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Pediatric Hip MCQs

Practice Set 63 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 1241

Topic: Pediatric Hip

A 4-year-old child presents with untreated unilateral developmental dysplasia of the hip. Which of the following surgical interventions is most commonly required to achieve and maintain a stable reduction?

. Closed reduction and spica cast
. Open reduction and spica casting only
. Open reduction, femoral shortening derotation osteotomy, and pelvic osteotomy
. Varus derotation osteotomy alone
. Shelf arthroplasty

Correct Answer & Explanation

. Open reduction, femoral shortening derotation osteotomy, and pelvic osteotomy

Explanation

In children older than 3 years with untreated DDH, open reduction alone is associated with a high risk of avascular necrosis and redislocation. Femoral shortening osteotomy is necessary to decompress the joint, combined with a pelvic osteotomy to provide adequate anterolateral coverage.

Question 1242

Topic: Pediatric Hip

A 12-year-old obese boy presents with left knee pain and an antalgic gait. Radiographs reveal a severe slipped capital femoral epiphysis (SCFE) with a slip angle of 60 degrees. After in situ pinning of the left hip, which of the following is the most accepted indication for prophylactic pinning of the contralateral asymptomatic hip?

. All patients regardless of age or endocrine status
. Male gender and obesity alone
. Endocrine disorders, radiation therapy, or age less than 10 years
. Family history of SCFE
. A slip angle greater than 50 degrees on the affected side

Correct Answer & Explanation

. Endocrine disorders, radiation therapy, or age less than 10 years

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with endocrine disorders, prior radiation therapy, or those presenting at an atypically young age (girls <10, boys <12). These patients have a significantly higher risk of sequential bilateral involvement.

Question 1243

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs demonstrate >50% loss of lateral pillar height. According to the Herring lateral pillar classification, what is the expected outcome without surgical intervention?
. Excellent outcome with full remodeling
. Good outcome with minimal residual deformity
. Fair outcome but no increased risk of early osteoarthritis
. Poor outcome with a high risk of early-onset osteoarthritis
. Spontaneous fusion of the hip joint

Correct Answer & Explanation

. Poor outcome with a high risk of early-onset osteoarthritis

Explanation

Loss of more than 50% of the lateral pillar height corresponds to Herring Group C. This group has a poor prognosis with a high likelihood of significant residual deformity (coxa magna, severe flattening) and early-onset osteoarthritis.

Question 1244

Topic: Pediatric Hip

A 6-week-old female is undergoing treatment with a Pavlik harness for developmental dysplasia of the hip (DDH). During the follow-up visit, the parents report that the child has stopped moving her left leg. Examination reveals decreased active knee extension and an absent patellar reflex on the left side. What is the most likely cause of this finding?

. Avascular necrosis of the femoral head
. Excessive hip flexion in the harness causing femoral nerve palsy
. Excessive hip abduction in the harness causing obturator nerve palsy
. Septic arthritis of the hip
. Transient synovitis

Correct Answer & Explanation

. Excessive hip flexion in the harness causing femoral nerve palsy

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment due to excessive hip flexion. The initial management is to temporarily remove or adjust the harness to decrease the flexion, which usually leads to spontaneous recovery.

Question 1245

Topic: Pediatric Hip

An 11-year-old boy presents with a 4-week history of left groin pain and a limp. Radiographs confirm a mild, stable slipped capital femoral epiphysis (SCFE) of the left hip. The right hip is radiographically normal. Which of the following is the strongest indication for prophylactic pinning of the contralateral (right) hip?

. Patient age of 11 years
. Presence of a positive Drehmann sign on the right
. Endocrinopathy such as hypothyroidism
. Family history of SCFE
. Body mass index in the 90th percentile

Correct Answer & Explanation

. Endocrinopathy such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is strongly indicated in patients with underlying endocrinopathies (e.g., hypothyroidism, renal osteodystrophy) or prior radiation therapy. These conditions significantly increase the risk of bilateral involvement.

Question 1246

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with early-stage Legg-Calvé-Perthes disease. He has a limp and restricted hip abduction. Which of the following factors at the time of presentation is considered the most significant indicator of a poor long-term prognosis?
. Male sex
. Age greater than 8 years
. Loss of internal rotation
. Catterall group II classification
. Slight widening of the medial joint space

Correct Answer & Explanation

. Age greater than 8 years

Explanation

Age at onset is the single most important prognostic factor in Legg-Calvé-Perthes disease. Patients older than 8 years at the onset of symptoms generally have a worse prognosis due to having less remaining growth for femoral head remodeling.

Question 1247

Topic: Pediatric Hip

A 6-month-old girl with Developmental Dysplasia of the Hip (DDH) undergoes closed reduction and spica casting. Which of the following intraoperative positioning parameters is most strongly associated with an increased risk of avascular necrosis (AVN) of the femoral head?

. Flexion of 100 degrees
. Abduction of 60 degrees
. Internal rotation of 10 degrees
. Extension of 10 degrees
. External rotation of 15 degrees

Correct Answer & Explanation

. Abduction of 60 degrees

Explanation

Excessive abduction (greater than 60 degrees) in a spica cast places the medial circumflex femoral artery under tension, significantly increasing the risk of avascular necrosis. The "human position" emphasizes safe limits of abduction to prevent this complication.

Question 1248

Topic: Pediatric Hip

A 13-year-old obese boy presents with sudden severe right hip pain and inability to bear weight after a minor fall. Radiographs confirm an unstable slipped capital femoral epiphysis (SCFE). What is the primary proposed benefit of performing an urgent capsulotomy and gentle reduction prior to pinning?

. Reduces the risk of chondrolysis
. Reduces the risk of avascular necrosis
. Prevents contralateral slip
. Enhances limb length equalization
. Prevents future femoroacetabular impingement

Correct Answer & Explanation

. Reduces the risk of avascular necrosis

Explanation

In unstable SCFE, urgent decompression via capsulotomy and gentle reduction decreases intracapsular pressure and restores capsular blood flow. This intervention is thought to lower the historically high risk of avascular necrosis in unstable slips.

Question 1249

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs show radiolucency and fragmentation. The lateral pillar of the femoral head maintains 40% of its original height. According to the Herring Lateral Pillar Classification, what is the grade and expected outcome without surgical containment?
. Group A, good outcome
. Group B, moderate outcome
. Group B/C, poor outcome
. Group C, poor outcome
. Group C, moderate outcome

Correct Answer & Explanation

. Group C, poor outcome

Explanation

Herring Group C is defined as less than 50% maintenance of the lateral pillar height. These patients generally have a poor natural history and a higher risk of developing a non-spherical femoral head.

Question 1250

Topic: Pediatric Hip

A 12-year-old boy is diagnosed with a unilateral stable slipped capital femoral epiphysis (SCFE). Which of the following factors most strongly supports the decision for prophylactic pinning of the contralateral hip?

. Male gender
. Obesity (BMI >95th percentile)
. Open triradiate cartilage
. Symptom duration greater than 3 months
. Slip angle of 30 degrees on the affected side

Correct Answer & Explanation

. Open triradiate cartilage

Explanation

An open triradiate cartilage indicates significant remaining skeletal growth, making it one of the strongest predictive risk factors for a subsequent contralateral slip. Prophylactic pinning is highly recommended in these high-risk patients.

Question 1251

Topic: Pediatric Hip

Which of the following is considered the most common extra-articular block to closed reduction in developmental dysplasia of the hip?

. Pulvinar
. Ligamentum teres
. Inverted limbus
. Transverse acetabular ligament
. Iliopsoas tendon

Correct Answer & Explanation

. Iliopsoas tendon

Explanation

The iliopsoas tendon is the most common extra-articular block to closed reduction in DDH, often causing an hourglass constriction of the capsule. The pulvinar, ligamentum teres, inverted limbus, and transverse acetabular ligament are intra-articular blocks.

Question 1252

Topic: Pediatric Hip

Which of the following factors at presentation is most strongly predictive of developing avascular necrosis following a slipped capital femoral epiphysis (SCFE)?

. Degree of slip angle
. Patient weight
. Instability defined as the inability to bear weight
. Age at presentation
. Bilateral involvement

Correct Answer & Explanation

. Instability defined as the inability to bear weight

Explanation

The inability to bear weight (instability) is the strongest predictor of avascular necrosis in SCFE. Unstable SCFE has an AVN rate approaching 50 percent, compared to almost zero for stable SCFE.

Question 1253

Topic: Pediatric Hip

An 8-year-old boy presents with lateral pillar B/C border Legg-Calve-Perthes disease. According to current evidence-based guidelines, what is the most appropriate management?

. Observation alone with non-weight bearing
. Application of bilateral Petrie casts
. Proximal femoral varus osteotomy or pelvic osteotomy
. Core decompression of the femoral head
. Articulated hip distraction external fixation

Correct Answer & Explanation

. Proximal femoral varus osteotomy or pelvic osteotomy

Explanation

Surgical containment, such as a proximal femoral varus osteotomy or pelvic osteotomy, is indicated for children over 8 years of age with lateral pillar B or B/C border Perthes disease. It provides better spherical outcomes than non-operative management in this age group.

Question 1254

Topic: Pediatric Hip

A 13-year-old boy develops severe hip pain and progressive loss of motion six months after undergoing in situ single screw fixation for a stable SCFE. Radiographs show significant joint space narrowing. What is the most likely etiology of this complication?

. Unrecognized avascular necrosis
. Deep surgical site infection
. Prominent hardware penetrating the joint
. Concurrent untreated hypothyroidism
. Autoimmune inflammatory arthropathy

Correct Answer & Explanation

. Prominent hardware penetrating the joint

Explanation

Chondrolysis in the setting of treated SCFE is most commonly caused by unrecognized penetration of the hardware into the joint space. It presents with pain, stiffness, and radiographic joint space narrowing.

Question 1255

Topic: Pediatric Hip

A 4-month-old infant with developmental dysplasia of the hip has been treated with a Pavlik harness. At the 4-week follow-up, an ultrasound demonstrates that the hip remains dislocated. What is the primary risk of continuing the Pavlik harness in this patient for an additional 3 weeks?

. Avascular necrosis of the femoral head
. Femoral nerve palsy
. Posterior acetabular rim damage
. Acetabular dysplasia
. Superior subluxation of the femoral head

Correct Answer & Explanation

. Posterior acetabular rim damage

Explanation

Continuing a Pavlik harness in an unreduced hip beyond 3 to 4 weeks can cause severe pressure on the posterior acetabulum. This leads to "Pavlik harness disease," which degrades the acetabulum and makes subsequent closed reduction much more difficult.

Question 1256

Topic: Pediatric Hip

An 11-year-old boy with a BMI in the 99th percentile presents with 3 weeks of knee pain and a limp. Examination reveals obligate external rotation of the hip with passive flexion. Radiographs confirm a stable slipped capital femoral epiphysis (SCFE). During in situ pinning, where should the single screw be positioned within the epiphysis?

. Anterior and superior
. Anterior and inferior
. Central and central
. Posterior and superior
. Posterior and inferior

Correct Answer & Explanation

. Central and central

Explanation

In situ pinning of a SCFE aims to place the screw in the center of the epiphysis to maximize mechanical stability and minimize the risk of joint penetration. The guide wire and screw should be placed centrally in both the anteroposterior and lateral planes.

Question 1257

Topic: Pediatric Hip

An 8-year-old boy presents with a painless limp. Radiographs demonstrate sclerosis and fragmentation of the left capital femoral epiphysis with lateral subluxation. According to the Herring lateral pillar classification, he has a Group B/C lesion. Which of the following factors is the strongest predictor of a poor long-term outcome in this patient?

. Age at onset greater than 8 years
. Male sex
. Involvement of the medial pillar
. Early loss of internal rotation
. Sclerosis of the metaphysis

Correct Answer & Explanation

. Age at onset greater than 8 years

Explanation

Age greater than 8 years at the onset of Legg-Calve-Perthes disease is the most significant predictor of a poor outcome. This is due to the limited remaining growth potential for femoral head remodeling before skeletal maturity.

Question 1258

Topic: Pediatric Hip
A 45-year-old female presents with secondary osteoarthritis due to developmental dysplasia of the hip (DDH). Preoperative radiographs reveal a subluxation of 60% of the femoral head relative to the true acetabulum. How is this classified according to the Crowe classification?
. Crowe I
. Crowe II
. Crowe III
. Crowe IV
. Crowe V

Correct Answer & Explanation

. Crowe II

Explanation

The Crowe classification grades DDH by proximal subluxation: I (<50%), II (50-74%), III (75-100%), and IV (>100%). A 60% subluxation falls into the Crowe II category.

Question 1259

Topic: Pediatric Hip

A 28-year-old male athlete presents with chronic groin pain exacerbated by hip flexion and internal rotation. A Dunn view radiograph shows an alpha angle of 65 degrees. This radiographic finding is most indicative of which of the following pathomorphologies?

. Decreased femoral head-neck offset (Cam morphology)
. Acetabular retroversion (Pincer morphology)
. Coxa profunda
. Developmental dysplasia of the hip
. Slipped capital femoral epiphysis

Correct Answer & Explanation

. Decreased femoral head-neck offset (Cam morphology)

Explanation

An alpha angle greater than 50-55 degrees indicates a decreased femoral head-neck offset, characteristic of Cam-type femoroacetabular impingement. This bony prominence impinges on the anterosuperior acetabular rim during hip flexion.

Question 1260

Topic: Pediatric Hip

Which of the following is considered the most critical prerequisite for a successful periacetabular osteotomy (Ganz osteotomy) in an adult patient with symptomatic developmental dysplasia of the hip?

. Presence of a cam deformity
. Alpha angle less than 45 degrees
. Open triradiate cartilage
. Joint congruency on functional (abduction/internal rotation) radiographs
. Tonnis grade 3 osteoarthritis

Correct Answer & Explanation

. Joint congruency on functional (abduction/internal rotation) radiographs

Explanation

A periacetabular osteotomy (PAO) relies on reorienting the acetabulum. Preoperative joint congruency in the anticipated corrected position (assessed via abduction/internal rotation views) is critical. Advanced arthritis (Tonnis 3) or lack of congruency are contraindications.

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