidence-based guidelines, which treatment yields the best radiographic outcome for this patient?
. Observation and protected weight-bearing
. A-frame bracing
. Surgical containment via femoral varus osteotomy or pelvic osteotomy
. Core decompression of the femoral head
. Hip arthrodesis

Correct Answer & Explanation

. Surgical containment via femoral varus osteotomy or pelvic osteotomy

Explanation

For children over the age of 8 with Lateral Pillar B or B/C involvement, surgical containment provides superior radiographic outcomes compared to nonoperative management. Osteotomies redirect the femoral head into the acetabulum to maintain sphericity during the healing phase.

Question 1203

Topic: Pediatric Hip

A 13-year-old boy presents to the emergency department with acute right hip pain after a minor fall. He is unable to bear weight. Radiographs demonstrate a slipped capital femoral epiphysis (SCFE) with 40 degrees of slip. What is the most significant risk associated with this specific presentation compared to a patient who is able to bear weight?

. Chondrolysis
. Avascular necrosis (AVN)
. Slip progression
. Cam impingement
. Leg length discrepancy

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

This patient has an unstable SCFE, defined by the inability to bear weight even with crutches. Unstable SCFE carries a significantly higher risk of avascular necrosis (AVN), up to 50%, compared to nearly 0% in stable SCFE.

Question 1204

Topic: Pediatric Hip

A 6-week-old female infant is referred for an ultrasound of the hips due to a breech presentation. The ultrasound report notes an alpha angle of 50 degrees and a beta angle of 65 degrees. According to the Graf classification, what is the most appropriate management for this patient?

. Observation with a repeat ultrasound in 4 weeks
. Application of a Pavlik harness
. Closed reduction and spica casting
. Open reduction and capsulorrhaphy
. Varus derotational osteotomy

Correct Answer & Explanation

. Application of a Pavlik harness

Explanation

An alpha angle less than 60 degrees indicates developmental dysplasia of the hip (Graf Type IIb or worse depending on age and specific angle). Treatment with a Pavlik harness is indicated for dysplastic hips in infants younger than 6 months.

Question 1205

Topic: Pediatric Hip

A 12-year-old obese boy presents with sudden inability to bear weight on his left leg after a minor fall. Radiographs show a severe left slipped capital femoral epiphysis (SCFE). He has a known medical history of panhypopituitarism. What is the most appropriate management for the contralateral, asymptomatic right hip?

. Observation with routine radiographic follow-up
. Prophylactic in situ pinning
. Spica casting
. Dunn procedure
. Valgus intertrochanteric osteotomy

Correct Answer & Explanation

. Prophylactic in situ pinning

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with endocrine disorders, such as panhypopituitarism, due to the high risk of bilateral involvement. Bilateral slips can occur in up to 100% of patients with certain endocrinopathies.

Question 1206

Topic: Pediatric Hip

An 18-month-old girl presents with a limp. Pelvic radiographs reveal a dislocated left hip with a false acetabulum and an acetabular index of 42 degrees. Which of the following is the most appropriate primary surgical management?

. Closed reduction and spica casting
. Pavlik harness application
. Open reduction with pelvic osteotomy
. Proximal femoral varus osteotomy alone
. Shelf osteotomy

Correct Answer & Explanation

. Open reduction with pelvic osteotomy

Explanation

In children older than 18 months with untreated Developmental Dysplasia of the Hip (DDH), closed reduction has a high failure rate and elevated risk of osteonecrosis. The standard of care is open reduction, often combined with a pelvic osteotomy (e.g., Salter) to address significant residual acetabular dysplasia.

Question 1207

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs reveal fragmentation of the capital femoral epiphysis with >50% maintenance of the lateral pillar height. According to the Herring lateral pillar classification, what is his group and expected outcome without surgical intervention?
. Group A; excellent outcome
. Group B; good outcome
. Group B; poor outcome
. Group C; good outcome
. Group C; poor outcome

Correct Answer & Explanation

. Group B; good outcome

Explanation

According to the Herring classification, maintenance of >50% of the lateral pillar height defines Group B. Children diagnosed before age 8 with Group B LCPD generally have good outcomes with conservative management and rarely require surgical containment.

Question 1208

Topic: Pediatric Hip

A 13-year-old obese boy presents with acute on chronic left hip pain. He is unable to bear weight. Radiographs confirm an unstable slipped capital femoral epiphysis. During surgical fixation, an anterior capsulotomy is performed. What is the primary theoretical purpose of the capsulotomy in this setting?

. To facilitate reduction of the epiphysis
. To reduce intracapsular pressure and potentially decrease the risk of avascular necrosis
. To allow direct visualization of the screw entering the epiphysis
. To repair an associated labral tear
. To prevent chondrolysis

Correct Answer & Explanation

. To reduce intracapsular pressure and potentially decrease the risk of avascular necrosis

Explanation

Unstable SCFE is associated with a high rate of avascular necrosis. Capsulotomy is often performed to decompress the hematoma, lower intracapsular pressure, and potentially decrease the risk of AVN, although its ultimate efficacy remains debated.

Question 1209

Topic: Pediatric Hip
In a 7-year-old boy diagnosed with Legg-Calvé-Perthes disease, radiographs demonstrate that 60% of the lateral pillar height is maintained. According to the Herring lateral pillar classification, what group does this patient fall into, and what is the general prognosis?
. Group A, excellent prognosis
. Group B, moderate prognosis
. Group B/C, poor prognosis
. Group C, poor prognosis
. Group C, excellent prognosis

Correct Answer & Explanation

. Group B, moderate prognosis

Explanation

According to the Herring lateral pillar classification, Group B indicates that greater than 50% of the lateral pillar height is maintained. It carries a moderate prognosis, and these patients often benefit from containment surgery if they are over 8 years old.

Question 1210

Topic: Pediatric Hip

A 5-month-old female with developmental dysplasia of the hip has failed a 4-week trial of Pavlik harness treatment. Ultrasound shows the hip remains persistently dislocated. What is the most appropriate next step in management?

. Continue Pavlik harness for 4 more weeks
. Transition to a rigid abduction orthosis
. Closed reduction and spica casting
. Open reduction and spica casting
. Varus derotational osteotomy

Correct Answer & Explanation

. Closed reduction and spica casting

Explanation

If Pavlik harness treatment fails (persistent dislocation after 3-4 weeks), it should be discontinued to prevent "Pavlik harness disease" (posterior lip erosion). Closed reduction with spica casting or transition to a rigid orthosis is the next recommended step.

Question 1211

Topic: Pediatric Hip

A 5-week-old female infant is treated with a Pavlik harness for a dislocated left hip. After 4 weeks of strict harness wear, ultrasound reveals the hip remains dislocated. What is the next best step in management?

. Continue the harness for 3 additional weeks
. Discontinue the harness and proceed with closed reduction and spica casting
. Add a hip abduction wedge
. Immediate open reduction
. Proximal femoral varus derotational osteotomy

Correct Answer & Explanation

. Discontinue the harness and proceed with closed reduction and spica casting

Explanation

If a hip remains dislocated after 3-4 weeks of Pavlik harness treatment, the harness must be discontinued to avoid Pavlik harness disease (acetabular damage). The next appropriate step is a closed reduction and spica casting or transitioning to a rigid abduction orthosis.

Question 1212

Topic: Pediatric Hip

A 12-year-old boy presents with an acute-on-chronic, unstable slipped capital femoral epiphysis of the left hip. He undergoes uncomplicated in-situ screw fixation. Which of the following is the strongest indication for prophylactic pinning of the contralateral asymptomatic hip?

. Age greater than 14 years
. Male sex
. Endocrine disorder such as hypothyroidism
. Obesity
. Severe slip angle on the affected side

Correct Answer & Explanation

. Endocrine disorder such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with endocrine or metabolic disorders due to the high risk of bilateral involvement. Age less than 10 years or an open triradiate cartilage are also strong indications.

Question 1213

Topic: Pediatric Hip

An 11-year-old girl with obesity presents with a unilateral slipped capital femoral epiphysis (SCFE). Which of the following factors most strongly indicates the need for prophylactic in situ fixation of her contralateral, asymptomatic hip?

. Patient's chronologic age
. A modified Oxford bone age score of 16
. Closed triradiate cartilage on radiographs
. Presentation with an acute slip
. Presence of a recognized endocrine disorder

Correct Answer & Explanation

. Presence of a recognized endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip is strongly indicated in patients with endocrine disorders (e.g., hypothyroidism), previous pelvic radiation, or an open triradiate cartilage (modified Oxford bone age score < 16). Endocrine disorders dramatically increase the risk of bilateral involvement.

Question 1214

Topic: Pediatric Hip
An 8-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs reveal fragmentation with exactly 50% maintenance of the lateral pillar height. According to the Herring lateral pillar classification, into which group does this patient fall, and what is the current treatment recommendation?
. Group A; conservative management
. Group B; conservative management with bracing
. Group B/C border; surgical containment
. Group C; conservative management
. Group C; surgical containment

Correct Answer & Explanation

. Group C; surgical containment

Explanation

Maintaining exactly 50% lateral pillar height defines the Herring B/C border group. In children over 8 years of age at disease onset, patients in the B or B/C border groups have significantly better radiographic outcomes with surgical containment (e.g., proximal femoral varus osteotomy).

Question 1215

Topic: Pediatric Hip

A 13-year-old boy with a 2-day history of inability to bear weight on his right leg is diagnosed with an unstable slipped capital femoral epiphysis (SCFE). He is taken to the operating room for urgent in situ pinning. Which of the following intraoperative maneuvers or findings most significantly increases the risk of developing avascular necrosis (AVN)?

. Capsulotomy to decompress the joint
. Inadvertent reduction of the slip during patient positioning
. Use of two cannulated screws instead of one
. Approaching the proximal femur from the lateral aspect
. Pinning the epiphysis strictly in situ without manipulation

Correct Answer & Explanation

. Pinning the epiphysis strictly in situ without manipulation

Explanation

Inadvertent or forceful reduction of an unstable SCFE dramatically increases the risk of avascular necrosis by disrupting the already compromised retinacular blood supply. Pinning in situ is the gold standard to minimize this risk.

Question 1216

Topic: Pediatric Hip

A 6-week-old infant is undergoing treatment for developmental dysplasia of the hip (DDH) with a Pavlik harness. During a routine follow-up, the parents report that the infant is no longer kicking the affected leg as much. On examination, there is decreased active extension of the knee on the affected side, but hip flexion remains active. What is the most likely cause of this finding?

. Avascular necrosis of the femoral head
. Femoral nerve palsy
. Sciatic nerve palsy
. Obturator nerve palsy
. Superior gluteal nerve palsy

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment, usually caused by excessive hyperflexion of the hip. It presents as decreased active knee extension and usually resolves after temporary harness adjustment or removal.

Question 1217

Topic: Pediatric Hip

When evaluating a patient with Legg-Calve-Perthes disease, which of the following radiographic or clinical findings is considered the most reliable predictor of a poor long-term outcome regarding hip joint congruency?

. Age of onset at 5 years
. Loss of hip internal rotation on examination
. A subchondral fracture line (Crescent sign) involving 30% of the head
. Lateral pillar involvement greater than 50% height collapse
. Male gender

Correct Answer & Explanation

. Lateral pillar involvement greater than 50% height collapse

Explanation

The Herring lateral pillar classification is highly prognostic in Legg-Calve-Perthes disease. Collapse of the lateral pillar greater than 50% (Group C) predicts severe deformity and a poor long-term outcome.

Question 1218

Topic: Pediatric Hip

A 4-week-old girl is being treated for developmental dysplasia of the hip with a Pavlik harness. During a follow-up visit, the mother notes that the child is no longer kicking her right leg as much. Examination reveals an inability to actively extend the right knee, though sensation appears intact. What is the most appropriate next step in management?

. Adjust the anterior straps to increase hip flexion
. Adjust the posterior straps to increase hip abduction
. Remove the Pavlik harness and observe for recovery
. Transition immediately to a rigid hip abduction orthosis
. Perform an emergent ultrasound to rule out a deep vein thrombosis

Correct Answer & Explanation

. Remove the Pavlik harness and observe for recovery

Explanation

The patient has developed a femoral nerve palsy, a known complication of excessive hip flexion in a Pavlik harness. The most appropriate management is to temporarily remove the harness to allow the nerve to recover before resuming treatment.

Question 1219

Topic: Pediatric Hip

A 13-year-old boy is diagnosed with a unilateral slipped capital femoral epiphysis (SCFE) and undergoes in-situ screw fixation. Prophylactic pinning of the asymptomatic contralateral hip is most strongly indicated if the patient has a history of which of the following?

. Type 1 diabetes mellitus
. Hypothyroidism
. Asthma treated with intermittent corticosteroids
. Attention-deficit/hyperactivity disorder
. Idiopathic short stature

Correct Answer & Explanation

. Hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is indicated in patients with endocrine disorders, such as hypothyroidism or renal osteodystrophy. These conditions significantly increase the risk of developing a subsequent contralateral slip.

Question 1220

Topic: Pediatric Hip

A 12-year-old girl with a slipped capital femoral epiphysis undergoes in-situ pinning. Six months later, she presents with severe hip stiffness and a painful limp. Radiographs demonstrate significant concentric joint space narrowing without focal collapse of the femoral head. What is the most likely underlying cause of this complication?

. Avascular necrosis of the femoral head
. Unrecognized intra-articular hardware penetration
. Natural progression of the slip
. Femoroacetabular impingement
. Post-infectious inflammatory arthritis

Correct Answer & Explanation

. Unrecognized intra-articular hardware penetration

Explanation

Concentric joint space narrowing following SCFE fixation is the hallmark of chondrolysis. The most common iatrogenic cause of chondrolysis is unrecognized penetration of the fixation screw into the hip joint space.

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