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Pediatric Hip MCQs

Practice Set 102 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 2021

Topic: Pediatric Hip

An 11-year-old obese male presents with acute severe groin pain and inability to bear weight on his right leg after a minor fall. Radiographs reveal an unstable slipped capital femoral epiphysis (SCFE). Which of the following interventions has the highest risk of causing avascular necrosis (AVN) of the femoral head in this setting?

. In situ pinning with a single screw.
. Forceful closed reduction before pinning.
. Open reduction via a surgical hip dislocation approach.
. Percutaneous pinning utilizing two screws.
. Capsulotomy without reduction.

Correct Answer & Explanation

. Forceful closed reduction before pinning.

Explanation

Forceful or non-gentle closed reduction of an unstable SCFE is highly associated with an increased risk of AVN due to kinking or disruption of the fragile retinacular vessels. Current best practices favor either in situ fixation with incidental reduction or an open reduction (e.g., modified Dunn procedure).

Question 2022

Topic: Pediatric Hip

A 5-month-old female with developmental dysplasia of the hip (DDH) has been treated in a Pavlik harness for 4 weeks. Ultrasound demonstrates continued complete dislocation of the left hip with no signs of reduction. What is the most appropriate next step in management?

. Continue Pavlik harness for 4 more weeks.
. Switch to a rigid abduction orthosis (e.g., Ilfeld splint).
. Proceed directly to open reduction and femoral shortening.
. Discontinue the harness and plan for closed reduction and spica casting.
. Perform a pelvic osteotomy.

Correct Answer & Explanation

. Discontinue the harness and plan for closed reduction and spica casting.

Explanation

If a hip remains completely dislocated after 3 to 4 weeks in a Pavlik harness, it must be discontinued to prevent damage to the posterior acetabulum (Pavlik harness disease). The subsequent step in a child of this age is typically a closed reduction under anesthesia followed by spica casting.

Question 2023

Topic: Pediatric Hip

A 14-year-old obese male presents with acute onset of severe hip pain and inability to bear weight. Radiographs confirm an unstable slipped capital femoral epiphysis (SCFE). He undergoes urgent in situ single-screw fixation. Which of the following complications is most highly associated with this specific presentation?

. Chondrolysis
. Avascular necrosis (AVN)
. Leg length discrepancy
. Implant failure
. Femoroacetabular impingement

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

Unstable SCFE (defined by the inability to bear weight) carries a high risk of avascular necrosis (up to 50%), regardless of the treatment method, due to the disruption of the epiphyseal blood supply.

Question 2024

Topic: Pediatric Hip

A 4-year-old girl is diagnosed with developmental dysplasia of the hip (DDH). Radiographs demonstrate an acetabular index of 40 degrees with anterolateral acetabular deficiency. The surgeon decides to perform a Pemberton osteotomy. What is the primary hinge point for this specific pelvic osteotomy?

. Pubic symphysis
. Sacroiliac joint
. Triradiate cartilage
. Ischial spine
. Obturator foramen

Correct Answer & Explanation

. Triradiate cartilage

Explanation

The Pemberton osteotomy is an incomplete pericapsular osteotomy that hinges on the flexible triradiate cartilage, allowing the acetabular roof to be hinged downward, reducing acetabular volume and improving anterolateral coverage.

Question 2025

Topic: Pediatric Hip
A 6-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Which of the following radiographic classifications is most reliable for determining the long-term prognosis and likelihood of a spherical femoral head?
. Catterall classification
. Salter-Thompson classification
. Herring lateral pillar classification
. Stulberg classification
. Waldenström staging

Correct Answer & Explanation

. Herring lateral pillar classification

Explanation

The Herring lateral pillar classification evaluates the height of the lateral aspect of the capital femoral epiphysis during the fragmentation stage and is the most reliable prognostic indicator for final head shape in Perthes disease.

Question 2026

Topic: Pediatric Hip

Which of the following findings is the most reliable determinant of 'instability' in a slipped capital femoral epiphysis (SCFE) according to the Loder classification?

. A slip angle greater than 50 degrees
. Presence of a joint effusion on ultrasound
. Inability to ambulate with or without crutches
. Disruption of the Shenton line
. A physeal step-off greater than 50% of the neck width

Correct Answer & Explanation

. Inability to ambulate with or without crutches

Explanation

The Loder classification defines an unstable SCFE based strictly on the clinical inability of the patient to bear weight, even with assistive devices like crutches. Unstable slips carry a significantly higher risk of avascular necrosis.

Question 2027

Topic: Pediatric Hip
According to the Herring Lateral Pillar Classification for Legg-Calvé-Perthes disease, a patient whose lateral pillar height is maintained at 40% of its normal height falls into which group, and what is the general prognosis?
. Group A; excellent prognosis
. Group B; fair to good prognosis
. Group B/C; fair prognosis
. Group C; poor prognosis
. Group D; universally poor prognosis

Correct Answer & Explanation

. Group C; poor prognosis

Explanation

Herring Group C is defined by a lateral pillar height of less than 50% of the normal height. This group has a generally poor prognosis, carrying a significantly higher risk of aspherical head remodeling and early osteoarthritis.

Question 2028

Topic: Pediatric Hip

A 45-year-old female with developmental dysplasia of the hip (DDH) Crowe type IV undergoes a total hip arthroplasty. To safely reduce the hip to the true acetabulum and minimize the risk of sciatic nerve palsy, which surgical maneuver is most frequently required?

. Greater trochanteric advancement
. Distal femoral shortening osteotomy
. Subtrochanteric shortening osteotomy
. Pelvic support osteotomy
. Extensive capsular plication

Correct Answer & Explanation

. Subtrochanteric shortening osteotomy

Explanation

In Crowe IV DDH, the femoral head is highly dislocated. Reducing the hip to the anatomic true acetabulum stretches the sciatic nerve; a subtrochanteric shortening osteotomy is commonly required to avoid stretch injury to the nerve.

Question 2029

Topic: Pediatric Hip
Which patient with Legg-Calvé-Perthes disease would show the most significant radiographic benefit from a surgical containment procedure (e.g., proximal femoral or pelvic osteotomy)?
. A 5-year-old with Herring lateral pillar group A
. A 6-year-old with Herring lateral pillar group B
. A 9-year-old with Herring lateral pillar group B/C border
. A 10-year-old with Herring lateral pillar group C
. A 4-year-old with Herring lateral pillar group C

Correct Answer & Explanation

. A 9-year-old with Herring lateral pillar group B/C border

Explanation

Surgical containment provides the greatest benefit in children over 8 years of age at disease onset who have Herring lateral pillar B or B/C border involvement. Patients in group C generally have poor outcomes regardless of the intervention.

Question 2030

Topic: Pediatric Hip

A 12-year-old obese male presents with acute-on-chronic hip pain and inability to bear weight. Radiographs show a severe slipped capital femoral epiphysis (SCFE). Intraoperatively, a capsulotomy is performed before pinning. What is the primary rationale for this capsulotomy?

. To improve visualization of the physis for pin placement
. To decrease intracapsular pressure and potentially lower the risk of avascular necrosis (AVN)
. To facilitate an open reduction of the epiphysis
. To remove loose bodies from the joint space
. To allow placement of an intra-articular drain

Correct Answer & Explanation

. To decrease intracapsular pressure and potentially lower the risk of avascular necrosis (AVN)

Explanation

In unstable SCFE, an acute hemarthrosis significantly elevates intracapsular pressure, compromising retinacular vessel flow. A capsulotomy decompresses this hematoma, theoretically restoring blood flow and lowering the high risk of AVN.

Question 2031

Topic: Pediatric Hip

An infant with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a follow-up visit, the parents report the infant is not kicking the affected leg. Examination reveals lack of knee extension. Which of the following harness adjustments is required?

. Increase the flexion of the anterior straps
. Decrease the flexion of the anterior straps
. Increase the abduction of the posterior straps
. Decrease the abduction of the posterior straps
. Discontinue the harness immediately for 4 weeks

Correct Answer & Explanation

. Decrease the flexion of the anterior straps

Explanation

Femoral nerve palsy is a known complication of excessive hip flexion in a Pavlik harness. The appropriate management is to decrease the flexion of the anterior straps and observe for clinical recovery.

Question 2032

Topic: Pediatric Hip

A 13-year-old obese male presents to the ED with a 2-day history of severe left hip pain and inability to bear weight. Radiographs demonstrate a Slipped Capital Femoral Epiphysis (SCFE). Which of the following factors best defines this as an 'unstable' SCFE?

. Slip angle greater than 50 degrees
. Presence of an effusion on ultrasound
. Inability to ambulate with or without crutches
. Duration of symptoms less than 3 weeks
. Open triradiate cartilage

Correct Answer & Explanation

. Inability to ambulate with or without crutches

Explanation

The Loder classification defines unstable SCFE as the patient's inability to bear weight on the affected limb, even with the use of crutches. Unstable SCFEs have a significantly higher risk of avascular necrosis.

Question 2033

Topic: Pediatric Hip

A 6-week-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During follow-up, the mother notes the infant has stopped kicking her right leg, and clinical examination reveals decreased active knee extension on that side. Which of the following harness adjustments should have been avoided to prevent this complication?

. Excessive hip flexion
. Excessive hip abduction
. Inadequate hip flexion
. Inadequate hip abduction
. Excessive knee flexion

Correct Answer & Explanation

. Excessive hip flexion

Explanation

Excessive hip flexion in a Pavlik harness can compress the femoral nerve against the inguinal ligament, leading to a femoral nerve palsy characterized by decreased active knee extension. Excessive hip abduction risks avascular necrosis (AVN) of the femoral head.

Question 2034

Topic: Pediatric Hip

A 10-year-old girl is diagnosed with a unilateral slipped capital femoral epiphysis (SCFE). Which of the following patient profiles represents the strongest indication for prophylactic in situ pinning of the contralateral, asymptomatic hip?

. A patient with BMI > 95th percentile
. A patient with primary hypothyroidism
. A patient with a family history of SCFE
. A patient with advanced skeletal maturity
. A male patient with traumatic SCFE onset

Correct Answer & Explanation

. A patient with primary hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip is strongly recommended in patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy) or prior pelvic radiation. These patients have a significantly higher risk of developing bilateral SCFE.

Question 2035

Topic: Pediatric Hip

Which of the following pediatric patients presenting with a unilateral slipped capital femoral epiphysis (SCFE) has the strongest indication for prophylactic in situ pinning of the contralateral hip?

. A 13-year-old boy with a BMI in the 95th percentile
. A 10-year-old girl with primary hypothyroidism
. A 14-year-old boy with a history of minor trauma
. A 12-year-old boy with a family history of SCFE
. An 11-year-old girl with a stable SCFE and normal endocrine labs

Correct Answer & Explanation

. A 10-year-old girl with primary hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip is strongly indicated in patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy) due to an exceedingly high risk of bilateral involvement. It is also highly recommended in children presenting at a young age (<10 years).

Question 2036

Topic: Pediatric Hip
A 6-week-old female infant born in breech presentation undergoes a screening ultrasound for developmental dysplasia of the hip (DDH). The alpha angle is reported as 45 degrees. According to Graf's classification, what is the most appropriate management?
. Reassurance and repeat ultrasound in 6 months
. Treatment with a Pavlik harness
. Closed reduction and spica casting
. Open reduction and pelvic osteotomy
. Use of double diapers

Correct Answer & Explanation

. Treatment with a Pavlik harness

Explanation

An alpha angle less than 60 degrees indicates a shallow acetabulum consistent with dysplasia (Graf Type IIc or III depending on the beta angle). The first-line treatment for an infant under 6 months with a dysplastic or subluxated hip is a Pavlik harness.

Question 2037

Topic: Pediatric Hip

A 13-year-old boy with a BMI of 38 presents with a stable slipped capital femoral epiphysis (SCFE) of the left hip. Routine preoperative blood work reveals untreated hypothyroidism. After in situ pinning of the left hip, what is the most appropriate recommendation regarding the right hip?

. Observation with serial clinical exams every 6 months
. Prophylactic in situ pinning of the right hip
. Immediate bilateral spica casting
. Physical therapy for weight loss before considering any further surgery
. Pre-emptive open subcapital osteotomy of the right hip

Correct Answer & Explanation

. Prophylactic in situ pinning of the right hip

Explanation

Patients with SCFE and underlying endocrinopathies (such as hypothyroidism) or renal failure are at an exceptionally high risk for bilateral involvement. Prophylactic pinning of the contralateral hip is strongly recommended in these high-risk populations to prevent future displacement.

Question 2038

Topic: Pediatric Hip

A 12-year-old obese boy presents with a 3-week history of left knee pain and a painful limp. On physical examination, his left hip obligatorily externally rotates when passively flexed. Radiographs confirm a stable Slipped Capital Femoral Epiphysis (SCFE). What is the most appropriate immediate management for this patient?

. Closed reduction and spica casting
. Open reduction and internal fixation
. In situ percutaneous pinning
. Non-weight bearing and physical therapy
. Proximal femoral osteotomy

Correct Answer & Explanation

. In situ percutaneous pinning

Explanation

Correct Answer: In situ percutaneous pinningThe standard of care for a stable Slipped Capital Femoral Epiphysis (SCFE) is in situ percutaneous pinning with a single cannulated screw. This prevents further slippage of the epiphysis and promotes premature closure of the physis. Closed reduction is contraindicated as it significantly increases the risk of avascular necrosis of the femoral head.

Question 2039

Topic: Pediatric Hip

A 13-year-old obese male presents with a 3-week history of left knee pain and a noticeable limp. He denies any recent trauma. On physical examination, as the affected hip is passively flexed, the thigh obligatorily deviates into external rotation. Internal rotation of the hip is significantly limited. What is the most appropriate initial management for the suspected diagnosis?

. Closed reduction and spica casting
. Immediate open reduction and internal fixation
. In situ pinning of the proximal femoral epiphysis
. Non-weight bearing and observation
. Aspiration of the hip joint

Correct Answer & Explanation

. In situ pinning of the proximal femoral epiphysis

Explanation

Correct Answer: CThe patient's clinical presentation (obese adolescent, knee/thigh pain, limp, obligatory external rotation with hip flexion, and limited internal rotation) is classic for a Slipped Capital Femoral Epiphysis (SCFE). The standard of care for a stable SCFE is in situ pinning, typically with a single cannulated screw placed in the center of the epiphysis. This prevents further slippage and promotes premature closure of the physis. Closed reduction is contraindicated as it significantly increases the risk of avascular necrosis (AVN) of the femoral head.

Question 2040

Topic: Pediatric Hip

A 6-week-old female infant is currently being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up exam, the parents report the infant has stopped kicking her right leg. On exam, there is an absence of active knee extension on the right side. What is the most likely iatrogenic cause of this finding?

. Excessive abduction of the hip
. Hyperflexion of the hip
. Excessive adduction of the hip
. Over-tightening of the chest strap
. Prolonged positioning in extension

Correct Answer & Explanation

. Hyperflexion of the hip

Explanation

Femoral nerve palsy is the most common nerve injury associated with Pavlik harness use and typically presents with decreased active knee extension. It is usually caused by excessive hyperflexion of the hip and resolves once the anterior straps are loosened.

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