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Pediatric Hip MCQs

Practice Set 64 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 1261

Topic: Pediatric Hip

A 12-year-old obese male presents with a slipped capital femoral epiphysis (SCFE) of the left hip. Radiographs show a slip angle of 40 degrees. Under which of the following circumstances is prophylactic in situ pinning of the contralateral, asymptomatic right hip most strongly indicated?

. Patient age greater than 14 years
. Presence of an underlying endocrine disorder such as hypothyroidism
. The symptomatic hip slip angle is >30 degrees
. Closed triradiate cartilage on the contralateral side
. Male sex

Correct Answer & Explanation

. Presence of an underlying endocrine disorder such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended in patients with an underlying endocrine disorder (e.g., hypothyroidism, renal osteodystrophy) due to the exceedingly high risk of bilateral involvement. A modified Oxford bone age score < 16 is also considered a strong predictor for bilateral disease.

Question 1262

Topic: Pediatric Hip
A 6-year-old boy presents with a painless limp and limited abduction and internal rotation of the right hip. Radiographs show sclerosis and fragmentation of the capital femoral epiphysis. According to the Herring lateral pillar classification, which of the following radiographic findings determines a Type B categorization?
. Greater than 50% maintenance of lateral pillar height
. Less than 50% maintenance of lateral pillar height
. No structural involvement of the lateral pillar
. Complete resorption of the lateral pillar
. Extrusion of the femoral head beyond the acetabular margin

Correct Answer & Explanation

. Greater than 50% maintenance of lateral pillar height

Explanation

In the Herring lateral pillar classification for Legg-Calvé-Perthes disease, Type B indicates that the lateral pillar maintains more than 50% of its original height. Type C indicates less than 50% height is maintained, which carries a worse prognosis and higher risk of aspherical head healing.

Question 1263

Topic: Pediatric Hip

When templating for a total hip arthroplasty in a patient with Crowe IV developmental dysplasia of the hip (DDH), where is the optimal location for the placement of the acetabular component to restore the anatomic center of rotation?

. Superior to the radiographic teardrop
. At the level of the radiographic teardrop
. Lateral to the ilioischial line
. Inferior to the obturator foramen
. Anterior to the anterior pelvic plane

Correct Answer & Explanation

. At the level of the radiographic teardrop

Explanation

In Crowe IV DDH, the hip is completely dislocated superiorly. The true acetabulum is located at the level of the radiographic teardrop, which remains the target for cup placement to restore the anatomic center of rotation and optimize abductor mechanics.

Question 1264

Topic: Pediatric Hip



An anteroposterior pelvis radiograph of a 28-year-old male with groin pain demonstrates a crossover sign and a prominent ischial spine sign. Which of the following pathologies do these findings most strongly suggest?

. Cam impingement with decreased femoral head-neck offset
. Pincer impingement due to acetabular retroversion
. Developmental dysplasia of the hip
. Slipped capital femoral epiphysis
. Coxa profunda

Correct Answer & Explanation

. Pincer impingement due to acetabular retroversion

Explanation

The crossover sign (anterior wall crossing lateral to the posterior wall) and the prominent ischial spine sign are classic radiographic indicators of true acetabular retroversion. This represents focal overcoverage leading to Pincer-type femoroacetabular impingement.

Question 1265

Topic: Pediatric Hip

A 35-year-old female with a history of untreated developmental dysplasia of the hip (DDH) presents for THA. Radiographs demonstrate a Crowe type IV dysplasia. If the surgeon decides to place the acetabular component at the true anatomic hip center, which concomitant procedure will most likely be required?

. Greater trochanteric advancement
. Iliopsoas tenotomy alone
. Extensive abductor release
. Distal femoral shortening
. Subtrochanteric shortening osteotomy

Correct Answer & Explanation

. Subtrochanteric shortening osteotomy

Explanation

In Crowe IV DDH, the femoral head is highly dislocated. Bringing the hip down to the true anatomic center severely stretches the sciatic nerve and surrounding soft tissues, nearly always necessitating a subtrochanteric shortening osteotomy to prevent neurologic injury.

Question 1266

Topic: Pediatric Hip

A 13-year-old boy with obesity undergoes in situ pinning for a severe, stable slipped capital femoral epiphysis (SCFE). Six months postoperatively, he develops severe hip stiffness and worsening pain. Radiographs demonstrate concentric joint space narrowing and subchondral osteopenia. What is the most likely diagnosis?

. Avascular necrosis of the femoral head
. Chondrolysis
. Slipped contralateral epiphysis
. Femoroacetabular impingement
. Hardware failure

Correct Answer & Explanation

. Chondrolysis

Explanation

Chondrolysis is a severe complication of SCFE characterized by acute cartilage destruction, leading to global stiffness and rapid concentric joint space narrowing. It is strongly associated with severe slips and unrecognized intra-articular hardware penetration.

Question 1267

Topic: Pediatric Hip
In a patient diagnosed with Legg-Calvé-Perthes disease, which of the following clinical or radiographic factors is most strongly associated with a poor long-term prognosis?
. Age less than 6 years at the time of symptom onset
. Catterall Group I classification
. Herring Lateral Pillar Group A classification
. Age greater than 8 years at the time of symptom onset
. Minimal epiphyseal involvement on initial radiographs

Correct Answer & Explanation

. Age greater than 8 years at the time of symptom onset

Explanation

Age at onset is the most critical prognostic factor in Legg-Calvé-Perthes disease. Patients older than 8 years have less remaining growth potential to remodel the deformed femoral head, leading to a higher risk of early osteoarthritis.

Question 1268

Topic: Pediatric Hip



A 45-year-old man presents with deep groin pain exacerbated by hip flexion and internal rotation. Radiographs demonstrate a 'pistol grip' deformity of the proximal femur. Which pathophysiologic mechanism best describes his condition?

. Pincer-type femoroacetabular impingement
. Cam-type femoroacetabular impingement
. Developmental dysplasia of the hip
. Avascular necrosis of the femoral head
. Legg-Calve-Perthes disease

Correct Answer & Explanation

. Cam-type femoroacetabular impingement

Explanation

A 'pistol grip' deformity indicates a loss of the normal anterior head-neck offset, characteristic of Cam-type femoroacetabular impingement. This leads to shear stress on the anterosuperior labrum and articular cartilage.

Question 1269

Topic: Pediatric Hip

A 24-year-old collegiate hockey player complains of anterior groin pain exacerbated by hip flexion and internal rotation.

An AP pelvis radiograph demonstrates a prominent crossover sign and a lateral center-edge angle of 45 degrees. Which of the following is the most likely diagnosis?

. Cam impingement
. Pincer impingement
. Femoral retroversion
. Legg-Calve-Perthes sequelae
. Slipped capital femoral epiphysis

Correct Answer & Explanation

. Pincer impingement

Explanation

A positive crossover sign and a lateral center-edge angle greater than 40 degrees indicate acetabular retroversion and overcoverage. These are the classic radiographic hallmarks of Pincer-type femoroacetabular impingement.

Question 1270

Topic: Pediatric Hip

A 13-year-old boy is diagnosed with a unilateral left-sided slipped capital femoral epiphysis (SCFE).

Prophylactic in situ pinning of the contralateral asymptomatic right hip is most strongly indicated in the presence of which of the following patient factors?

. Patient age > 14 years
. An underlying endocrine disorder
. Male gender
. Body Mass Index > 30
. Left SCFE slip angle > 50 degrees

Correct Answer & Explanation

. An underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended for patients with endocrine or metabolic disorders (e.g., hypothyroidism, renal osteodystrophy). These patients have an exceptionally high incidence of developing subsequent contralateral slips.

Question 1271

Topic: Pediatric Hip

A 22-year-old collegiate athlete presents with chronic anterior groin pain exacerbated by hip flexion and internal rotation. A Dunn view radiograph of the hip demonstrates an alpha angle of 65 degrees. This radiographic finding is most consistent with which of the following pathomorphologies?

. Pincer-type femoroacetabular impingement
. Cam-type femoroacetabular impingement
. Developmental dysplasia of the hip
. Legg-Calve-Perthes disease
. Slipped capital femoral epiphysis

Correct Answer & Explanation

. Cam-type femoroacetabular impingement

Explanation

An alpha angle greater than 50-55 degrees on a lateral or Dunn view radiograph indicates decreased head-neck offset, which is characteristic of Cam-type femoroacetabular impingement. This pathomorphology causes shear stresses on the anterosuperior acetabular cartilage and labrum during flexion.

Question 1272

Topic: Pediatric Hip

A 25-year-old professional hockey player presents with gradual onset of anterior hip pain exacerbated by hip flexion and internal rotation. Radiographs reveal an alpha angle of 68 degrees and a prominent bump at the anterolateral femoral head-neck junction. What is the most likely diagnosis?

. Pincer-type femoroacetabular impingement
. Cam-type femoroacetabular impingement
. Slipped capital femoral epiphysis
. Legg-Calve-Perthes disease
. Avascular necrosis of the femoral head

Correct Answer & Explanation

. Cam-type femoroacetabular impingement

Explanation

An elevated alpha angle (>50-55 degrees) and a bump at the head-neck junction (pistol grip deformity) are diagnostic of Cam-type FAI. This is commonly seen in young, active males.

Question 1273

Topic: Pediatric Hip

A 6-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip. After 2 weeks, her parents note that she is no longer actively kicking or extending the knee on the treated side. What is the most appropriate next step in management?

. Continue the harness as this is a normal transient response
. Adjust the anterior straps to increase hip flexion
. Remove the harness immediately and observe for neurological recovery
. Transition to a rigid hip spica cast
. Perform a closed reduction under general anesthesia

Correct Answer & Explanation

. Remove the harness immediately and observe for neurological recovery

Explanation

Decreased active knee extension in a Pavlik harness indicates a femoral nerve palsy, typically caused by excessive hip flexion. The harness must be removed to prevent permanent nerve damage, and the palsy usually resolves with observation.

Question 1274

Topic: Pediatric Hip

A 35-year-old woman with a history of untreated developmental dysplasia of the hip (DDH) is planned for a THA. Preoperative planning reveals a Crowe Type IV dysplasia. Which of the following surgical techniques is most likely required to successfully reconstruct this hip and avoid sciatic nerve palsy?

. Subtrochanteric shortening osteotomy
. Greater trochanteric advancement
. Use of an extra-large non-cemented acetabular cup
. Use of a constrained acetabular liner
. Placement of the cup in the high false acetabulum

Correct Answer & Explanation

. Subtrochanteric shortening osteotomy

Explanation

Crowe Type IV DDH features a high dislocation of the femoral head. Bringing the hip down to the true acetabulum often requires a subtrochanteric shortening osteotomy to safely reduce the joint and prevent stretching the sciatic nerve.

Question 1275

Topic: Pediatric Hip

A 12-year-old boy with hypothyroidism and a BMI of 35 presents with an unstable slipped capital femoral epiphysis (SCFE) of the left hip. Radiographs show a moderate slip. Which of the following factors is the strongest indication for prophylactic in situ pinning of the contralateral right hip?

. The patient's BMI
. The severity of the left-sided slip
. The presence of an underlying endocrinopathy
. The unstable nature of the left slip
. The patient's age

Correct Answer & Explanation

. The presence of an underlying endocrinopathy

Explanation

Prophylactic pinning of the contralateral hip is strongly recommended in patients with SCFE who have an underlying endocrinopathy, such as hypothyroidism or renal osteodystrophy. These conditions drastically increase the risk of developing a bilateral slip.

Question 1276

Topic: Pediatric Hip

A 12-year-old boy with a BMI in the 98th percentile is diagnosed with a severe, slipped capital femoral epiphysis (SCFE) of the left hip. Radiographs of the right hip are normal. According to current evidence, which of the following is the strongest indication for prophylactic in situ pinning of his contralateral asymptomatic right hip?

. His chronological age
. His obesity (BMI > 95th percentile)
. The severity of the left-sided slip
. A highly positive family history of SCFE
. Open triradiate cartilages

Correct Answer & Explanation

. Open triradiate cartilages

Explanation

The status of the triradiate cartilage is a primary indicator of skeletal maturity and the risk of a contralateral slip. Open triradiate cartilages indicate significant remaining growth, making it the strongest indication for prophylactic contralateral pinning in SCFE.

Question 1277

Topic: Pediatric Hip

A 6-week-old female infant is treated with a Pavlik harness for developmental dysplasia of the hip. At the 3-week follow-up, ultrasound shows the hip remains dislocated. What is the most appropriate next step in management?

. Continue Pavlik harness for an additional 3 weeks
. Transition to a rigid abduction orthosis
. Discontinue Pavlik harness and proceed to closed reduction and spica casting
. Open reduction through an anterior approach
. Perform a Dega osteotomy

Correct Answer & Explanation

. Discontinue Pavlik harness and proceed to closed reduction and spica casting

Explanation

Prolonged use of a Pavlik harness in a persistently dislocated hip can lead to Pavlik harness disease and AVN. If unreduced after 3 to 4 weeks, it should be abandoned in favor of closed reduction and spica casting.

Question 1278

Topic: Pediatric Hip

A 13-year-old obese boy presents with a mild slipped capital femoral epiphysis (SCFE) of the left hip. When is prophylactic pinning of the contralateral, asymptomatic hip most strongly indicated?

. In all patients presenting with unilateral SCFE
. In patients with an underlying endocrinopathy or metabolic bone disease
. In patients older than 14 years
. If the slip angle on the affected side is greater than 50 degrees
. If the patient has closed triradiate cartilages

Correct Answer & Explanation

. In patients with an underlying endocrinopathy or metabolic bone disease

Explanation

Prophylactic pinning of the contralateral hip is strongly recommended in patients with underlying endocrinopathies (e.g., hypothyroidism) or metabolic bone diseases due to an extremely high risk of bilateral involvement.

Question 1279

Topic: Pediatric Hip

Which of the following is considered a 'head-at-risk' sign in Legg-Calve-Perthes disease?

. Medial subluxation of the femoral head
. Decreased radiodensity of the epiphysis
. Lateral calcification of the epiphysis
. Gage sign (a V-shaped radiolucency in the lateral portion of the epiphysis)
. Narrowing of the medial joint space

Correct Answer & Explanation

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

Explanation

Catterall's 'head-at-risk' signs indicate a poor prognosis and include Gage's sign, lateral subluxation of the femoral head, calcification lateral to the epiphysis, and a horizontal growth plate.

Question 1280

Topic: Pediatric Hip

A 45-year-old woman with a history of bilateral developmental dysplasia of the hip (Crowe type IV) is undergoing THA. Preoperative planning indicates the native femoral head is migrated 5 centimeters proximally. Which of the following surgical strategies is most appropriate to restore normal biomechanics while minimizing complications?

. Placement of the acetabular component in the high false acetabulum with a standard stem
. Placement of the acetabular component in the true paleopelvis combined with a subtrochanteric shortening osteotomy
. Use of a constrained liner in the false acetabulum
. Routine THA using an extended trochanteric osteotomy and extensive soft tissue release
. Placement of the acetabular component in the true paleopelvis and aggressive sciatic nerve stretching

Correct Answer & Explanation

. Placement of the acetabular component in the true paleopelvis combined with a subtrochanteric shortening osteotomy

Explanation

In Crowe IV DDH, the acetabular component should be placed in the true paleopelvis to restore the anatomical center of rotation. A subtrochanteric shortening osteotomy is typically required to allow joint reduction without causing sciatic nerve stretch injury.

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