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Pediatric Hip MCQs

Practice Set 26 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 501

Topic: Pediatric Hip
A 6-year-old boy presents with a 3-month history of a painless limp. Radiographs demonstrate fragmentation and increased sclerosis of the capital femoral epiphysis, consistent with Legg-Calvé-Perthes disease. The lateral pillar classification (Herring) is widely utilized to determine the prognosis of this condition. This classification system relies on evaluating the height of which specific portion of the capital femoral epiphysis on an anteroposterior (AP) radiograph?
. The anterior third
. The central third
. The lateral third
. The posterior third
. The medial third

Correct Answer & Explanation

. The lateral third

Explanation

The Herring Lateral Pillar Classification is assessed on the AP radiograph during the fragmentation stage of Legg-Calvé-Perthes disease. It evaluates the height of the lateral third of the capital femoral epiphysis compared to the contralateral normal side. Group A has no lateral pillar involvement; Group B has >50% lateral pillar height maintained; Group C has <50% of the lateral pillar height maintained. The condition of the lateral pillar is the most significant prognostic factor for late femoral head deformity.

Question 502

Topic: Pediatric Hip

A 13-year-old obese boy presents with left thigh pain and an obligatory external rotation of the left hip during flexion.

He is diagnosed with a Slipped Capital Femoral Epiphysis (SCFE). Which of the following is considered an absolute indication for prophylactic pinning of the contralateral asymptomatic hip?

. Endocrine disorder (e.g., hypothyroidism)
. Age greater than 15 years
. Male gender
. Obesity (BMI greater than 95th percentile)
. Modified Klein line intersection on the normal hip

Correct Answer & Explanation

. Endocrine disorder (e.g., hypothyroidism)

Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial but generally recommended in patients with a high risk of developing a contralateral slip. Absolute indications or strong recommendations include the presence of an underlying endocrine disorder (hypothyroidism, panhypopituitarism, renal osteodystrophy) or prior radiation therapy, as these patients have a much higher rate of bilateral involvement.

Question 503

Topic: Pediatric Hip

A 13-year-old female undergoes in situ percutaneous pinning for a stable slipped capital femoral epiphysis (SCFE). Six months postoperatively, she presents with progressive hip stiffness, pain, and a severely restricted range of motion. Anteroposterior radiographs of the pelvis demonstrate concentric joint space narrowing of the affected hip to less than 3 mm. What is the most likely diagnosis?

. Avascular necrosis of the femoral head
. Chondrolysis
. Hardware failure
. Femoroacetabular impingement
. Septic arthritis

Correct Answer & Explanation

. Chondrolysis

Explanation

Chondrolysis is a devastating complication of SCFE, characterized by acute cartilage necrosis resulting in progressive joint space narrowing (typically defined as <3 mm), severe stiffness, and pain. It is strongly associated with unrecognized intra-articular pin penetration during fixation. While avascular necrosis (AVN) is another severe complication, it typically presents with segmental collapse and sclerosis of the femoral head rather than isolated symmetric joint space narrowing.

Question 504

Topic: Pediatric Hip

A 9-year-old boy with panhypopituitarism and a BMI of 32 presents with right knee pain and a limp. He is diagnosed with a right slipped capital femoral epiphysis (SCFE).

Which of the following is the strongest indication for prophylactic in situ pinning of his contralateral asymptomatic left hip?

. His BMI greater than 30.
. His age at presentation and endocrine disorder.
. The degree of slip on the symptomatic right side.
. The presence of right knee pain instead of hip pain.
. His male gender.

Correct Answer & Explanation

. His age at presentation and endocrine disorder.

Explanation

Prophylactic pinning of the contralateral hip in SCFE is recommended for patients at very high risk for a subsequent bilateral slip. High-risk factors include underlying endocrine disorders (e.g., hypothyroidism, panhypopituitarism, renal osteodystrophy) and young age at presentation (typically <10 years old for boys or <11 for girls).

Question 505

Topic: Pediatric Hip

In a 7-year-old boy diagnosed with Legg-Calve-Perthes disease (LCPD), AP pelvis radiographs are obtained during the fragmentation phase.

The lateral pillar of the femoral head maintains exactly 40% of its normal height. According to the Herring lateral pillar classification, what group does this patient fall into, and what is the general prognosis?

. Group A; good prognosis without surgical intervention.
. Group B; fair prognosis, may benefit from containment surgery.
. Group C; poor prognosis, high risk of aspherical head and premature arthritis.
. Group B/C border; excellent prognosis.
. Group A; poor prognosis requiring immediate osteotomy.

Correct Answer & Explanation

. Group C; poor prognosis, high risk of aspherical head and premature arthritis.

Explanation

The Herring lateral pillar classification evaluates the height of the lateral third of the femoral head on an AP radiograph during the fragmentation stage. Group A: no loss of height. Group B: >50% lateral pillar height maintained. Group C: <50% lateral pillar height maintained. Group C patients have a poor prognosis, frequently resulting in an aspherical head and early-onset osteoarthritis.

Question 506

Topic: Pediatric Hip

A 12-year-old obese male presents with left thigh pain and obligatory external rotation during hip flexion.

What is the most widely accepted absolute indication for prophylactic in situ pinning of the asymptomatic contralateral hip in the setting of Slipped Capital Femoral Epiphysis (SCFE)?

. Modified Oxford bone age of 14
. Acute, unstable slip on the affected side
. Underlying endocrinopathy or renal osteodystrophy
. Patient weight greater than the 95th percentile
. Southwick slip angle greater than 50 degrees on the affected side

Correct Answer & Explanation

. Underlying endocrinopathy or renal osteodystrophy

Explanation

While the decision to prophylactically pin the contralateral hip in SCFE is often debated, absolute indications generally include patients with a known endocrinopathy (such as hypothyroidism or growth hormone deficiency) or renal osteodystrophy, as they have a significantly higher risk of a sequential slip. Other relative indications include young age (e.g., modified Oxford bone age < 16) or an inability to follow up, but endocrine disorders represent the most universally accepted absolute indication.

Question 507

Topic: Pediatric Hip

A 2-month-old female is diagnosed with Developmental Dysplasia of the Hip (DDH). Ultrasound confirms a dislocated but reducible left hip. The orthopedist elects to initiate treatment with a Pavlik harness rather than rigid spica casting. What is the primary physiological advantage of using a Pavlik harness in this scenario?

. Lower risk of femoral nerve palsy
. Decreased risk of avascular necrosis of the femoral head
. Superior correction of acetabular version
. Faster rate of concentric reduction
. Prevention of residual pelvic obliquity

Correct Answer & Explanation

. Decreased risk of avascular necrosis of the femoral head

Explanation

The primary advantage of the Pavlik harness over rigid immobilization (like a spica cast) in an infant is a significantly decreased risk of avascular necrosis (AVN) of the femoral head. The harness maintains the hip in the 'safe zone' of Ramsey (flexion and limited, non-forced abduction) while allowing active motion. Rigid casting, especially in excessive abduction (frog-leg position), forces the medial circumflex femoral artery against the labrum, leading to ischemia and AVN.

Question 508

Topic: Pediatric Hip
A 12-year-old obese male undergoes in-situ percutaneous screw fixation for a unilateral Slipped Capital Femoral Epiphysis (SCFE). Prophylactic pinning of the contralateral, asymptomatic hip is considered. Which of the following patient profiles is the strongest indication for prophylactic contralateral pinning?
. Male sex and a body mass index (BMI) > 95th percentile
. Age of 14 years at initial presentation
. A known underlying diagnosis of hypothyroidism
. A severe (Grade III) slip on the affected side
. Closed triradiate cartilages bilaterally

Correct Answer & Explanation

. A known underlying diagnosis of hypothyroidism

Explanation

The risk of developing a contralateral SCFE is significant (around 20-30%, higher in certain populations). Strong indications for prophylactic pinning of the contralateral hip include patients with underlying endocrinopathies (e.g., hypothyroidism, renal osteodystrophy, growth hormone deficiency), patients presenting at an unusually young age (males < 10, females < 9), and patients who are unreliable for follow-up. Obesity alone, while a risk factor for the primary slip, is not an absolute indication for prophylactic pinning.

Question 509

Topic: Pediatric Hip

A 4-month-old female with Developmental Dysplasia of the Hip (DDH) is being treated with a Pavlik harness. Two weeks into treatment, examination reveals absent active knee extension on the affected side. What is the most likely iatrogenic cause?

. Obturator nerve palsy from excessive abduction
. Femoral nerve palsy from excessive hyperflexion
. Sciatic nerve palsy from excessive extension
. Development of a septic hip joint
. Avascular necrosis of the femoral head

Correct Answer & Explanation

. Femoral nerve palsy from excessive hyperflexion

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by excessive hip hyperflexion which compresses the femoral nerve against the inguinal ligament. It manifests as decreased spontaneous leg movement and absent active knee extension. The harness should be adjusted to reduce flexion or temporarily removed.

Question 510

Topic: Pediatric Hip

A 12-year-old obese boy presents with left hip pain and an obligate external rotation of the hip during flexion. A radiograph is shown below. What is the most appropriate initial management for the condition demonstrated?

. Non-weight bearing and urgent in-situ percutaneous pinning
. Closed reduction and hip spica casting
. Open reduction and surgical dislocation (Dunn procedure)
. Protected weight-bearing and serial observation
. Proximal femoral intertrochanteric osteotomy

Correct Answer & Explanation

. Non-weight bearing and urgent in-situ percutaneous pinning

Explanation

The clinical presentation and radiograph represent a stable Slipped Capital Femoral Epiphysis (SCFE). The gold standard for initial management of a stable SCFE is in-situ pinning, typically utilizing a single partially threaded cannulated screw placed in the center-center position of the epiphysis to prevent further slip and promote physeal closure.

Question 511

Topic: Pediatric Hip

A 12-year-old boy presents with a left-sided stable slipped capital femoral epiphysis (SCFE). Which of the following is the strongest indication for prophylactic in situ pinning of the contralateral asymptomatic right hip?

. Patient age greater than 14 years
. Presence of an underlying endocrine disorder
. Male gender
. Body mass index greater than 35
. Slipped angle greater than 50 degrees on the affected side

Correct Answer & Explanation

. Presence of an underlying endocrine disorder

Explanation

The risk of developing a contralateral SCFE is significantly elevated in patients with underlying endocrinopathies (such as hypothyroidism, panhypopituitarism, or renal osteodystrophy). In idiopathic cases, contralateral slip occurs in about 20-40% of patients. However, in patients with endocrine or metabolic disorders, the risk of a bilateral slip approaches 100%. Therefore, an underlying endocrine disorder is an absolute indication for prophylactic pinning of the contralateral hip.

Question 512

Topic: Pediatric Hip

A 12-year-old obese boy presents with acute on chronic Slipped Capital Femoral Epiphysis (SCFE) of the left hip.

In considering treatment options for the asymptomatic contralateral right hip, which of the following is considered the strongest indication for prophylactic in situ pinning?

. Age > 14 years
. Female gender
. Presence of an underlying endocrine disorder
. Severe initial slip > 50 degrees on the affected side
. Body Mass Index in the 90th percentile

Correct Answer & Explanation

. Presence of an underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral asymptomatic hip in SCFE is highly recommended in patients with an underlying endocrine disorder (e.g., hypothyroidism, growth hormone deficiency, renal osteodystrophy) due to an exceedingly high rate of bilateral involvement (up to 100% in some series). Other relative indications include age < 10 years and inability to ensure reliable follow-up.

Question 513

Topic: Pediatric Hip

Figure 46 shows the radiograph of an obese 12-year-old boy who has had left hip pain for the past 3 months. What is the best course of action?

Pediatrics Board Review 2004: High-Yield MCQs (Set 4) - Figure 8

. Decreased activities and physical therapy
. Left hip reduction and internal fixation
. Left hip pinning in situ
. Bilateral hip pinning in situ
. Spica cast immobilization

Correct Answer & Explanation

. Left hip pinning in situ

Explanation

The patient has an obvious slipped capital femoral epiphysis of the left hip for which the recommended treatment is percutaneus pinning in situ. Development of a contralateral slip is less likely at this age; therefore, observation of the right hip is indicated because there is no general agreement regarding prophylactic fixation. Typically, there is no role for spica casting. Physical therapy is not indicated as a primary treatment, and reduction is contraindicated, as it has been associated with osteonecrosis. Loder RT, Aronsson DD, Greenfield ML: The epidemiology of bilateral slipped capital femoral epiphysis: A study of children in Michigan. J Bone Joint Surg Am 1993;75:1141-1147. Aronsson DD, Karol LA: Stable slipped capital femoral epiphysis: Evaluation and management. J Am Acad Orthop Surg 1996;4:173-181. Hurley JM, Betz RR, Loder RT, Davidson RS, Alburger PD, Steel HH: Slipped capital femoral epiphysis: The prevalence of late contralateral slip. J Bone Joint Surg Am 1996;78:226-230.

Question 514

Topic: Pediatric Hip

A 2-year-old girl is diagnosed with unilateral developmental dysplasia of the hip (DDH). Radiographs, seen here, show a dislocated left hip with an acetabular index of 45 degrees and evidence of femoral head flattening. Attempts at closed reduction under general anesthesia are unsuccessful.

What is the most appropriate next step in management?

. Repeat closed reduction with higher force.
. Observation with serial radiographs.
. Open reduction with capsulorrhaphy and possibly femoral shortening osteotomy.
. Pavlik harness application.
. Triple innominate osteotomy.

Correct Answer & Explanation

. Open reduction with capsulorrhaphy and possibly femoral shortening osteotomy.

Explanation

This 2-year-old girl has a late-presenting, irreducible developmental dysplasia of the hip (DDH). The inability to achieve a closed reduction under general anesthesia, coupled with a dislocated hip and significant acetabular dysplasia (acetabular index of 45 degrees, normal < 30 degrees for age), indicates the need for surgical intervention. By 18-24 months of age, closed reduction becomes less successful due to soft tissue contractures (e.g., iliopsoas, adductors), an inverted labrum, and a hypertrophied ligamentum teres, and a dysplastic acetabulum.Option A (repeat closed reduction with higher force) is contraindicated. Forceful reduction attempts in late-presenting DDH significantly increase the risk of avascular necrosis (AVN) of the femoral head.Option B (observation) is incorrect; an unreduced dislocated hip will lead to severe long-term disability and degenerative arthritis.Option C (open reduction with capsulorrhaphy and possibly femoral shortening osteotomy) is the most appropriate next step. Open reduction addresses the soft tissue impediments to reduction and allows for direct visualization of the femoral head and acetabulum. Capsulorrhaphy stabilizes the hip after reduction. Femoral shortening osteotomy is often required in older children (typically >18-24 months) to reduce tension on the femoral head after reduction, thereby reducing the risk of AVN and facilitating a stable reduction. Addressing the acetabular dysplasia (e.g., with a Dega or Salter osteotomy) may also be necessary at the time of open reduction or as a staged procedure, depending on the residual dysplasia after reduction.Option D (Pavlik harness) is effective for reducible DDH in infants younger than 6 months and is ineffective and contraindicated for irreducible or late-presenting DDH in a 2-year-old.Option E (Triple innominate osteotomy) is an acetabular redirection osteotomy typically performed for residual acetabular dysplasia in older children (usually 6-12 years) after successful hip reduction, not as a primary treatment for an irreducible dislocation in a 2-year-old.

Question 515

Topic: Pediatric Hip

A 13-year-old obese male presents with a 3-month history of right hip and knee pain, worsening with activity. Physical examination reveals a painful gait, decreased internal rotation, and external rotation with hip flexion (Drehmann sign). Radiographs show a right slipped capital femoral epiphysis (SCFE) with a moderate slip angle.

What is the MOST appropriate acute management for this patient?

. Non-weight bearing immediately, followed by in situ pinning of the affected hip.
. Surgical osteotomy to correct the slip angle immediately.
. Bed rest and traction for 2 weeks, then consideration of pinning.
. Observation with activity modification and close follow-up.
. In situ pinning of both hips to prevent contralateral slip.

Correct Answer & Explanation

. Non-weight bearing immediately, followed by in situ pinning of the affected hip.

Explanation

The patient's presentation is classic for a stable slipped capital femoral epiphysis (SCFE). The Drehmann sign is pathognomonic. The MOST appropriate acute management for a stable SCFE is immediate non-weight bearing to prevent further slippage, followed by in situ pinning of the affected hip. In situ pinning stabilizes the physis and prevents progression of the slip. Surgical osteotomy is reserved for severe slips or malunion after initial pinning. Bed rest and traction are not standard acute management. Observation is contraindicated due to the risk of progression and avascular necrosis. Prophylactic pinning of the contralateral hip is often considered, especially in high-risk patients (e.g., endocrine disorders, severe obesity), but the immediate priority is the symptomatic hip.

Question 516

Topic: Pediatric Hip

An 11-year-old obese male presents with a 3-month history of left knee pain, which he attributes to 'growing pains.' He denies any specific trauma. On examination, he has an antalgic gait, and active range of motion of the left hip reveals significantly limited internal rotation and abduction. Radiographs of the hips (AP and frog-leg lateral views, as shown) are ordered.

The images show a stable Slipped Capital Femoral Epiphysis (SCFE) on the left. What is the MOST appropriate definitive treatment for this condition?

. Spica cast immobilization for 6-8 weeks.
. Closed reduction and single screw fixation in situ.
. Open reduction with osteotomy and internal fixation.
. Percutaneous single screw fixation in situ without attempted reduction.
. Non-weight-bearing with crutches until symptoms resolve.

Correct Answer & Explanation

. Percutaneous single screw fixation in situ without attempted reduction.

Explanation

For a stable Slipped Capital Femoral Epiphysis (SCFE), the standard of care is percutaneous single screw fixation in situ without attempting any reduction maneuver. Attempted closed reduction of a stable SCFE significantly increases the risk of avascular necrosis (AVN) of the femoral head. Fixation in situ aims to stabilize the physis and prevent further slip. Non-weight-bearing is important prior to fixation but is not definitive treatment. Spica cast immobilization is ineffective in preventing further slip and is not a definitive treatment. Open reduction and osteotomy are reserved for severe, unstable, or chronic SCFE with significant deformity after initial fixation, or for salvage procedures.

Question 517

Topic: Pediatric Hip

A 9-month-old female is diagnosed with a unilateral left developmental dysplasia of the hip (DDH) that failed Pavlik harness treatment despite good compliance. Clinical examination reveals a reducible but unstable hip. An anteroposterior pelvic radiograph confirms a dislocated hip with a severely dysplastic acetabulum and a high riding femoral head.

Given the age and failed conservative management, what is the MOST appropriate next step in management?

. Continue Pavlik harness treatment with increased abduction.
. Refer for a triple innominate osteotomy.
. Proceed with a closed reduction under general anesthesia with subsequent hip spica casting.
. Perform an open reduction and femoral shortening osteotomy.
. Initiate traction followed by repeat Pavlik harness application.

Correct Answer & Explanation

. Proceed with a closed reduction under general anesthesia with subsequent hip spica casting.

Explanation

The image provided is a hip X-ray likely showing DDH. For a 9-month-old infant with DDH that has failed Pavlik harness treatment, the typical next step is a closed reduction under general anesthesia. The Pavlik harness is most effective in infants up to 6 months of age. Beyond this age, particularly if conservative measures fail or the hip remains irreducible/unstable, more invasive methods are considered.At 9 months, the hip is typically still reducible, and soft tissue contractures are not as severe as in older children. A closed reduction aims to relocate the femoral head into the acetabulum, followed by immobilization in a hip spica cast, usually in the 'human' position (hip flexion 90-100°, abduction 45-60°, slight internal rotation). Arthrography is often performed during the procedure to confirm concentric reduction and identify any impediments to reduction.Rationale for options:A. Pavlik harness is typically ineffective and contraindicated after 6-9 months of age or after failure, due to increased stiffness and potential for avascular necrosis (AVN) with excessive force.B. Closed reduction under general anesthesia with subsequent hip spica casting is the standard next step for failed Pavlik harness in an infant of this age with a reducible hip. This is the correct answer.C. A triple innominate osteotomy is an acetabular redirection osteotomy performed in older children (typically > 18-24 months) or adolescents for residual dysplasia after successful reduction, not as the primary reduction method in an infant.D. Open reduction and femoral shortening osteotomy is indicated for irreducible hips, severe dislocations, or older children (typically >12-18 months) where significant soft tissue contractures or bony deformities prevent closed reduction. At 9 months, closed reduction is usually attempted first unless there's clear evidence of irreducibility.E. Traction may be used as a preparatory step for open or closed reduction in older infants (e.g., >12 months) to stretch soft tissues, but it is not followed by another Pavlik harness application after failed initial treatment.

Question 518

Topic: Pediatric Hip

A 13-year-old obese male presents with a 3-week history of left thigh pain and a limp. Examination reveals obligate external rotation upon flexing the left hip. Radiographs confirm a stable Slipped Capital Femoral Epiphysis (SCFE). During in situ single-screw fixation, to minimize the risk of avascular necrosis (AVN), the screw should ideally be positioned in which quadrant of the femoral head?

. Anterior-superior
. Anterior-inferior
. Posterior-superior
. Posterior-inferior
. Directly in the fovea capitis

Correct Answer & Explanation

. Posterior-inferior

Explanation

In the treatment of SCFE, the femoral head typically slips posterior and inferior relative to the femoral neck. To avoid joint penetration and to stay away from the vulnerable blood supply entering the superior-posterior capsule (retinacular vessels from the medial femoral circumflex artery), the starting point on the lateral femur is anterior, and the screw trajectory aims for the center of the epiphysis, typically ending up in the posterior-inferior quadrant of the head. Placing screws in the anterior-superior quadrant has the highest risk of unrecognized joint penetration and AVN.

Question 519

Topic: Pediatric Hip

A 12-year-old obese male presents with chronic left groin pain and an obligatory slip into external rotation with passive hip flexion. Radiograph of the hip is shown.

Which of the following represents the strongest indication for prophylactic in situ pinning of the contralateral, asymptomatic hip in a patient with a Slipped Capital Femoral Epiphysis (SCFE)?

. Underlying endocrine disorder
. Age greater than 14 years
. Male gender
. Weight greater than the 99th percentile

Correct Answer & Explanation

. Underlying endocrine disorder

Explanation

The strongest indications for prophylactic pinning of the contralateral hip in a patient with SCFE include an underlying endocrine disorder (such as hypothyroidism, panhypopituitarism, or renal osteodystrophy), prior radiation therapy, or age less than 10 years. Endocrine disorders carry a significantly higher risk of bilateral involvement compared to idiopathic SCFE.

Question 520

Topic: Pediatric Hip

A 4-week-old female infant is currently undergoing treatment with a Pavlik harness for developmental dysplasia of the hip (DDH). At the 2-week follow-up appointment, the mother notes that the infant has stopped kicking her left leg, and the knee rests in a persistently extended position. What is the most likely iatrogenic cause of this finding?

. The harness is adjusted with excessive hip abduction
. The harness is adjusted with excessive hip flexion
. An acute superior dislocation of the hip
. Ischemic necrosis of the proximal femoral epiphysis

Correct Answer & Explanation

. The harness is adjusted with excessive hip flexion

Explanation

The clinical picture describes a femoral nerve palsy, a known complication of Pavlik harness treatment. It is caused by hyperflexion of the hip (usually >120 degrees), which compresses the femoral nerve against the inguinal ligament. This results in decreased quadriceps function (absence of kicking and an extended resting knee). Treatment involves loosening the anterior straps to decrease hip flexion. Excessive abduction, by contrast, is associated with avascular necrosis of the femoral head.

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