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Pediatric Lower Extremity MCQs

Practice Set 2 of 18

This practice set contains high-yield board review questions covering key concepts in Pediatric Lower Extremity. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 21

Topic: Pediatric Lower Extremity

A newborn is noted to have a shortened leg, anterior bowing of the tibia, and an absent lateral ray of the foot.

Radiographs confirm fibular hemimelia. Which of the following knee conditions is most commonly associated with this anomaly?

. Absent anterior cruciate ligament
. Patella alta
. Medial collateral ligament deficiency
. Congenital patellar dislocation
. Bipartite patella

Correct Answer & Explanation

. Absent anterior cruciate ligament

Explanation

Fibular hemimelia is frequently associated with knee instability, most notably an absent or hypoplastic anterior cruciate ligament (ACL). Other associations include ball-and-socket ankle joint and tarsal coalitions.

Question 22

Topic: Pediatric Lower Extremity

According to the Aitken classification for Proximal Focal Femoral Deficiency (PFFD), Class A is defined by which of the following characteristics?

. Absence of the femoral head and acetabulum
. Severe femoral shortening with no connection between the femur and the acetabulum
. Presence of a normal femoral head with a bony connection to the shaft resulting in a subtrochanteric varus deformity
. Complete absence of the femur
. Absent femoral head with a functional acetabulum

Correct Answer & Explanation

. Presence of a normal femoral head with a bony connection to the shaft resulting in a subtrochanteric varus deformity

Explanation

Aitken Class A PFFD is characterized by the presence of a femoral head and a functional acetabulum. The femoral head is connected to the shaft by a cartilaginous model that eventually ossifies, though there is often a severe subtrochanteric varus deformity and limb shortening.

Question 23

Topic: Pediatric Lower Extremity

In the Ponseti method for treating idiopathic clubfoot, what is the correct sequence of deformity correction?

. Cavus, Adductus, Varus, Equinus
. Equinus, Varus, Adductus, Cavus
. Adductus, Varus, Cavus, Equinus
. Cavus, Varus, Adductus, Equinus
. Varus, Cavus, Equinus, Adductus

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus

Explanation

The CAVE mnemonic dictates the order of correction in the Ponseti method: Cavus (by elevating the first ray), Adductus, Varus, and finally Equinus (usually requiring a percutaneous Achilles tenotomy).

Question 24

Topic: Pediatric Lower Extremity

In the initial casting phase of the Ponseti method for a newborn with idiopathic clubfoot, the first step focuses on correcting which component of the deformity?

. Equinus
. Varus
. Cavus
. Adduction
. Internal rotation

Correct Answer & Explanation

. Cavus

Explanation

The first step in the Ponseti method is correcting the cavus deformity. This is achieved by elevating the first ray, which supines the forefoot to align it with the hindfoot.

Question 25

Topic: Pediatric Lower Extremity

A 13-year-old male athlete presents with localized pain, swelling, and tenderness over the tibial tubercle, which worsens with jumping. He is diagnosed with Osgood-Schlatter disease. What is the primary underlying pathology?

. Degeneration of the patellar tendon
. Traction apophysitis of the tibial tubercle
. Avascular necrosis of the inferior pole of the patella
. Osteochondral defect of the tibial plateau
. Bursitis of the superficial infrapatellar bursa

Correct Answer & Explanation

. Traction apophysitis of the tibial tubercle

Explanation

Osgood-Schlatter disease is an overuse injury caused by repetitive microtrauma and traction from the patellar tendon on the unossified tibial tubercle apophysis, leading to a traction apophysitis.

Question 26

Topic: Pediatric Lower Extremity

During the correction of idiopathic clubfoot using the Ponseti method, the deformities are addressed in a specific sequence. Which deformity is corrected last?

. Cavus
. Adductus
. Varus
. Equinus
. Internal rotation

Correct Answer & Explanation

. Equinus

Explanation

The Ponseti method corrects clubfoot deformities in the CAVE sequence: Cavus, Adductus, Varus, and finally Equinus. Correction of equinus usually requires a percutaneous Achilles tenotomy as the final step.

Question 27

Topic: Pediatric Lower Extremity

In the Ponseti method for treating idiopathic clubfoot, what is the correct sequence of deformity correction?

. Cavus, Adductus, Varus, Equinus
. Equinus, Varus, Adductus, Cavus
. Cavus, Varus, Adductus, Equinus
. Adductus, Cavus, Equinus, Varus
. Varus, Cavus, Adductus, Equinus

Correct Answer & Explanation

. Cavus, Varus, Adductus, Equinus

Explanation

The mnemonic CAVE dictates the sequence of correction in the Ponseti method: Cavus (elevating the first ray), Adductus, Varus, and finally Equinus (often requiring a percutaneous Achilles tenotomy).

Question 28

Topic: Pediatric Lower Extremity

A newborn is diagnosed with fibular hemimelia. Which of the following associated anomalies is most consistently seen in this condition?

. Acetabular dysplasia
. Anteromedial tibial bowing
. Absent medial rays of the foot
. Tarsal coalition
. Cruciate ligament deficiency

Correct Answer & Explanation

. Cruciate ligament deficiency

Explanation

Fibular hemimelia is frequently associated with anterolateral tibial bowing, absent lateral rays, ball-and-socket ankle, and knee anomalies including anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) deficiency.

Question 29

Topic: Pediatric Lower Extremity

A 2-week-old infant is undergoing Ponseti casting for idiopathic clubfoot. The deformity is being corrected sequentially. What is the final component of the clubfoot deformity to be corrected before application of the final cast?

. Cavus
. Adductus
. Varus
. Equinus
. Supination

Correct Answer & Explanation

. Equinus

Explanation

The Ponseti method corrects deformities in the specific order of CAVE (Cavus, Adductus, Varus, Equinus). Equinus is corrected last, frequently requiring a percutaneous Achilles tenotomy to achieve adequate dorsiflexion.

Question 30

Topic: Pediatric Lower Extremity
A 3-year-old obese female presents with progressive bowing of her right leg. Radiographs reveal a metaphyseal-diaphyseal angle (Drennan angle) of 18 degrees. What is the most appropriate initial management?
. Observation and reassurance
. Knee-ankle-foot orthosis (KAFO)
. Proximal tibial osteotomy
. Epiphysiodesis of the lateral proximal tibia
. Hemiepiphysiodesis of the medial proximal tibia

Correct Answer & Explanation

. Knee-ankle-foot orthosis (KAFO)

Explanation

A metaphyseal-diaphyseal angle >16 degrees in a 3-year-old with characteristic bowing strongly indicates infantile Blount's disease. Initial management for children under age 4 with Langenskiöld stage I-II disease is full-time bracing with a KAFO.

Question 31

Topic: Pediatric Lower Extremity
Which of the following terms best describes the condition shown?
. Calcaneovalgus
. Equinovarus
. Posteromedial bow
. Fibular hemimelia
. Metatarsus adductus

Correct Answer & Explanation

. Calcaneovalgus

Explanation

This patient's foot is in calcaneovalgus. Treatment is not required because calcaneovalgus spontaneously resolves.

Question 32

Topic: Pediatric Lower Extremity

During the Ponseti casting technique for idiopathic clubfoot, what is the final deformity corrected before considering an Achilles tenotomy?

. Cavus
. Adductus
. Varus
. Equinus
. Forefoot pronation

Correct Answer & Explanation

. Equinus

Explanation

The Ponseti method corrects deformities in the order of CAVE: Cavus, Adductus, Varus, and finally Equinus. An Achilles tenotomy is frequently required to correct the residual equinus.

Question 33

Topic: Pediatric Lower Extremity

All of the following conditions may affect lower extremities in children. Which one of the conditions does not have a high incidence of spontaneous improvement:

. Posteromedial bow of the tibia
. C alcaneovalgus foot
. Metatarsus adductus
. Internal tibial torsion
. Anterolateral bowing of the tibia

Correct Answer & Explanation

. Anterolateral bowing of the tibia

Explanation

Anterolateral bowing of the tibia is usually associated with tibial dysplasia and may progress to pseudarthrosis. Anterolateral bowing of the tibia does not resolve in most patients. Posteromedial bowing of the tibia usually resolves, although there may be a residual shortening of the tibia. All of the other conditions often completely resolve.

Question 34

Topic: Pediatric Lower Extremity

During the initial phase of the Ponseti method for idiopathic clubfoot, which component of the deformity is corrected first?

. Equinus
. Hindfoot varus
. Forefoot adductus
. Cavus
. Internal tibial torsion

Correct Answer & Explanation

. Cavus

Explanation

The sequence of correction in the Ponseti method follows the acronym CAVE: Cavus, Adductus, Varus, and Equinus. Cavus is corrected first by elevating the first ray to align the forefoot with the hindfoot.

Question 35

Topic: Pediatric Lower Extremity

What is the most common cause of relapse in an infant successfully treated for idiopathic clubfoot with the Ponseti method?

. Failure to perform an Achilles tenotomy
. Inadequate initial correction of cavus
. Noncompliance with the foot abduction orthosis
. Muscle imbalance due to an absent anterior tibial artery
. Undiagnosed tethered spinal cord

Correct Answer & Explanation

. Noncompliance with the foot abduction orthosis

Explanation

Noncompliance with the foot abduction orthosis (Denis Browne splint) is universally recognized as the most common cause of relapse following successful initial casting correction.

Question 36

Topic: Pediatric Lower Extremity

During clubfoot treatment using the Ponseti technique, what is the primary indication for performing a percutaneous Achilles tenotomy?

. Prior to the application of the first cast
. When the cavus is fully corrected but adductus remains
. When the midfoot is corrected but ankle dorsiflexion remains less than 10-15 degrees
. Only if there is a recurrent deformity after 6 months of bracing
. Routinely at the age of 12 months

Correct Answer & Explanation

. When the midfoot is corrected but ankle dorsiflexion remains less than 10-15 degrees

Explanation

An Achilles tenotomy is indicated before the final cast when the midfoot is fully corrected (adductus, varus, and cavus are resolved) but residual equinus prevents 10 to 15 degrees of ankle dorsiflexion.

Question 37

Topic: Pediatric Lower Extremity

In a patient with unilateral idiopathic clubfoot, the affected lower extremity typically demonstrates which of the following associated rotational profiles compared to the normal side?

. Internal tibial torsion
. External tibial torsion
. Internal femoral torsion
. External femoral torsion
. No significant torsional difference

Correct Answer & Explanation

. Internal tibial torsion

Explanation

Idiopathic clubfoot is consistently associated with internal tibial torsion of the affected limb. This internal rotation typically persists even after the foot deformities have been fully corrected.

Question 38

Topic: Pediatric Lower Extremity

A 2-year-old boy presents with a relapsed clubfoot deformity after successful initial treatment with the Ponseti method. What is the most common cause of recurrence, and what is the appropriate next step in management?

. Noncompliance with bracing; repeat casting
. Noncompliance with bracing; immediate posteromedial release
. Achilles tendon tightness; isolated tenotomy
. Anterior tibial tendon overactivity; split anterior tibial tendon transfer
. Subtalar contracture; lateral column lengthening

Correct Answer & Explanation

. Noncompliance with bracing; repeat casting

Explanation

Noncompliance with the abduction brace is the leading cause of clubfoot recurrence. The initial management of a relapsed clubfoot is a brief period of repeat Ponseti casting, which may be followed by a tendon transfer if dynamic supination persists.

Question 39

Topic: Pediatric Lower Extremity

During the Ponseti casting for a rigid clubfoot, which sequence correctly describes the order of deformity correction?

. Cavus, adductus, varus, equinus
. Equinus, varus, adductus, cavus
. Varus, adductus, cavus, equinus
. Cavus, varus, adductus, equinus
. Adductus, varus, cavus, equinus

Correct Answer & Explanation

. Cavus, varus, adductus, equinus

Explanation

The Ponseti method systematically corrects clubfoot deformities using the mnemonic CAVE: Cavus (by elevating the first ray), Adductus, Varus, and finally Equinus (often requiring a percutaneous Achilles tenotomy).

Question 40

Topic: Pediatric Lower Extremity
A 3-year-old child with infantile Blount's disease (tibia vara) presents with a Langenskiöld stage III lesion. Which of the following is the most appropriate treatment to correct the deformity and prevent further progression?
. Observation with serial radiographs
. Long leg bracing during nighttime only
. Proximal tibial valgus-derotation osteotomy
. Epiphysiodesis of the lateral proximal tibia
. Distal femoral varus-producing osteotomy

Correct Answer & Explanation

. Proximal tibial valgus-derotation osteotomy

Explanation

Langenskiöld stage III infantile Blount's disease represents a progressive deformity with a "step-off" of the medial metaphysis. Surgical intervention with a proximal tibial valgus and derotation osteotomy is indicated to restore mechanical alignment.

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