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Pediatric Lower Extremity MCQs

Practice Set 13 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 241

Topic: Pediatric Lower Extremity

Which of the following statements about clubfoot (congenital talipes equinovarus) is FALSE?

. It is more common in males than females.
. The Ponseti method is the gold standard for initial treatment.
. Surgical correction is typically performed if the Ponseti method fails or for recurrent deformity.
. The deformity primarily involves abnormal development of the talus.
. The classic deformities include forefoot adduction, midfoot cavus, hindfoot varus, and equinus.

Correct Answer & Explanation

. The deformity primarily involves abnormal development of the talus.

Explanation

The deformity in clubfoot primarily involves an abnormal relationship between the talus and calcaneus, navicular, and cuboid, with the talus maintaining its normal relationship with the tibia and fibula. The navicular is medially dislocated on the talar head. It is not an abnormal development of the talus itself, but rather its malpositioning. All other statements are true: clubfoot is more common in males, the Ponseti method (manipulation, casting, Achilles tenotomy) is the gold standard, surgery is for failed conservative treatment, and the classic deformities are forefoot adduction, midfoot cavus, hindfoot varus, and equinus (CAVE).

Question 242

Topic: Pediatric Lower Extremity

A 16-year-old male presents with chronic anterior knee pain, worsening with prolonged sitting, ascending/descending stairs, and squatting. There is tenderness along the medial facet of the patella. Patellar apprehension test is negative. What is the most likely diagnosis?

. Patellar tendinopathy
. Osgood-Schlatter disease
. Patellofemoral pain syndrome (PFPS)
. Osteochondritis dissecans of the medial femoral condyle
. Medial plica syndrome

Correct Answer & Explanation

. Patellofemoral pain syndrome (PFPS)

Explanation

The classic symptoms of anterior knee pain, exacerbated by prolonged sitting (theater sign), stairs, and squatting, with tenderness around the patella, are highly characteristic of patellofemoral pain syndrome (PFPS). This is a diagnosis of exclusion. Patellar tendinopathy causes pain specifically at the inferior pole of the patella. Osgood-Schlatter affects the tibial tuberosity in younger adolescents. Osteochondritis dissecans would typically cause mechanical symptoms and localized pain in the condyle, not primarily patellofemoral. Medial plica syndrome can mimic PFPS but usually has a palpable painful plica and is less common.

Question 243

Topic: Pediatric Lower Extremity

According to the Ponseti method for the treatment of idiopathic clubfoot, what is the correct sequence of deformity correction?

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

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus

Explanation

The Ponseti method follows the CAVE sequence for correcting clubfoot deformities: Cavus, Adductus, Varus, and finally Equinus. The cavus is corrected first by supinating the forefoot to align it with the hindfoot.

Question 244

Topic: Pediatric Lower Extremity

During the Ponseti method of serial casting for idiopathic clubfoot, what is the correct biomechanical sequence of deformity correction?

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

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus

Explanation

The mnemonic CAVE dictates the correct order of correction in the Ponseti method: Cavus, Adductus, Varus, and finally Equinus. The cavus is corrected first by supinating the forefoot to align it with the hindfoot.

Question 245

Topic: Pediatric Lower Extremity

In the Ponseti method for correcting idiopathic clubfoot, what is the final deformity to be corrected before the application of the last cast and potential Achilles tenotomy?

. Cavus
. Adductus
. Varus
. Equinus
. Forefoot pronation

Correct Answer & Explanation

. Equinus

Explanation

The Ponseti method corrects deformities in a strict sequence known by the acronym CAVE: Cavus, Adductus, Varus, and Equinus. Equinus is the final deformity addressed, frequently requiring a percutaneous Achilles tenotomy to finalize correction.

Question 246

Topic: Pediatric Lower Extremity

According to the Ponseti method for treating idiopathic clubfoot, which deformity must be addressed first during the serial casting phase?

. Equinus
. Varus
. Adductus
. Cavus
. Internal tibial torsion

Correct Answer & Explanation

. Equinus

Explanation

The components of clubfoot are corrected in the specific order of CAVE: Cavus, Adductus, Varus, then Equinus. The cavus is corrected first by supinating the forefoot to align it with the hindfoot.

Question 247

Topic: Pediatric Lower Extremity

When applying the Ponseti method for the correction of a severe idiopathic clubfoot, which of the following represents the correct sequential order of deformity correction?

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

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus

Explanation

The Ponseti method corrects clubfoot deformities in a specific sequence summarized by the acronym CAVE: Cavus, Adductus, Varus, and Equinus. The cavus is corrected first by elevating the first ray. The adductus and varus are then corrected simultaneously by abducting the foot around the head of the talus. Equinus is corrected last, often requiring a percutaneous Achilles tenotomy.

Question 248

Topic: Pediatric Lower Extremity

An orthopaedic surgeon is treating a newborn with an idiopathic clubfoot using the Ponseti method of serial casting.

Which of the following describes the correct sequential order of deformity correction using this technique?

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

Correct Answer & Explanation

. Equinus, Varus, Adductus, Cavus

Explanation

The Ponseti method dictates a very specific sequential correction of the clubfoot deformities, remembered by the acronym CAVE: 1) Cavus (corrected by supinating the forefoot to align it with the hindfoot), 2) Adductus, 3) Varus (corrected simultaneously by abducting the foot around the talar head), and finally 4) Equinus (often requiring a percutaneous Achilles tenotomy once the heel is in valgus or neutral).

Question 249

Topic: Pediatric Lower Extremity

A newborn is evaluated for a congenital limb deficiency. Clinical examination and radiographs demonstrate an absent lateral malleolus, a shortened tibia, absent lateral rays of the foot, and marked anteromedial bowing of the tibia.

Which of the following internal knee derangements is nearly universally associated with this condition?

. Anterior cruciate ligament (ACL) deficiency
. Posterior cruciate ligament (PCL) deficiency
. Discoid lateral meniscus
. Medial patellofemoral ligament (MPFL) dysplasia
. Bipartite patella

Correct Answer & Explanation

. Anterior cruciate ligament (ACL) deficiency

Explanation

The clinical picture describes fibular hemimelia (longitudinal deficiency of the fibula). It is well established that fibular hemimelia is a spectrum that affects the entire limb. A nearly universal association with fibular hemimelia is the absence or severe deficiency of the anterior cruciate ligament (ACL). Other common associations include a ball-and-socket ankle joint, tarsal coalitions, and absence of the lateral rays of the foot.

Question 250

Topic: Pediatric Lower Extremity

A newborn is diagnosed with Aitken Class A proximal focal femoral deficiency (PFFD). The predicted leg length discrepancy at maturity is 15 cm. The hip joint is present with a cartilaginous connection between the femoral head and shaft, and the foot is normal. Which of the following is the most appropriate long-term surgical strategy?

. Early knee fusion and Boyd amputation
. Ilizarov lengthening of the femur and tibia
. Van Nes rotationplasty
. Hip arthrodesis and Syme amputation
. Pelvic support osteotomy

Correct Answer & Explanation

. Early knee fusion and Boyd amputation

Explanation

Aitken Class A PFFD is characterized by the presence of a femoral head and acetabulum, with a cartilaginous connection to the shortened femoral shaft that typically ossifies later, providing a stable, functioning hip. For patients with stable hip and knee joints, a functional foot, and a predicted limb length discrepancy (LLD) of less than 20 cm, limb lengthening procedures (usually staged femoral and tibial lengthening) are indicated. Amputations and rotationplasties are reserved for more severe deficiencies (Aitken C and D, or LLD > 20 cm) where joints are unstable or absent.

Question 251

Topic: Pediatric Lower Extremity

In a patient with Proximal Focal Femoral Deficiency (PFFD), the Aitken classification is widely used to guide treatment.

Which Aitken type is characterized by the complete absence of a femoral head and an absent or severely dysplastic acetabulum, precluding joint reconstruction?

. Type A
. Type B
. Type C
. Type D
. Type E

Correct Answer & Explanation

. Type A

Explanation

The Aitken classification of PFFD includes four types (A-D). Type D represents the most severe form, characterized by an absent acetabulum, absent femoral head, and severely shortened femoral shaft without a proximal tuft. Types A and B have an existing femoral head with an osseous or cartilaginous connection to the shaft, while Type C has an absent femoral head but a present acetabulum.

Question 252

Topic: Pediatric Lower Extremity

You are treating an infant with an idiopathic clubfoot using the Ponseti method. The first step involves correcting the cavus deformity. What specific manipulation is required to achieve this first step?

. Supination of the forefoot with depression of the first metatarsal
. Pronation of the forefoot with depression of the first metatarsal
. Elevation of the first metatarsal to supinate the forefoot
. Abduction of the midfoot with counter-pressure on the medial malleolus
. Forced dorsiflexion of the ankle

Correct Answer & Explanation

. Supination of the forefoot with depression of the first metatarsal

Explanation

In the Ponseti method, the acronym CAVE guides the sequence of correction: Cavus, Adductus, Varus, and Equinus. The cavus is corrected first. Because the cavus in a clubfoot is caused by a plantarflexed first ray, correction is achieved by supinating the forefoot to match the hindfoot, which specifically requires elevating the first metatarsal.

Question 253

Topic: Pediatric Lower Extremity
A 4-year-old boy previously treated for idiopathic clubfoot with the Ponseti method presents with a relapsed deformity. Gait analysis reveals dynamic supination of the foot during the swing phase. Passive range of motion demonstrates a fully correctable deformity. What is the most appropriate definitive management?
. Repeat Achilles tendon lengthening
. Tibialis anterior tendon transfer to the lateral cuneiform
. Tibialis posterior tendon transfer to the dorsal foot
. Split anterior tibial tendon transfer (SPLATT)
. Lateral column lengthening (Evans osteotomy)

Correct Answer & Explanation

. Tibialis anterior tendon transfer to the lateral cuneiform

Explanation

Dynamic supination during the swing phase in a relapsed clubfoot is typically caused by an overactive tibialis anterior. If the foot is passively correctable, a full tibialis anterior tendon transfer (TATT) to the lateral (third) cuneiform is the treatment of choice.

Question 254

Topic: Pediatric Lower Extremity

A 3-year-old female presents with progressive unilateral genu varum. Standing lower extremity radiographs are obtained. Measurement of the metaphyseal-diaphyseal angle (Drennan's angle) is most predictive of progression to infantile Blount's disease when it exceeds what threshold?

. 5 degrees
. 9 degrees
. 11 degrees
. 16 degrees
. 22 degrees

Correct Answer & Explanation

. 5 degrees

Explanation

The metaphyseal-diaphyseal angle (Drennan's angle) is used to differentiate physiologic bowing from infantile Blount's disease. An angle greater than 16 degrees has a high predictive value for progression to Blount's disease.

Question 255

Topic: Pediatric Lower Extremity
A 4-year-old boy with a history of idiopathic clubfoot treated successfully with the Ponseti method presents with a relapsed deformity. Gait analysis shows dynamic supination of the foot during the swing phase. Passive range of motion demonstrates a fully correctable deformity. What is the most appropriate surgical intervention?
. Repeat percutaneous Achilles tenotomy
. Split tibialis anterior tendon transfer (SPLATT)
. Full tibialis anterior tendon transfer to the lateral cuneiform
. Calcaneocuboid fusion
. Comprehensive posteromedial release

Correct Answer & Explanation

. Full tibialis anterior tendon transfer to the lateral cuneiform

Explanation

Dynamic supination during the swing phase in a relapsed, fully correctable clubfoot is best treated with a full tibialis anterior tendon transfer (TATT) to the lateral cuneiform. This balances the forefoot forces; a SPLATT is contraindicated in Ponseti relapses as it does not sufficiently address the deforming force.

Question 256

Topic: Pediatric Lower Extremity

An infant born with idiopathic clubfoot is treated with the Ponseti method. After successful sequential casting and a percutaneous Achilles tenotomy, the foot is placed in a foot abduction orthosis. The parents ask what the most common cause of future deformity recurrence is. What is the correct response?

. Failure to perform an anterior tibial tendon transfer at age 2
. Incomplete initial correction of the equinus deformity
. Non-compliance with the post-correction bracing protocol
. An underlying undiagnosed neuromuscular disorder
. Premature initiation of weight-bearing and standing

Correct Answer & Explanation

. Failure to perform an anterior tibial tendon transfer at age 2

Explanation

The vast majority of clubfoot relapses following successful Ponseti casting and tenotomy are directly attributed to poor parental adherence to the foot abduction orthosis (Denis Browne splint) bracing protocol. Strict compliance significantly minimizes relapse rates.

Question 257

Topic: Pediatric Lower Extremity

A 4-year-old boy previously treated for idiopathic clubfoot with the Ponseti method presents with a dynamic supination deformity during the swing phase of gait. Passive ankle dorsiflexion is 15 degrees. What is the most appropriate surgical management?

. Repeat serial casting
. Tibialis anterior tendon transfer
. Achilles tendon lengthening
. Lateral column shortening
. Posteromedial soft tissue release

Correct Answer & Explanation

. Repeat serial casting

Explanation

Dynamic supination during the swing phase in a relapsed clubfoot, when passive dorsiflexion is adequate, is treated with a tibialis anterior tendon transfer to the lateral cuneiform.

Question 258

Topic: Pediatric Lower Extremity

A 2-week-old infant is diagnosed with the condition shown:

The Ponseti method is initiated. What is the correct initial manipulative step to correct the cavus deformity prior to cast application?

. Pronation of the forefoot
. Elevation of the first ray to supinate the forefoot
. Direct pressure over the calcaneocuboid joint
. Maximal dorsiflexion of the ankle
. Eversion of the hindfoot

Correct Answer & Explanation

. Pronation of the forefoot

Explanation

The first step in the Ponseti casting technique for idiopathic clubfoot is correcting the cavus. This is achieved by elevating the first metatarsal (first ray), which effectively supinates the forefoot so that it aligns with the supinated hindfoot. Subsequent casts will abduct the forefoot around the head of the talus.

Question 259

Topic: Pediatric Lower Extremity

An infant with bilateral idiopathic clubfeet is undergoing Ponseti casting. After three casts, the treating physician notices the foot has become severely plantarflexed, the midfoot is deeply creased with a transverse plantar crease, and the heel is slipping out of the cast. What is the most appropriate modification to the standard Ponseti technique for this 'atypical' clubfoot?

. Proceed directly to a posteromedial release
. Perform a percutaneous Achilles tenotomy immediately, regardless of hindfoot varus
. Remove the cast, immobilize the knee in 110 degrees of flexion, and correct cavus and equinus simultaneously
. Apply a short leg cast to focus purely on forefoot abduction
. Transition to the French functional taping method

Correct Answer & Explanation

. Proceed directly to a posteromedial release

Explanation

An 'atypical' or complex clubfoot is characterized by a short, stubby foot, severe plantar flexion, a deep transverse plantar crease, and a tendency for the cast to slip. The Ponseti method must be modified: the knee is flexed to 110 degrees to prevent cast slippage, and equinus and varus are corrected simultaneously rather than sequentially.

Question 260

Topic: Pediatric Lower Extremity

A 3-year-old girl is evaluated for bilateral severe genu varum. Standing radiographs demonstrate medial beaking of the proximal tibial epiphyses.

Measurement of the metaphyseal-diaphyseal (MD) angle is obtained. Which of the following MD angle measurements most strongly supports the diagnosis of infantile Blount's disease rather than physiologic bowing?

. Greater than 5 degrees
. Greater than 9 degrees
. Greater than 11 degrees
. Greater than 16 degrees
. Less than 10 degrees

Correct Answer & Explanation

. Greater than 5 degrees

Explanation

An MD angle of greater than 16 degrees on standing AP radiographs indicates a high likelihood of progression to true infantile Blount's disease. Angles less than 10 degrees are typically associated with physiologic bowing that will spontaneously resolve.

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