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Pediatric Hip MCQs

Practice Set 62 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 1221

Topic: Pediatric Hip
Figure 10 shows the AP pelvis radiograph of an 8-year-old boy with a persistent limp. He is diagnosed with Legg-Calvé-Perthes disease. Which of the following factors represents the most significant prognostic indicator for long-term hip outcome in this patient?
. Gender of the patient
. Age at the onset of disease
. Presence of a positive Trendelenburg sign
. Body mass index
. Duration of conservative treatment prior to diagnosis

Correct Answer & Explanation

. Age at the onset of disease

Explanation

Age at the onset of Legg-Calvé-Perthes disease is the most critical clinical prognostic factor. Patients who develop the disease after age 8 have a significantly worse prognosis due to having less remaining growth for femoral head remodeling.

Question 1222

Topic: Pediatric Hip

An 18-month-old girl who recently started walking presents with a painless limp and a positive Galeazzi sign on the left. Radiographs confirm a completely dislocated left hip with a dysplastic acetabulum. What is the most appropriate management?

. Application of a Pavlik harness
. Closed reduction and spica casting
. Open reduction with possible pelvic and/or femoral osteotomy
. Observation and physical therapy
. Varus derotational osteotomy alone without opening the joint

Correct Answer & Explanation

. Open reduction with possible pelvic and/or femoral osteotomy

Explanation

In a child over 18 months of age with developmental dysplasia of the hip, conservative treatments and isolated closed reductions have high failure rates. Open reduction, often combined with a pelvic or femoral osteotomy to correct the dysplasia, is the standard of care.

Question 1223

Topic: Pediatric Hip

A 3-month-old girl with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During her first follow-up visit, the parents report that she has stopped kicking her left leg. On physical examination, the infant exhibits a lack of active knee extension on the left side, but withdrawal to pain is intact. What is the most appropriate next step in management?

. Adjust the anterior straps to increase hip flexion
. Remove the harness and admit for closed reduction and spica casting
. Decrease hip flexion by adjusting the anterior straps or temporarily discontinue the harness
. Switch to a rigid abduction orthosis (e.g., Ilfeld splint)
. Obtain an urgent ultrasound to evaluate for deep vein thrombosis

Correct Answer & Explanation

. Decrease hip flexion by adjusting the anterior straps or temporarily discontinue the harness

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment and is caused by hyperflexion of the hip. Management requires immediate reduction of hip flexion by adjusting the anterior straps or temporarily discontinuing the harness until active quadriceps function returns.

Question 1224

Topic: Pediatric Hip

A 13-year-old girl with a history of a slipped capital femoral epiphysis (SCFE) treated with in-situ pinning 6 months ago presents with worsening hip stiffness and pain. Physical examination reveals a significant global loss of hip motion. Radiographs are shown in Figure 10.

Assuming the radiograph demonstrates diffuse joint space narrowing without focal collapse of the femoral head, what is the most likely iatrogenic cause of this patient's current condition?

. Aggressive physical therapy initiated immediately postoperatively
. Unrecognized hardware penetration into the joint
. Failure to perform a capsulotomy during the index procedure
. Use of a fully threaded screw instead of a partially threaded screw
. Placement of the screw in the anterior half of the femoral head

Correct Answer & Explanation

. Unrecognized hardware penetration into the joint

Explanation

Global loss of motion and diffuse joint space narrowing after SCFE fixation is the hallmark of chondrolysis. The most common iatrogenic cause of chondrolysis in this setting is unrecognized pin or screw penetration into the hip joint, necessitating prompt hardware removal.

Question 1225

Topic: Pediatric Hip

A 12-year-old obese boy presents with sudden severe left groin pain and inability to bear weight after a minor fall. Radiographs show a severe left slipped capital femoral epiphysis. He is treated with urgent open reduction and internal fixation via a surgical hip dislocation approach to decompress the intracapsular hematoma. Which of the following is the most likely complication of this injury?

. Chondrolysis
. Osteonecrosis
. Premature osteoarthritis
. Femoral neck fracture
. Deep space infection

Correct Answer & Explanation

. Osteonecrosis

Explanation

Unstable SCFE (inability to bear weight) has a much higher rate of osteonecrosis compared to stable SCFE. Urgent decompression and anatomic reduction may help minimize this risk, but AVN remains the most devastating complication.

Question 1226

Topic: Pediatric Hip

A 6-week-old female infant is treated with a Pavlik harness for a dislocated left hip (Graf Type IV). After 3 weeks of strict harness wear, ultrasound shows the hip remains persistently dislocated. What is the most appropriate next step in management?

. Continue harness for another 3 weeks
. Abandon harness and proceed to closed reduction and spica casting
. Transition to an abduction orthosis and re-evaluate in 4 weeks
. Immediate open reduction and pelvic osteotomy
. Modify the Pavlik harness to increase flexion to 120 degrees

Correct Answer & Explanation

. Abandon harness and proceed to closed reduction and spica casting

Explanation

Continued use of a Pavlik harness for a persistently dislocated hip beyond 3 to 4 weeks risks posterior acetabular wear (Pavlik harness disease). The next step is abandonment of the harness and progression to closed reduction and spica casting.

Question 1227

Topic: Pediatric Hip

A 13-year-old obese boy presents with 2 weeks of worsening left hip pain and an inability to bear weight. Radiographs reveal a severe slipped capital femoral epiphysis (SCFE). He cannot ambulate even with crutches. Which of the following management strategies carries the highest risk of avascular necrosis (AVN) in this patient?

. In situ pinning with a single cannulated screw
. Modified Dunn procedure
. Forceful closed reduction followed by pinning
. Capsulotomy and pinning
. Imhauser osteotomy

Correct Answer & Explanation

. Forceful closed reduction followed by pinning

Explanation

Forceful closed reduction of an unstable SCFE significantly increases the risk of AVN. It disrupts the vulnerable, stretched retinacular vessels supplying the femoral head.

Question 1228

Topic: Pediatric Hip

An 8-week-old female infant is being treated with a Pavlik harness for developmental dysplasia of the left hip. At her 2-week follow-up, the mother reports the infant is no longer kicking her left leg. On examination, the knee lacks active extension, but ankle and toe movements are normal. What is the most likely cause of this complication?

. Hyperabduction of the hip causing avascular necrosis
. Hyperflexion of the hip causing femoral nerve palsy
. Sciatic nerve compression from the posterior strap
. Iliopsoas contracture
. Slipped capital femoral epiphysis

Correct Answer & Explanation

. Hyperflexion of the hip causing femoral nerve palsy

Explanation

Femoral nerve palsy in a Pavlik harness is typically caused by excessive hip flexion pressing the nerve against the pelvis. The treatment is temporary adjustment or removal of the harness, and the palsy usually resolves spontaneously.

Question 1229

Topic: Pediatric Hip

A 13-year-old obese boy presents with acute on chronic left groin pain and an inability to bear weight. Radiographs confirm a severe, unstable slipped capital femoral epiphysis (SCFE). Which of the following complications is most significantly increased in this patient compared to a stable SCFE?

. Chondrolysis
. Avascular necrosis
. Femoroacetabular impingement
. Slipped capital femoral epiphysis of the contralateral hip
. Premature physeal closure

Correct Answer & Explanation

. Avascular necrosis

Explanation

Unstable SCFE (defined by the inability to bear weight) carries a much higher risk of avascular necrosis (up to 50%) compared to stable SCFE. Urgent decompression and fixation can help mitigate this risk.

Question 1230

Topic: Pediatric Hip

A 2-month-old girl is being treated for developmental dysplasia of the hip with a Pavlik harness. At her 2-week follow-up, she exhibits decreased active knee extension on the right side. The harness is noted to be holding the hips in 120 degrees of flexion. What is the most appropriate next step in management?

. Adjust the anterior straps to decrease hip flexion
. Adjust the posterior straps to increase hip abduction
. Immediate surgical release of the iliopsoas
. Switch to a rigid hip spica cast
. Obtain an urgent MRI of the lumbar spine

Correct Answer & Explanation

. Adjust the anterior straps to decrease hip flexion

Explanation

The infant has developed a femoral nerve palsy secondary to excessive hyperflexion in the Pavlik harness. The anterior straps should be loosened immediately to reduce hip flexion, which usually allows for full resolution.

Question 1231

Topic: Pediatric Hip
A 6-year-old boy is diagnosed with Legg-Calvé-Perthes disease. During the fragmentation stage, his anteroposterior radiograph demonstrates that the lateral aspect of the capital femoral epiphysis has maintained 40% of its original height. According to the Herring lateral pillar classification, what is his grade?
. Group A
. Group B
. Group B/C
. Group C
. Group D

Correct Answer & Explanation

. Group C

Explanation

In the Herring lateral pillar classification, Group C is defined by the lateral pillar maintaining less than 50% of its original height. Group B maintains >50%, and Group A has no lateral pillar involvement.

Question 1232

Topic: Pediatric Hip

A 14-year-old boy with a BMI of 38 presents with left hip pain and an antalgic gait for 6 weeks. Radiographs show a mild slipped capital femoral epiphysis. He undergoes uncomplicated in situ pinning. Three years later, he presents with groin pain exacerbated by hip flexion and internal rotation. What is the most likely cause of his current symptoms?

. Avascular necrosis of the femoral head
. Chondrolysis
. Femoroacetabular impingement
. Hardware failure
. Unrecognized contralateral slipped capital femoral epiphysis

Correct Answer & Explanation

. Femoroacetabular impingement

Explanation

Following in situ pinning of SCFE, the residual anterior metaphyseal prominence can lead to cam-type femoroacetabular impingement (FAI). This typically presents as groin pain with flexion and internal rotation due to abutment against the anterior acetabular rim.

Question 1233

Topic: Pediatric Hip

A 6-month-old girl with developmental dysplasia of the hip is taken to the operating room for a closed reduction and spica casting. An intraoperative arthrogram demonstrates a medial dye pool of 7 mm. What is the most appropriate next step in management?

. Accept the reduction and apply a spica cast in the "human position"
. Apply a spica cast with the hip in 120 degrees of flexion to tighten the capsule
. Perform an adductor tenotomy and repeat the arthrogram
. Perform an open reduction of the hip
. Transition to a rigid abduction orthosis

Correct Answer & Explanation

. Perform an open reduction of the hip

Explanation

A medial dye pool greater than 5 mm on an arthrogram indicates an interposed soft tissue structure preventing a concentric reduction. Open reduction is indicated to clear obstructions such as an inverted limbus, pulvinar, or transverse acetabular ligament.

Question 1234

Topic: Pediatric Hip
A 9-year-old boy presents with a 4-month history of right hip pain and a painless limp. Radiographs reveal fragmentation of the right capital femoral epiphysis. The lateral pillar maintains 40% of its normal height. According to the Herring classification, what is the most appropriate treatment?
. Observation and activity restriction
. Petrie cast application
. Proximal femoral varus derotational osteotomy
. Shelf acetabuloplasty
. Hip arthrodesis

Correct Answer & Explanation

. Proximal femoral varus derotational osteotomy

Explanation

This patient has Herring Group C (less than 50% lateral pillar height) Legg-Calvé-Perthes disease. In children older than 8 years of age with Group B or B/C borderline disease, surgical containment via proximal femoral osteotomy has been shown to yield better outcomes than nonoperative management.

Question 1235

Topic: Pediatric Hip

A 6-week-old female infant is undergoing treatment for developmental dysplasia of the left hip with a Pavlik harness. After 4 weeks of strict full-time harness wear, a follow-up ultrasound reveals that the left hip remains completely dislocated. What is the most appropriate next step?

. Continue the Pavlik harness for an additional 4 weeks
. Add an abduction wedge to the Pavlik harness
. Discontinue the harness and proceed to closed reduction and spica casting
. Discontinue the harness and observe until the child is 6 months old
. Perform an immediate open reduction

Correct Answer & Explanation

. Add an abduction wedge to the Pavlik harness

Explanation

Continued use of a Pavlik harness in a persistently dislocated hip beyond 3 to 4 weeks significantly increases the risk of "Pavlik harness disease," which involves damage to the posterior acetabular wall. The harness should be discontinued, and the patient transitioned to a rigid orthosis or closed reduction.

Question 1236

Topic: Pediatric Hip

A 13-year-old obese boy presents with 3 weeks of vague groin pain and a limp. Radiographs confirm a stable slipped capital femoral epiphysis (SCFE). He undergoes in situ percutaneous pinning with a single screw. Which of the following screw positions carries the highest risk of accelerating chondrolysis?

. Anterosuperior to the center of the epiphysis
. Center-center in the epiphysis
. Posteroinferior to the center of the epiphysis
. Anteroinferior to the center of the epiphysis
. Directly through the anterior femoral neck cortex

Correct Answer & Explanation

. Posteroinferior to the center of the epiphysis

Explanation

Screws placed in the anterosuperior quadrant of the femoral head frequently have unrecognized joint penetration, which is the leading cause of chondrolysis in SCFE pinning. The ideal position is center-center or slightly posteroinferior.

Question 1237

Topic: Pediatric Hip

A 6-week-old female infant is diagnosed with a dislocated but reducible left hip. She is placed in a Pavlik harness. After 3 weeks of compliant harness wear, ultrasound demonstrates the left hip remains dislocated. What is the most appropriate next step in management?

. Continue the Pavlik harness for an additional 3 weeks
. Transition to a rigid abduction orthosis
. Perform closed reduction and spica casting
. Perform open reduction and spica casting
. Wait until 6 months of age for closed reduction

Correct Answer & Explanation

. Transition to a rigid abduction orthosis

Explanation

Failure to reduce a dislocated hip after 3 to 4 weeks of Pavlik harness treatment requires discontinuation of the harness to prevent Pavlik harness disease. The next standard non-operative step is a rigid abduction orthosis, such as an Ilfeld or Rhino brace.

Question 1238

Topic: Pediatric Hip

A 4-week-old female with a history of breech presentation is diagnosed with developmental dysplasia of the hip (DDH). Ultrasound shows an alpha angle of 45 degrees, a beta angle of 75 degrees, and 40% femoral head coverage. Treatment with a Pavlik harness is initiated. What is the most common iatrogenic nerve complication associated with this treatment?

. Femoral nerve palsy
. Sciatic nerve palsy
. Obturator nerve palsy
. Superior gluteal nerve palsy
. Tibial nerve palsy

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

The most common nerve complication of a Pavlik harness is femoral nerve palsy, typically caused by excessive hyperflexion of the hips. It usually resolves completely after temporarily removing or adjusting the harness.

Question 1239

Topic: Pediatric Hip

A 13-year-old obese boy presents with 2 days of severe right hip pain after a minor fall and is completely unable to bear weight. Radiographs show a posterior and inferior slip of the proximal femoral epiphysis. What is the most appropriate management for this acute, unstable slipped capital femoral epiphysis (SCFE)?

. Immediate forceful closed reduction and spica casting
. Urgent gentle closed reduction and multiple screw fixation
. Urgent in situ single screw fixation
. Delayed in situ single screw fixation after 1 week of traction
. Subtrochanteric derotational osteotomy

Correct Answer & Explanation

. Urgent in situ single screw fixation

Explanation

Unstable SCFE requires urgent in situ fixation, typically with a single screw, to decompress the joint capsule and stabilize the slip. Forceful closed reduction is contraindicated as it significantly increases the risk of avascular necrosis.

Question 1240

Topic: Pediatric Hip

A 7-year-old boy presents with a painless limp. Radiographs demonstrate fragmentation of the capital femoral epiphysis consistent with Legg-Calve-Perthes disease. According to the Herring lateral pillar classification, a hip that maintains 60% of its lateral pillar height is classified into which group, and what is the generally expected outcome?

. Group A - excellent outcome regardless of age
. Group B - good outcome if the patient is under 8 years old
. Group B - poor outcome regardless of age
. Group C - good outcome if the patient is over 8 years old
. Group C - poor outcome regardless of age

Correct Answer & Explanation

. Group B - good outcome if the patient is under 8 years old

Explanation

Group B involves maintenance of >50% lateral pillar height. Patients under 8 years of age at the onset of Group B LCPD generally have good outcomes with containment treatment, whereas older children may have less favorable results.

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