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Pediatric Hip MCQs

Practice Set 8 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 141

Topic: Pediatric Hip

A 24-month-old girl is newly diagnosed with developmental dysplasia of the hip (DDH) demonstrating a completely dislocated right hip. What is the most appropriate initial management?

. Pavlik harness application
. Closed reduction and spica casting
. Open reduction and spica casting
. Open reduction, pelvic osteotomy, and femoral shortening
. Observation until age 4 followed by salvage osteotomy

Correct Answer & Explanation

. Open reduction, pelvic osteotomy, and femoral shortening

Explanation

In children older than 18 to 24 months with a completely dislocated hip, open reduction is generally required as closed reduction is rarely successful. Concomitant pelvic and femoral shortening osteotomies are frequently necessary to safely reduce the hip without excessive tension that risks avascular necrosis.

Question 142

Topic: Pediatric Hip

The result of treatment of developmental dysplasia of the hip with Salter osteotomy is is worse with which of the following:

. A higher degree of the dislocation before treatment (Tonnis grade)
. Bilaterality
. Higher preoperative acetabular index
. Increased age at surgery
. Performing open reduction at a separate surgery than the osteotomy

Correct Answer & Explanation

. A higher degree of the dislocation before treatment (Tonnis grade)

Explanation

Salter osteotomy is effective in treating developmental dysplasia of the hip in young children. The result is worse with higher degrees of dislocation as assessed by the Tonnis system. It is better if the open reduction (if needed) is performed as a separate step than the osteotomy. The other factors have not been shown to be predictive.

Question 143

Topic: Pediatric Hip

A 4-month-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip. The parents report that the infant has stopped kicking the affected leg over the past two days. On examination, there is decreased active knee extension but normal foot and toe movement. Which of the following is the most appropriate next step in management?

. Switch to a rigid hip spica cast immediately
. Adjust the anterior straps to increase hip flexion
. Discontinue the Pavlik harness temporarily
. Order an urgent MRI of the lumbar spine
. Perform an immediate closed reduction in the operating room

Correct Answer & Explanation

. Discontinue the Pavlik harness temporarily

Explanation

The clinical presentation is highly suggestive of a femoral nerve palsy, a known complication of hyperflexion in a Pavlik harness. The most appropriate immediate management is to discontinue the harness or significantly loosen the anterior straps to allow the nerve to recover.

Question 144

Topic: Pediatric Hip

Which of the following conditions constitutes the strongest absolute indication for prophylactic in situ pinning of the contralateral asymptomatic hip in a 12-year-old patient presenting with a unilateral slipped capital femoral epiphysis (SCFE)?

. Obesity greater than 95th percentile
. Family history of SCFE
. Renal osteodystrophy
. Male gender
. African American ethnicity

Correct Answer & Explanation

. Renal osteodystrophy

Explanation

Endocrine and metabolic disorders, particularly renal osteodystrophy and hypothyroidism, significantly increase the risk of bilateral SCFE. Prophylactic pinning of the contralateral hip is highly recommended in these patients to prevent a subsequent slip.

Question 145

Topic: Pediatric Hip

In a patient presenting with Legg-Calve-Perthes disease, which of the following combinations of factors at the time of presentation portends the poorest prognosis?

. Age 5 years and greater than 50% lateral pillar involvement
. Age 9 years and greater than 50% lateral pillar involvement
. Age 4 years and Catterall group II
. Age 7 years and intact lateral pillar
. Age 6 years and Salter-Thompson group A

Correct Answer & Explanation

. Age 9 years and greater than 50% lateral pillar involvement

Explanation

The most significant prognostic factors in Legg-Calve-Perthes disease are the chronological age at onset and the extent of lateral pillar involvement (Herring classification). Onset after age 8 combined with greater than 50% lateral pillar collapse (Herring Group C) has the worst radiographic and clinical outcomes.

Question 146

Topic: Pediatric Hip

An 11-year-old boy with a BMI in the 99th percentile presents with a unilateral stable slipped capital femoral epiphysis (SCFE). Prophylactic pinning of the contralateral asymptomatic hip is most strongly indicated in patients with which of the following concomitant conditions?

. Type 1 diabetes mellitus
. Down syndrome
. Endocrine disorders such as hypothyroidism
. Legg-Calve-Perthes disease
. Achondroplasia

Correct Answer & Explanation

. Endocrine disorders such as hypothyroidism

Explanation

Endocrine disorders (e.g., hypothyroidism, renal osteodystrophy) significantly increase the risk of bilateral SCFE. This justifies prophylactic fixation of the contralateral hip.

Question 147

Topic: Pediatric Hip

Which of the following factors at the time of presentation confers the worst prognosis in a child with Legg-Calve-Perthes disease?

. Chronological age less than 6 years
. Bone age of 5 years
. Lateral pillar type C involvement
. Intact lateral pillar
. Decreased range of motion in abduction

Correct Answer & Explanation

. Lateral pillar type C involvement

Explanation

The Herring lateral pillar classification is highly prognostic. Lateral pillar type C (greater than 50% loss of lateral pillar height) predicts a poor radiographic and clinical outcome.

Question 148

Topic: Pediatric Hip

A 14-year-old boy undergoes in situ pinning for an unstable slipped capital femoral epiphysis (SCFE). Which of the following is the most common severe complication associated specifically with an unstable SCFE?

. Chondrolysis
. Osteonecrosis (avascular necrosis)
. Femoral neck fracture
. Implant failure
. Leg length discrepancy

Correct Answer & Explanation

. Osteonecrosis (avascular necrosis)

Explanation

Unstable SCFE, defined as the inability to bear weight even with crutches, carries a high risk of osteonecrosis (up to 47%). This is compared to a nearly 0% osteonecrosis rate in stable SCFE.

Question 149

Topic: Pediatric Hip

During the treatment of Developmental Dysplasia of the Hip (DDH) with a Pavlik harness, excessive hyperflexion of the hips can lead to which of the following complications?

. Avascular necrosis of the femoral head
. Femoral nerve palsy
. Sciatic nerve palsy
. Inferior dislocation of the hip
. Obturator nerve palsy

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Excessive hyperflexion in a Pavlik harness compresses the femoral nerve against the inguinal ligament, leading to nerve palsy. Excessive abduction, on the other hand, is associated with avascular necrosis of the femoral head.

Question 150

Topic: Pediatric Hip

A 10-year-old boy with chronic kidney disease presents with a stable slipped capital femoral epiphysis (SCFE) of the left hip. After in situ pinning of the left hip, what is the most appropriate management for the asymptomatic right hip?

. Observation with regular clinical follow-up
. Observation with MRI every 6 months
. Prophylactic in situ pinning
. Proximal femoral osteotomy
. Spica cast immobilization

Correct Answer & Explanation

. Prophylactic in situ pinning

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in SCFE patients with endocrine disorders or renal failure due to the very high risk of bilateral involvement. Observation may be appropriate for selected idiopathic cases, but not metabolic cases.

Question 151

Topic: Pediatric Hip

In the Herring lateral pillar classification for Legg-Calve-Perthes disease, a Group B classification indicates what degree of lateral pillar height maintenance?

. 100%
. > 50%
. < 50%
. 0%
. Extrusion of the lateral pillar

Correct Answer & Explanation

. > 50%

Explanation

In the Herring classification, Group A has no lateral pillar involvement. Group B maintains > 50% of the lateral pillar height, and Group C has < 50% lateral pillar height maintained.

Question 152

Topic: Pediatric Hip

When evaluating an infant for developmental dysplasia of the hip (DDH) using the Graf ultrasound method, the alpha angle evaluates which of the following structures?

. The depth of the cartilaginous acetabular roof
. The depth of the bony acetabular roof
. The degree of femoral head coverage
. The angle of the femoral neck anteversion
. The concavity of the labrum

Correct Answer & Explanation

. The depth of the bony acetabular roof

Explanation

The alpha angle measures the concavity of the bony acetabular roof (ilium) relative to the straight iliac border. An alpha angle > 60 degrees is considered normal and is classified as Graf Type I.

Question 153

Topic: Pediatric Hip

A 13-year-old obese male presents with acute severe groin pain and inability to bear weight after a minor fall. Radiographs show a severe, unstable slipped capital femoral epiphysis (SCFE). Intraoperative forceful reduction of the slip is avoided primarily to prevent which of the following?

. Chondrolysis
. Femoral nerve injury
. Avascular necrosis of the femoral head
. Premature physeal closure
. Subtrochanteric fracture

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Forceful reduction or manipulation of an unstable SCFE significantly increases the risk of stretching or tearing the vulnerable posterior retinacular vessels, leading to avascular necrosis (AVN) of the femoral head. In situ pinning without forceful reduction is standard.

Question 154

Topic: Pediatric Hip
A 12-year-old boy presents with a left Slipped Capital Femoral Epiphysis (SCFE). Which of the following is the strongest indication for prophylactic in situ pinning of the contralateral asymptomatic hip?
. Age greater than 14 years
. Female gender
. Presence of an endocrine disorder
. Body mass index > 95th percentile
. Grade III slip on the affected side

Correct Answer & Explanation

. Presence of an endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy) due to the high risk of bilateral involvement. Age less than 10 or greater than 16 also increases the risk of bilaterality.

Question 155

Topic: Pediatric Hip

An infant is being treated with a Pavlik harness for Developmental Dysplasia of the Hip (DDH). Excessive flexion of the hips in the harness increases the risk of which of the following complications?

. Avascular necrosis of the femoral head
. Femoral nerve palsy
. Sciatic nerve palsy
. Inferior dislocation of the hip
. Knee flexion contracture

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Excessive flexion of the hip in a Pavlik harness can cause femoral nerve palsy, which manifests as decreased active knee extension. Conversely, excessive abduction places the vascular supply at risk, leading to avascular necrosis.

Question 156

Topic: Pediatric Hip
In Legg-Calvé-Perthes disease, which of the following radiographic findings (from the lateral pillar classification) is most predictive of the long-term outcome?
. Gage sign
. Calcification lateral to the epiphysis
. Height of the lateral pillar of the capital femoral epiphysis
. Presence of a subchondral fracture
. Metaphyseal cysts

Correct Answer & Explanation

. Height of the lateral pillar of the capital femoral epiphysis

Explanation

The Herring lateral pillar classification, based on the height of the lateral pillar of the capital femoral epiphysis during the fragmentation stage, is the most accurate prognostic indicator for long-term outcome in Legg-Calvé-Perthes disease.

Question 157

Topic: Pediatric Hip

A 13-year-old boy undergoes in situ single-screw fixation for a stable slipped capital femoral epiphysis (SCFE). Which of the following is the most common major complication if the screw penetrates the joint anteriorly and is left unrecognized?

. Avascular necrosis
. Chondrolysis
. Infection
. Premature physeal closure
. Femoral neck fracture

Correct Answer & Explanation

. Chondrolysis

Explanation

Chondrolysis is a devastating complication in SCFE management, frequently caused by unrecognized hardware penetration into the joint space. Proper fluoroscopic evaluation with an approach-withdrawal technique is crucial to ensure the screw is entirely within the bone.

Question 158

Topic: Pediatric Hip

A 2-year-old girl is diagnosed with a neglected left developmental dysplasia of the hip (DDH). The hip is completely dislocated. Which of the following surgical strategies is most likely necessary to achieve a stable, concentric reduction?

. Closed reduction and spica cast alone
. Open reduction, femoral shortening osteotomy, and pelvic osteotomy
. Pavlik harness application
. Adductor tenotomy and abduction bracing
. Greater trochanteric epiphysiodesis

Correct Answer & Explanation

. Open reduction, femoral shortening osteotomy, and pelvic osteotomy

Explanation

In children older than 18-24 months with a completely dislocated DDH, open reduction is almost universally required. Femoral shortening osteotomy is typically necessary to relieve soft tissue tension, and a pelvic osteotomy is needed to correct acetabular dysplasia.

Question 159

Topic: Pediatric Hip
A 6-year-old boy presents with right hip pain, a limp, and limited internal rotation. Radiographs demonstrate a subchondral radiolucent line in the anterolateral aspect of the femoral head. What is this sign called and what does it indicate?
. Crescent sign; indicating Legg-Calvé-Perthes disease
. Klein line; indicating SCFE
. Gage sign; indicating Legg-Calvé-Perthes disease
. Thurston Holland sign; indicating a physeal fracture
. Hilgenreiner line; indicating DDH

Correct Answer & Explanation

. Crescent sign; indicating Legg-Calvé-Perthes disease

Explanation

The subchondral radiolucent line is the "crescent sign", representing a subchondral fracture occurring in the early stages of avascular necrosis, such as Legg-Calvé-Perthes disease. It typically dictates the extent of epiphyseal involvement.

Question 160

Topic: Pediatric Hip

A 12-year-old obese boy presents with left knee pain and a waddling gait. Radiographs reveal a severe slipped capital femoral epiphysis (SCFE) on the left. The right hip is radiographically normal. Which of the following is the primary indication for prophylactic pinning of the contralateral right hip?

. Male sex
. Age greater than 14 years
. Endocrine disorders such as hypothyroidism
. Duration of symptoms greater than 3 weeks
. Severity of the left-sided slip

Correct Answer & Explanation

. Endocrine disorders such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is strongly indicated in patients with underlying endocrine disorders (such as hypothyroidism) or those treated prior to age 10. These factors significantly increase the risk of a contralateral slip.

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