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Pediatric Hip MCQs

Practice Set 90 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 1781

Topic: Pediatric Hip

Which of the following endocrine disorders is most strongly associated with Slipped Capital Femoral Epiphysis (SCFE) in a patient presenting under the age of 10, frequently warranting prophylactic pinning of the contralateral hip?

. Hyperthyroidism
. Hypothyroidism
. Cushing's syndrome
. Addison's disease
. Hyperparathyroidism

Correct Answer & Explanation

. Hypothyroidism

Explanation

Hypothyroidism is the most common endocrine disorder associated with SCFE. Patients presenting with SCFE at an atypical age (< 10 years or > 16 years), or those with extreme short stature, should be evaluated for endocrine abnormalities, particularly hypothyroidism and growth hormone deficiency. Because the risk of bilateral involvement is very high in endocrine-associated SCFE, prophylactic pinning of the contralateral hip is generally indicated.

Question 1782

Topic: Pediatric Hip

Following in-situ pinning of a severe slipped capital femoral epiphysis (SCFE), a 15-year-old patient develops symptomatic femoroacetabular impingement (FAI). Which of the following anatomic abnormalities is the primary cause of this impingement?

. Pincer-type impingement from acetabular retroversion
. Cam-type impingement from anterolateral metaphyseal prominence
. Subspinous impingement from AIIS hypertrophy
. Ischiofemoral impingement from residual coxa vara
. Pincer-type impingement from coxa magna

Correct Answer & Explanation

. Cam-type impingement from anterolateral metaphyseal prominence

Explanation

In a severe SCFE, the femoral epiphysis slips posteriorly and medially relative to the metaphysis. This leaves the anterolateral metaphysis prominent. During hip flexion and internal rotation, this bony prominence abuts the anterior acetabular rim, causing classic cam-type femoroacetabular impingement.

Question 1783

Topic: Pediatric Hip

A 10-year-old girl presents with a unilateral slipped capital femoral epiphysis (SCFE). She is at the 15th percentile for weight and 10th percentile for height. Considering her atypical presentation for SCFE, she undergoes an endocrine workup. Which of the following underlying conditions is the strongest indication for prophylactic pinning of the contralateral asymptomatic hip?

. Hyperthyroidism
. Hypothyroidism
. Type 1 Diabetes Mellitus
. Hyperparathyroidism
. Achondroplasia

Correct Answer & Explanation

. Hypothyroidism

Explanation

Patients with SCFE who present outside the typical age range (girls 11-13, boys 13-15) or who are not overweight should be evaluated for endocrine disorders. Hypothyroidism is the most common endocrine disorder associated with SCFE. Bilateral involvement is significantly higher in patients with endocrine disorders, and prophylactic pinning of the contralateral hip is highly recommended in this population to prevent a future slip.

Question 1784

Topic: Pediatric Hip

A 4-month-old female infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During follow-up, the mother notes the child is no longer kicking her right leg. Examination reveals decreased quadriceps tone and an absent patellar reflex on the right. What positioning error in the Pavlik harness typically leads to this complication?

. Excessive flexion of the hip
. Excessive extension of the hip
. Excessive abduction of the hip
. Excessive adduction of the hip
. Excessive internal rotation of the hip

Correct Answer & Explanation

. Excessive flexion of the hip

Explanation

The clinical picture describes a femoral nerve palsy, a known complication of Pavlik harness treatment. This is caused by excessive flexion of the hip, which can compress the femoral nerve against the inguinal ligament. Excessive abduction, on the other hand, is associated with a different severe complication: avascular necrosis (AVN) of the femoral head due to compression of the posterior circumflex femoral artery.

Question 1785

Topic: Pediatric Hip

A 6-week-old female infant is undergoing treatment for developmental dysplasia of the hip (DDH) utilizing a Pavlik harness. Ultrasound evaluation at 4 weeks into treatment demonstrates that the left hip remains persistently dislocated. What is the most appropriate next step in management?

. Add a hip abduction brace directly over the Pavlik harness
. Continue the Pavlik harness for an additional 4 weeks and re-evaluate
. Switch to double-diapering therapy
. Abandon the harness and plan for closed reduction and spica casting
. Proceed to immediate open reduction and femoral shortening osteotomy

Correct Answer & Explanation

. Abandon the harness and plan for closed reduction and spica casting

Explanation

If a dislocated hip fails to reduce after 3 to 4 weeks of proper Pavlik harness treatment, the harness should be abandoned to prevent "Pavlik harness disease" (damage to the posterior acetabular wall). The next step is a closed reduction and spica casting or a rigid orthosis.

Question 1786

Topic: Pediatric Hip

A 13-year-old overweight boy is diagnosed with an unstable slipped capital femoral epiphysis (SCFE). Which of the following factors most significantly increases his risk of developing avascular necrosis (AVN) following treatment?

. Preoperative slip angle greater than 50 degrees
. Inability to bear weight on the affected limb prior to surgery
. Use of two screws instead of a single screw for fixation
. Base of neck capsulotomy performed during the procedure
. Initiation of physical therapy within the first postoperative week

Correct Answer & Explanation

. Inability to bear weight on the affected limb prior to surgery

Explanation

An unstable SCFE, defined clinically by the inability to bear weight even with crutches, carries a significantly higher risk of AVN (up to 50%) compared to stable slips. Capsulotomy may actually reduce intracapsular pressure, potentially lowering AVN risk.

Question 1787

Topic: Pediatric Hip

A 4-month-old infant is being treated for developmental dysplasia of the hip (DDH) with a Pavlik harness. During a follow-up ultrasound, the hip remains dislocated, and the infant demonstrates decreased active knee extension on the affected side. What is the most likely cause of this neurologic finding?

. Obturator nerve palsy from excessive hip abduction
. Sciatic nerve palsy from excessive hip flexion
. Femoral nerve palsy from hyperflexion of the hip
. Peroneal nerve palsy from strap compression at the fibular head
. Tibial nerve palsy from tight foot straps

Correct Answer & Explanation

. Femoral nerve palsy from hyperflexion of the hip

Explanation

Femoral nerve palsy in a Pavlik harness is typically caused by excessive hip flexion pressing the nerve against the inguinal ligament. It presents with decreased active knee extension and requires immediate loosening or removal of the harness.

Question 1788

Topic: Pediatric Hip

A 4-month-old infant with developmental dysplasia of the hip (DDH) is treated with a Pavlik harness. Two weeks later, the parents report the infant has stopped kicking the affected leg. Examination reveals absent active knee extension. What is the most likely cause?

. Sciatic nerve palsy from excessive hip flexion
. Femoral nerve palsy from excessive hip flexion
. Obturator nerve palsy from excessive abduction
. Avascular necrosis of the femoral head
. Inferior hip dislocation

Correct Answer & Explanation

. Femoral nerve palsy from excessive hip flexion

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment caused by excessive hip flexion. It typically resolves spontaneously when the hyperflexion is corrected or the harness is temporarily removed.

Question 1789

Topic: Pediatric Hip

A 6-year-old boy presents with a painless limp and limited hip internal rotation. Radiographs show fragmentation and sclerosis of the proximal femoral epiphysis. Which vascular structure's compromise is primarily implicated in the pathogenesis of this disease?

. Artery of the ligamentum teres
. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Inferior gluteal artery
. Superior gluteal artery

Correct Answer & Explanation

. Medial femoral circumflex artery

Explanation

The presentation is classic for Legg-Calve-Perthes disease. The blood supply to the femoral head at this age depends heavily on the lateral epiphyseal branches of the medial femoral circumflex artery.

Question 1790

Topic: Pediatric Hip

A 6-year-old boy presents with a persistent right leg limp and anterior thigh pain. Radiographs reveal a fragmented, sclerotic proximal femoral epiphysis consistent with Legg-Calve-Perthes disease. Which of the following is considered the most significant prognostic factor at the time of initial presentation?

. Age of the patient at clinical onset
. Patient sex
. Body mass index
. Duration of the limp
. Degree of internal rotation lost

Correct Answer & Explanation

. Age of the patient at clinical onset

Explanation

Age at clinical onset is the most critical prognostic factor in Legg-Calve-Perthes disease. Patients who develop the disease before the age of 6 generally have a better prognosis and greater potential for spherical remodeling of the femoral head.

Question 1791

Topic: Pediatric Hip

A 3-month-old infant is being treated in a Pavlik harness for developmental dysplasia of the hip (DDH). The mother brings the child in because she notices the baby is no longer actively kicking the affected leg, although the toes continue to move. What is the most likely complication occurring in this patient?

. Sciatic nerve palsy
. Femoral nerve palsy
. Obturator nerve palsy
. Avascular necrosis of the femoral head
. Inferior dislocation of the hip

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment, typically caused by hyperflexion of the hip which compresses the nerve against the rim of the pelvis. Treatment requires immediate adjustment or removal of the harness until active quadriceps function returns.

Question 1792

Topic: Pediatric Hip

In the evaluation of a 7-year-old boy with Legg-Calve-Perthes disease, the Herring lateral pillar classification is used on AP pelvis radiographs. A patient classified as Herring Group C has which of the following characteristics?

. No involvement of the lateral pillar
. >50% maintained lateral pillar height
. <50% maintained lateral pillar height
. Extrusion of the femoral head laterally
. Subchondral fracture line (crescent sign)

Correct Answer & Explanation

. <50% maintained lateral pillar height

Explanation

The Herring lateral pillar classification assesses the height of the lateral portion of the capital femoral epiphysis during the fragmentation stage. Group A has no involvement; Group B maintains >50% of the lateral pillar height; Group C maintains <50% of lateral pillar height. Group C portends the worst prognosis.

Question 1793

Topic: Pediatric Hip

A 12-year-old obese boy presents with acute on chronic left hip pain and inability to bear weight. He is diagnosed with an unstable Slipped Capital Femoral Epiphysis (SCFE). In addition to urgent in situ fixation, which of the following statements regarding the risk of avascular necrosis (AVN) in this condition is true?

. Unstable SCFE carries a >40% risk of AVN, whereas stable SCFE carries <5% risk
. The risk of AVN is lower in unstable SCFE compared to stable SCFE
. Capsulotomy has been definitively proven in all large prospective trials to eliminate AVN risk
. Prophylactic pinning of the contralateral hip decreases the AVN risk of the affected hip
. The primary blood supply compromised in SCFE AVN is the anterior retinacular artery

Correct Answer & Explanation

. Unstable SCFE carries a >40% risk of AVN, whereas stable SCFE carries <5% risk

Explanation

An unstable SCFE (defined by Loder as the inability to bear weight even with crutches) is a surgical emergency with a high risk of avascular necrosis, reported to be up to 40-50%. In contrast, stable SCFE has a very low AVN risk (<5%). The lateral epiphyseal vessels (branches of the medial femoral circumflex artery) are the primary compromised vessels.

Question 1794

Topic: Pediatric Hip

A 12-year-old obese boy presents with acute-on-chronic left hip pain. He is brought in via wheelchair and is completely unable to bear weight. Radiographs show a slipped capital femoral epiphysis (SCFE). He is scheduled for in situ pinning. What is the most significant complication risk associated with his specific presentation?

. Chondrolysis
. Osteoarthritis
. Avascular necrosis of the femoral head
. Leg length discrepancy
. Femoral shaft fracture

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

The patient has an unstable SCFE, clinically defined by the inability to bear weight even with crutches. Unstable SCFE carries a dramatically higher risk of avascular necrosis of the femoral head (up to 47%) compared to stable SCFE.

Question 1795

Topic: Pediatric Hip

A 13-year-old obese male presents with knee pain and a limp. Examination shows obligatory external rotation of the hip during passive flexion. He is diagnosed with a stable Slipped Capital Femoral Epiphysis (SCFE). What is the primary blood supply at risk during in situ pinning of this condition?

. Anterior retinacular artery
. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Artery of the ligamentum teres
. Inferior gluteal artery

Correct Answer & Explanation

. Medial femoral circumflex artery

Explanation

The medial femoral circumflex artery (MFCA) provides the primary blood supply to the femoral head in adolescents and adults. Its deep branch gives rise to the lateral epiphyseal (retinacular) vessels, which are critically vulnerable during both the natural progression of SCFE and its surgical fixation, risking avascular necrosis (AVN).

Question 1796

Topic: Pediatric Hip

A 4-month-old female is diagnosed with Developmental Dysplasia of the Hip (DDH). During an ultrasound evaluation, the alpha angle is measured. In the Graf classification, what does the alpha angle represent, and what is the normal value in a mature infant hip?

. Measures the cartilaginous roof; normal > 50 degrees
. Measures the cartilaginous roof; normal > 60 degrees
. Measures the bony roof (acetabular concavity); normal > 60 degrees
. Measures the bony roof (acetabular concavity); normal < 50 degrees
. Measures femoral head coverage; normal > 50%

Correct Answer & Explanation

. Measures the bony roof (acetabular concavity); normal > 60 degrees

Explanation

In Graf's ultrasound classification for DDH, the alpha angle measures the osseous (bony) roof of the acetabulum (the concavity of the iliac bone). A normal alpha angle (representing a Type I hip) is 60 degrees or greater. The beta angle measures the cartilaginous roof.

Question 1797

Topic: Pediatric Hip

A 6-week-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During follow-up, the infant shows absent active knee extension. What is the most likely cause?

. Obturator nerve palsy due to excessive abduction
. Sciatic nerve palsy due to excessive extension
. Femoral nerve palsy due to excessive hyperflexion
. Tibial nerve palsy due to strap compression
. Peroneal nerve palsy due to tight stirrups

Correct Answer & Explanation

. Femoral nerve palsy due to excessive hyperflexion

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness caused by hyperflexion of the hips. Management involves loosening the anterior straps or temporarily discontinuing the harness until function returns.

Question 1798

Topic: Pediatric Hip

A 4-month-old female is diagnosed with developmental dysplasia of the hip (DDH) and placed in a Pavlik harness. Which of the following limb positions is most highly associated with an iatrogenic femoral nerve palsy?

. Excessive hip flexion
. Excessive hip extension
. Excessive hip adduction
. Excessive hip abduction
. Forced knee extension

Correct Answer & Explanation

. Excessive hip flexion

Explanation

Hyperflexion of the hip in a Pavlik harness can compress the femoral nerve against the inguinal ligament, leading to transient femoral nerve palsy. Excessive abduction, conversely, places the vascular supply to the femoral head at risk, leading to avascular necrosis.

Question 1799

Topic: Pediatric Hip
A 6-year-old boy presents with a painless limp and restricted hip internal rotation. Radiographs reveal fragmentation of the proximal femoral epiphysis. According to the Herring Lateral Pillar Classification for Legg-Calvé-Perthes disease, which of the following defines a Group B classification?
. No involvement of the lateral pillar
. Greater than 50% maintained lateral pillar height
. Less than 50% maintained lateral pillar height
. Complete collapse of the lateral pillar
. Medial pillar collapse only

Correct Answer & Explanation

. Greater than 50% maintained lateral pillar height

Explanation

The Herring Lateral Pillar classification predicts the outcome of Legg-Calvé-Perthes disease. Group B indicates that >50% of the lateral pillar height is maintained, while Group C involves >50% collapse of the lateral pillar.

Question 1800

Topic: Pediatric Hip

A 3-month-old female is being treated with a Pavlik harness for Developmental Dysplasia of the Hip (DDH). At her follow-up, she exhibits an inability to actively extend her knee. This complication is most likely due to which improper positioning in the harness?

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

Correct Answer & Explanation

. Excessive hip flexion

Explanation

Excessive hip flexion in a Pavlik harness can cause femoral nerve compression against the inguinal ligament, leading to transient femoral nerve palsy (manifesting as an inability to extend the knee). Excessive abduction is associated with avascular necrosis of the femoral head.

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