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Pediatric Hip MCQs

Practice Set 92 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 1821

Topic: Pediatric Hip
A 6-year-old boy is diagnosed with Legg-Calvé-Perthes disease. His orthopedic surgeon explains that his prognosis depends heavily on the extent of epiphyseal involvement. According to the lateral pillar (Herring) classification, which radiographic finding during the fragmentation stage is associated with the worst prognosis?
. >50% maintenance of lateral pillar height.
. <50% maintenance of lateral pillar height.
. Subchondral radiolucency (crescent sign).
. Calcification lateral to the epiphysis.
. Metaphyseal cysts.

Correct Answer & Explanation

. <50% maintenance of lateral pillar height.

Explanation

The Herring lateral pillar classification is utilized during the fragmentation stage of Legg-Calvé-Perthes disease to determine prognosis based on the height of the lateral portion of the capital femoral epiphysis. Group A has no lateral pillar involvement. Group B has >50% lateral pillar height maintained. Group C has <50% lateral pillar height maintained and is associated with the worst prognosis, often leading to aspherical congruency or incongruency of the hip joint and early-onset osteoarthritis.

Question 1822

Topic: Pediatric Hip

A 13-year-old obese male presents with acute-on-chronic left hip pain. He is unable to bear weight on the affected limb, even with the assistance of crutches. Radiographs confirm a slipped capital femoral epiphysis (SCFE). According to the Loder classification, what is the most significant prognostic implication of his inability to bear weight?

. Increased risk of chondrolysis
. Increased risk of avascular necrosis (AVN)
. Increased risk of contralateral slip
. Decreased likelihood of requiring surgical pinning
. Increased risk of premature physeal closure

Correct Answer & Explanation

. Increased risk of avascular necrosis (AVN)

Explanation

Correct Answer: Increased risk of avascular necrosis (AVN)The Loder classification categorizes slipped capital femoral epiphysis (SCFE) into stable and unstable based on the patient's ability to bear weight. An unstable SCFE is defined by the inability to ambulate with or without crutches. This distinction is critical because it carries significant prognostic value regarding the development of avascular necrosis (AVN). Unstable SCFE has a high rate of AVN, historically reported between 24% and 47%, due to the acute disruption of the retinacular vessels supplying the femoral head. Stable SCFE, where the patient can bear weight, has an AVN rate of nearly 0%.

Question 1823

Topic: Pediatric Hip

A 9-month-old female is diagnosed with late-presenting developmental dysplasia of the hip (DDH). Radiographs confirm a laterally subluxated and superiorly migrated left femoral head with a dysplastic acetabulum. Which of the following is the most appropriate initial management?

. Pavlik harness application
. Closed reduction and spica casting
. Open reduction and femoral shortening osteotomy
. Pemberton pelvic osteotomy
. Observation until 1 year of age

Correct Answer & Explanation

. Closed reduction and spica casting

Explanation

For DDH presenting between 6 and 18 months of age, closed reduction and application of a hip spica cast is the initial treatment of choice. The Pavlik harness is typically reserved for reducible hips in infants younger than 6 months.

Question 1824

Topic: Pediatric Hip

A 6-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip. At her 2-week follow-up, the parents report she has stopped kicking her left leg. On exam, she lacks active knee extension on the left side but has normal sensation. What is the most likely cause of this clinical presentation?

. Hyperflexion of the hip in the harness
. Excessive abduction of the hip in the harness
. Excessive adduction of the hip in the harness
. Hyperextension of the knee due to strap malposition
. Inadequate flexion of the hip in the harness

Correct Answer & Explanation

. Hyperflexion of the hip in the harness

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment caused by hyperflexion of the hip. Excessive abduction, conversely, increases the risk of avascular necrosis of the femoral head.

Question 1825

Topic: Pediatric Hip

An 8-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the parents note the infant has stopped kicking her left leg. On examination, there is an absence of active knee extension on the left side, but ankle and toe movements are normal. The hip is positioned in 120 degrees of flexion. Which of the following is the most appropriate next step in management?

. Immediate closed reduction and spica casting
. Obtain an emergent MRI of the lumbar spine
. Decrease the degree of hip flexion in the harness
. Decrease the degree of hip abduction in the harness
. Switch to a rigid abduction orthosis

Correct Answer & Explanation

. Decrease the degree of hip flexion in the harness

Explanation

The clinical presentation is consistent with a femoral nerve palsy, the most common neurologic complication of a Pavlik harness, caused by hyperflexion of the hip. The appropriate management is to decrease the degree of hip flexion or temporarily remove the harness until nerve function returns.

Question 1826

Topic: Pediatric Hip
A 3-year-old child presents with a limp and pain in the right hip. Radiographs show flattening and sclerosis of the right femoral head epiphysis, with widening of the medial joint space. What is the most likely diagnosis?
. Developmental dysplasia of the hip (DDH)
. Septic arthritis of the hip
. Transient synovitis of the hip
. Legg-Calvé-Perthes disease (LCPD)
. Slipped capital femoral epiphysis (SCFE)

Correct Answer & Explanation

. Legg-Calvé-Perthes disease (LCPD)

Explanation

The radiographic findings of flattening and sclerosis of the femoral head epiphysis, along with widening of the medial joint space, are classic for Legg-Calvé-Perthes disease (LCPD), an idiopathic avascular necrosis of the femoral head in children typically aged 4-8 years. DDH involves acetabular and femoral head dysplasia. Septic arthritis presents with acute, severe pain and fever, and radiographic changes are typically joint effusions and cartilage destruction. Transient synovitis is a self-limiting inflammatory condition with minimal radiographic changes. SCFE usually occurs in adolescents (10-16 years) and involves a posterior and inferior slippage of the femoral head epiphysis.

Question 1827

Topic: Pediatric Hip

Which of the following is the most reliable radiographic sign for detecting a slipped capital femoral epiphysis (SCFE)?

. Widening of the physis
. Irregularity of the femoral head
. Trethowan's sign (Klein's line failing to intersect the lateral part of the femoral head)
. Decreased femoral neck-shaft angle
. Increased medial clear space

Correct Answer & Explanation

. Trethowan's sign (Klein's line failing to intersect the lateral part of the femoral head)

Explanation

Trethowan's sign, or Klein's line, is considered the most reliable radiographic sign for detecting SCFE on an anteroposterior (AP) view. Klein's line is drawn along the superior border of the femoral neck; normally, it should intersect a portion of the femoral head epiphysis. In SCFE, due to posterior and inferior slippage, Klein's line will fail to intersect or will intersect a smaller portion of the epiphysis. While widening of the physis and decreased femoral neck-shaft angle can be present, Klein's line is the most sensitive and specific sign for early diagnosis on standard AP radiographs.

Question 1828

Topic: Pediatric Hip

An obese 12-year-old boy presents with left hip pain and the radiograph shown. He is diagnosed with a slipped capital femoral epiphysis (SCFE). Which of the following treatments is contraindicated due to its association with a high risk of osteonecrosis?

. Percutaneous pinning in situ
. Closed reduction prior to pinning
. Prophylactic pinning of the contralateral hip
. Open subtrochanteric osteotomy
. Spica cast immobilization

Correct Answer & Explanation

. Closed reduction prior to pinning

Explanation

Correct Answer: BForceful closed reduction of a slipped capital femoral epiphysis is contraindicated because it significantly increases the risk of osteonecrosis (avascular necrosis) of the femoral head by disrupting the already tenuous retinacular blood supply. The standard of care is in situ fixation. Spica casting is generally not used as primary treatment due to poor control and stiffness, but closed reduction is the most dangerous intervention listed.

Question 1829

Topic: Pediatric Hip

A 32-year-old woman presents with right hip pain and the radiograph shown, demonstrating developmental dysplasia of the hip (DDH) with a high acetabular index. A Bernese (Ganz) periacetabular osteotomy is planned. Which of the following is a primary biomechanical goal of this procedure?

. Medialization of the hip joint center
. Lateralization of the hip joint center
. Increasing the femoral neck-shaft angle
. Decreasing the femoral anteversion
. Proximalization of the greater trochanter

Correct Answer & Explanation

. Medialization of the hip joint center

Explanation

Correct Answer: AThe Bernese periacetabular osteotomy (PAO) is designed to reorient the acetabulum to improve femoral head coverage. A key biomechanical goal and advantage of the PAO is the ability to medialize the hip joint center, which decreases the joint reactive forces by reducing the lever arm of the body weight, thereby improving the mechanical environment of the dysplastic hip.

Question 1830

Topic: Pediatric Hip
A 38-year-old runner presents with right hip pain. Imaging reveals a well-circumscribed, radiolucent lesion with a sclerotic margin in the anterosuperior aspect of the femoral neck. This lesion, known as a synovial herniation pit, is most frequently associated with which of the following underlying conditions?
. Legg-Calvé-Perthes disease
. Slipped capital femoral epiphysis
. Femoroacetabular impingement
. Developmental dysplasia of the hip
. Avascular necrosis of the femoral head

Correct Answer & Explanation

. Femoroacetabular impingement

Explanation

Synovial herniation pits (Pitt's pits) are benign, often incidental, radiolucent lesions with sclerotic margins typically located in the anterosuperior femoral neck. They are thought to result from mechanical abrasion and herniation of synovium into the bone. They are highly associated with cam-type femoroacetabular impingement (FAI), where the abnormal femoral head-neck junction abuts the acetabular rim.

Question 1831

Topic: Pediatric Hip
A 7-year-old boy with a history of a painless limp is diagnosed with Legg-Calvé-Perthes disease. An arthrogram is performed to evaluate joint congruency. The maximum abduction/internal rotation view is shown in Figure A, and the abduction view is shown in Figure B. The failure of the lateral epiphysis to slide under the acetabular edge with abduction, accompanied by medial dye pooling, is pathognomonic for which of the following conditions?
. Cam impingement
. Hinge abduction
. Pincer impingement
. Coxa magna
. Slipped capital femoral epiphysis

Correct Answer & Explanation

. Hinge abduction

Explanation

The arthrogram images demonstrate classic hinge abduction, a critical finding in severe Legg-Calvé-Perthes disease. Hinge abduction occurs when the enlarged, deformed lateral portion of the femoral head extrudes and impinges against the lateral margin of the acetabulum during abduction. Instead of gliding smoothly into the acetabulum, the femoral head hinges on the acetabular rim, causing the medial joint space to widen (distract), which is visualized as medial dye pooling on the arthrogram. Persistent hinge abduction prevents normal spherical remodeling of the femoral head and is an indication for surgical intervention to restore congruency.

Question 1832

Topic: Pediatric Hip

A 32-year-old woman presents with chronic right hip pain. The AP pelvis radiograph demonstrates developmental dysplasia of the hip with a high acetabular index (27 degrees) and anterior undercoverage. Assuming the joint space is well-preserved and there is no advanced osteoarthritis, which of the following is the most appropriate surgical intervention?

. Total hip arthroplasty
. Hip arthrodesis
. Bernese (Ganz) periacetabular osteotomy
. Proximal femoral derotational osteotomy
. Surgical hip dislocation and osteochondroplasty

Correct Answer & Explanation

. Bernese (Ganz) periacetabular osteotomy

Explanation

Correct Answer: Bernese (Ganz) periacetabular osteotomyThe radiograph shows symptomatic developmental dysplasia of the hip (DDH) with significant anterolateral undercoverage. In a young, active patient with preserved joint space and symptomatic dysplasia, a redirectional pelvic osteotomy is indicated to improve femoral head coverage and biomechanics, thereby delaying or preventing the onset of osteoarthritis. The Bernese (Ganz) periacetabular osteotomy is the most widely accepted procedure for this indication in adults, as it allows for multiplanar correction while maintaining the integrity of the posterior column.

Question 1833

Topic: Pediatric Hip
A 7-year-old boy with a history of a painless limp undergoes an arthrogram of the hip, as shown in the provided images. The failure of the lateral epiphysis to slide under the acetabular edge during abduction is diagnostic of which of the following?
. Cam impingement
. Pincer impingement
. Hinge abduction
. Slipped capital femoral epiphysis
. Coxa vara

Correct Answer & Explanation

. Hinge abduction

Explanation

The arthrogram demonstrates hinge abduction, a severe complication of Legg-Calvé-Perthes disease where the deformed, extruded lateral portion of the femoral head hinges against the lateral acetabular margin during abduction, preventing concentric reduction. This persistent hinge abduction prevents femoral head remodeling by the acetabulum.

Question 1834

Topic: Pediatric Hip

An obese 12-year-old boy presents with left hip pain and an antalgic gait. A radiograph is provided. Which of the following complications is most strongly associated with attempts at closed reduction of this condition?

. Chondrolysis
. Osteonecrosis of the femoral head
. Femoroacetabular impingement
. Premature physeal closure
. Slipped capital femoral epiphysis of the contralateral hip

Correct Answer & Explanation

. Osteonecrosis of the femoral head

Explanation

Correct Answer: Osteonecrosis of the femoral headThe radiograph shows a slipped capital femoral epiphysis (SCFE). Closed reduction of a SCFE is contraindicated because it significantly increases the risk of osteonecrosis (avascular necrosis) of the femoral head. The recommended treatment is percutaneous pinning in situ.

Question 1835

Topic: Pediatric Hip

A 32-year-old woman presents with chronic right hip pain. A radiograph is provided, demonstrating developmental dysplasia of the hip with a high acetabular index. Which of the following is the primary biomechanical goal of the most appropriate joint-preserving surgery for this patient?

. Medialization of the hip center of rotation and improvement of anterior and lateral femoral head coverage
. Lateralization of the hip center of rotation to increase abductor moment arm
. Creation of a fibrous hinge to prevent superior migration
. Resection of the cam lesion to prevent impingement
. Proximalization of the greater trochanter

Correct Answer & Explanation

. Medialization of the hip center of rotation and improvement of anterior and lateral femoral head coverage

Explanation

Correct Answer: Medialization of the hip center of rotation and improvement of anterior and lateral femoral head coverageThe radiograph shows developmental dysplasia of the hip (DDH). The Bernese (Ganz) periacetabular osteotomy is the treatment of choice for symptomatic dysplasia with preserved joint space. Its biomechanical goals include improving anterior and lateral coverage of the femoral head and medializing the hip center of rotation to decrease joint contact forces.

Question 1836

Topic: Pediatric Hip

A 7-year-old boy with a history of a painless limp presents with limited abduction and spasm on internal rotation. Radiographs obtained during an arthrogram are shown. The failure of the lateral epiphysis to slide under the acetabular edge during abduction is diagnostic of which of the following?

. Cam-type femoroacetabular impingement
. Hinge abduction
. Pincer-type femoroacetabular impingement
. Slipped capital femoral epiphysis
. Chondrolysis

Correct Answer & Explanation

. Hinge abduction

Explanation

Correct Answer: BThe radiographs demonstrate classic hinge abduction in a patient with Legg-Calve-Perthes disease. Hinge abduction occurs when the enlarged, deformed lateral portion of the femoral head impinges on the lateral acetabular margin during abduction, preventing the head from sliding concentrically into the acetabulum. The arthrogram shows medial dye pooling due to distraction of the joint. Persistent hinge abduction prevents proper femoral head remodeling and is an indication for surgical intervention.

Question 1837

Topic: Pediatric Hip

An obese 12-year-old boy presents with left hip pain and an obligatory external rotation during hip flexion. An AP pelvis radiograph is shown. Which of the following is the most appropriate definitive management for the left hip?

. Spica cast immobilization
. Closed reduction and internal fixation
. Percutaneous pinning in situ
. Proximal femoral osteotomy
. Observation and non-weight bearing

Correct Answer & Explanation

. Percutaneous pinning in situ

Explanation

Correct Answer: CThe radiograph demonstrates a slipped capital femoral epiphysis (SCFE) of the left hip. The standard of care for a stable SCFE is percutaneous pinning in situ with a single cannulated screw to prevent further slippage and promote physeal closure. Closed reduction is contraindicated as it significantly increases the risk of osteonecrosis. Spica casting and observation are not appropriate definitive treatments.

Question 1838

Topic: Pediatric Hip

A 32-year-old woman presents with right hip pain that has failed conservative management. An AP pelvis radiograph is shown, demonstrating a high acetabular index and anterolateral undercoverage of the femoral head with preserved joint space. Which of the following surgical interventions is most appropriate?

. Total hip arthroplasty
. Hip arthrodesis
. Bernese (Ganz) periacetabular osteotomy
. Proximal femoral varus osteotomy
. Arthroscopic labral debridement

Correct Answer & Explanation

. Bernese (Ganz) periacetabular osteotomy

Explanation

Correct Answer: CThe radiograph reveals developmental dysplasia of the hip (DDH) with significant anterolateral undercoverage but preserved joint space. In a young, active patient with symptomatic DDH and minimal osteoarthritis, a Bernese (Ganz) periacetabular osteotomy is the procedure of choice. It reorients the acetabulum to improve femoral head coverage and biomechanics, delaying or preventing the need for total hip arthroplasty.

Question 1839

Topic: Pediatric Hip

A 7-year-old boy with a known history of Legg-Calve-Perthes disease presents with worsening pain and a limp. An AP radiograph in maximum abduction is shown. The failure of the lateral epiphysis to slide under the acetabular edge with abduction is known as hinge abduction. This biomechanical phenomenon is most likely to result in which of the following?

. Spontaneous resolution of the deformity
. Prevention of femoral head remodeling by the acetabulum
. Medial subluxation of the femoral head
. Overgrowth of the greater trochanter
. Avascular necrosis of the acetabulum

Correct Answer & Explanation

. Prevention of femoral head remodeling by the acetabulum

Explanation

Correct Answer: BThe radiograph demonstrates hinge abduction, where the extruded, enlarged lateral portion of the femoral head hinges against the lateral acetabular margin during abduction. This prevents the femoral head from seating concentrically in the acetabulum, thereby preventing the acetabulum from acting as a spherical mold to remodel the femoral head during the healing phase of Legg-Calve-Perthes disease.

Question 1840

Topic: Pediatric Hip

A 13-year-old boy presents with an acute, unstable slipped capital femoral epiphysis (SCFE) and cannot bear weight. He undergoes urgent single-screw in situ fixation. Which of the following complications has the highest incidence specifically associated with the unstable nature of this slip?

. Chondrolysis
. Avascular necrosis (AVN)
. Femoroacetabular impingement
. Contralateral slip
. Implant failure

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

Unstable SCFE is defined by the inability to bear weight and carries a significantly higher risk of avascular necrosis (AVN), ranging from 10% to 50%. The disruption of the retinacular vessels during the acute displacement is the primary cause.

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