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Pediatric Hip MCQs

Practice Set 42 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 821

Topic: Pediatric Hip

A 12-year-old obese boy presents with severe groin pain and an inability to bear weight after a minor fall. Radiographs show a slipped capital femoral epiphysis (SCFE). According to the Loder classification, what specific clinical finding defines this slip as "unstable"?

. Slip angle > 50 degrees
. Inability to ambulate with or without crutches
. Presence of an intra-articular effusion on ultrasound
. Duration of symptoms less than 3 weeks
. Metaphyseal blanch sign on the AP radiograph

Correct Answer & Explanation

. Inability to ambulate with or without crutches

Explanation

The Loder classification functionally defines an unstable slipped capital femoral epiphysis (SCFE) as the inability to ambulate with or without crutches. Unstable SCFE has a significantly higher rate of avascular necrosis (up to 47%) compared to stable SCFE.

Question 822

Topic: Pediatric Hip

A 12-year-old obese boy presents to the emergency department with severe acute hip pain and inability to bear weight. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Because he cannot bear weight, even with crutches, this is classified as an unstable SCFE. Which of the following complications is significantly higher in this patient compared to a stable SCFE?

. Chondrolysis
. Avascular necrosis (AVN)
. Femoroacetabular impingement (FAI)
. Slipped contralateral epiphysis
. Septic arthritis

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

An unstable SCFE is defined clinically by the inability to bear weight. This instability implies a disruption of the epiphyseal vascular supply, carrying a much higher risk of avascular necrosis (up to 47%) compared to stable slips.

Question 823

Topic: Pediatric Hip

A 3-month-old girl with developmental dysplasia of the hip (DDH) is treated with a Pavlik harness. At her follow-up visit, the parents report that she is no longer actively extending her left knee. Which improper adjustment of the Pavlik harness is the most likely cause of this finding?

. The anterior strap is too loose
. The anterior strap is too tight causing hyperflexion
. The posterior strap is too tight causing hyperabduction
. The posterior strap is too loose causing adduction
. The chest strap is fastened too tightly

Correct Answer & Explanation

. The anterior strap is too tight causing hyperflexion

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment caused by excessive hip flexion (typically >120 degrees). This occurs when the anterior straps are pulled too tightly, compressing the nerve against the pubis.

Question 824

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs demonstrate that the lateral pillar of the femoral head maintains 60% of its normal height. According to the Herring Lateral Pillar Classification, which group does this represent, and what is the general prognosis?
. Group A; excellent prognosis
. Group B; better prognosis than Group C, but surgery may be indicated if older than 8
. Group C; poor prognosis
. Group B/C; universal progression to severe osteoarthritis
. Group A; guarded prognosis requiring immediate osteotomy

Correct Answer & Explanation

. Group B; better prognosis than Group C, but surgery may be indicated if older than 8

Explanation

Group B of the Herring classification is defined by >50% maintenance of the lateral pillar height. It carries a better prognosis than Group C (<50%), though children older than 8 years in Group B benefit significantly from surgical containment.

Question 825

Topic: Pediatric Hip

A 13-year-old obese male presents with acute left hip pain and an inability to bear weight following a minor fall. He reports intermittent mild hip pain for 3 months prior. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Which of the following is the most significant risk factor for developing avascular necrosis (AVN) in this patient?

. Duration of prodromal symptoms
. Inability to bear weight at presentation
. Degree of posterior slip angle
. Use of a single cannulated screw for fixation
. Age of the patient

Correct Answer & Explanation

. Duration of prodromal symptoms

Explanation

The inability to bear weight, with or without crutches, defines an unstable SCFE according to the Loder classification. Unstable slips carry a significantly higher risk of AVN (up to 47%) compared to stable slips.

Question 826

Topic: Pediatric Hip

A 6-week-old female infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At her 2-week follow-up, the parents report she has stopped actively kicking her left leg. Examination reveals decreased active knee extension on the left side. What is the most appropriate next step in management?

. Immediate surgical exploration
. Adjustment of the anterior straps to increase hip flexion
. Discontinuation of the Pavlik harness for a period of rest
. Application of a rigid abduction orthosis
. Reassurance and continued use of the harness as prescribed

Correct Answer & Explanation

. Immediate surgical exploration

Explanation

The infant has developed a femoral nerve palsy, a known complication of hyperflexion in a Pavlik harness. The harness should be discontinued temporarily until active quadriceps function returns, followed by a reassessment of treatment options.

Question 827

Topic: Pediatric Hip
A 12-year-old boy presents with right hip pain and inability to bear weight for the past 24 hours. Radiographs confirm a slipped capital femoral epiphysis (SCFE). According to the Loder classification, which of the following is the most likely major complication associated with his condition?
. Chondrolysis
. Avascular necrosis (AVN)
. Legg-Calvé-Perthes disease
. Femoroacetabular impingement
. Premature physeal closure

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

The inability to bear weight with or without crutches defines an unstable SCFE according to the Loder classification. Unstable slips carry a high risk of avascular necrosis (AVN), ranging from 20% to 50%, compared to nearly 0% in stable slips.

Question 828

Topic: Pediatric Hip

A 3-month-old girl with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a follow-up visit, her parents report that she is no longer actively extending her knee on the treated side. Which of the following positioning errors is the most likely cause of this complication?

. Hyperabduction of the hip
. Hyperadduction of the hip
. Hyperflexion of the hip
. Hyperextension of the hip
. Excessive internal rotation

Correct Answer & Explanation

. Hyperabduction of the hip

Explanation

Hyperflexion of the hip in a Pavlik harness can compress the femoral nerve against the inguinal ligament, leading to a femoral nerve palsy and decreased active knee extension. Hyperabduction increases the risk of avascular necrosis (AVN) of the femoral head.

Question 829

Topic: Pediatric Hip
A 9-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Anteroposterior pelvis radiographs reveal that the lateral pillar of the femoral head has collapsed to less than 50% of its original height. According to the Herring Lateral Pillar Classification, into which group does he fall, and what is the general prognosis?
. Group A; Excellent prognosis with non-operative care
. Group B; Good prognosis with surgical containment
. Group C; Poor prognosis regardless of treatment
. Group B/C border; Excellent prognosis with physical therapy
. Group C; Good prognosis with immediate femoral osteotomy

Correct Answer & Explanation

. Group C; Poor prognosis regardless of treatment

Explanation

Maintaining <50% of the lateral pillar height defines Herring Group C. Children over the age of 8 with Group C involvement have a generally poor prognosis regarding joint congruency and early osteoarthritis, regardless of whether surgical containment is performed.

Question 830

Topic: Pediatric Hip

A 9-year-old girl, whose weight is in the 40th percentile, presents with right groin pain and a limp. Radiographs confirm a slipped capital femoral epiphysis (SCFE).

Given her presentation, an endocrine workup is indicated. Which of the following is the most common underlying endocrine disorder associated with this condition?

. Hypothyroidism
. Growth hormone deficiency
. Hyperparathyroidism
. Hypogonadism
. Panhypopituitarism

Correct Answer & Explanation

. Hypothyroidism

Explanation

Atypical SCFE (patients aged <10 or >16, or weight < 50th percentile) warrants an endocrine workup. Hypothyroidism is the most common underlying endocrine disorder associated with atypical SCFE.

Question 831

Topic: Pediatric Hip

A 3-month-old girl with developmental dysplasia of the hip (DDH) is being treated in a Pavlik harness. During a follow-up examination, the orthopedist notes decreased active extension of the left knee. What is the most likely cause of this finding?

. Sciatic nerve palsy
. Femoral nerve palsy
. Obturator nerve palsy
. Avascular necrosis of the femoral head
. Septic arthritis

Correct Answer & Explanation

. Sciatic nerve palsy

Explanation

Hyperflexion of the hip in a Pavlik harness can compress the femoral nerve against the inguinal ligament, leading to a transient femoral nerve palsy. This presents as decreased active knee extension and usually resolves with temporary relaxation of the anterior straps.

Question 832

Topic: Pediatric Hip

A 13-year-old boy underwent in situ pinning for a stable slipped capital femoral epiphysis (SCFE) 6 months ago. He now presents with a severely stiff, painful hip. Radiographs show a concentric, severe narrowing of the joint space. What is the most likely diagnosis?

. Avascular necrosis (AVN)
. Chondrolysis
. Septic arthritis
. Implant failure
. Femoroacetabular impingement

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

Chondrolysis is a devastating complication of SCFE characterized by acute loss of articular cartilage and a globally stiff, painful hip. It is strongly associated with unrecognized intra-articular hardware penetration.

Question 833

Topic: Pediatric Hip

A 13-year-old obese boy presents with 3 weeks of left knee pain and a limp. Examination reveals obligatory external rotation of the left hip when it is passively flexed. Radiographs confirm a mild slipped capital femoral epiphysis (SCFE). Which of the following is the most appropriate initial management?

. Closed reduction and spica casting
. In situ pinning with a single cannulated screw
. In situ pinning with three cannulated screws
. Open reduction and internal fixation
. Proximal femoral osteotomy

Correct Answer & Explanation

. Closed reduction and spica casting

Explanation

The standard of care for a stable, mild SCFE is in situ pinning with a single central cannulated screw. Multiple screws increase the risk of joint penetration and avascular necrosis without providing significant biomechanical advantage.

Question 834

Topic: Pediatric Hip

A 7-year-old boy presents with a painless limp of 2 months duration. Radiographs reveal fragmentation and increased density of the right capital femoral epiphysis consistent with Legg-Calve-Perthes disease. Which of the following is the most significant prognostic factor for the final outcome of his hip?

. Gender
. Weight at onset
. Age at clinical presentation
. Duration of symptoms prior to diagnosis
. Presence of a limp

Correct Answer & Explanation

. Gender

Explanation

Age at clinical presentation is the most critical prognostic factor in Legg-Calve-Perthes disease. Children who present at an older age (typically >8 years) have a higher risk of a poor radiographic and clinical outcome compared to younger children.

Question 835

Topic: Pediatric Hip

A 2-month-old girl is being treated with a Pavlik harness for developmental dysplasia of the hip. At her 2-week follow-up, the mother reports that the infant has stopped kicking her left leg. On examination, the left knee does not actively extend, but passive range of motion is normal. Which of the following is the most appropriate management?

. Adjust the posterior strap to increase abduction
. Adjust the anterior strap to increase flexion
. Remove the harness and place in a spica cast
. Discontinue the harness temporarily
. Order an urgent MRI of the lumbar spine

Correct Answer & Explanation

. Adjust the posterior strap to increase abduction

Explanation

Transient femoral nerve palsy is a known complication of the Pavlik harness, typically caused by hyperflexion. The appropriate management is to temporarily discontinue or loosen the harness until active quadriceps function returns.

Question 836

Topic: Pediatric Hip

A 14-year-old girl underwent uncomplicated in situ pinning for a stable SCFE 6 months ago. She now presents with a worsening limp and a stiff hip. Examination reveals a painful, global restriction of hip motion. Radiographs show concentric narrowing of the hip joint space. What is the most likely diagnosis?

. Avascular necrosis
. Chondrolysis
. Implant failure
. Septic arthritis
. Femoroacetabular impingement

Correct Answer & Explanation

. Avascular necrosis

Explanation

Chondrolysis is a recognized complication of SCFE characterized by acute cartilage necrosis, presenting with severe stiffness, global loss of motion, and concentric joint space narrowing on radiographs. It can occur spontaneously or secondary to hardware penetration.

Question 837

Topic: Pediatric Hip

A 12-year-old obese boy presents with acute-on-chronic left hip pain and inability to bear weight. Radiographs confirm an unstable slipped capital femoral epiphysis (SCFE). Which of the following is the most appropriate initial management to minimize the risk of avascular necrosis?

. Urgent open reduction and internal fixation
. Closed reduction and spica casting
. In situ pinning with a single cannulated screw
. Urgent capsulotomy and in situ pinning
. Prophylactic pinning of the contralateral hip

Correct Answer & Explanation

. Urgent open reduction and internal fixation

Explanation

Unstable SCFE is associated with a high rate of avascular necrosis. Urgent capsulotomy and in situ pinning or gentle reduction are recommended to decompress the joint and stabilize the epiphysis.

Question 838

Topic: Pediatric Hip

A 3-month-old girl is being treated for developmental dysplasia of the hip with a Pavlik harness. During a follow-up visit, the mother notes that the child is no longer kicking her left leg. Examination reveals absent active knee extension on the left. The most appropriate next step is to:

. Adjust the anterior straps to increase flexion
. Adjust the posterior straps to decrease abduction
. Discontinue the harness immediately
. Schedule an urgent MRI of the lumbar spine
. Transition to a rigid hip spica cast

Correct Answer & Explanation

. Adjust the anterior straps to increase flexion

Explanation

Absent active knee extension indicates a femoral nerve palsy, a known complication of hyperflexion in a Pavlik harness. The harness should be discontinued immediately to allow the nerve to recover.

Question 839

Topic: Pediatric Hip
A 6-year-old boy presents with a limp and hip pain. Radiographs demonstrate Legg-Calve-Perthes disease with >50% lateral pillar collapse (Herring Group C). According to the literature, which of the following best describes the expected outcome?
. Excellent outcome regardless of treatment
. Poor outcome regardless of treatment in this age group
. Significant benefit from varus derotational osteotomy
. Complete head revascularization within 3 months
. Benefit from conservative management with a Scottish Rite brace

Correct Answer & Explanation

. Poor outcome regardless of treatment in this age group

Explanation

According to the Herring lateral pillar classification, patients over 8 years with Group B/C have better outcomes with surgery. However, Group C hips (regardless of age) generally have poor outcomes, and surgical containment does not significantly alter the natural history.

Question 840

Topic: Pediatric Hip

A 13-year-old obese boy presents to the emergency department with sudden, severe left hip pain after tripping on a step. He is entirely unable to bear weight on the left leg, even with the use of crutches. Radiographs demonstrate a displaced slipped capital femoral epiphysis (SCFE). Which of the following represents the most significant complication risk specific to this presentation compared to a patient who can bear weight?

. Chondrolysis
. Osteonecrosis (avascular necrosis)
. Femoroacetabular impingement
. Contralateral SCFE development
. Premature physeal closure

Correct Answer & Explanation

. Chondrolysis

Explanation

The inability to bear weight even with assistive devices clinically defines an unstable SCFE. Unstable SCFE carries a significantly higher risk of osteonecrosis (up to 47%) compared to stable SCFE, necessitating careful surgical management and often joint decompression.

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