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4. Pediatrics MCQs

Practice Set 31 of 334

This practice set contains high-yield board review questions covering key concepts in 4. Pediatrics. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 601

Topic: Pediatric Lower Extremity
A 4-year-old child successfully treated with the Ponseti method for idiopathic clubfoot presents with a relapse characterized by dynamic supination during the swing phase of gait. Which of the following is the most appropriate management?
. Complete surgical soft tissue release
. Split anterior tibial tendon transfer (SPLATT)
. Calcaneal osteotomy
. Repeat casting followed by full anterior tibial tendon transfer
. Talectomy

Correct Answer & Explanation

. Repeat casting followed by full anterior tibial tendon transfer

Explanation

Relapsing dynamic supination in a Ponseti-treated clubfoot is best managed by a period of corrective casting to achieve a plantigrade foot, followed by a full transfer of the anterior tibial tendon to the lateral cuneiform.

Question 602

Topic: 4. Pediatrics

A 3-year-old girl presents with severe bilateral genu varum. Radiographs demonstrate a sharp angular deformity at the medial proximal tibial metaphysis with a metaphyseal-diaphyseal angle of 20 degrees. What is the most likely diagnosis?

. Physiologic bowing
. Infantile Blount disease
. Rickets
. Achondroplasia
. Osteogenesis imperfecta

Correct Answer & Explanation

. Infantile Blount disease

Explanation

A metaphyseal-diaphyseal angle greater than 16 degrees strongly suggests infantile Blount disease (tibia vara) rather than physiologic bowing. This condition requires brace treatment or surgical realignment.

Question 603

Topic: 4. Pediatrics
Which Salter-Harris fracture classification describes a fracture line that extends through the epiphysis, crosses the physis, and exits through the metaphysis?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type IV

Explanation

A Salter-Harris Type IV fracture crosses the epiphysis, physis, and metaphysis. Because it is intra-articular and disrupts the growth plate, anatomic reduction is required to prevent growth arrest.

Question 604

Topic: Pediatric Upper Extremity & Spine
A 6-year-old girl presents with an extension-type, Gartland III supracondylar fracture of the humerus with posteromedial displacement of the distal fragment. Which nerve is most commonly injured in this specific displacement pattern?
. Median nerve
. Ulnar nerve
. Radial nerve
. Musculocutaneous nerve
. Axillary nerve

Correct Answer & Explanation

. Radial nerve

Explanation

In posteromedially displaced extension-type supracondylar fractures, the proximal humerus fragment is displaced anterolaterally. This makes the radial nerve the most commonly injured structure.

Question 605

Topic: Pediatric Hip

During the treatment of Developmental Dysplasia of the Hip (DDH) with a Pavlik harness, excessive hyperflexion of the hips can lead to which of the following complications?

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

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Excessive hyperflexion in a Pavlik harness compresses the femoral nerve against the inguinal ligament, leading to nerve palsy. Excessive abduction, on the other hand, is associated with avascular necrosis of the femoral head.

Question 606

Topic: Pediatric Hip

A 10-year-old boy with chronic kidney disease presents with a stable slipped capital femoral epiphysis (SCFE) of the left hip. After in situ pinning of the left hip, what is the most appropriate management for the asymptomatic right hip?

. Observation with regular clinical follow-up
. Observation with MRI every 6 months
. Prophylactic in situ pinning
. Proximal femoral osteotomy
. Spica cast immobilization

Correct Answer & Explanation

. Prophylactic in situ pinning

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in SCFE patients with endocrine disorders or renal failure due to the very high risk of bilateral involvement. Observation may be appropriate for selected idiopathic cases, but not metabolic cases.

Question 607

Topic: Pediatric Hip

In the Herring lateral pillar classification for Legg-Calve-Perthes disease, a Group B classification indicates what degree of lateral pillar height maintenance?

. 100%
. > 50%
. < 50%
. 0%
. Extrusion of the lateral pillar

Correct Answer & Explanation

. > 50%

Explanation

In the Herring classification, Group A has no lateral pillar involvement. Group B maintains > 50% of the lateral pillar height, and Group C has < 50% lateral pillar height maintained.

Question 608

Topic: 4. Pediatrics

The pathogenesis of achondroplasia is caused by a mutation in the FGFR3 gene resulting in which of the following cellular effects?

. Decreased osteoblast differentiation
. Accelerated osteoclast activity
. Inhibition of chondrocyte proliferation
. Defective type I collagen cross-linking
. Overproduction of unmineralized osteoid

Correct Answer & Explanation

. Inhibition of chondrocyte proliferation

Explanation

Achondroplasia is caused by a gain-of-function mutation in FGFR3. This overactivity abnormally inhibits chondrocyte proliferation in the proliferative zone of the physis, leading to short-limb dwarfism.

Question 609

Topic: 4. Pediatrics

A 7-year-old child with spastic diplegic cerebral palsy demonstrates an equinus gait pattern. The Silfverskiold test reveals limited ankle dorsiflexion with the knee extended, but normal dorsiflexion with the knee flexed. Which surgical intervention is most appropriate?

. Achilles tendon lengthening
. Gastrocnemius recession
. Soleus lengthening
. Tibialis anterior tendon transfer
. Tibialis posterior tendon lengthening

Correct Answer & Explanation

. Gastrocnemius recession

Explanation

The Silfverskiold test differentiates isolated gastrocnemius contracture from combined gastrocnemius-soleus contracture. Improvement in dorsiflexion with knee flexion indicates an isolated gastrocnemius contracture, best treated with a gastrocnemius recession.

Question 610

Topic: Pediatric Hip

When evaluating an infant for developmental dysplasia of the hip (DDH) using the Graf ultrasound method, the alpha angle evaluates which of the following structures?

. The depth of the cartilaginous acetabular roof
. The depth of the bony acetabular roof
. The degree of femoral head coverage
. The angle of the femoral neck anteversion
. The concavity of the labrum

Correct Answer & Explanation

. The depth of the bony acetabular roof

Explanation

The alpha angle measures the concavity of the bony acetabular roof (ilium) relative to the straight iliac border. An alpha angle > 60 degrees is considered normal and is classified as Graf Type I.

Question 611

Topic: Pediatric Lower Extremity

A 4-year-old boy treated successfully in infancy for a right clubfoot with the Ponseti method presents with recurrent dynamic supination of the foot during the swing phase of gait. Passive range of motion is normal. What is the surgical treatment of choice?

. Repeat Achilles tenotomy
. Calcaneal sliding osteotomy
. Tibialis anterior tendon transfer
. Split tibialis posterior tendon transfer
. Triple arthrodesis

Correct Answer & Explanation

. Tibialis anterior tendon transfer

Explanation

Dynamic supination in a previously corrected clubfoot is a classic presentation of relapse. If the foot remains passively correctable, a full tibialis anterior tendon transfer (TATT) to the lateral cuneiform is the treatment of choice to balance the foot.

Question 612

Topic: 4. Pediatrics

A patient with Klippel-Feil syndrome is noted to have congenital fusion of the cervical vertebrae. Which of the following evaluations is highly recommended due to common associated anomalies?

. Ophthalmic examination for cataracts
. Renal ultrasound
. Pulmonary function tests
. Upper extremity Doppler ultrasound
. Colonoscopy

Correct Answer & Explanation

. Renal ultrasound

Explanation

Klippel-Feil syndrome is associated with several anomalies, notably genitourinary abnormalities (occurring in up to 30% of patients), congenital heart defects, and Sprengel deformity. A renal ultrasound is routinely recommended to check for an absent or horseshoe kidney.

Question 613

Topic: Pediatric Hip

A 13-year-old obese male presents with acute severe groin pain and inability to bear weight after a minor fall. Radiographs show a severe, unstable slipped capital femoral epiphysis (SCFE). Intraoperative forceful reduction of the slip is avoided primarily to prevent which of the following?

. Chondrolysis
. Femoral nerve injury
. Avascular necrosis of the femoral head
. Premature physeal closure
. Subtrochanteric fracture

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Forceful reduction or manipulation of an unstable SCFE significantly increases the risk of stretching or tearing the vulnerable posterior retinacular vessels, leading to avascular necrosis (AVN) of the femoral head. In situ pinning without forceful reduction is standard.

Question 614

Topic: 4. Pediatrics

In a child with congenital coxa vara, surgical correction with a valgus producing proximal femoral osteotomy is universally indicated when the Hilgenreiner-epiphyseal (H-E) angle exceeds:

. 20 degrees
. 30 degrees
. 45 degrees
. 60 degrees
. 80 degrees

Correct Answer & Explanation

. 60 degrees

Explanation

Surgery is strictly indicated for congenital coxa vara when the Hilgenreiner-epiphyseal (H-E) angle is greater than 60 degrees due to the high risk of progression. Angles between 45 and 59 degrees are typically observed, while those < 45 degrees often resolve spontaneously.

Question 615

Topic: Pediatric Hip
A 12-year-old boy presents with a left Slipped Capital Femoral Epiphysis (SCFE). Which of the following is the strongest indication for prophylactic in situ pinning of the contralateral asymptomatic hip?
. Age greater than 14 years
. Female gender
. Presence of an endocrine disorder
. Body mass index > 95th percentile
. Grade III slip on the affected side

Correct Answer & Explanation

. Presence of an endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy) due to the high risk of bilateral involvement. Age less than 10 or greater than 16 also increases the risk of bilaterality.

Question 616

Topic: Pediatric Hip

An infant is being treated with a Pavlik harness for Developmental Dysplasia of the Hip (DDH). Excessive flexion of the hips in the harness increases the risk of which of the following complications?

. Avascular necrosis of the femoral head
. Femoral nerve palsy
. Sciatic nerve palsy
. Inferior dislocation of the hip
. Knee flexion contracture

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Excessive flexion of the hip in a Pavlik harness can cause femoral nerve palsy, which manifests as decreased active knee extension. Conversely, excessive abduction places the vascular supply at risk, leading to avascular necrosis.

Question 617

Topic: Pediatric Hip
In Legg-Calvé-Perthes disease, which of the following radiographic findings (from the lateral pillar classification) is most predictive of the long-term outcome?
. Gage sign
. Calcification lateral to the epiphysis
. Height of the lateral pillar of the capital femoral epiphysis
. Presence of a subchondral fracture
. Metaphyseal cysts

Correct Answer & Explanation

. Height of the lateral pillar of the capital femoral epiphysis

Explanation

The Herring lateral pillar classification, based on the height of the lateral pillar of the capital femoral epiphysis during the fragmentation stage, is the most accurate prognostic indicator for long-term outcome in Legg-Calvé-Perthes disease.

Question 618

Topic: Pediatric Lower Extremity

A 4-year-old child previously treated for idiopathic clubfoot with the Ponseti method presents with dynamic supination deformity during the swing phase of gait. There is no fixed deformity. What is the most appropriate next step in management?

. Achilles tendon lengthening
. Tibialis anterior tendon transfer to the lateral cuneiform
. Split tibialis posterior tendon transfer
. Calcaneocuboid fusion
. Application of a hinged ankle-foot orthosis

Correct Answer & Explanation

. Tibialis anterior tendon transfer to the lateral cuneiform

Explanation

Dynamic supination during the swing phase in a previously corrected clubfoot is typically caused by a strong tibialis anterior acting on a flexible foot. The standard treatment is transferring the tibialis anterior tendon to the lateral cuneiform to balance the foot.

Question 619

Topic: 4. Pediatrics

Which of the following parameters is the most critical to monitor for hip displacement in a child with spastic quadriplegic cerebral palsy?

. Neck-shaft angle
. Reimer's migration percentage
. Center-edge angle of Wiberg
. Acetabular index
. Alpha angle

Correct Answer & Explanation

. Reimer's migration percentage

Explanation

Reimer's migration percentage is the standard radiographic measurement used to monitor hip subluxation in children with cerebral palsy. A migration percentage greater than 30% typically prompts consideration for surgical intervention to prevent complete dislocation.

Question 620

Topic: 4. Pediatrics
A 2-year-old obese girl presents with bilateral bowing of the legs. Radiographs demonstrate an abrupt sharp angulation of the medial proximal tibial metaphysis with a metaphyseal-diaphyseal angle (Drennan angle) of 18 degrees. What is the most appropriate management?
. Reassurance and annual observation
. Vitamin D supplementation
. Knee-ankle-foot orthosis (KAFO)
. Proximal tibial valgus osteotomy
. Guided growth with a lateral tension band

Correct Answer & Explanation

. Knee-ankle-foot orthosis (KAFO)

Explanation

For early-onset (infantile) Blount's disease in children under age 3 with Langenskiöld stage I or II, bracing with a KAFO is the initial treatment of choice. A metaphyseal-diaphyseal angle >16 degrees strongly suggests true Blount disease rather than physiologic bowing.

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