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Pediatric Hip MCQs

Practice Set 73 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 1441

Topic: Pediatric Hip

In a 7-year-old boy diagnosed with Legg-Calve-Perthes disease, which of the following radiographic findings is considered a head-at-risk sign indicating a poorer prognosis and potential need for surgical containment?

. Medial subluxation of the femoral head
. Gage sign (a V-shaped radiolucency in the lateral epiphysis)
. Ossification of the femoral head occurring before age 8
. Narrowing of the teardrop distance
. Presence of a concurrent slipped capital femoral epiphysis

Correct Answer & Explanation

. Medial subluxation of the femoral head

Explanation

Catterall's head-at-risk signs include the Gage sign, lateral calcification, lateral subluxation of the femoral head, and a horizontal physis. These signs indicate a loss of containment and a higher risk for permanent femoral head deformation.

Question 1442

Topic: Pediatric Hip

A 4-week-old female is placed in a Pavlik harness for developmental dysplasia of the hip. At her one-week follow-up, she is noted to have absent active knee extension on the affected side. Which of the following is the most appropriate next step in management?

. Adjust the harness to increase abduction
. Discontinue the harness temporarily or significantly decrease anterior strap tension
. Proceed to closed reduction and spica casting
. Increase anterior strap tension to secure reduction
. Transition immediately to a rigid hip abduction orthosis

Correct Answer & Explanation

. Adjust the harness to increase abduction

Explanation

Absent active knee extension indicates a femoral nerve palsy, a known complication of the Pavlik harness occurring in about 2% of cases. It is caused by excessive hyperflexion, which compresses the femoral nerve against the inguinal ligament. The most appropriate immediate management is to discontinue the harness temporarily or decrease the tension on the anterior flexion straps to allow the nerve to recover. Recovery typically occurs within a few days to a week.

Question 1443

Topic: Pediatric Hip

A 12-year-old boy with a BMI of 32 presents with a left slipped capital femoral epiphysis (SCFE). Prophylactic pinning of the contralateral asymptomatic hip is most strongly indicated in which of the following scenarios?

. The patient is an African American male
. The patient presents with a chronic SCFE rather than an acute one
. The patient has underlying renal osteodystrophy
. The patient has a closed triradiate cartilage on the AP pelvis radiograph
. The patient has a positive family history of SCFE

Correct Answer & Explanation

. The patient is an African American male

Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial for idiopathic cases but is strongly indicated in patients with underlying endocrinopathies or metabolic bone diseases (e.g., renal osteodystrophy, hypothyroidism, panhypopituitarism) and in patients receiving radiation therapy, because the risk of contralateral slip approaches 50-100% in these populations.

Question 1444

Topic: Pediatric Hip
In Legg-Calvé-Perthes disease, which of the following clinical factors is considered the most significant prognostic factor for long-term hip joint survival and prevention of early osteoarthritis?
. Age at clinical presentation
. Gender of the patient
. Presence of a Gage sign on radiographs
. Degree of metaphyseal cyst formation
. Amount of initial limb length discrepancy

Correct Answer & Explanation

. Age at clinical presentation

Explanation

Age at clinical presentation is universally recognized as the most critical prognostic factor in Legg-Calvé-Perthes disease. Children who present at less than 6 to 8 years of age have a significant remodeling potential and generally fare better. Those over age 8 at presentation have a much higher rate of poor outcomes and early secondary osteoarthritis. The Lateral Pillar classification is the most significant radiographic prognostic factor.

Question 1445

Topic: Pediatric Hip

A 13-year-old boy presents to the emergency department unable to bear weight on his right leg after a minor fall 2 days ago. He has a history of vague right groin pain for 3 months. Radiographs demonstrate a severe, unstable slipped capital femoral epiphysis (SCFE). Which of the following best describes the rationale for performing a capsulotomy during surgical fixation?

. To assist with anatomic closed reduction
. To reduce intracapsular pressure and minimize the risk of avascular necrosis
. To prevent chondrolysis
. To facilitate removal of loose bodies
. To allow for placement of a second stabilizing screw

Correct Answer & Explanation

. To assist with anatomic closed reduction

Explanation

Unstable SCFE (defined by the inability to bear weight) carries a high risk of avascular necrosis (AVN), reportedly up to 50%. The primary rationale for performing an anterior capsulotomy during surgical treatment of an unstable SCFE is to evacuate the fracture hematoma, thereby decompressing the joint and reducing intracapsular pressure, which theoretically improves perfusion to the femoral head and decreases the risk of AVN.

Question 1446

Topic: Pediatric Hip

An 11-year-old girl with a body mass index (BMI) in the 99th percentile is diagnosed with a unilateral slipped capital femoral epiphysis (SCFE).

Which of the following is considered an absolute indication for prophylactic in situ pinning of the contralateral, asymptomatic hip?

. A modified Southwick angle greater than 50 degrees on the symptomatic side
. Patient age younger than 12 years at the time of presentation
. The presence of an underlying endocrine or metabolic disorder (e.g., hypothyroidism)
. A patient BMI exceeding the 95th percentile
. Female sex

Correct Answer & Explanation

. A modified Southwick angle greater than 50 degrees on the symptomatic side

Explanation

While factors such as young age, obesity, and open triradiate cartilage are relative indications that surgeons consider when discussing prophylactic pinning, the presence of an underlying endocrine or metabolic disorder (such as hypothyroidism, panhypopituitarism, or renal osteodystrophy) is universally considered an absolute indication for prophylactic pinning of the contralateral hip due to the extremely high risk of a subsequent slip.

Question 1447

Topic: Pediatric Hip
An 8-year-old boy presents with a painful limp and limited hip abduction. Radiographs reveal fragmentation of the proximal femoral epiphysis with maintained height of the lateral pillar (>50% of original height), classifying it as Herring Lateral Pillar Group B Legg-Calvé-Perthes disease (LCPD). According to the multicenter prospective study by Herring et al., which intervention provides the best radiographic outcome for this specific patient profile?
. Non-weight-bearing strictly enforced with crutches
. Scottish Rite abduction bracing
. Surgical containment via a proximal femoral varus osteotomy or pelvic osteotomy
. Core decompression of the femoral head
. Total hip arthroplasty

Correct Answer & Explanation

. Surgical containment via a proximal femoral varus osteotomy or pelvic osteotomy

Explanation

According to the landmark multicenter prospective LCPD study by Herring et al., surgical containment (proximal femoral varus osteotomy or pelvic osteotomy) provides significantly better radiographic outcomes (Stulberg classification) compared to nonoperative treatment for children who are 8 years of age or older at the time of onset and who have Lateral Pillar Group B or B/C border disease.

Question 1448

Topic: Pediatric Hip

A 13-year-old obese boy presents with acute on chronic left groin pain and an inability to bear weight on the left leg for the past 24 hours. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Which of the following is the most significant prognostic factor for the development of osteonecrosis in this patient?

. The degree of posterior epiphyseal tilt
. The chronicity of his preceding pain
. His body mass index (BMI)
. The inability to bear weight at presentation
. The presence of bilateral involvement

Correct Answer & Explanation

. The degree of posterior epiphyseal tilt

Explanation

The inability to bear weight (with or without crutches) defines an 'unstable' SCFE according to the Loder classification. This is the most critical prognostic factor for avascular necrosis (AVN). Unstable SCFE has a significantly higher rate of AVN, ranging from 24% to 47%, compared to stable SCFE, where the risk is near zero.

Question 1449

Topic: Pediatric Hip
An 8-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs reveal approximately 25% collapse of the lateral pillar of the femoral head. According to the Herring lateral pillar classification, what is his classification group, and what is the recommended treatment based on prospective multicenter studies?
. Group A; symptomatic treatment only
. Group B; observation with restricted weight-bearing
. Group B; surgical containment (e.g., femoral or pelvic osteotomy)
. Group C; physical therapy and NSAIDs
. Group C; surgical containment

Correct Answer & Explanation

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

Explanation

This patient has a Herring Lateral Pillar Group B hip (defined as >50% of lateral pillar height maintained; here, 25% collapse means 75% is maintained). According to the benchmark multicenter prospective study by Herring et al., children aged 8 years or older at the time of disease onset with Group B (or B/C border) hips have significantly better radiographic outcomes when treated with surgical containment compared to nonoperative treatment.

Question 1450

Topic: Pediatric Hip

A 12-year-old obese boy is brought to the emergency department unable to bear weight on his left leg after a minor fall 12 hours ago. He has a 3-week history of preceding left groin pain. Radiographs confirm a severe left slipped capital femoral epiphysis (SCFE). Which of the following accurately describes his risk of developing avascular necrosis (AVN) based on his presentation, and the appropriate urgency of treatment?

. High risk (up to 50%); urgent pinning or open reduction within 24 hours
. Low risk (<10%); elective pinning within 1 week
. High risk (up to 50%); closed reduction followed by spica casting
. Low risk (<10%); urgent open reduction and internal fixation
. Absolute risk (100%); primary proximal femoral osteotomy

Correct Answer & Explanation

. High risk (up to 50%); urgent pinning or open reduction within 24 hours

Explanation

The inability to bear weight even with crutches defines an unstable SCFE according to the Loder classification. Unstable SCFE has a very high risk of avascular necrosis (up to 47-50%), in stark contrast to stable SCFE (<10% risk).Current literature suggests that urgent decompression of the intracapsular hematoma and stable fixation (either pinning in situ or open reduction with a modified Dunn procedure) within 24 hours can mitigate the risk of AVN. Forceful closed reduction is contraindicated as it further increases AVN risk.

Question 1451

Topic: Pediatric Hip

A 4-year-old girl is undergoing surgical treatment for residual developmental dysplasia of the hip (DDH). The surgeon

plans an incomplete transiliac osteotomy that hinges on the triradiate cartilage, allowing primarily anterior and lateral coverage of the femoral head by changing the volume and shape of the acetabulum, without disrupting the sciatic notch. Which osteotomy is being described?

. Salter osteotomy
. Pemberton osteotomy
. Dega osteotomy
. Steel triple osteotomy
. Chiari osteotomy

Correct Answer & Explanation

. Salter osteotomy

Explanation

The Pemberton osteotomy is a pericapsular, incomplete osteotomy of the ilium that uses the flexible triradiate (Y) cartilage as a hinge. It redirects the acetabular roof to provide anterolateral coverage and effectively decreases acetabular volume. The Salter osteotomy is a complete transiliac cut that hinges at the pubic symphysis. The Dega is an incomplete transiliac osteotomy typically hinging on intact medial iliac cortex, used heavily in neuromuscular dysplasia to provide lateral, anterior, and posterior coverage without entering the sciatic notch.

Question 1452

Topic: Pediatric Hip
A 9-year-old boy presents with a painless limp. Radiographs demonstrate fragmentation of the right capital femoral epiphysis with >50% loss of lateral pillar height. Based on the Herring Lateral Pillar Classification, what is the assigned grade and the expected prognosis?
. Lateral Pillar B; good outcome with nonoperative treatment
. Lateral Pillar C; poor outcome regardless of treatment
. Lateral Pillar B/C; excellent outcome if contained surgically
. Lateral Pillar C; improved outcome with surgical containment compared to conservative
. Lateral Pillar A; good outcome without treatment

Correct Answer & Explanation

. Lateral Pillar C; poor outcome regardless of treatment

Explanation

According to the Herring Lateral Pillar classification for Legg-Calve-Perthes disease: Group A = no loss of lateral pillar height; Group B = <50% loss; Group C = >50% loss. This patient has Pillar C. The multicenter prospective study by Herring et al. demonstrated that patients over the age of 8 years at the time of disease onset who present with Pillar C hips have uniformly poor outcomes (development of non-spherical femoral heads and early osteoarthritis) regardless of whether they receive conservative or operative containment treatment.

Question 1453

Topic: Pediatric Hip

A 3-month-old infant is being treated with a Pavlik harness for Developmental Dysplasia of the Hip (DDH). During follow-up, the parents note the child is not kicking the affected leg. On examination, there is decreased spontaneous extension of the knee on the affected side. What is the most likely cause?

. Sciatic nerve palsy due to hyperflexion
. Obturator nerve palsy due to hyperabduction
. Femoral nerve palsy due to hyperflexion
. Avascular necrosis of the femoral head
. Transient synovitis

Correct Answer & Explanation

. Sciatic nerve palsy due to hyperflexion

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by excessive hip flexion (usually >100-110 degrees). It presents as an inability to extend the knee (quadriceps weakness). The treatment involves relaxing the anterior straps to decrease hip flexion, which usually leads to spontaneous recovery. Hyperabduction, on the other hand, puts the hip at risk for avascular necrosis (AVN).

Question 1454

Topic: Pediatric Hip

A 12-year-old boy requires in-situ fixation for a severe, stable slipped capital femoral epiphysis (SCFE).

Which of the following clinical profiles is a strong, widely accepted indication for prophylactic pinning of the contralateral, asymptomatic hip?

. A 12-year-old obese male with an acute unstable SCFE
. A 10-year-old with panhypopituitarism and a history of cranial radiation therapy
. A 14-year-old female with a chronic stable SCFE
. An 11-year-old male with a positive family history of SCFE
. A 13-year-old male with an isolated slip angle of 45 degrees

Correct Answer & Explanation

. A 12-year-old obese male with an acute unstable SCFE

Explanation

Prophylactic pinning of the contralateral hip in SCFE remains controversial for typical idiopathic cases. However, it is strongly indicated in patients with underlying endocrine disorders (such as hypothyroidism, panhypopituitarism), renal osteodystrophy, previous pelvic/cranial radiation, or very young age at presentation (<10 years old), because their risk of developing a contralateral slip can exceed 50-100%.

Question 1455

Topic: Pediatric Hip
A 6-year-old boy is undergoing treatment for Legg-Calvé-Perthes disease. You are grading the severity using the Herring Lateral Pillar classification. During the fragmentation phase, the radiograph shows that approximately 60% of the lateral pillar height is maintained. How is this classified?
. Lateral Pillar Group A
. Lateral Pillar Group B
. Lateral Pillar Group B/C
. Lateral Pillar Group C
. Catterall Group IV

Correct Answer & Explanation

. Lateral Pillar Group B

Explanation

The Herring Lateral Pillar classification is assessed during the early fragmentation phase. Group A: no involvement of the lateral pillar (100% height). Group B: >50% of lateral pillar height maintained. Group C: <50% of lateral pillar height maintained. Group B/C is a border category with intermediate findings (thin lateral pillar, exactly 50%). Since 60% is maintained, it is Group B.

Question 1456

Topic: Pediatric Hip

A 6-week-old female is being treated with a Pavlik harness for Developmental Dysplasia of the Hip (DDH).

At her 2-week follow-up, the parents report she is not kicking her left leg as much. On examination, she has decreased active extension of the left knee, though passive range of motion is normal. What is the most likely cause of this finding?

. Avascular necrosis of the femoral head
. Obturator nerve palsy due to excessive abduction
. Femoral nerve palsy due to hyperflexion
. Sciatic nerve palsy due to tight posterior straps
. Inferior dislocation of the hip

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Hyperflexion of the hips in a Pavlik harness can cause compression of the femoral nerve, leading to a transient femoral nerve palsy. This presents clinically as decreased active extension of the knee. Treatment involves adjusting the anterior straps to decrease the degree of hip flexion or temporarily discontinuing the harness until function returns.

Question 1457

Topic: Pediatric Hip

A 13-year-old obese male with a stable left Slipped Capital Femoral Epiphysis (SCFE) undergoes in situ pinning with a single cannulated screw.

Six months postoperatively, he develops severe, constant hip pain and a significantly restricted range of motion in all planes. Radiographs demonstrate concentric joint space narrowing without hardware failure. What is the most likely diagnosis?

. Avascular necrosis
. Chondrolysis
. Septic arthritis
. Screw cut-out
. Femoroacetabular impingement

Correct Answer & Explanation

. Avascular necrosis

Explanation

Chondrolysis is a severe complication of SCFE, highly associated with unrecognized intra-articular screw penetration. It presents with pain, global stiffness, and diffuse, concentric joint space narrowing on radiographs. Avascular necrosis typically presents with subchondral collapse and sclerosis rather than global joint space narrowing.

Question 1458

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Anteroposterior radiographs of the pelvis demonstrate that exactly 50% of the lateral pillar height is maintained on the affected side. According to the Herring lateral pillar classification, into which group does this patient fall?
. Group A
. Group B
. Group B/C
. Group C
. Group D

Correct Answer & Explanation

. Group B/C

Explanation

The Herring Lateral Pillar classification is a strong prognostic indicator in LCP. Group A has 100% height maintenance; Group B has >50% height; Group C has <50% height. Group B/C is a distinct, intermediate category where exactly 50% of the pillar height is maintained or the pillar is very narrow (2-3 mm). Patients in Group B/C have outcomes worse than Group B but better than Group C.

Question 1459

Topic: Pediatric Hip

A 12-year-old obese male presents with severe left hip pain and is completely unable to bear weight, even with the assistance of crutches. Radiographs confirm a severe left Slipped Capital Femoral Epiphysis (SCFE). Which of the following best describes his classification and the associated risk of the most catastrophic complication?

. Stable SCFE; highest risk is chondrolysis
. Stable SCFE; highest risk is avascular necrosis (AVN)
. Unstable SCFE; highest risk is chondrolysis
. Unstable SCFE; highest risk is avascular necrosis (AVN)
. Acute-on-chronic SCFE; highest risk is femoroacetabular impingement

Correct Answer & Explanation

. Stable SCFE; highest risk is chondrolysis

Explanation

According to the Loder classification, an unstable SCFE is defined by the inability to bear weight, with or without crutches. Unstable SCFE carries a significantly higher risk of avascular necrosis (AVN), occurring in up to 50% of cases.

Question 1460

Topic: Pediatric Hip

An 18-month-old female with late-presenting Developmental Dysplasia of the Hip (DDH) undergoes closed reduction and spica casting in the operating room. To minimize the risk of iatrogenic avascular necrosis (AVN) of the femoral head, which of the following extreme positions must be strictly avoided during casting?

. Extreme flexion
. Extreme extension
. Extreme abduction
. Extreme adduction
. Extreme internal rotation

Correct Answer & Explanation

. Extreme flexion

Explanation

Extreme abduction places excessive pressure on the cartilaginous femoral head and compresses the medial circumflex femoral artery. This is the most significant risk factor for iatrogenic AVN following closed reduction and spica casting for DDH.

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