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Pediatric Hip MCQs

Practice Set 27 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 521

Topic: Pediatric Hip

A 12-year-old boy presents with a left-sided slipped capital femoral epiphysis (SCFE). He is noticeably short for his age and has a documented history of hypothyroidism. What is the most appropriate management regarding his completely asymptomatic, radiographically normal contralateral right hip?

. Observation until closure of the right proximal femoral physis.
. Prophylactic in situ pinning of the right hip due to his endocrine abnormality.
. Prophylactic right proximal femoral varus osteotomy.
. Spica cast immobilization for 6 weeks.
. Wait for symptoms to develop before initiating treatment on the right hip.

Correct Answer & Explanation

. Prophylactic in situ pinning of the right hip due to his endocrine abnormality.

Explanation

Patients with underlying endocrine or metabolic disorders (such as hypothyroidism, panhypopituitarism, or renal osteodystrophy) have a significantly higher risk of developing a contralateral SCFE (often reported near 100% in some series). Therefore, prophylactic in situ pinning of the unaffected hip is strongly indicated in this population.

Question 522

Topic: Pediatric Hip

A 12-year-old boy undergoes in situ single screw fixation for a stable slipped capital femoral epiphysis (SCFE). Over the next 6 months, he develops severe hip stiffness, pain, and a concentric loss of joint space on radiographs. This complication is most strongly associated with which intraoperative error?

. Placement of the screw in the anterior half of the epiphysis
. Failure to use a second screw for rotational stability
. Unrecognized intra-articular penetration by the hardware
. Over-reduction of the slip prior to pinning
. Starting the screw superior to the lesser trochanter

Correct Answer & Explanation

. Unrecognized intra-articular penetration by the hardware

Explanation

Chondrolysis is characterized by progressive joint stiffness and narrowing of the joint space. It is most commonly associated with unrecognized intra-articular penetration of the pins or screws during fixation of a SCFE.

Question 523

Topic: Pediatric Hip

A 12-year-old boy with a BMI of 35 presents with left groin pain and an obligate external rotation of the hip with flexion. Radiographs show a severe left slipped capital femoral epiphysis (SCFE). When considering prophylactic pinning of the contralateral asymptomatic right hip, which of the following represents the strongest indication?

. The patient's chronological age.
. The patient's BMI.
. A modified Oxford Bone Age score of 20.
. Open triradiate cartilage.
. The severity of the symptomatic slip.

Correct Answer & Explanation

. Open triradiate cartilage.

Explanation

Prophylactic pinning of the contralateral hip in SCFE is recommended in patients with a high risk of a future slip. Open triradiate cartilage is a strong radiographic marker of skeletal immaturity and is considered one of the most reliable predictors for a contralateral slip. A low modified Oxford bone age score (e.g., 16) also indicates immaturity, whereas a score of 20 indicates skeletal maturity.

Question 524

Topic: Pediatric Hip



A 6-month-old female presents with a neglected developmental dysplasia of the hip (DDH). Ultrasound and plain radiographs confirm a dislocated left hip. She has never received treatment. What is the most appropriate initial management?

. Pavlik harness.
. Closed reduction and spica casting under anesthesia.
. Open reduction via an anterior approach.
. Femoral derotational osteotomy.
. Observation with serial ultrasounds.

Correct Answer & Explanation

. Closed reduction and spica casting under anesthesia.

Explanation

At 6 months of age, a Pavlik harness is generally less effective and carries a higher failure rate. The standard initial management for a 6-month-old with a dislocated hip is an examination under anesthesia, closed reduction, and spica casting. Open reduction is indicated if a concentric closed reduction cannot be achieved or if the child presents at an older age (e.g., typically >18 months).

Question 525

Topic: Pediatric Hip

A 12-year-old obese male presents with left knee pain and an antalgic gait. Radiographs confirm a mild, stable slipped capital femoral epiphysis (SCFE) on the left. Which of the following is an absolute indication for prophylactic pinning of the contralateral asymptomatic hip?

. Patient age > 14 years
. Female gender
. Presence of an underlying endocrine disorder
. Initial slip angle > 50 degrees
. Body mass index > 99th percentile

Correct Answer & Explanation

. Presence of an underlying 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. Other relative indications include young age (<10 years) and poor follow-up compliance.

Question 526

Topic: Pediatric Hip

A 13-year-old obese male presents with a 3-week history of left knee pain and an antalgic gait. Exam shows obligatory external rotation of the left hip upon flexion. Radiographs confirm a severe left slipped capital femoral epiphysis (SCFE). Which of the following parameters is the strongest indication for prophylactic pinning of the asymptomatic contralateral hip?

. Age under 10 or open triradiate cartilage
. Male gender
. Severity of the symptomatic slip
. BMI greater than 95th percentile
. Endocrine disorder such as hypothyroidism

Correct Answer & Explanation

. Endocrine disorder such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip is strongly indicated in patients with underlying endocrinopathies, such as hypothyroidism or renal osteodystrophy. Other relative indications include open triradiate cartilage and age less than 10 years, but endocrine disorders carry the highest risk of bilateral involvement.

Question 527

Topic: Pediatric Hip
A 6-week-old female infant born breech undergoes a screening hip ultrasound. The Graf classification reveals an alpha angle of 45 degrees and a beta angle of 80 degrees. What does this indicate, and what is the most appropriate management?
. Normal hip; reassurance
. Physiologic immaturity; repeat ultrasound in 4 weeks
. Subluxated hip (Graf Type III); Pavlik harness
. Dislocated hip (Graf Type IV); closed reduction and spica cast
. Septic hip; urgent aspiration

Correct Answer & Explanation

. Subluxated hip (Graf Type III); Pavlik harness

Explanation

An alpha angle less than 60 degrees indicates acetabular dysplasia. Specifically, an alpha angle < 50 degrees and beta angle > 77 degrees denotes a Graf Type III hip (subluxated). The first-line treatment for a reducible dysplastic hip at this age is a Pavlik harness.

Question 528

Topic: Pediatric Hip

A 12-year-old obese boy presents with right hip pain and a limp. Radiographs confirm a stable severe right slipped capital femoral epiphysis (SCFE) with a Southwick slip angle of 65 degrees.

What is the strongest primary indication for prophylactic in situ pinning of the contralateral, asymptomatic hip?

. Southwick angle greater than 50 degrees on the symptomatic side
. Age less than 10 years or open triradiate cartilage
. Presence of an underlying endocrine disorder such as hypothyroidism
. Male gender and BMI greater than the 95th percentile
. Family history of early onset hip osteoarthritis

Correct Answer & Explanation

. Presence of an underlying endocrine disorder such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is universally recommended in patients with underlying endocrine or metabolic disorders (e.g., hypothyroidism, renal osteodystrophy). These patients have an exceptionally high risk of developing bilateral disease.

Question 529

Topic: Pediatric Hip

A 12-year-old obese male presents with 3 weeks of left groin pain and a limp. Exam shows obligate external rotation with hip flexion. Radiographs confirm a stable left slipped capital femoral epiphysis (SCFE). Which of the following is the most appropriate absolute indication for prophylactic pinning of the contralateral asymptomatic hip?

. Moderate slip angle on affected side
. Female gender
. Endocrine disorder (e.g., hypothyroidism)
. Age > 14 years
. BMI > 95th percentile

Correct Answer & Explanation

. Endocrine disorder (e.g., hypothyroidism)

Explanation

Prophylactic pinning of the contralateral hip is strongly recommended in patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy) or prior radiation therapy, as their risk of bilateral SCFE approaches 100%. Age < 10 is also a significant risk factor, whereas older age and simple obesity are not absolute indications.

Question 530

Topic: Pediatric Hip

A 12-year-old boy with a BMI of 32 presents with right knee pain and an obligate external rotation of the hip during passive flexion. Radiographs confirm a severe, stable slipped capital femoral epiphysis (SCFE). Prophylactic pinning of the contralateral, asymptomatic hip is most strongly indicated if the patient has a history of which of the following?

. Type 1 Diabetes Mellitus
. Hypothyroidism
. Down syndrome
. Asthma requiring intermittent corticosteroids
. Attention deficit hyperactivity disorder

Correct Answer & Explanation

. Hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended in patients with underlying endocrine disorders such as hypothyroidism, growth hormone deficiency, or renal osteodystrophy. These systemic factors significantly increase the risk of a subsequent contralateral slip.

Question 531

Topic: Pediatric Hip

A 6-month-old infant is diagnosed with developmental dysplasia of the hip (DDH) after failing conservative management in a Pavlik harness. The orthopaedic surgeon plans a closed reduction and spica casting. An arthrogram performed intraoperatively shows a medial dye pool of 7 mm. Which of the following structures is LEAST likely to block concentric reduction in this patient?

. Inverted limbus
. Hypertrophied pulvinar
. Ligamentum teres
. Psoas tendon
. Iliacus muscle

Correct Answer & Explanation

. Iliacus muscle

Explanation

Obstacles to concentric reduction in DDH include an inverted limbus, hypertrophied pulvinar, elongated ligamentum teres, constricted transverse acetabular ligament, and a tight psoas tendon. The iliacus muscle is not a recognized mechanical block to reduction in DDH.

Question 532

Topic: Pediatric Hip

When treating developmental dysplasia of the hip (DDH) with a Pavlik harness, excessive hyperflexion (greater than 120 degrees) increases the risk of which complication?

. Avascular necrosis of the femoral head
. Transient femoral nerve palsy
. Inferior dislocation of the hip
. Obturator nerve palsy
. Acetabular dysplasia

Correct Answer & Explanation

. Transient femoral nerve palsy

Explanation

Hyperflexion in a Pavlik harness can compress the femoral nerve against the rim of the pelvis, leading to a transient femoral nerve palsy. Excessive abduction, conversely, increases the risk of avascular necrosis.

Question 533

Topic: Pediatric Hip

A 12-year-old boy presents with a unilateral Slipped Capital Femoral Epiphysis (SCFE). Which of the following is an absolute indication for prophylactic in-situ pinning of the contralateral, asymptomatic hip?

. Age greater than 14 years at presentation
. Body Mass Index greater than the 95th percentile
. Presentation with acute-on-chronic slip
. High primary slip angle (>50 degrees)
. Presence of an underlying endocrine disorder

Correct Answer & Explanation

. Presence of an underlying endocrine disorder

Explanation

Patients with underlying endocrine disorders (such as hypothyroidism or renal osteodystrophy) have a highly elevated risk of bilateral SCFE, often approaching 100%. Prophylactic fixation of the contralateral hip is universally recommended in these specific metabolic cases.

Question 534

Topic: Pediatric Hip
In Legg-Calvรฉ-Perthes disease, the lateral pillar (Herring) classification is the most reliable predictor of long-term outcome. At what stage of the disease should this classification be applied to ensure accuracy?
. Initial (ischemic) stage
. Early fragmentation stage
. Late fragmentation stage
. Reossification stage
. Residual stage

Correct Answer & Explanation

. Late fragmentation stage

Explanation

The lateral pillar classification assesses the height of the lateral aspect of the femoral head to predict outcomes. It is most accurately and reliably applied during the late fragmentation stage, when the maximum extent of epiphyseal collapse is visible.

Question 535

Topic: Pediatric Hip

A 6-week-old infant is undergoing treatment with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, it is noted that the anterior straps are overly tightened, placing the hip in excessive flexion. What is the most likely iatrogenic complication of this specific malpositioning?

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

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

In Pavlik harness treatment, excessive hip flexion (over-tightened anterior straps) stretches the femoral nerve against the inguinal ligament, causing a femoral nerve palsy. Conversely, excessive abduction (over-tightened posterior straps) increases the risk of avascular necrosis.

Question 536

Topic: Pediatric Hip
A 4-month-old girl is diagnosed with developmental dysplasia of the hip (DDH). Ultrasound confirms a dislocated left hip that is reducible. Treatment with a Pavlik harness is initiated. Which complication is most likely if the hips are positioned in excessive hyperflexion (>120 degrees)?
. Avascular necrosis of the femoral head
. Femoral nerve palsy
. Inferior hip dislocation
. Persistent acetabular dysplasia
. Obturator nerve palsy

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Hyperflexion of the hips in a Pavlik harness compresses the femoral nerve against the inguinal ligament, leading to transient femoral nerve palsy. Conversely, excessive abduction significantly increases the risk of avascular necrosis of the femoral head.

Question 537

Topic: Pediatric Hip

A 13-year-old obese male presents with a 2-week history of worsening groin pain and a sudden inability to bear weight on the right leg after a minor slip. Radiographs confirm a severe slipped capital femoral epiphysis (SCFE). Which of the following factors is the most significant predictor for the development of avascular necrosis (AVN) in this patient?

. Severity of the slip angle
. Duration of prodromal symptoms
. Inability to bear weight (instability)
. Body mass index
. Male gender

Correct Answer & Explanation

. Inability to bear weight (instability)

Explanation

Instability, defined clinically as the inability to bear weight even with crutches, is the most significant risk factor for AVN in SCFE. The rate of AVN in unstable SCFE can approach 50%, compared to near zero in stable slips.

Question 538

Topic: Pediatric Hip

A 12-year-old obese boy presents with a 3-week history of left thigh pain and an antalgic gait. Radiographs confirm a slipped capital femoral epiphysis (SCFE). According to the modified Southwick classification, which of the following defines a "moderate" slip on a frog-leg lateral radiograph?

. An epiphyseal-shaft angle difference of less than 30 degrees compared to the normal side
. An epiphyseal-shaft angle difference of 30 to 50 degrees compared to the normal side
. An epiphyseal-shaft angle difference of greater than 50 degrees compared to the normal side
. Translation of less than 33% of the femoral neck diameter
. Translation of 33% to 50% of the femoral neck diameter

Correct Answer & Explanation

. An epiphyseal-shaft angle difference of 30 to 50 degrees compared to the normal side

Explanation

The Southwick classification uses the difference in the epiphyseal-shaft angle between the affected and normal hips on a frog-leg lateral radiograph. A difference of less than 30 degrees is mild, 30-50 degrees is moderate, and greater than 50 degrees is severe. Translation percentages refer to the Wilson classification.

Question 539

Topic: Pediatric Hip

An infant is undergoing treatment for Developmental Dysplasia of the Hip (DDH) using a Pavlik harness. During a follow-up, you notice decreased active knee extension on the affected side. What is the most likely cause of this complication?

. Excessive flexion of the hip causing femoral nerve compression
. Excessive abduction of the hip causing obturator nerve stretch
. Excessive extension causing sciatic nerve stretch
. Avascular necrosis of the femoral head
. Normal physiological response to the harness

Correct Answer & Explanation

. Excessive flexion of the hip causing femoral nerve compression

Explanation

Decreased active knee extension indicates a femoral nerve palsy, the most common nerve injury associated with the Pavlik harness. It is caused by hyperflexion of the hip and usually resolves upon adjusting the anterior straps.

Question 540

Topic: Pediatric Hip

A 13-year-old obese boy presents with an acute-on-chronic exacerbation of groin pain and an inability to bear weight. Radiographs confirm an unstable slipped capital femoral epiphysis (SCFE). Which of the following complications has the highest incidence following surgical management of this specific injury pattern?

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

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

Unstable SCFE, defined clinically by an inability to bear weight, carries a high risk of avascular necrosis (up to 47%). Urgent decompression and stabilization are debated, but the AVN risk remains inherently tied to the initial vascular insult of the unstable slip.

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