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Pediatric Hip MCQs

Practice Set 54 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 1061

Topic: Pediatric Hip

A 3-month-old infant with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a follow-up visit, the parents report that the infant is not moving the right leg as much as the left. On physical examination, the right knee is held in extension, and the patellar reflex is absent on the right side. What is the most likely cause of this clinical finding?

. Femoral nerve palsy due to hyperflexion
. Obturator nerve palsy due to excessive abduction
. Sciatic nerve palsy due to hyperflexion
. Osteonecrosis of the femoral head
. Transient synovitis of the hip

Correct Answer & Explanation

. Femoral nerve palsy due to hyperflexion

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by excessive flexion of the hip which compresses the femoral nerve against the inguinal ligament. Clinical signs include an inability to actively extend the knee and an absent patellar reflex. The treatment is adjusting the harness to decrease the amount of flexion or temporarily removing it until nerve function recovers.

Question 1062

Topic: Pediatric Hip

A 12-year-old boy presents with right hip pain and an antalgic gait. He is diagnosed with a severe right slipped capital femoral epiphysis (SCFE). His weight is greater than the 95th percentile for his age. You plan to perform in situ pinning of the right hip. Which of the following is considered the strongest indication for prophylactic pinning of the contralateral asymptomatic hip?

. Male gender
. Age greater than 14 years
. Presence of an endocrine disorder (e.g., hypothyroidism)
. Severe slip angle on the affected side
. Presentation during the summer months

Correct Answer & Explanation

. Presence of an endocrine disorder (e.g., hypothyroidism)

Explanation

Prophylactic pinning of the contralateral hip is heavily debated, but universally accepted indications include the presence of an underlying endocrine disorder (e.g., hypothyroidism, renal osteodystrophy, panhypopituitarism) or a history of radiation therapy, as these patients have an exceptionally high risk of developing a contralateral slip. Other factors that lower the threshold for prophylactic pinning include an inability to reliably follow up, open triradiate cartilage, and young chronological age at presentation.

Question 1063

Topic: Pediatric Hip

A 12-year-old boy who is at the 99th percentile for BMI presents with right thigh pain and an antalgic gait. Radiographs confirm a mild right slipped capital femoral epiphysis (SCFE). Which of the following is the most reliable radiographic predictor that this patient will subsequently develop a contralateral SCFE?

. Initial slip angle greater than 30 degrees
. Presence of a closed triradiate cartilage
. Open triradiate cartilage (modified Oxford bone age score less than 16)
. High alpha angle on the asymptomatic side
. Klein's line intersecting less than 20% of the epiphysis on the right

Correct Answer & Explanation

. Open triradiate cartilage (modified Oxford bone age score less than 16)

Explanation

The most significant predictor of a future contralateral SCFE is skeletal immaturity at the time of the initial presentation. An open triradiate cartilage, which corresponds to a modified Oxford bone age score of less than 16, indicates substantial remaining growth and a high risk of developing a contralateral slip. Therefore, prophylactic in situ pinning of the contralateral hip is strongly considered in these patients. Slip severity and BMI are factors, but the status of the triradiate cartilage is the most specific predictor of a subsequent contralateral slip.

Question 1064

Topic: Pediatric Hip
A 9-year-old boy presents with an 8-month history of a painless limp. Radiographs reveal fragmentation of the left femoral head. According to the Herring lateral pillar classification, the hip is categorized as Type B. Range of motion is well preserved. Based on current evidence, which of the following treatments provides the best long-term radiographic outcome for this patient?
. Strict bed rest and continuous skin traction
. Use of an A-frame abduction orthosis
. Surgical containment (e.g., proximal femoral varus osteotomy)
. Observation and activity modification
. Core decompression of the femoral head

Correct Answer & Explanation

. Surgical containment (e.g., proximal femoral varus osteotomy)

Explanation

The Herring lateral pillar classification and the patient's age at onset dictate treatment in Legg-Calvé-Perthes disease. Multiple multicenter studies have demonstrated that children who are 8 years or older at the onset of symptoms and have a Lateral Pillar Type B or B/C border hip achieve significantly better radiographic and clinical outcomes with surgical containment (such as a proximal femoral osteotomy or pelvic osteotomy) compared to nonoperative management. Those under 8 years generally do well without surgery for Type B, and Type C does poorly regardless of treatment.

Question 1065

Topic: Pediatric Hip

A 24-month-old girl presents with a waddling gait. An anteroposterior radiograph of the pelvis demonstrates a completely dislocated left hip. The acetabular index on the left is 42 degrees, compared to 20 degrees on the right. She has not had any prior treatment. What is the most appropriate management strategy?

. Application of a Pavlik harness
. Closed reduction and spica casting
. Open reduction with spica casting alone
. Open reduction, femoral shortening osteotomy, and pelvic osteotomy
. Wait until skeletal maturity for a periacetabular osteotomy

Correct Answer & Explanation

. Open reduction, femoral shortening osteotomy, and pelvic osteotomy

Explanation

In a child of this age (24 months) presenting late with Developmental Dysplasia of the Hip (DDH), closed reduction has an unacceptably high rate of failure and avascular necrosis. The standard of care requires open reduction to clear intra-articular obstacles. Because of the significant secondary acetabular dysplasia (acetabular index >40 degrees), a pelvic osteotomy (e.g., Salter or Pemberton) is necessary. Furthermore, due to severe soft tissue contractures that occur in late presentations, a femoral shortening osteotomy is indicated to relieve joint pressure during reduction, drastically decreasing the risk of avascular necrosis.

Question 1066

Topic: Pediatric Hip

A 13-year-old obese male presents with a 1-day history of extreme left groin pain following a minor fall. He is completely unable to bear weight on the left leg, even with the assistance of crutches. Radiographs reveal a severe left slipped capital femoral epiphysis (SCFE). He is scheduled for urgent surgical stabilization. Which of the following surgical steps is associated with the highest increased risk of postoperative avascular necrosis (AVN) in this patient?

. Performing an anterior capsulotomy prior to pinning
. Forceful or repeated closed reduction maneuvers prior to fixation
. Inadvertent penetration of the joint space with a guidewire during drilling
. Using two screws instead of a single screw for fixation
. Performing the procedure via a percutaneous approach

Correct Answer & Explanation

. Forceful or repeated closed reduction maneuvers prior to fixation

Explanation

This patient has an unstable SCFE, defined clinically by the inability to bear weight even with assistive devices. Unstable SCFE has a significantly high baseline risk for avascular necrosis (up to 47%). Performing forceful or repeated closed reduction maneuvers drastically increases this risk by further disrupting the already tenuous retinacular blood supply to the epiphysis. Current recommendations advise against forceful reduction; incidental repositioning may occur by simply placing the patient on the fracture table. A capsulotomy (option 0) is actually advocated by many surgeons to decrease intracapsular pressure and potentially reduce AVN risk.

Question 1067

Topic: Pediatric Hip

A 6-week-old female infant is diagnosed with a completely dislocated but reducible left hip (Developmental Dysplasia of the Hip). She is placed in a Pavlik harness. At the 3-week follow-up ultrasound, the left hip remains dislocated within the harness. What is the next best step in management?

. Continue the Pavlik harness for an additional 3 weeks
. Perform a closed reduction and spica casting under general anesthesia
. Perform an open reduction and capsulorrhaphy
. Transition the patient to a rigid abduction orthosis (e.g., Ilfeld or Rhino Cruiser)
. Perform a femoral shortening osteotomy

Correct Answer & Explanation

. Transition the patient to a rigid abduction orthosis (e.g., Ilfeld or Rhino Cruiser)

Explanation

If a Pavlik harness fails to reduce a dislocated hip within 3-4 weeks, continuing its use is contraindicated due to the risk of 'Pavlik harness disease' (damage to the posterior acetabular wall) and avascular necrosis. The generally accepted next step is a trial of a rigid abduction orthosis. If the rigid orthosis also fails, the next step would be closed reduction and spica casting under anesthesia, potentially with an arthrogram.

Question 1068

Topic: Pediatric Hip

A 12-year-old obese boy presents with left groin and knee pain for 2 months. Radiographs confirm a mild, stable slipped capital femoral epiphysis (SCFE) on the left. In which of the following scenarios is prophylactic percutaneous pinning of the contralateral (asymptomatic) right hip most strongly indicated?

. Patient age greater than 14 years
. The slip on the left side is classified as 'unstable'
. Presence of an underlying endocrine disorder
. Patient BMI > 95th percentile
. Male gender

Correct Answer & Explanation

. Presence of an underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip is strongly considered in patients at a high risk of developing bilateral SCFE. Classic indications for prophylactic pinning include underlying endocrine disorders (such as hypothyroidism, renal osteodystrophy, or panhypopituitarism), a history of previous radiation therapy, and a young age at presentation (typically < 10 years for boys, < 11 years for girls) with widely open triradiate cartilage.

Question 1069

Topic: Pediatric Hip
A 7-year-old boy presents with a painless limp of 3 months' duration. Radiographs show sclerosis, fragmentation, and lateral displacement of the right capital femoral epiphysis, consistent with Legg-Calvé-Perthes disease. Which of the following radiographic findings represents one of Catterall's 'head-at-risk' signs, indicating a poorer prognosis?
. Medial subluxation of the femoral head
. Narrowing of the teardrop distance
. Anterior physeal closure
. Increased height of the lateral pillar
. Calcification lateral to the epiphysis

Correct Answer & Explanation

. Calcification lateral to the epiphysis

Explanation

Catterall's 'head-at-risk' signs for Legg-Calvé-Perthes disease identify patients with a poorer prognosis and a higher likelihood of significant femoral head deformity. These signs include: calcification lateral to the epiphysis, Gage sign (a V-shaped radiolucency in the lateral portion of the epiphysis/metaphysis), lateral subluxation of the femoral head, horizontal orientation of the growth plate, and metaphyseal cysts.

Question 1070

Topic: Pediatric Hip

A 12-year-old boy with a BMI in the 99th percentile undergoes in situ pinning of a severe left slipped capital femoral epiphysis (SCFE). Which of the following factors most strongly indicates the need for prophylactic pinning of the contralateral, asymptomatic right hip?

. Age 12 years at presentation
. Severe slip angle on the index side
. Presence of an underlying endocrine disorder (e.g., hypothyroidism)
. Male gender and elevated BMI
. Family history of SCFE

Correct Answer & Explanation

. Presence of an underlying endocrine disorder (e.g., hypothyroidism)

Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial for idiopathic cases but is universally recommended for patients with an underlying endocrinopathy (such as hypothyroidism, renal osteodystrophy, or growth hormone deficiency) due to the exceedingly high risk of bilateral involvement. Age <10 years or the inability to follow up reliably are also relative indications, whereas severity of the primary slip and BMI are not independent absolute indications.

Question 1071

Topic: Pediatric Hip
An 8-year-old boy presents with a limp and right hip pain for 3 months. Radiographs reveal fragmentation of the right capital femoral epiphysis consistent with Legg-Calvé-Perthes disease. The lateral pillar height is evaluated and found to be 40% of the normal contralateral side. Based on the Herring Lateral Pillar Classification, what is the prognosis and recommended treatment?
. Group A; symptomatic treatment and observation as outcomes are universally excellent
. Group B; symptomatic treatment and observation as surgery offers no benefit
. Group B; proximal femoral or pelvic osteotomy to improve outcomes
. Group C; proximal femoral or pelvic osteotomy has not been shown to significantly alter the final radiographic outcome
. Group C; immediate total hip arthroplasty due to inevitable joint destruction

Correct Answer & Explanation

. Group C; proximal femoral or pelvic osteotomy has not been shown to significantly alter the final radiographic outcome

Explanation

According to the Herring Lateral Pillar Classification, a lateral pillar height <50% places the hip in Group C. The prospective multicenter study by Herring et al. demonstrated that for Group C hips, surgical containment (osteotomy) does not significantly improve the final Stulberg radiographic outcome compared to non-operative treatment, as these hips tend to have poor results regardless of intervention. In contrast, children >8 years old with Group B or B/C border hips benefit significantly from surgical containment.

Question 1072

Topic: Pediatric Hip

A 12-year-old boy with a body mass index (BMI) in the 99th percentile undergoes uneventful in situ single-screw fixation for a stable right slipped capital femoral epiphysis (SCFE). The parents inquire about the necessity of prophylactic fixation for the asymptomatic left hip. Which of the following patient factors most strongly supports proceeding with prophylactic pinning of the contralateral hip?

. Chronological age of 12 years
. Open triradiate cartilage
. A measured slip angle of 40 degrees on the right
. Male sex
. The chronicity of the right-sided slip symptoms prior to presentation

Correct Answer & Explanation

. Open triradiate cartilage

Explanation

The decision to perform prophylactic pinning of the contralateral hip in SCFE is based on the risk of a subsequent slip. An open triradiate cartilage (or a modified Oxford bone age score of 16 or lower) is one of the strongest radiographic predictors for a future contralateral slip. Other significant risk factors include endocrine disorders (e.g., hypothyroidism), renal osteodystrophy, history of radiation therapy, and younger age (typically boys < 10-12 years or girls < 10 years). While obesity is a risk factor for SCFE generally, the biologic immaturity indicated by an open triradiate cartilage is a more specific and potent indicator for prophylactic fixation.

Question 1073

Topic: Pediatric Hip

An infant is undergoing treatment with a Pavlik harness for developmental dysplasia of the hip (DDH). During a routine follow-up evaluation, the parents report that the child has stopped kicking the affected leg. On physical examination, the affected knee is held in extension and there is an absence of active quadriceps contraction. This specific complication is most directly caused by which of the following positioning errors within the harness?

. Excessive abduction of the hip
. Inadequate abduction of the hip
. Excessive flexion of the hip
. Inadequate flexion of the hip
. Excessive internal rotation of the hip

Correct Answer & Explanation

. Inadequate flexion of the hip

Explanation

Femoral nerve palsy is a well-documented complication of Pavlik harness treatment for DDH, typically presenting as an inability to actively extend the knee or a decrease in spontaneous kicking on the affected side. It is caused by hyperflexion of the hips, which compresses the femoral nerve against the inguinal ligament. Management involves adjusting the anterior straps to decrease hip flexion, which almost universally results in spontaneous resolution of the nerve palsy within a few days to weeks. Conversely, excessive abduction in the harness increases the risk of avascular necrosis (AVN) of the femoral head.

Question 1074

Topic: Pediatric Hip
An 8.5-year-old boy presents with a 4-month history of a painless limp. Radiographs demonstrate Legg-Calvé-Perthes disease in the fragmentation stage. Analysis of the anteroposterior pelvis radiograph shows that the lateral pillar of the affected capital femoral epiphysis maintains 60% of its normal height. Based on the Herring lateral pillar classification and prospective multicenter data, which of the following statements most accurately reflects the current consensus on his management and prognosis?
. Nonoperative management with bracing provides superior outcomes compared to surgery due to his advanced age.
. Surgical containment yields significantly better radiographic outcomes compared to nonoperative treatment.
. Surgical containment is contraindicated due to the severity of lateral pillar collapse.
. He is classified as Lateral Pillar Group C, and outcomes are uniformly excellent without intervention.
. He is classified as Lateral Pillar Group A, and should be treated with immediate prophylactic pinning.

Correct Answer & Explanation

. Surgical containment yields significantly better radiographic outcomes compared to nonoperative treatment.

Explanation

According to the Herring lateral pillar classification for Legg-Calvé-Perthes disease, a femoral head that maintains >50% of its lateral pillar height is classified as Group B. The prospective multicenter study by Herring et al. demonstrated that for children older than 8 years of age at the time of disease onset with Group B or Group B/C border involvement, surgical containment (e.g., femoral varus osteotomy or pelvic osteotomy) results in significantly better long-term radiographic outcomes (measured by the Stulberg classification) compared to nonoperative management. Patients under age 8 with Group B generally have favorable outcomes regardless of treatment, whereas Group C patients over age 8 often have poor outcomes despite surgical intervention.

Question 1075

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 parents report the infant is no longer kicking her right leg. Examination reveals decreased active knee extension on the right, but normal sensation. What is the most appropriate next step in management?

. Proceed to closed reduction and spica casting
. Remove the harness temporarily and observe
. Adjust the posterior straps to increase hip abduction
. Adjust the anterior straps to increase hip flexion
. Obtain an urgent MRI of the lumbar spine

Correct Answer & Explanation

. Remove the harness temporarily and observe

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically resulting from hyperflexion of the hip due to overly tight anterior straps. The harness should be temporarily removed or adjusted; the palsy almost always resolves spontaneously.

Question 1076

Topic: Pediatric Hip

A 13-year-old obese boy presents with acute-on-chronic hip pain and an inability to bear weight. Radiographs confirm a Slipped Capital Femoral Epiphysis (SCFE). He undergoes urgent in situ percutaneous pinning. Which of the following complications is most highly associated with this specific preoperative presentation?

. Chondrolysis
. Avascular necrosis (AVN) of the femoral head
. Femoral nerve palsy
. Slipped capital femoral epiphysis of the contralateral hip
. Hardware failure

Correct Answer & Explanation

. Avascular necrosis (AVN) of the femoral head

Explanation

The inability to bear weight defines an unstable SCFE, which carries a significantly higher risk of avascular necrosis (AVN) of the femoral head compared to stable SCFE. Urgent decompression and fixation are often advocated to mitigate this risk.

Question 1077

Topic: Pediatric Hip
In the management of Legg-Calvé-Perthes disease, the Herring Lateral Pillar Classification is most accurately assessed and clinically useful during which stage of the disease?
. Initial stage
. Early fragmentation stage
. Late fragmentation stage
. Reossification stage
. Healed stage

Correct Answer & Explanation

. Early fragmentation stage

Explanation

The Herring Lateral Pillar Classification evaluates the height of the lateral pillar of the femoral head and is the most reliable prognostic indicator. It is most accurately applied during the early to late fragmentation stage of the disease.

Question 1078

Topic: Pediatric Hip

A 6-week-old infant is placed in a Pavlik harness for Developmental Dysplasia of the Hip (DDH). At the 2-week follow-up, the mother reports the infant is not extending the knee on the affected side. On examination, the quadriceps muscle is flaccid. What is the most appropriate next step in management?

. Remove the harness temporarily until quadriceps function returns
. Adjust the anterior straps to increase hip flexion
. Adjust the posterior straps to decrease hip abduction
. Proceed immediately to closed reduction and spica casting
. Proceed immediately to open reduction

Correct Answer & Explanation

. Remove the harness temporarily until quadriceps function returns

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by hyperflexion of the hip. The appropriate management is to remove the harness temporarily or significantly decrease hip flexion until clinical resolution of the nerve palsy occurs.

Question 1079

Topic: Pediatric Hip

A 12-year-old boy presents with left hip pain and an obligatory external rotation of the hip during active flexion. He is diagnosed with a stable slipped capital femoral epiphysis (SCFE). Which of the following is the strongest indication for prophylactic in situ pinning of the contralateral asymptomatic hip?

. Male sex
. Age greater than 14 years
. Underlying endocrine disorder
. African American race
. Symptom duration greater than 6 months

Correct Answer & Explanation

. Underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended in patients with endocrine disorders (e.g., hypothyroidism, growth hormone deficiency, renal osteodystrophy) due to the substantially increased risk of bilateral involvement.

Question 1080

Topic: Pediatric Hip
An 8-year-old boy presents with a painful limp of insidious onset. Radiographs demonstrate changes consistent with Legg-Calvé-Perthes disease. According to the Herring lateral pillar classification, what specific radiographic finding characterizes a Group B hip?
. Greater than 50% of the lateral pillar height is maintained
. No involvement of the lateral pillar
. Less than 50% of the lateral pillar height is maintained
. Complete collapse of the lateral pillar
. Extrusion of the femoral head lateral to the acetabular margin

Correct Answer & Explanation

. Less than 50% of the lateral pillar height is maintained

Explanation

In the Herring lateral pillar classification, Group A has no lateral pillar involvement, Group B maintains >50% of the original lateral pillar height, and Group C has <50% of the height maintained. This classification is heavily used for determining prognosis.

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