Menu

Pediatric Hip MCQs

Practice Set 16 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 301

Topic: Pediatric Hip

A 50-year-old male with a history of developmental dysplasia of the hip (DDH) and subsequent severe osteoarthritis is undergoing a primary total hip replacement. Pre-operative templating reveals a shallow, anteverted acetabulum. The surgeon plans to use a posterior approach. To optimize stability and minimize dislocation risk in this challenging case, which of the following combined anteversion targets is generally considered optimal?

. 10-20 degrees
. 20-30 degrees
. 35-45 degrees
. 50-60 degrees
. 65-75 degrees

Correct Answer & Explanation

. 35-45 degrees

Explanation

Correct Answer: CThe teaching case, under 'Biomechanics of Prosthetic Stability' and 'Summary of Key Literature / Guidelines,' states: 'Combined Anteversion: The sum of acetabular anteversion and femoral anteversion. Optimal combined anteversion (typically 35-45°) provides stability across a functional range of motion, minimizing both anterior and posterior impingement.' While Lewinnek's safe zone provides guidelines for individual component placement, the concept of combined anteversion is increasingly recognized as critical for overall hip stability, especially in complex cases like DDH where native anatomy might be altered. Achieving a combined anteversion of 35-45 degrees helps ensure that the hip remains stable through its functional range of motion, balancing the risk of anterior and posterior impingement.A. 10-20 degrees:This range is too low for combined anteversion and would likely lead to posterior impingement and instability.B. 20-30 degrees:This is still on the lower side for optimal combined anteversion and may not provide sufficient stability against posterior dislocation.D. 50-60 degrees:This range is too high for combined anteversion and would likely lead to anterior impingement and instability.E. 65-75 degrees:This range is excessively high and would almost certainly result in anterior impingement and dislocation.

Question 302

Topic: Pediatric Hip

A 45-year-old female with Crowe IV developmental dysplasia of the hip undergoes a complex total hip arthroplasty with a subtrochanteric shortening osteotomy. What is the primary purpose of utilizing a subtrochanteric shortening osteotomy in this setting?

. To increase the abductor moment arm
. To allow placement of the acetabular cup in the true acetabulum without excessive sciatic nerve traction
. To prevent limb length discrepancy in the contralateral limb
. To reduce the risk of heterotopic ossification
. To bypass an associated proximal femoral deformity

Correct Answer & Explanation

. To allow placement of the acetabular cup in the true acetabulum without excessive sciatic nerve traction

Explanation

In Crowe IV DDH, the hip center is extremely high. Bringing the femur down to a cup placed in the true acetabulum risks massive sciatic nerve traction injury. A subtrochanteric shortening osteotomy prevents this overtensioning while restoring native hip biomechanics.

Question 303

Topic: Pediatric Hip
A 4-year-old child presents with a painless limp. Examination reveals limited abduction and internal rotation of the hip. Radiographs show increased density and flattening of the femoral epiphysis. What is the most likely diagnosis?
. Developmental dysplasia of the hip (DDH)
. Septic arthritis of the hip
. Slipped capital femoral epiphysis (SCFE)
. Legg-Calvé-Perthes disease
. Transient synovitis

Correct Answer & Explanation

. Legg-Calvé-Perthes disease

Explanation

The clinical picture of a painless limp in a 4-year-old with limited hip abduction and internal rotation, coupled with radiographic findings of increased density (sclerosis) and flattening (fragmentation/collapse) of the femoral epiphysis, is characteristic of Legg-Calvé-Perthes disease. This condition is idiopathic avascular necrosis of the femoral head. SCFE typically occurs in older, often obese adolescents. DDH presents earlier and with different radiographic findings. Septic arthritis and transient synovitis are acute painful conditions.

Question 304

Topic: Pediatric Hip

A 3-month-old female is being treated with a Pavlik harness for developmental dysplasia of the hip. At the 2-week follow-up, the mother notes the child is no longer kicking her leg on the affected side. Examination reveals absent active knee extension but intact ankle movements. What is the most appropriate next step in management?

. 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

. Discontinue the harness immediately

Explanation

The patient has developed a femoral nerve palsy, a known complication of hyperflexion in a Pavlik harness. The most appropriate immediate step is to discontinue the harness to allow for nerve recovery before attempting alternative treatments.

Question 305

Topic: Pediatric Hip

An obese 13-year-old male presents with right knee pain and an antalgic limp. Examination reveals obligate external rotation of the right hip with passive flexion. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Which of the following is the most recognized complication of in-situ percutaneous pinning of a stable SCFE?

. Chondrolysis
. Avascular necrosis
. Femoral nerve palsy
. Leg length discrepancy > 3 cm
. Heterotopic ossification

Correct Answer & Explanation

. Chondrolysis

Explanation

Chondrolysis is a severe complication associated with SCFE treatment, often linked to unrecognized intra-articular hardware penetration during in-situ pinning. AVN is much more commonly associated with unstable SCFE or aggressive reduction attempts rather than standard pinning of a stable slip.

Question 306

Topic: Pediatric Hip

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

. Male sex
. Age greater than 14 years
. Weight greater than 95th percentile
. Underlying endocrinopathy
. Family history of SCFE

Correct Answer & Explanation

. Underlying endocrinopathy

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with an underlying endocrinopathy (e.g., hypothyroidism) or prior pelvic radiation, as their risk for bilateral involvement is significantly elevated.

Question 307

Topic: Pediatric Hip

A 6-month-old female with developmental dysplasia of the hip has failed 4 weeks of Pavlik harness treatment. Ultrasound demonstrates continued posterior dislocation of the femoral head. What is the most appropriate next step in management?

. Continue Pavlik harness for an additional 4 weeks
. Switch to a rigid abduction orthosis
. Closed reduction and spica casting under anesthesia
. Open reduction and pelvic osteotomy
. Observation until 1 year of age

Correct Answer & Explanation

. Closed reduction and spica casting under anesthesia

Explanation

If a Pavlik harness fails to achieve reduction within 3-4 weeks, it should be discontinued to prevent Pavlik harness disease (damage to the posterior acetabular wall). The next appropriate step is closed reduction and spica casting under general anesthesia with an arthrogram.

Question 308

Topic: Pediatric Hip

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

. Observation until age 1
. Switch to an abduction orthosis without confirmation of reduction
. Closed reduction with hip spica casting
. Open reduction with femoral shortening osteotomy
. Salter innominate osteotomy

Correct Answer & Explanation

. Closed reduction with hip spica casting

Explanation

For infants between 6 and 18 months, or those who fail Pavlik harness treatment, closed reduction under anesthesia followed by spica casting is the standard next step. An intraoperative arthrogram is typically performed to assess the adequacy of reduction.

Question 309

Topic: Pediatric Hip

A 4-month-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At her 2-week follow-up, the mother notes the child is no longer actively extending her left knee. Which nerve is most likely affected by incorrect harness positioning?

. Sciatic nerve
. Femoral nerve
. Obturator nerve
. Common peroneal nerve
. Tibial nerve

Correct Answer & Explanation

. Femoral nerve

Explanation

Excessive hyperflexion in a Pavlik harness can cause compression of the femoral nerve against the inguinal ligament, leading to transient femoral nerve palsy (loss of active knee extension). Treatment involves altering the harness to reduce flexion.

Question 310

Topic: Pediatric Hip

A 12-year-old obese male presents with acute severe hip pain and inability to bear weight. Radiographs show a severe slipped capital femoral epiphysis (SCFE). Which of the following treatments is associated with the highest risk of iatrogenic avascular necrosis (AVN) of the femoral head?

. In situ pinning with a single cannulated screw
. In situ pinning with two cannulated screws
. Closed reduction with forceful manipulation prior to pinning
. Prophylactic pinning of the contralateral hip
. Open subcapital realignment (modified Dunn procedure) by an experienced surgeon

Correct Answer & Explanation

. Closed reduction with forceful manipulation prior to pinning

Explanation

Forceful closed reduction or overzealous manipulation of an acute or unstable SCFE severely compromises the already tenuous epiphyseal blood supply. This drastically increases the rate of avascular necrosis and is strictly contraindicated.

Question 311

Topic: Pediatric Hip

A 13-year-old obese male presents with a stable slipped capital femoral epiphysis (SCFE) on the left side. Which of the following factors is the strongest predictor for the subsequent development of a contralateral slip?

. High body mass index alone
. Lower modified Oxford bone age score
. High Southwick slip angle on the ipsilateral side
. Symptom duration greater than 3 months
. Failure of Klein's line to intersect the epiphysis

Correct Answer & Explanation

. Lower modified Oxford bone age score

Explanation

A lower modified Oxford bone age score indicates more remaining skeletal growth, which is a strong, validated predictor for a subsequent contralateral slipped capital femoral epiphysis.

Question 312

Topic: Pediatric Hip

A 13-year-old obese male presents with acute on chronic slipped capital femoral epiphysis (SCFE). He undergoes in situ pinning. Which of the following is the most common complication following this procedure for an unstable SCFE?

. Chondrolysis
. Avascular necrosis (AVN)
. Femoral neck fracture
. Deep space infection
. Premature physeal closure

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

Avascular necrosis is the most devastating and relatively common complication following an unstable SCFE, occurring in up to 47% of cases. Chondrolysis is more commonly associated with unrecognized hardware penetration into the joint.

Question 313

Topic: Pediatric Hip

A 4-month-old female with developmental dysplasia of the hip (DDH) has been treated with a Pavlik harness for 4 weeks. Ultrasound demonstrates continued posterior dislocation of the femoral head with no reduction. What is the most appropriate next step in management?

. Continue Pavlik harness for an additional 4 weeks
. Switch to a rigid abduction orthosis (e.g., Ilfeld splint)
. Closed reduction and spica casting under general anesthesia
. Open reduction via an anterior approach
. Observation until 6 months of age followed by pelvic osteotomy

Correct Answer & Explanation

. Closed reduction and spica casting under general anesthesia

Explanation

Failure to achieve reduction in a Pavlik harness within 3 to 4 weeks is an indication to abandon the harness to prevent Pavlik harness disease (posterior acetabular erosion). The standard next step is closed reduction and spica casting under anesthesia.

Question 314

Topic: Pediatric Hip

During an oral examination, you are presented with a 12-year-old obese male complaining of chronic left knee pain. Physical exam reveals obligatory external rotation of the left hip during passive hip flexion. Which of the following radiographic findings is MOST characteristic of this condition?

. Anterior displacement of the femoral epiphysis
. Failure of Klein's line to intersect the lateral epiphysis
. A crescent sign in the superior femoral head
. Widening of the sacroiliac joint
. A fragmented, sclerotic capital femoral epiphysis

Correct Answer & Explanation

. Failure of Klein's line to intersect the lateral epiphysis

Explanation

The clinical presentation is classic for a Slipped Capital Femoral Epiphysis (SCFE). On the AP pelvis radiograph, the Trethowan sign is positive when Klein's line (drawn along the superior femoral neck) fails to intersect the lateral portion of the femoral epiphysis.

Question 315

Topic: Pediatric Hip

An infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the parents report the infant is no longer actively kicking the affected leg. On examination, the hip is held in excessive hyperflexion. Which nerve is most likely compressed?

. Sciatic nerve
. Obturator nerve
. Femoral nerve
. Superior gluteal nerve
. Lateral femoral cutaneous nerve

Correct Answer & Explanation

. Femoral nerve

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness when the hip is placed in excessive hyperflexion. If this occurs, the harness must be removed or adjusted immediately to allow nerve recovery.

Question 316

Topic: Pediatric Hip
You are evaluating a 12-year-old obese boy who presents with inability to bear weight on his right leg after a minor fall. Radiographs reveal a severe, displaced slipped capital femoral epiphysis (SCFE). Which of the following factors represents the greatest risk for the development of avascular necrosis (AVN) in this patient?
. The degree of radiographic slip angle
. The duration of symptoms prior to presentation
. The patient's elevated body mass index (BMI)
. The inability to bear weight (instability) at presentation
. The use of a single cannulated screw for fixation

Correct Answer & Explanation

. The inability to bear weight (instability) at presentation

Explanation

The clinical stability of the slip, defined as the ability to bear weight with or without crutches, is the greatest predictor of AVN. Unstable SCFE has an AVN risk of up to 50%, whereas stable SCFE has a nearly zero risk.

Question 317

Topic: Pediatric Hip

A 6-month-old female with developmental dysplasia of the hip (DDH) has failed 6 weeks of Pavlik harness treatment. Ultrasound confirms persistent dislocation of the left hip. What is the MOST appropriate next step in management?

. Transition to a rigid abduction orthosis (e.g., Ilfeld brace)
. Closed reduction and spica casting under general anesthesia with an arthrogram
. Open reduction via an anterior approach and spica casting
. Varus derotational osteotomy (VDRO) of the proximal femur
. Pemberton pelvic osteotomy

Correct Answer & Explanation

. Closed reduction and spica casting under general anesthesia with an arthrogram

Explanation

When a Pavlik harness fails to achieve reduction in an infant with DDH around 6 months of age, the next standard step is an examination under anesthesia, arthrogram, and attempted closed reduction followed by spica cast application.

Question 318

Topic: Pediatric Hip
A 6-year-old boy presents with a limp and pain in his right hip. On examination, he has limited abduction and internal rotation of the hip. X-rays show flattening and increased density of the right femoral epiphysis. What is the most likely diagnosis?
. Developmental dysplasia of the hip (DDH)
. Slipped capital femoral epiphysis (SCFE)
. Transient synovitis
. Legg-Calvé-Perthes disease (LCPD)
. Septic arthritis of the hip

Correct Answer & Explanation

. Legg-Calvé-Perthes disease (LCPD)

Explanation

The clinical presentation of a 6-year-old boy with a limp, limited abduction and internal rotation, and radiographic findings of flattening and increased density (sclerosis) of the femoral epiphysis are classic for Legg-Calvé-Perthes disease (LCPD). SCFE typically occurs in older, often obese, adolescents. DDH presents earlier in infancy/toddlerhood. Transient synovitis is a self-limiting inflammatory condition without radiographic changes of epiphyseal collapse. Septic arthritis would present with acute, severe pain, fever, and systemic signs of infection, and often rapid joint destruction, not chronic epiphyseal changes.

Question 319

Topic: Pediatric Hip

A 12-year-old girl with a history of chronic renal failure and renal osteodystrophy presents with a unilateral slipped capital femoral epiphysis (SCFE). After successful in situ pinning of the symptomatic hip, what is the most appropriate management for the contralateral asymptomatic hip?

. Clinical observation with close radiographic follow-up
. Prophylactic in situ pinning
. Prophylactic spica cast application
. Valgus intertrochanteric osteotomy
. Trochanteric epiphysiodesis

Correct Answer & Explanation

. Prophylactic in situ pinning

Explanation

Patients with underlying endocrine disorders or renal failure are at a significantly elevated risk for bilateral SCFE. Prophylactic pinning of the contralateral asymptomatic hip is strongly indicated in this population to prevent future displacement.

Question 320

Topic: Pediatric Hip

A 4-month-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the parents report the infant has stopped kicking the affected leg. Physical examination reveals absent active knee extension. Which harness adjustment error most likely caused this complication?

. Excessive hip abduction
. Inadequate hip abduction
. Excessive hip flexion
. Inadequate hip flexion
. Posterior straps applied too loosely

Correct Answer & Explanation

. Excessive hip flexion

Explanation

Excessive hip flexion in a Pavlik harness can lead to compression of the femoral nerve against the inguinal ligament, causing transient femoral nerve palsy. Excessive hip abduction is classically associated with avascular necrosis (AVN) of the femoral head.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page