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Pediatric Hip MCQs

Practice Set 50 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 981

Topic: Pediatric Hip

A 7-year-old boy is diagnosed with Legg-Calve-Perthes disease. Which of the following is considered the most important prognostic factor for long-term hip joint congruency?

. Age at clinical onset
. Body mass index (BMI)
. Gender
. Bilateral versus unilateral involvement
. Presence of a limp at presentation

Correct Answer & Explanation

. Age at clinical onset

Explanation

Age at the onset of Legg-Calve-Perthes disease is the most critical prognostic factor. Children younger than 6 years generally have a favorable outcome due to greater remodeling potential, whereas older children (especially >8 years) have a higher risk of developing a permanently deformed, incongruous femoral head.

Question 982

Topic: Pediatric Hip

A 5-month-old infant with developmental dysplasia of the hip has been treated in a Pavlik harness for 4 weeks. Serial ultrasounds show that the hip remains persistently dislocated and cannot be reduced in the harness. What is the most appropriate next step?

. Continue the Pavlik harness for another 4 weeks
. Discontinue the harness and proceed to closed reduction and spica casting
. Adjust the harness to provide maximum forced abduction
. Switch to a rigid abduction brace and observe
. Perform an immediate open reduction and pelvic osteotomy

Correct Answer & Explanation

. Continue the Pavlik harness for another 4 weeks

Explanation

If a hip remains dislocated after 3 to 4 weeks of Pavlik harness treatment, the harness must be discontinued. Prolonged use of the harness on a dislocated hip causes posterior acetabular wear ('Pavlik harness disease'). The next step is a closed reduction with an arthrogram and spica casting.

Question 983

Topic: Pediatric Hip

A 4-year-old girl presents with an untreated, completely dislocated left hip. Radiographs confirm developmental dysplasia of the hip (DDH) with a false acetabulum and significant superior migration of the femoral head. What is the most appropriate surgical management?

. Closed reduction and spica cast application
. Open reduction alone
. Open reduction with femoral shortening osteotomy and pelvic osteotomy
. Innominate osteotomy alone
. Varus derotational femoral osteotomy alone

Correct Answer & Explanation

. Closed reduction and spica cast application

Explanation

In a 4-year-old with an untreated dislocated hip, open reduction is required. Femoral shortening is necessary to reduce joint reaction forces and minimize the risk of osteonecrosis, while a pelvic osteotomy addresses the secondary acetabular dysplasia.

Question 984

Topic: Pediatric Hip

A 3-month-old female with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a follow-up visit, the mother notes the child is no longer kicking her left leg. Examination reveals absent active knee extension on the left. What is the most appropriate next step in management?

. Increase the tension on the anterior straps
. Increase the tension on the posterior straps
. Discontinue the Pavlik harness
. Perform an emergent closed reduction
. Switch to a rigid hip abduction orthosis

Correct Answer & Explanation

. Increase the tension on the anterior straps

Explanation

The patient has developed a femoral nerve palsy, a known complication of Pavlik harness treatment caused by excessive hip flexion. The appropriate management is immediate discontinuation of the harness to allow for nerve recovery. Once neurologic function returns, alternative treatments such as rigid bracing or closed reduction should be considered.

Question 985

Topic: Pediatric Hip

A 6-week-old female is 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. On examination, there is decreased active knee extension. What is the most appropriate next step in management?

. Continue the harness and reassure the mother
. Adjust the anterior straps to decrease hip flexion
. Adjust the posterior straps to increase hip abduction
. Remove the harness and switch to a rigid abduction orthosis
. Obtain an urgent MRI of the lumbar spine

Correct Answer & Explanation

. Continue the harness and reassure the mother

Explanation

The scenario describes a femoral nerve palsy, a known complication of hyperflexion in a Pavlik harness. The appropriate management is to adjust the anterior straps to decrease hip flexion or temporarily remove the harness until nerve function recovers.

Question 986

Topic: Pediatric Hip

An 18-month-old child presents with untreated developmental dysplasia of the right hip. Closed reduction is attempted but is unsuccessful due to soft tissue interposition. Which of the following structures is most commonly a block to closed reduction in this setting?

. Ligamentum teres
. Gluteus medius muscle
. Ischiofemoral ligament
. Pectineus muscle
. Iliotibial band

Correct Answer & Explanation

. Ligamentum teres

Explanation

Common blocks to closed reduction in DDH include an inverted limbus, hypertrophied ligamentum teres, contracted transverse acetabular ligament, and a constricted iliopsoas tendon.

Question 987

Topic: Pediatric Hip

The "safe zone" of Ramsey in the treatment of DDH with a spica cast is defined as the position between:

. Maximum internal rotation and maximum external rotation
. Maximum hip flexion and minimum hip extension
. The angle of maximal abduction and the angle of redislocation
. Maximum adduction and minimum abduction
. The angle of functional coverage and the angle of subluxation

Correct Answer & Explanation

. Maximum internal rotation and maximum external rotation

Explanation

Ramsey's safe zone for DDH reduction is the arc of abduction between the angle of redislocation (when the hip adducts) and the angle of maximal abduction. Immobilization within this zone minimizes the risk of both redislocation and avascular necrosis.

Question 988

Topic: Pediatric Hip

An 18-month-old girl presents with a painless limp and a positive Trendelenburg sign on the right. Radiographs reveal a dislocated right hip with a false acetabulum and breaking of Shenton's line.

What is the most appropriate definitive management?

. Pavlik harness
. Closed reduction and spica casting
. Open reduction with possible pelvic/femoral osteotomy
. Observation until age 3
. Hip arthroscopy

Correct Answer & Explanation

. Pavlik harness

Explanation

Children over 18 months of age with a dislocated hip typically have significant soft tissue contractures and acetabular dysplasia. Open reduction, often combined with pelvic or femoral osteotomies, is required to achieve and maintain concentric reduction.

Question 989

Topic: Pediatric Hip

Following closed reduction of a dysplastic hip in a 9-month-old, the surgeon applies a spica cast. To minimize the risk of avascular necrosis of the femoral head, the hip should NOT be placed in which of the following positions?

. Flexion of 100 degrees
. Abduction > 60 degrees
. Internal rotation of 10 degrees
. Abduction of 40 degrees
. Flexion of 90 degrees

Correct Answer & Explanation

. Flexion of 100 degrees

Explanation

Excessive abduction (>60 degrees) during spica casting for DDH significantly increases the risk of avascular necrosis. The safe zone of Ramsey limits abduction to avoid compressing the medial circumflex femoral vessels.

Question 990

Topic: Pediatric Hip

A 4-week-old infant is treated with a Pavlik harness for a dislocated left hip. After 3 weeks of strict compliance, ultrasound reveals the hip remains completely dislocated. What is the most appropriate next step in management?

. Continue the harness for an additional 3 weeks
. Discontinue the harness and proceed to closed reduction and spica casting
. Switch to a Denis Browne splint
. Perform an immediate open reduction via a medial approach
. Observe without treatment until 6 months of age

Correct Answer & Explanation

. Continue the harness for an additional 3 weeks

Explanation

Continuing a Pavlik harness beyond 3-4 weeks in a persistently dislocated hip increases the risk of 'Pavlik harness disease' and acetabular posterior lip damage. The most appropriate next step is to transition to a rigid abduction orthosis or proceed with closed reduction and spica casting.

Question 991

Topic: Pediatric Hip

On an anteroposterior pelvis radiograph of a 6-month-old female, the ossific nucleus of the right femoral head is located in the superolateral quadrant formed by Hilgenreiner's and Perkin's lines. What is the diagnosis?

. Normal hip joint development
. Developmental dysplasia of the hip
. Congenital coxa vara
. Slipped capital femoral epiphysis
. Legg-Calvé-Perthes disease

Correct Answer & Explanation

. Normal hip joint development

Explanation

In a normal pediatric pelvis radiograph, the ossific nucleus of the femoral head sits in the inferomedial quadrant. A superolateral position relative to Hilgenreiner's and Perkin's lines is diagnostic of developmental dysplasia of the hip (DDH).

Question 992

Topic: Pediatric Hip

A newborn with arthrogryposis multiplex congenita presents with rigid, bilateral dislocated hips. What is the generally recommended initial management for these hip dislocations?

. Immediate Pavlik harness application
. Serial hip casting starting at birth
. Observation until 6 months of age followed by open reduction
. Immediate open reduction via a medial approach
. Bilateral proximal femoral shortening osteotomies at 3 months

Correct Answer & Explanation

. Immediate Pavlik harness application

Explanation

Teratologic hip dislocations, such as those seen in arthrogryposis, are notoriously rigid. Pavlik harnesses are contraindicated as they frequently fail and can cause iatrogenic fractures or cartilage damage. Observation until roughly 6 months of age followed by single-stage open reduction is standard.

Question 993

Topic: Pediatric Hip

A 4-year-old girl is undergoing surgical treatment for late-presenting developmental dysplasia of the hip. The surgeon plans a redirectional pelvic osteotomy that hinges at the symphysis pubis to provide primarily anterolateral coverage. Which osteotomy is being described?

. Pemberton osteotomy
. Salter innominate osteotomy
. Dega osteotomy
. Chiari osteotomy
. Shelf arthroplasty

Correct Answer & Explanation

. Pemberton osteotomy

Explanation

The Salter innominate osteotomy is a complete, trans-iliac redirectional osteotomy that hinges on the symphysis pubis to provide anterolateral head coverage. The Pemberton and Dega osteotomies are incomplete osteotomies that hinge at the triradiate cartilage.

Question 994

Topic: Pediatric Hip

A 6-week-old female infant, born breech, undergoes a screening ultrasound of the hips. The alpha angle is measured at 48 degrees and the beta angle at 65 degrees. Dynamic stress views show subluxation. What is the most appropriate initial management?

. Reassurance and repeat ultrasound in 6 weeks
. Pavlik harness application
. Rigid hip abduction orthosis
. Closed reduction and spica casting
. Open reduction

Correct Answer & Explanation

. Reassurance and repeat ultrasound in 6 weeks

Explanation

An alpha angle less than 60 degrees at 6 weeks with instability indicates Developmental Dysplasia of the Hip (DDH). A Pavlik harness is the gold standard first-line treatment for reducible DDH in infants under 6 months of age.

Question 995

Topic: Pediatric Hip

A 3-month-old infant is being treated for DDH with a Pavlik harness. During a follow-up visit, you notice the infant lacks active knee extension on the treated side, though the harness is holding the hips in 110 degrees of flexion. What is the most likely cause of this finding?

. Avascular necrosis of the femoral head
. Femoral nerve palsy due to hyperflexion
. Obturator nerve palsy due to hyperabduction
. Inferior dislocation of the hip
. Sciatic nerve compression

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Excessive hip flexion in a Pavlik harness can compress the femoral nerve against the inguinal ligament, leading to a temporary femoral nerve palsy (manifesting as decreased active knee extension). This requires immediate adjustment or temporary removal of the harness.

Question 996

Topic: Pediatric Hip

A 5-month-old infant has been treated in a Pavlik harness for 4 weeks for a completely dislocated right hip. A repeat ultrasound shows the hip remains persistently dislocated. What is the most appropriate next step in management?

. Continue the Pavlik harness for an additional 4 weeks
. Switch to a dynamic abduction orthosis
. Perform a closed reduction and place in a spica cast
. Perform an open reduction and pelvic osteotomy
. Observe and plan for an open reduction at 12 months of age

Correct Answer & Explanation

. Continue the Pavlik harness for an additional 4 weeks

Explanation

Failure to achieve reduction in a Pavlik harness after 3 to 4 weeks is an indication to abandon the harness to prevent 'Pavlik harness disease' (posterior acetabular wear). The next step is a closed reduction under anesthesia, typically with an arthrogram, followed by spica casting.

Question 997

Topic: Pediatric Hip

A 6-week-old female infant presents with a positive Ortolani sign on the left hip. Ultrasound shows an alpha angle of 45 degrees. What is the most appropriate next step in management?

. Reassurance and follow-up in 4 weeks
. Pavlik harness application
. Rigid abduction orthosis
. Closed reduction and spica casting
. Open reduction

Correct Answer & Explanation

. Reassurance and follow-up in 4 weeks

Explanation

The patient presents with clinical DDH and an abnormal ultrasound alpha angle (normal is >60 degrees). The Pavlik harness is the gold standard for reducible hip dysplasia in infants under 6 months of age.

Question 998

Topic: Pediatric Hip

A 4-month-old girl with left developmental dysplasia of the hip has been treated in a Pavlik harness for 4 weeks. Repeat ultrasound shows failure of reduction with the femoral head remaining chronically dislocated. What is the most appropriate next step in management?

. Continue Pavlik harness for 4 more weeks
. Discontinue Pavlik harness and proceed with closed reduction and spica casting
. Increase Pavlik harness flexion to 120 degrees
. Perform immediate open reduction and varus derotational osteotomy
. Observe and re-evaluate at 1 year of age

Correct Answer & Explanation

. Continue Pavlik harness for 4 more weeks

Explanation

If a dislocated hip is not reduced after 3 to 4 weeks of Pavlik harness use, it should be discontinued to prevent "Pavlik disease" (excoriation of the posterior acetabulum). The next appropriate step is transition to a rigid orthosis or closed reduction and spica casting.

Question 999

Topic: Pediatric Hip

A 38-year-old female presents with persistent groin pain exacerbated by hip flexion. Radiographs demonstrate a crossover sign on the AP pelvis view. This radiographic finding is most strongly associated with which of the following pathologies?

. Cam-type femoroacetabular impingement
. Developmental dysplasia of the hip
. Pincer-type femoroacetabular impingement secondary to acetabular retroversion
. Slipped capital femoral epiphysis
. Legg-Calve-Perthes disease

Correct Answer & Explanation

. Cam-type femoroacetabular impingement

Explanation

The crossover sign on an AP pelvis radiograph indicates cranial retroversion of the acetabulum, where the anterior wall crosses over the posterior wall. This is a classic hallmark of pincer-type femoroacetabular impingement (FAI).

Question 1000

Topic: Pediatric Hip

A 28-year-old male presents with groin pain and decreased internal rotation of the hip. He has a history of a slipped capital femoral epiphysis (SCFE) treated with in situ pinning during adolescence. This patient is at highest risk for developing which of the following conditions?

. Cam-type femoroacetabular impingement
. Pincer-type femoroacetabular impingement
. Coxa valga
. Ischiofemoral impingement
. Greater trochanteric pain syndrome

Correct Answer & Explanation

. Cam-type femoroacetabular impingement

Explanation

In situ pinning of a SCFE often leaves a residual prominent anterior head-neck junction. This decreased offset frequently leads to Cam-type femoroacetabular impingement in early adulthood.

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