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Pediatric Hip MCQs

Practice Set 74 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 1461

Topic: Pediatric Hip
A 9-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs demonstrate that less than 50% of the lateral pillar height is maintained. Based on the Herring Lateral Pillar Classification, which of the following is true regarding his prognosis and management?
. He is classified as Lateral Pillar A and will have a good outcome without surgery.
. He is classified as Lateral Pillar B and should be treated with immediate spica casting.
. He is classified as Lateral Pillar C and has a poor prognosis regardless of treatment, though containment surgery may be considered.
. He is classified as Lateral Pillar B/C and requires hinged distraction external fixation.
. He is classified as Lateral Pillar C and is best managed with isolated adductor tenotomy.

Correct Answer & Explanation

. He is classified as Lateral Pillar C and has a poor prognosis regardless of treatment, though containment surgery may be considered.

Explanation

Herring Lateral Pillar Type C is defined by <50% maintenance of the lateral pillar height and carries the poorest prognosis. In children over 8 years old with severe involvement, while surgical containment (femoral or pelvic osteotomy) may be attempted, the long-term outcome remains guarded.

Question 1462

Topic: Pediatric Hip
A 9-year-old boy presents with a limp and groin pain. Radiographs demonstrate Legg-Calvé-Perthes disease classified as Lateral Pillar B. He has maintained good range of motion. What is the most appropriate surgical treatment to prevent femoral head deformation in this patient?
. In situ pinning of the femoral head
. Varus derotation osteotomy of the proximal femur
. Valgus extension osteotomy
. Core decompression of the femoral head
. Hip arthrodesis

Correct Answer & Explanation

. Varus derotation osteotomy of the proximal femur

Explanation

For patients older than 8 years with Lateral Pillar B or B/C border Legg-Calvé-Perthes disease, surgical containment yields better outcomes than nonoperative management. A varus derotation osteotomy (VDRO) centers the femoral head within the acetabulum to allow spherical remodeling.

Question 1463

Topic: Pediatric Hip

A 12-year-old boy with a BMI in the 99th percentile presents with left knee pain and an inability to bear weight on his left leg. Radiographs confirm a severe Slipped Capital Femoral Epiphysis (SCFE). Which of the following factors is the greatest predictor for the development of avascular necrosis (AVN) in this patient?

. The chronicity of symptoms exceeding 3 months
. The severity of the slip angle on the lateral radiograph
. The patient's obesity percentile
. Inability to bear weight even with crutches
. Bilateral epiphyseal involvement

Correct Answer & Explanation

. The chronicity of symptoms exceeding 3 months

Explanation

The inability to bear weight defines an unstable SCFE, which carries a significantly higher risk of avascular necrosis (up to 47%) compared to stable slips. Slip severity or chronicity does not predict AVN as strongly as clinical stability.

Question 1464

Topic: Pediatric Hip
A 6-week-old female undergoes a screening hip ultrasound for breech presentation. The alpha angle is 45 degrees, and the beta angle is 80 degrees. According to the Graf classification, what is the most appropriate initial management?
. Application of a Pavlik harness
. Application of a rigid hip abduction orthosis
. Closed reduction and spica casting
. Open reduction and capsulorrhaphy
. Observation with repeat ultrasound in 4 weeks

Correct Answer & Explanation

. Application of a Pavlik harness

Explanation

An alpha angle of <50 degrees corresponds to a Graf Type III or severe Type IIc hip, indicating significant developmental dysplasia of the hip (DDH). The gold standard initial treatment for a child <6 months of age with DDH is a Pavlik harness.

Question 1465

Topic: Pediatric Hip
A 10-year-old boy with known Legg-Calvé-Perthes disease presents with increasing hip pain and stiffness. An arthrogram demonstrates "hinge abduction" with lateral subluxation of the femoral head against the acetabular rim during hip abduction. What is the most appropriate surgical treatment?
. Varus derotation osteotomy of the proximal femur
. Valgus extension intertrochanteric osteotomy
. Shelf acetabuloplasty
. Triple pelvic osteotomy
. Core decompression

Correct Answer & Explanation

. Valgus extension intertrochanteric osteotomy

Explanation

Hinge abduction occurs when an enlarged, deformed femoral head impinges on the lateral acetabular margin, preventing spherical containment. A valgus extension osteotomy redirects the head, moves the impingement away from the acetabular rim, and improves congruency.

Question 1466

Topic: Pediatric Hip

A 12-year-old boy presents with a 3-week history of right hip pain and a limp. He is unable to bear weight on the right leg, even with crutches. Radiographs confirm a Slipped Capital Femoral Epiphysis (SCFE). According to the Loder classification, what is the most significant prognostic factor associated with this specific presentation?

. Development of chondrolysis
. Risk of contralateral slip
. Development of avascular necrosis (AVN)
. Progression of slip severity
. Premature physeal closure

Correct Answer & Explanation

. Development of chondrolysis

Explanation

The inability to bear weight defines an unstable SCFE according to the Loder classification. Unstable slips carry a significantly higher risk of developing avascular necrosis (up to 47%) compared to stable slips.

Question 1467

Topic: Pediatric Hip

An 8-year-old boy is diagnosed with Legg-Calve-Perthes disease. Radiographs show greater than 50% collapse of the lateral pillar of the femoral head. According to the Herring lateral pillar classification, what is his stage and expected prognosis?

. Group B; good prognosis with conservative care
. Group C; poor prognosis regardless of treatment
. Group B; favorable prognosis if surgical containment is performed
. Group C; excellent prognosis with immediate femoral osteotomy
. Group A; self-limiting condition requiring observation

Correct Answer & Explanation

. Group B; good prognosis with conservative care

Explanation

Herring Lateral Pillar Group C is defined by >50% loss of lateral pillar height. It is associated with a poor prognosis, particularly in children over 8 years of age, and often leads to a poorly spherical femoral head regardless of intervention.

Question 1468

Topic: Pediatric Hip

A 4-week-old female with an irreducible but dilatable left developmental dysplasia of the hip (DDH) is placed in a Pavlik harness. After 4 weeks of strictly compliant wear, dynamic ultrasound shows the hip remains completely dislocated. What is the most appropriate next step in management?

. Continue the Pavlik harness for another 4 weeks
. Adjust the harness straps to enforce maximum flexion and abduction
. Discontinue the Pavlik harness and transition to a rigid abduction orthosis or plan for closed reduction
. Perform an immediate open reduction
. Proceed directly to a pelvic (Salter) osteotomy

Correct Answer & Explanation

. Continue the Pavlik harness for another 4 weeks

Explanation

Continuing a Pavlik harness for a hip that remains dislocated after 3-4 weeks is contraindicated because it can cause 'Pavlik harness disease' due to posterior acetabular wear. The harness must be abandoned in favor of a rigid orthosis or closed reduction and spica casting.

Question 1469

Topic: Pediatric Hip
An 8-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Anteroposterior radiographs demonstrate greater than 50% loss of the lateral pillar height. According to the Herring classification, which group does this represent and what is the expected outcome?
. Group A; excellent outcome with conservative care
. Group B; fair outcome, may benefit from surgery
. Group B/C; guarded outcome
. Group C; poor outcome, high risk of aspherical head
. Group C; excellent outcome if treated with immediate bracing

Correct Answer & Explanation

. Group C; poor outcome, high risk of aspherical head

Explanation

Herring Group C is characterized by >50% collapse of the lateral pillar height. This group is associated with poor prognostic outcomes and a high rate of aspherical femoral heads at maturity.

Question 1470

Topic: Pediatric Hip

A 14-year-old obese male presents with a stable slipped capital femoral epiphysis (SCFE) of the left hip. He undergoes in situ pinning. Which of the following conditions represents the strongest indication for prophylactic pinning of the asymptomatic contralateral hip?

. Obesity (BMI > 95th percentile)
. Age greater than 15 years
. Male gender
. Underlying hypothyroidism
. Family history of SCFE

Correct Answer & Explanation

. Obesity (BMI > 95th percentile)

Explanation

Endocrine disorders, such as hypothyroidism or panhypopituitarism, and renal osteodystrophy significantly increase the risk of bilateral SCFE, making prophylactic contralateral pinning highly recommended.

Question 1471

Topic: Pediatric Hip

A 2.5-year-old girl presents with a limp. Clinical examination and radiographs confirm a unilaterally dislocated left hip (Developmental Dysplasia of the Hip). What is the most appropriate definitive management?

. Pavlik harness application
. Closed reduction and spica casting
. Open reduction and spica casting
. Open reduction with a concomitant pelvic osteotomy
. Observation until skeletal maturity

Correct Answer & Explanation

. Pavlik harness application

Explanation

In children older than 18-24 months with an untreated DDH, open reduction is generally required, often combined with a pelvic osteotomy to address acetabular dysplasia, and occasionally a femoral shortening osteotomy.

Question 1472

Topic: Pediatric Hip

A 6-week-old female infant is undergoing screening for developmental dysplasia of the hip (DDH). An ultrasound of the hip is provided:

In the Graf classification system, the alpha angle is measured to assess the bony roof. Which anatomic structure determines the primary baseline used to establish this angle?

. Bony roof of the acetabulum
. Cartilaginous labrum
. Straight portion of the ilium
. Triradiate cartilage
. Center of the femoral head

Correct Answer & Explanation

. Bony roof of the acetabulum

Explanation

In the Graf ultrasound method for DDH, three lines are drawn. The primary baseline is drawn parallel to the straight portion of the ilium. The second line is drawn along the bony roof of the acetabulum to measure the alpha angle, while the third line is drawn along the cartilaginous roof to measure the beta angle.

Question 1473

Topic: Pediatric Hip

A 12-year-old obese boy presents with left hip pain and an obligatory external rotation with hip flexion. The radiograph is shown:

He undergoes in situ pinning for a Slipped Capital Femoral Epiphysis (SCFE). Which of the following is the most reliable predictor for a future contralateral slip?

. Chronologic age
. Degree of initial slip
. Modified Oxford bone age
. Body Mass Index (BMI)
. Duration of symptoms prior to surgery

Correct Answer & Explanation

. Chronologic age

Explanation

The modified Oxford bone age is the most accurate predictor of a contralateral slip in patients with a unilateral SCFE. A score derived from pelvic radiographs helps determine skeletal maturity; a score of 16 indicates a high risk for a subsequent contralateral slip, justifying prophylactic pinning.

Question 1474

Topic: Pediatric Hip

An 8-year-old boy presents with a painless limp of 6 months duration. Radiographs are provided:

According to the Herring classification for Legg-Calve-Perthes disease, which specific anatomic region is evaluated to determine the prognosis?

. Height of the lateral pillar of the epiphysis
. Extent of metaphyseal cysts
. Subchondral fracture extent
. Sphericity of the femoral head
. Medial joint space widening

Correct Answer & Explanation

. Height of the lateral pillar of the epiphysis

Explanation

The Herring classification focuses on the height of the lateral pillar (the lateral one-third of the epiphysis) on an AP radiograph during the fragmentation stage of Perthes disease. Type A has no involvement, Type B maintains >50% lateral pillar height, and Type C has <50% height, which carries the worst prognosis.

Question 1475

Topic: Pediatric Hip

A 13-year-old boy with a BMI of 32 presents with acute-on-chronic groin pain. He is unable to bear weight. Radiographs show a displaced Slipped Capital Femoral Epiphysis (SCFE).

Based on the Loder classification, what is the primary clinical significance of his inability to bear weight?

. It indicates an associated labral tear
. It defines an unstable SCFE, which has a much higher rate of avascular necrosis (AVN)
. It indicates bilateral involvement is highly likely
. It demonstrates impending slip progression requiring an emergent open reduction
. It precludes the use of in-situ pinning

Correct Answer & Explanation

. It indicates an associated labral tear

Explanation

The Loder classification divides SCFE into stable (able to bear weight with or without crutches) and unstable (unable to bear weight even with crutches). Unstable SCFE has a significantly higher rate of avascular necrosis (AVN), reported to be between 10% and 47%, compared to less than 10% for stable slips.

Question 1476

Topic: Pediatric Hip

A 6-week-old female with a completely dislocated left hip (Graf Type IV) is placed in a Pavlik harness. After 4 weeks of compliant, full-time wear, ultrasound demonstrates the hip remains persistently dislocated. What is the most appropriate next step in management?

. Continue the Pavlik harness for an additional 4 weeks
. Adjust the anterior straps to increase hip flexion past 120 degrees
. Discontinue the Pavlik harness and transition to a rigid abduction orthosis or consider closed reduction
. Proceed immediately to a Salter innominate osteotomy
. Perform an adductor tenotomy and reapply the Pavlik harness

Correct Answer & Explanation

. Continue the Pavlik harness for an additional 4 weeks

Explanation

If a Pavlik harness fails to reduce a dislocated hip after 3 to 4 weeks, it must be discontinued to prevent 'Pavlik harness disease' (erosion and damage to the posterior acetabular wall). The next step is transitioning to a rigid abduction orthosis (e.g., Rhino Cruiser or Ilfeld brace) or proceeding directly to a closed reduction and spica casting.

Question 1477

Topic: Pediatric Hip
An 8-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs obtained during the fragmentation phase reveal that the lateral pillar of the femoral head maintains 60% of its original height. According to the Herring Lateral Pillar Classification, what group is this, and what is the typical recommendation for a child of this age?
. Group A; symptomatic treatment and observation
. Group B; surgical containment (e.g., pelvic or femoral osteotomy)
. Group C; symptomatic treatment and observation
. Group B/C border; immediate hip arthrodesis
. Group C; surgical containment

Correct Answer & Explanation

. Group B; surgical containment (e.g., pelvic or femoral osteotomy)

Explanation

According to the Herring Lateral Pillar classification, Group A has 100% lateral pillar height, Group B maintains >50% height, and Group C has <50% height. For children aged 8 or older with Group B (or B/C border) hips, surgical containment (femoral or pelvic osteotomy) has been shown to result in significantly better spherical outcomes compared to non-operative treatment.

Question 1478

Topic: Pediatric Hip

A 13-year-old male is diagnosed with a unilateral slipped capital femoral epiphysis (SCFE). Prophylactic in situ pinning of the contralateral hip is being considered. Which of the following is the strongest clinical indication for prophylactic contralateral pinning?

. Male sex
. Obesity (BMI > 95th percentile)
. Concomitant endocrine disorder (e.g., hypothyroidism)
. Mild initial slip angle
. Age greater than 14 years

Correct Answer & Explanation

. Male sex

Explanation

Endocrine disorders (such as hypothyroidism, growth hormone deficiency, or renal osteodystrophy) dramatically increase the risk of a contralateral slip in SCFE patients. Prophylactic pinning of the unaffected hip is highly recommended in these populations.

Question 1479

Topic: Pediatric Hip

A 3-month-old female infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During follow-up, the mother notes the child is no longer actively kicking or extending the affected knee. Sensation appears intact. Which nerve is most likely compressed due to improper harness positioning?

. Obturator nerve
. Sciatic nerve
. Femoral nerve
. Superior gluteal nerve
. Lateral femoral cutaneous nerve

Correct Answer & Explanation

. Obturator nerve

Explanation

Femoral nerve palsy in a Pavlik harness is typically caused by excessive hip hyperflexion. It presents as an inability to actively extend the knee. The harness should be loosened or temporarily removed until function returns.

Question 1480

Topic: Pediatric Hip

An 8-year-old boy is diagnosed with Legg-Calve-Perthes disease. Radiographs reveal more than 50% loss of lateral pillar height. Which of the following factors at the time of presentation is the most reliable predictor of long-term prognosis?

. Gender of the patient
. Body Mass Index (BMI)
. Age at the onset of disease
. Bilateral vs. unilateral involvement
. History of preceding trauma

Correct Answer & Explanation

. Gender of the patient

Explanation

Age at clinical onset is one of the most critical prognostic factors in Legg-Calve-Perthes disease. Children who develop the disease after age 8 generally have a worse prognosis due to having less remaining time for remodeling before skeletal maturity.

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