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Pediatric Hip MCQs

Practice Set 11 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 201

Topic: Pediatric Hip

Which of the following factors should prompt a workup for an underlying disorder in a patient with slipped capital femoral epiphysis:

. A bilateral slip
. Weight over the 50th percentile for age
. Weight under the 50th percentile for age
. A positive family history
. A slip of grade II or higher

Correct Answer & Explanation

. Weight under the 50th percentile for age

Explanation

A positive age-weight test is defined as a patient who is under the 50th percentile of weight for age or older than 16 years of age at presentation with slipped capital femoral epiphysis. These patients should have a workup for underlying renal or endocrine disease. A positive family history is found in 5% to 10% of patients with slipped capital femoral epiphysis.

Question 202

Topic: Pediatric Hip
Which of the following categories of slipped capital femoral epiphysis (SCFE) is associated with the highest risk of a grade III slip?
. Renal failure
. Idiopathic SCFE
. Radiation therapy
. Hypothyroidism
. Growth hormone deficiency

Correct Answer & Explanation

. Renal failure

Explanation

A grade III slip refers to more than 50% displacement of the epiphysis. Renal failure is associated with the highest risk (43%) of progressing to a grade III slip. Fortunately, these slips are usually stable.

Question 203

Topic: Pediatric Hip

An 8-year-old female presents with bilateral slipped capital femoral epiphysis (SCFE). Given her age and presentation, which of the following laboratory investigations is most appropriate?

. Hemoglobin A1c
. Thyroid-stimulating hormone (TSH)
. Serum parathyroid hormone (PTH)
. 25-hydroxyvitamin D
. Fasting blood glucose

Correct Answer & Explanation

. Thyroid-stimulating hormone (TSH)

Explanation

Patients presenting with SCFE outside the typical age range (under 10 or over 16) or with bilateral involvement should be screened for underlying endocrine disorders. Hypothyroidism is the most common associated endocrinopathy, making TSH the best initial screening test.

Question 204

Topic: Pediatric Hip

Which of the following is an absolute indication for prophylactic in situ pinning of the contralateral asymptomatic hip in a patient with a unilateral slipped capital femoral epiphysis (SCFE)?

. Age greater than 14 years in males
. Presence of an endocrine disorder such as hypothyroidism
. Triradiate cartilage closure
. Male gender
. African American descent

Correct Answer & Explanation

. Presence of an endocrine disorder such as hypothyroidism

Explanation

Prophylactic contralateral pinning is highly recommended in patients with endocrine or metabolic disorders, as they have a significantly higher rate of bilateral involvement. Other relative indications include previous radiation therapy and young age (<10 years).

Question 205

Topic: Pediatric Hip
In the lateral pillar classification of Legg-Calvรฉ-Perthes disease described by Herring, which portion of the femoral head is evaluated on the anteroposterior radiograph to determine the prognosis?
. The central third of the epiphysis
. The medial third of the epiphysis
. The lateral third of the epiphysis
. The anterior third of the epiphysis
. The posterior third of the epiphysis

Correct Answer & Explanation

. The lateral third of the epiphysis

Explanation

The Herring lateral pillar classification evaluates the height of the lateral third of the capital femoral epiphysis on an AP radiograph during the fragmentation stage. Maintenance of lateral pillar height is the most significant prognostic indicator for long-term hip congruency.

Question 206

Topic: Pediatric Hip

A 12-year-old obese male presents with acute-on-chronic left hip pain and an inability to bear weight. Radiographs confirm an unstable slipped capital femoral epiphysis (SCFE). Which of the following represents the most significant risk associated with urgent, aggressive closed reduction of this injury prior to pinning?

. Chondrolysis
. Avascular necrosis (AVN) of the femoral head
. Femoroacetabular impingement
. Leg length discrepancy
. Premature physeal closure

Correct Answer & Explanation

. Avascular necrosis (AVN) of the femoral head

Explanation

Forceful or aggressive closed reduction of an unstable SCFE significantly increases the risk of avascular necrosis (AVN) of the femoral head. Gentle, incidental reduction during patient positioning is acceptable, but intentional forceful manipulation is contraindicated.

Question 207

Topic: Pediatric Hip

Of all slipped capital femoral epiphyses, which percentage is unstable:

. 5%
. 15%
. 25%
. 35%
. 50%

Correct Answer & Explanation

. 5%

Explanation

Unstable slipped capital femoral epiphysis places the patient at a high risk of avascular necrosis (up to 47%). Fortunately, it comprises only about 5% of all slips.

Question 208

Topic: Pediatric Hip

An overweight 13-year-old boy presents with left knee pain and a limp. Examination reveals obligate external rotation of the hip during passive flexion. Following diagnosis of a stable slipped capital femoral epiphysis (SCFE), what is the most appropriate surgical treatment?

. Closed reduction and spica casting
. Open reduction and internal fixation with multiple pins
. In situ fixation with a single cannulated screw
. Proximal femoral corrective osteotomy
. Core decompression of the femoral head

Correct Answer & Explanation

. In situ fixation with a single cannulated screw

Explanation

The gold standard treatment for a stable slipped capital femoral epiphysis is in situ pinning with a single cannulated screw placed in the center of the epiphysis. Attempts at closed reduction significantly increase the risk of avascular necrosis.

Question 209

Topic: Pediatric Hip

Which of the following is an absolute indication for prophylactic in situ fixation of the contralateral hip in a patient with a unilateral Slipped Capital Femoral Epiphysis (SCFE)?

. Age greater than 14 years
. Female gender
. Underlying endocrine disorder
. Body Mass Index greater than 35
. Grade I slip severity

Correct Answer & Explanation

. Underlying endocrine disorder

Explanation

Patients with underlying endocrine disorders (such as hypothyroidism), prior radiation, or renal failure have an exceptionally high risk of contralateral slip. In these populations, prophylactic pinning of the unaffected hip is strongly recommended.

Question 210

Topic: Pediatric Hip

A 6-month-old infant is diagnosed with developmental dysplasia of the hip (DDH) that has failed Pavlik harness treatment. An ultrasound confirms persistent dislocation. What is the next most appropriate step in management?

. Continue Pavlik harness for 6 more weeks
. Closed reduction and spica casting
. Open reduction and femoral osteotomy
. Pelvic osteotomy (Salter)
. Observation until walking age

Correct Answer & Explanation

. Closed reduction and spica casting

Explanation

After failure of a Pavlik harness, or if diagnosed between 6 and 18 months of age, closed reduction under general anesthesia followed by spica casting is the standard next step in DDH management.

Question 211

Topic: Pediatric Hip

A 12-year-old obese boy presents with a unilateral slipped capital femoral epiphysis (SCFE). Prophylactic in situ pinning of the contralateral asymptomatic hip is most strongly recommended if the patient has a concurrent history of:

. Asthma
. Renal osteodystrophy
. Type 1 Diabetes Mellitus
. Developmental dysplasia of the hip
. Legg-Calve-Perthes disease

Correct Answer & Explanation

. Renal osteodystrophy

Explanation

Prophylactic pinning of the contralateral hip is indicated in patients at high risk for bilateral disease. This includes those with endocrine disorders (e.g., hypothyroidism) and metabolic bone disease such as renal osteodystrophy.

Question 212

Topic: Pediatric Hip

A 12-year-old obese boy presents with acute-on-chronic left knee pain and an inability to bear weight. He is diagnosed with an unstable slipped capital femoral epiphysis (SCFE). Which of the following interventions carries the highest risk of iatrogenic avascular necrosis (AVN)?

. In situ percutaneous pinning
. Forceful closed reduction to improve alignment prior to pinning
. Open reduction and internal fixation via surgical hip dislocation
. Prophylactic pinning of the contralateral hip
. Capsulotomy at the time of in situ fixation

Correct Answer & Explanation

. Forceful closed reduction to improve alignment prior to pinning

Explanation

Forceful closed reduction of an unstable SCFE severely compromises the already tenuous epiphyseal blood supply, drastically increasing the risk of avascular necrosis. Current recommendations favor either in situ pinning or open reduction using a surgical hip dislocation approach to meticulously protect the retinacular vessels.

Question 213

Topic: Pediatric Hip
Which of the following findings is an indication for the Bernese (Ganz) osteotomy?
. Acetabular dysplasia in a 10-year-old boy.
. A 20-year-old woman with a complete developmental dislocation of the hip.
. A 19-year-old man with osteonecrosis (Stulberg-Stage 4) secondary to Perthes disease.
. A 30-year-old woman with an anteroposterior (AP) center-edge angle of 10ยฐ and a joint space of 1 mm.
. A 35-year-old woman with an AP center-edge angle of 0ยฐ and a joint space of 2 mm

Correct Answer & Explanation

. A 30-year-old woman with an anteroposterior (AP) center-edge angle of 10ยฐ and a joint space of 1 mm.

Explanation

The Bernese (Ganz) osteotomy is contraindicated in patients with open triradiate cartilages because it crosses the cartilage. The procedure is also contraindicated in complete dislocations, incongruous hips, and advanced osteoarthritis with a joint space of 1 mm or less.

Question 214

Topic: Pediatric Hip

A 13-year-old obese boy presents with a 3-month history of right groin pain and a limp. On examination, his right hip obligatory externally rotates when passively flexed to 90 degrees. Radiographs confirm a stable, severe slipped capital femoral epiphysis (SCFE). Which of the following is the most appropriate initial management?

. Closed reduction and spica casting
. In situ percutaneous pinning
. Open reduction and internal fixation
. Proximal femoral osteotomy
. Skeletal traction

Correct Answer & Explanation

. In situ percutaneous pinning

Explanation

In situ percutaneous pinning with a single cannulated screw is the gold standard treatment for a stable SCFE to prevent further slippage. Closed reduction is contraindicated due to a high risk of iatrogenic avascular necrosis.

Question 215

Topic: Pediatric Hip

A 7-month-old infant is referred for developmental dysplasia of the hip (DDH) after failing a 6-week trial of a Pavlik harness. Ultrasound confirms persistent superior and lateral displacement of the femoral head. What is the most appropriate next step in management?

. Continue Pavlik harness for 4 more weeks
. Transition to a rigid abduction orthosis
. Closed reduction and spica casting
. Open reduction and pelvic osteotomy
. Varus derotational osteotomy

Correct Answer & Explanation

. Closed reduction and spica casting

Explanation

In an infant older than 6 months who has failed Pavlik harness treatment, the next appropriate step is an examination under anesthesia, arthrogram, and closed reduction with spica casting. Continuing a failed harness risks "Pavlik harness disease" (posterior acetabular wear).

Question 216

Topic: Pediatric Hip

A 13-year-old obese boy presents with sudden inability to bear weight on his left leg after a minor trip. Radiographs show a slipped capital femoral epiphysis (SCFE). What is the most significant risk factor for the development of avascular necrosis (AVN) in this patient?

. Degree of posterior slip
. Patient body mass index (BMI)
. Instability of the slip (inability to bear weight)
. Bilateral involvement
. Age at presentation

Correct Answer & Explanation

. Instability of the slip (inability to bear weight)

Explanation

Slip stability is the primary prognostic factor for developing AVN in SCFE. Unstable slips, defined clinically by the inability to bear weight even with crutches, carry an AVN risk of up to 47%, compared to less than 10% for stable slips.

Question 217

Topic: Pediatric Hip

A 6-week-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At the first follow-up, the infant shows decreased active knee extension on the treated side. This complication is most commonly caused by:

. Hyperflexion of the hip in the harness
. Excessive abduction of the hip in the harness
. Inadequate flexion of the hip in the harness
. Excessive adduction of the hip in the harness
. Direct pressure over the fibular head

Correct Answer & Explanation

. Hyperflexion of the hip in the harness

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by hyperflexion of the hips. Management involves adjusting the harness to decrease flexion and monitoring for spontaneous recovery.

Question 218

Topic: Pediatric Hip

A 4-year-old child presents with a widened cranial vault, frontal bossing, and delayed closure of the fontanelles. On examination, he is able to bring his shoulders together anteriorly without discomfort. Which of the following orthopedic conditions is most frequently associated with this syndrome?

. Developmental dysplasia of the hip
. Coxa vara
. Anterolateral bowing of the tibia
. Posteromedial bowing of the tibia
. Slipped capital femoral epiphysis

Correct Answer & Explanation

. Coxa vara

Explanation

This patient has cleidocranial dysplasia, an autosomal dominant condition caused by a RUNX2 (CBFA1) mutation resulting in clavicular hypoplasia. Coxa vara is the most common and significant orthopedic manifestation, occurring in up to one-third of these patients.

Question 219

Topic: Pediatric Hip

A 4-year-old boy with disproportionate short-trunk dwarfism is evaluated in the clinic. He has a history of a cleft palate and severe myopia. Radiographs reveal delayed ossification of the pubic bones, severe coxa vara, and platyspondyly. This condition is caused by a mutation affecting which of the following?

. Type I collagen
. Type II collagen
. Type IX collagen
. Type X collagen
. Fibroblast growth factor receptor 3

Correct Answer & Explanation

. Type II collagen

Explanation

Spondyloepiphyseal dysplasia congenita (SEDC) is characterized by short-trunk dwarfism, coxa vara, cleft palate, and visual impairments like myopia or retinal detachment. It is an autosomal dominant disorder caused by a mutation in the COL2A1 gene, affecting Type II collagen.

Question 220

Topic: Pediatric Hip

A 14-year-old obese boy presents with acute-on-chronic slipped capital femoral epiphysis (SCFE). He undergoes in situ pinning. What is the most significant risk factor for developing chondrolysis in this patient?

. Unrecognized pin penetration into the joint
. Severity of the slip
. Acute nature of the presentation
. Patient obesity
. Delayed surgical intervention

Correct Answer & Explanation

. Unrecognized pin penetration into the joint

Explanation

Unrecognized hardware penetration into the joint is the most consistently identified risk factor for chondrolysis following the surgical treatment of SCFE. Accurate intraoperative fluoroscopy is critical to confirm the pin is completely within the femoral head.

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