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Pediatric Hip MCQs

Practice Set 99 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 1961

Topic: Pediatric Hip

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

. Age greater than 14 years
. Male sex
. Endocrine disorder (e.g., hypothyroidism)
. Body mass index > 95th percentile
. Presentation with an unstable slip

Correct Answer & Explanation

. Endocrine disorder (e.g., hypothyroidism)

Explanation

Correct Answer: Endocrine disorder (e.g., hypothyroidism)Patients with endocrine disorders (such as hypothyroidism, renal osteodystrophy, or growth hormone deficiency) have a significantly higher risk of developing bilateral SCFE, often presenting at an atypical age. Prophylactic pinning of the contralateral hip is highly recommended in this population to prevent future displacement and associated complications.

Question 1962

Topic: Pediatric Hip

A 6-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the parents report that the infant has stopped kicking her right leg. On examination, there is absent active knee extension on the right, but ankle and toe movements are normal. What is the most likely cause of this finding?

. Excessive flexion of the anterior straps causing femoral nerve palsy
. Excessive abduction of the posterior straps causing obturator nerve palsy
. Inadequate flexion of the anterior straps causing sciatic nerve palsy
. Avascular necrosis of the femoral head
. Septic arthritis of the hip

Correct Answer & Explanation

. Excessive flexion of the anterior straps causing femoral nerve palsy

Explanation

Correct Answer: Excessive flexion of the anterior straps causing femoral nerve palsyFemoral nerve palsy is a known complication of Pavlik harness treatment, typically caused by excessive hyperflexion of the hip due to the anterior straps being too tight. It presents with decreased or absent active knee extension. If this occurs, the harness should be adjusted to reduce flexion or temporarily discontinued until nerve function returns.

Question 1963

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Which of the following radiographic findings is considered a 'head-at-risk' sign according to Catterall, indicating a poorer prognosis?
. Medial subluxation of the femoral head
. Gage sign (V-shaped radiolucency in the lateral epiphysis)
. Ossification of the capital femoral epiphysis
. Narrowing of the medial joint space
. Hypertrophy of the greater trochanter

Correct Answer & Explanation

. Gage sign (V-shaped radiolucency in the lateral epiphysis)

Explanation

Catterall described several 'head-at-risk' signs for Perthes disease that correlate with a poorer prognosis and potential for hinge abduction. These include Gage sign (a V-shaped radiolucency in the lateral portion of the epiphysis and adjacent metaphysis), lateral subluxation of the femoral head, calcification lateral to the epiphysis, and a horizontal growth plate.

Question 1964

Topic: Pediatric Hip

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

. Age greater than 14 years
. Underlying endocrine disorder
. Male sex
. Grade I slip on the symptomatic side
. BMI greater than the 95th percentile

Correct Answer & Explanation

. Underlying endocrine disorder

Explanation

Correct Answer: Underlying endocrine disorderProphylactic pinning of the contralateral hip in SCFE is highly recommended in patients with underlying endocrine disorders (such as hypothyroidism, panhypopituitarism, or renal osteodystrophy) due to the significantly increased risk of bilateral involvement. While obesity and young age (e.g., males < 12, females < 10) are also risk factors for bilaterality, an underlying endocrinopathy is the strongest absolute indication for prophylactic fixation.

Question 1965

Topic: Pediatric Hip

A 6-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the parents report that the infant has stopped kicking her leg on the treated side. On examination, there is an absence of active knee extension. 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 harness and observe
. Transition to a rigid abduction orthosis
. Perform an immediate closed reduction and spica casting

Correct Answer & Explanation

. Remove the harness and observe

Explanation

Correct Answer: Remove the harness and observeThe clinical presentation is consistent with a femoral nerve palsy, a known complication of hyperflexion in a Pavlik harness. The femoral nerve becomes compressed against the rim of the pelvis. The most appropriate next step is to remove the harness and observe until neurologic function returns, which typically occurs within a few days to weeks. Continuing the harness or increasing flexion can lead to permanent nerve damage or failure of treatment.

Question 1966

Topic: Pediatric Hip

In the evaluation of Legg-Calve-Perthes disease, the lateral pillar classification is used to determine prognosis. During which stage of the disease is this classification most accurately applied?

. Initial (necrosis) stage
. Fragmentation stage
. Reossification stage
. Remodeling stage
. Residual stage

Correct Answer & Explanation

. Fragmentation stage

Explanation

Correct Answer: Fragmentation stageThe Herring lateral pillar classification is most accurately applied during the early fragmentation stage of Legg-Calve-Perthes disease. It assesses the height of the lateral pillar of the capital femoral epiphysis on an AP radiograph. A lateral pillar height of >100% is Group A, >50% is Group B, and <50% is Group C. This classification correlates strongly with the long-term outcome and risk of aspherical femoral head development.

Question 1967

Topic: Pediatric Hip
A 12-year-old boy with a BMI in the 99th percentile undergoes in situ pinning for a stable left slipped capital femoral epiphysis (SCFE). Which of the following is the most widely accepted indication for prophylactic pinning of the contralateral asymptomatic hip?
. Age greater than 14 years
. Presence of an endocrine disorder (e.g., hypothyroidism)
. Female sex
. Grade III slip on the affected side
. Presentation with knee pain rather than hip pain

Correct Answer & Explanation

. Presence of an endocrine disorder (e.g., hypothyroidism)

Explanation

Prophylactic pinning of the contralateral hip in SCFE remains a topic of debate, but it is generally recommended for patients at high risk for bilateral involvement. High-risk factors include the presence of an endocrine disorder (such as hypothyroidism, renal osteodystrophy, or panhypopituitarism), previous radiation therapy, and young age at presentation (typically less than 10 years old for boys). Older age, severity of the initial slip, and presentation with knee pain do not independently mandate prophylactic contralateral pinning.

Question 1968

Topic: Pediatric Hip

A 6-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the parents report that the infant has stopped kicking her leg on the affected side. On examination, there is an absence of active knee extension. 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
. Discontinue the Pavlik harness immediately
. Switch to a rigid hip spica cast
. Order an urgent MRI of the lumbar spine

Correct Answer & Explanation

. Discontinue the Pavlik harness immediately

Explanation

Correct Answer: Discontinue the Pavlik harness immediatelyThe clinical presentation describes a femoral nerve palsy, which is a known complication of excessive hip flexion in a Pavlik harness. The femoral nerve becomes compressed against the rim of the pelvis or the inguinal ligament. The appropriate management is to discontinue the harness (or significantly loosen the anterior straps to reduce hip flexion) to relieve the pressure on the nerve. Most cases resolve spontaneously within a few days to weeks after removing the hyperflexion force. Continuing the harness or switching to a spica cast without allowing nerve recovery is contraindicated.

Question 1969

Topic: Pediatric Hip
In the evaluation of a 7-year-old boy with Legg-Calvé-Perthes disease, which of the following radiographic classification systems is most predictive of the long-term outcome and risk of early osteoarthritis?
. Catterall classification
. Salter-Thompson classification
. Herring Lateral Pillar classification
. Waldenström classification
. Stulberg classification

Correct Answer & Explanation

. Herring Lateral Pillar classification

Explanation

The Herring Lateral Pillar classification, assessed during the fragmentation phase of Legg-Calvé-Perthes disease, is the most reliable and widely used prognostic indicator. It evaluates the height of the lateral pillar of the femoral head (Group A: >100% height maintained; Group B: >50% height maintained; Group C: <50% height maintained). The Stulberg classification is used at skeletal maturity to assess the final joint congruency, not during the active disease process. Waldenström describes the temporal stages of the disease.

Question 1970

Topic: Pediatric Hip

A 9-year-old boy with a BMI in the 99th percentile presents with a stable slipped capital femoral epiphysis (SCFE) of the left hip. He has a known medical history of hypothyroidism. What is the most appropriate management for the contralateral right hip?

. Observation with serial radiographs every 6 months
. Spica casting in internal rotation
. Prophylactic in situ pinning
. Closed reduction and percutaneous pinning
. Open reduction and internal fixation

Correct Answer & Explanation

. Prophylactic in situ pinning

Explanation

Correct Answer: Prophylactic in situ pinningProphylactic pinning of the contralateral hip is highly recommended in patients with SCFE who have underlying endocrine disorders (such as hypothyroidism or panhypopituitarism), renal osteodystrophy, previous radiation therapy, or are under 10 years of age. These patients have a significantly higher risk of developing bilateral involvement compared to idiopathic cases.

Question 1971

Topic: Pediatric Hip

During an open reduction of a developmental dysplasia of the hip (DDH) via a medial approach, the surgeon encounters resistance to concentric reduction. Which of the following structures is considered an intra-articular block to reduction?

. Iliopsoas tendon
. Adductor longus
. Transverse acetabular ligament
. Rectus femoris
. Tensor fasciae latae

Correct Answer & Explanation

. Transverse acetabular ligament

Explanation

Correct Answer: Transverse acetabular ligamentBlocks to reduction in DDH are categorized as extra-articular or intra-articular. Extra-articular blocks include the iliopsoas tendon and adductor longus. Intra-articular blocks include the inverted limbus, hypertrophied pulvinar, ligamentum teres, and a contracted transverse acetabular ligament. The transverse acetabular ligament must often be incised to allow the femoral head to seat deeply within the true acetabulum.

Question 1972

Topic: Pediatric Hip
In the evaluation of a 7-year-old boy with Legg-Calvé-Perthes disease, which of the following radiographic classifications is considered the most reliable prognostic indicator for long-term hip outcome?
. Catterall classification
. Salter-Thompson classification
. Herring lateral pillar classification
. Stulberg classification
. Waldenström stages

Correct Answer & Explanation

. Herring lateral pillar classification

Explanation

The Herring lateral pillar classification, assessed during the fragmentation phase of the disease, is the most reliable prognostic indicator for Legg-Calvé-Perthes disease. It evaluates the height of the lateral pillar of the capital femoral epiphysis. Group A has no lateral pillar involvement, Group B has >50% lateral pillar height maintained, and Group C has <50% lateral pillar height maintained. Group C has the poorest prognosis.

Question 1973

Topic: Pediatric Hip

A 13-year-old obese male undergoes in situ pinning for a stable slipped capital femoral epiphysis (SCFE). Postoperatively, he develops severe hip stiffness and pain. Radiographs show concentric joint space narrowing. What is the most likely cause of this complication?

. Avascular necrosis
. Unrecognized hardware penetration into the joint
. Septic arthritis
. Femoroacetabular impingement
. Slipped contralateral hip

Correct Answer & Explanation

. Unrecognized hardware penetration into the joint

Explanation

Correct Answer: Unrecognized hardware penetration into the jointChondrolysis is characterized by concentric joint space narrowing and severe stiffness following treatment for SCFE. The most common iatrogenic cause is unrecognized pin penetration into the joint space. Avascular necrosis typically presents with segmental collapse rather than concentric joint space narrowing.

Question 1974

Topic: Pediatric Hip

A 6-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the parents report that the infant has stopped kicking her leg on the affected side. On examination, there is absent active knee extension. Which of the following adjustments to the harness is most appropriate?

. 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 and schedule closed reduction

Correct Answer & Explanation

. Decrease the flexion of the anterior straps

Explanation

Correct Answer: Decrease the flexion of the anterior strapsHyperflexion in a Pavlik harness can lead to a compressive femoral nerve palsy, presenting as decreased active knee extension and a lack of kicking. The appropriate management is to decrease the flexion of the anterior straps or temporarily discontinue the harness until nerve function recovers.

Question 1975

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Which of the following factors is considered the most significant predictor of the final radiographic and clinical outcome?
. Gender of the patient
. Age at the time of clinical onset
. Body mass index (BMI)
. Presence of a limp at presentation
. Family history of the disease

Correct Answer & Explanation

. Age at the time of clinical onset

Explanation

Age at the onset of symptoms is the most critical prognostic factor in Legg-Calvé-Perthes disease. Children who develop the disease at a younger age (typically under 6-8 years) have a better prognosis due to greater potential for remodeling of the femoral head before skeletal maturity.

Question 1976

Topic: Pediatric Hip

A 24-month-old girl recently emigrated from a developing country and is evaluated for a painless limp. Examination reveals a positive Galeazzi sign and asymmetric thigh folds. Radiographs confirm an untreated unilateral developmental dysplasia of the hip (DDH) with a dislocated left hip. What is the most appropriate initial management?

. Pavlik harness trial
. Closed reduction and spica casting
. Open reduction and spica casting
. Observation until skeletal maturity
. Total hip arthroplasty

Correct Answer & Explanation

. Open reduction and spica casting

Explanation

For children over 18-24 months of age with a completely dislocated hip, open reduction is generally the initial treatment of choice. Closed reduction and Pavlik harness have unacceptably high failure and AVN rates in this older age group.

Question 1977

Topic: Pediatric Hip
Which of the following factors is considered the most significant prognostic indicator for the long-term outcome in a child diagnosed with Legg-Calvé-Perthes disease?
. Age at the onset of the disease
. Gender of the patient
. Patient's body mass index (BMI)
. Bilateral versus unilateral involvement
. Degree of initial hip pain

Correct Answer & Explanation

. Age at the onset of the disease

Explanation

Age at disease onset is the most important prognostic factor in Legg-Calvé-Perthes disease, alongside the lateral pillar classification. Children who develop the disease before age 6 to 8 generally have better remodeling potential and long-term outcomes.

Question 1978

Topic: Pediatric Hip

A 13-year-old boy undergoes in situ single-screw fixation for a stable slipped capital femoral epiphysis (SCFE). At his 6-week follow-up, he complains of severe, constant hip pain and profound loss of hip motion in all planes. Radiographs show a significant reduction in the joint space compared to the immediate post-operative films. What is the most likely diagnosis?

. Avascular necrosis of the femoral head
. Chondrolysis
. Undiagnosed septic arthritis
. Hardware failure
. Contralateral SCFE

Correct Answer & Explanation

. Chondrolysis

Explanation

Chondrolysis is a devastating complication of SCFE characterized by acute narrowing of the joint space and severe, painful restriction of motion. It is strongly associated with unrecognized pin penetration into the joint space.

Question 1979

Topic: Pediatric Hip

An 8-year-old boy with Legg-Calve-Perthes disease presents for follow-up. Radiographs reveal a V-shaped radiolucent defect in the lateral portion of the proximal femoral epiphysis. What is the name of this specific radiographic finding, and what does it indicate?

. Gage sign, indicating a "head at risk" for poor outcome
. Trethowan sign, indicating a stable lesion
. Klein's line, indicating impending physeal slip
. Hilgenreiner's line, indicating severe lateral subluxation
. Perkins sign, indicating early re-ossification

Correct Answer & Explanation

. Gage sign, indicating a "head at risk" for poor outcome

Explanation

The Gage sign is a V-shaped radiolucency in the lateral epiphysis and adjacent metaphysis. It is one of Catterall's "head at risk" signs in Legg-Calve-Perthes disease, which correlate with a poorer prognosis and progressive deformity.

Question 1980

Topic: Pediatric Hip

An 18-month-old girl undergoes closed reduction for developmental dysplasia of the hip (DDH). Intraoperative arthrography reveals an hourglass-shaped capsular constriction preventing the femoral head from seating concentrically in the acetabulum. Which anatomical structure is responsible for creating this extra-articular constriction?

. Transverse acetabular ligament
. Iliopsoas tendon
. Ligamentum teres
. Inverted limbus
. Reflected head of the rectus femoris

Correct Answer & Explanation

. Iliopsoas tendon

Explanation

The iliopsoas tendon crosses the anterior aspect of the hip capsule, creating an hourglass capsular constriction that can physically block concentric closed reduction in DDH. The transverse ligament, ligamentum teres, and limbus are intra-articular blocks.

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