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4. Pediatrics MCQs

Practice Set 179 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 3561

Topic: 4. Pediatrics
A 6-year-old boy with Osteogenesis Imperfecta (Sillence Type III) has sustained multiple femoral bowing deformities and recurrent fractures. He is scheduled for bilateral femoral rodding. Which of the following devices is most appropriate to accommodate longitudinal bone growth?
. Flexible titanium intramedullary nails
. Rigid stainless steel intramedullary nails
. Fassier-Duval telescoping nails
. Locking compression plates
. Circular external fixator

Correct Answer & Explanation

. Fassier-Duval telescoping nails

Explanation

In growing children with severe osteogenesis imperfecta, telescoping intramedullary nails (e.g., Fassier-Duval) are the implants of choice. They provide internal splinting while elongating with the growing bone.

Question 3562

Topic: Pediatric Lower Extremity

A 3-year-old boy treated with the Ponseti method for idiopathic clubfoot presents with dynamic supination of the foot during the swing phase of gait. Passive range of motion is full, and dorsiflexion is 15 degrees. What is the most appropriate management?

. Anterior tibial tendon transfer to the lateral cuneiform
. Achilles tendon lengthening
. Posterior medial release
. Serial casting
. Split posterior tibial tendon transfer

Correct Answer & Explanation

. Anterior tibial tendon transfer to the lateral cuneiform

Explanation

Dynamic supination in a previously treated clubfoot with adequate passive dorsiflexion is best treated with an anterior tibial tendon transfer to the lateral cuneiform. This corrects the muscle imbalance causing the deformity.

Question 3563

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy sustains a completely displaced extension-type supracondylar humerus fracture. Examination shows an inability to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which nerve is most likely injured?

. Anterior interosseous nerve
. Posterior interosseous nerve
. Ulnar nerve
. Superficial radial nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar humerus fractures. It innervates the flexor pollicis longus and flexor digitorum profundus to the index and middle fingers.

Question 3564

Topic: Pediatric Hip

A 5-week-old female infant is treated with a Pavlik harness for a dislocated left hip. After 4 weeks of strict harness wear, ultrasound reveals the hip remains dislocated. What is the next best step in management?

. Continue the harness for 3 additional weeks
. Discontinue the harness and proceed with closed reduction and spica casting
. Add a hip abduction wedge
. Immediate open reduction
. Proximal femoral varus derotational osteotomy

Correct Answer & Explanation

. Discontinue the harness and proceed with closed reduction and spica casting

Explanation

If a hip remains dislocated after 3-4 weeks of Pavlik harness treatment, the harness must be discontinued to avoid Pavlik harness disease (acetabular damage). The next appropriate step is a closed reduction and spica casting or transitioning to a rigid abduction orthosis.

Question 3565

Topic: Pediatric Hip

A 12-year-old boy presents with an acute-on-chronic, unstable slipped capital femoral epiphysis of the left hip. He undergoes uncomplicated in-situ screw fixation. Which of the following is the strongest indication for prophylactic pinning of the contralateral asymptomatic hip?

. Age greater than 14 years
. Male sex
. Endocrine disorder such as hypothyroidism
. Obesity
. Severe slip angle on the affected side

Correct Answer & Explanation

. Endocrine disorder such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with endocrine or metabolic disorders due to the high risk of bilateral involvement. Age less than 10 years or an open triradiate cartilage are also strong indications.

Question 3566

Topic: 4. Pediatrics

A 3-year-old girl is diagnosed with infantile Blount disease (Tibia vara) with a metaphyseal-diaphyseal angle of 18 degrees on standing AP radiographs. What is the most appropriate initial management?

. Observation and reassurance
. Knee-ankle-foot orthoses (KAFOs)
. Proximal tibial valgus osteotomy
. Guided growth with eight-Plates
. Epiphyseal distraction

Correct Answer & Explanation

. Knee-ankle-foot orthoses (KAFOs)

Explanation

For infantile Blount disease in a child under 3-4 years old with a metaphyseal-diaphyseal angle greater than 16 degrees, daytime bracing with KAFOs is the initial treatment of choice. Surgery is indicated if bracing fails or if the child is older than 4 years.

Question 3567

Topic: 4. Pediatrics

In a 7-year-old child with spastic quadriplegic cerebral palsy, the hip migration percentage is measured at 45% on an AP pelvis radiograph. The child has hip pain and limited abduction. What is the most appropriate surgical intervention?

. Adductor tenotomy alone
. Proximal femoral varus derotational osteotomy (VDRO) and pelvic osteotomy
. Total hip arthroplasty
. Botulinum toxin injection to the adductors
. Selective dorsal rhizotomy

Correct Answer & Explanation

. Proximal femoral varus derotational osteotomy (VDRO) and pelvic osteotomy

Explanation

A hip migration percentage greater than 40% in a symptomatic child with cerebral palsy indicates significant subluxation requiring bony reconstruction. Soft tissue releases alone are insufficient, making a proximal femoral VDRO combined with a pelvic osteotomy the standard of care.

Question 3568

Topic: 4. Pediatrics

A 6-year-old sustains the fracture pattern shown in the

radiograph. Upon evaluation in the emergency department, the child's hand is pink and well-perfused, but the radial pulse is absent. What is the most appropriate next step in management?

. Immediate CT angiography of the upper extremity
. Closed reduction and percutaneous pinning
. Open exploration of the brachial artery
. Observation and application of a long-arm cast
. Doppler ultrasound of the brachial artery

Correct Answer & Explanation

. Closed reduction and percutaneous pinning

Explanation

A pink, pulseless hand after a severely displaced supracondylar humerus fracture is a clinical indication for urgent closed reduction and percutaneous pinning. Vascular exploration is generally only indicated if the hand remains white and ischemic after adequate reduction.

Question 3569

Topic: 4. Pediatrics

A 6-week-old infant treated with a Pavlik harness for developmental dysplasia of the hip presents to the clinic. The mother reports that the infant has stopped kicking her left leg. On examination, there is decreased active extension of the left knee, though hip flexion and ankle movements are intact. What is the most likely cause of this finding?

. Femoral nerve palsy due to excessive hip flexion
. Obturator nerve palsy from tight posterior straps
. Avascular necrosis of the femoral head
. Sciatic nerve palsy from excessive abduction
. Inferior hip dislocation

Correct Answer & Explanation

. Femoral nerve palsy due to excessive hip flexion

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment caused by excessive hip flexion. The harness should be temporarily discontinued or adjusted; recovery of the nerve is typically spontaneous within a few days to weeks.

Question 3570

Topic: Pediatric Lower Extremity
A 3-year-old boy, who was treated successfully for idiopathic clubfoot as an infant using the Ponseti method, now presents with recurrent dynamic supination of the foot during the swing phase of gait. Passive range of motion is fully correctable. What is the most appropriate surgical management?
. Achilles tendon lengthening
. Split anterior tibial tendon transfer (SPLATT)
. Tibialis anterior tendon transfer to the lateral cuneiform
. Extensive posterior-medial-lateral release
. Lateral closing wedge calcaneal osteotomy

Correct Answer & Explanation

. Tibialis anterior tendon transfer to the lateral cuneiform

Explanation

Dynamic supination during gait in a relapsed Ponseti-treated clubfoot, when passively correctable, is best treated with a full tibialis anterior tendon transfer to the lateral cuneiform. This functionally balances the foot during dorsiflexion and prevents further relapse.

Question 3571

Topic: Pediatric Hip

An 11-year-old girl with obesity presents with a unilateral slipped capital femoral epiphysis (SCFE). Which of the following factors most strongly indicates the need for prophylactic in situ fixation of her contralateral, asymptomatic hip?

. Patient's chronologic age
. A modified Oxford bone age score of 16
. Closed triradiate cartilage on radiographs
. Presentation with an acute slip
. Presence of a recognized endocrine disorder

Correct Answer & Explanation

. Presence of a recognized endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip is strongly indicated in patients with endocrine disorders (e.g., hypothyroidism), previous pelvic radiation, or an open triradiate cartilage (modified Oxford bone age score < 16). Endocrine disorders dramatically increase the risk of bilateral involvement.

Question 3572

Topic: Pediatric Hip
An 8-year-old boy is diagnosed with Legg-Calvรฉ-Perthes disease. Radiographs reveal fragmentation with exactly 50% maintenance of the lateral pillar height. According to the Herring lateral pillar classification, into which group does this patient fall, and what is the current treatment recommendation?
. Group A; conservative management
. Group B; conservative management with bracing
. Group B/C border; surgical containment
. Group C; conservative management
. Group C; surgical containment

Correct Answer & Explanation

. Group C; surgical containment

Explanation

Maintaining exactly 50% lateral pillar height defines the Herring B/C border group. In children over 8 years of age at disease onset, patients in the B or B/C border groups have significantly better radiographic outcomes with surgical containment (e.g., proximal femoral varus osteotomy).

Question 3573

Topic: 4. Pediatrics

A 6-year-old girl with spastic quadriplegic cerebral palsy (GMFCS Level V) is found to have a Reimer's migration index of 50% on screening pelvic radiographs. She is completely asymptomatic. What is the most appropriate management?

. Observation with repeat radiographs in 1 year
. Botulinum toxin injections to the adductors
. Bilateral adductor and psoas release
. Varus derotational osteotomy (VDRO) of the proximal femur with or without pelvic osteotomy
. Total hip arthroplasty

Correct Answer & Explanation

. Varus derotational osteotomy (VDRO) of the proximal femur with or without pelvic osteotomy

Explanation

In a child with cerebral palsy, a migration percentage >40% typically requires bony reconstructive surgery (VDRO and frequently a pelvic osteotomy). Soft tissue releases alone are inadequate for this degree of subluxation and will not prevent progression to painful dislocation.

Question 3574

Topic: 4. Pediatrics

An infant is evaluated for a congenitally short lower extremity. Radiographs reveal a short femur with severe coxa vara and a radiolucent defect in the subtrochanteric region. The femoral head is seated well within the acetabulum (Aitken Class A Proximal Focal Femoral Deficiency). What is the expected long-term natural history of the subtrochanteric defect?

. It progressively widens requiring early amputation
. It forms a symptomatic pseudarthrosis
. It ossifies spontaneously and forms a bony connection
. It undergoes malignant transformation in the second decade
. It requires vascularized fibular grafting for stability

Correct Answer & Explanation

. It ossifies spontaneously and forms a bony connection

Explanation

In Aitken Class A PFFD, there is initially a cartilaginous (radiolucent) connection between the femoral neck and the shaft. With time, this defect characteristically ossifies spontaneously, establishing a continuous bony connection but typically resulting in a severe residual coxa vara deformity.

Question 3575

Topic: Pediatric Hip

A 13-year-old boy with a 2-day history of inability to bear weight on his right leg is diagnosed with an unstable slipped capital femoral epiphysis (SCFE). He is taken to the operating room for urgent in situ pinning. Which of the following intraoperative maneuvers or findings most significantly increases the risk of developing avascular necrosis (AVN)?

. Capsulotomy to decompress the joint
. Inadvertent reduction of the slip during patient positioning
. Use of two cannulated screws instead of one
. Approaching the proximal femur from the lateral aspect
. Pinning the epiphysis strictly in situ without manipulation

Correct Answer & Explanation

. Pinning the epiphysis strictly in situ without manipulation

Explanation

Inadvertent or forceful reduction of an unstable SCFE dramatically increases the risk of avascular necrosis by disrupting the already compromised retinacular blood supply. Pinning in situ is the gold standard to minimize this risk.

Question 3576

Topic: Pediatric Upper Extremity & Spine
A 5-year-old girl presents with a Gartland type III supracondylar humerus fracture. On initial examination, her hand is pink but lacks a palpable radial pulse. Following closed reduction and percutaneous pinning, the hand remains well-perfused and pink, but the radial pulse is still absent on palpation and Doppler. What is the most appropriate next step in management?
. Observation and hospital admission for close neurovascular monitoring
. Immediate arteriography
. Open exploration of the brachial artery
. Removal of the percutaneous pins and re-reduction
. Prophylactic fasciotomy of the forearm

Correct Answer & Explanation

. Observation and hospital admission for close neurovascular monitoring

Explanation

A "pink, pulseless" hand following adequate reduction and pinning of a supracondylar fracture typically has sufficient collateral circulation and should be observed. Open vascular exploration is indicated if the hand remains "white and pulseless" after reduction.

Question 3577

Topic: Pediatric Hip

A 6-week-old infant is undergoing treatment for developmental dysplasia of the hip (DDH) with a Pavlik harness. During a routine follow-up, the parents report that the infant is no longer kicking the affected leg as much. On examination, there is decreased active extension of the knee on the affected side, but hip flexion remains active. What is the most likely cause of this finding?

. Avascular necrosis of the femoral head
. Femoral nerve palsy
. Sciatic nerve palsy
. Obturator nerve palsy
. Superior gluteal nerve palsy

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment, usually caused by excessive hyperflexion of the hip. It presents as decreased active knee extension and usually resolves after temporary harness adjustment or removal.

Question 3578

Topic: Pediatric Lower Extremity

An infant is undergoing serial casting for an idiopathic clubfoot utilizing the Ponseti method. To ensure successful correction and minimize the risk of a rocker-bottom deformity, what is the correct sequence of deformity correction?

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

Correct Answer & Explanation

. Adductus, Cavus, Varus, Equinus

Explanation

The Ponseti method corrects the clubfoot deformities in a specific sequence: Cavus, Adductus, Varus, and finally Equinus (the mnemonic CAVE). Attempting to correct equinus early can lead to a rocker-bottom foot.

Question 3579

Topic: 4. Pediatrics
A 13-year-old girl sustains an external rotation injury to her ankle. Radiographs demonstrate a Salter-Harris type III fracture of the anterolateral aspect of the distal tibial epiphysis. What anatomical structure is responsible for the avulsion of this specific fracture fragment?
. Anterior inferior tibiofibular ligament
. Deltoid ligament
. Calcaneofibular ligament
. Posterior inferior tibiofibular ligament
. Anterior talofibular ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament

Explanation

This describes a juvenile Tillaux fracture, which occurs due to avulsion by the anterior inferior tibiofibular ligament (AITFL). It happens in adolescents because the distal tibial physis closes from central to anteromedial to posteromedial, leaving the anterolateral physis open and vulnerable last.

Question 3580

Topic: 4. Pediatrics
A 4-year-old boy presents with severe, progressive bilateral bowing of his legs. Standing radiographs reveal depression of the medial tibial plateaus with metaphyseal beaking. The metaphyseal-diaphyseal angle is measured at 20 degrees bilaterally, and he is classified as Langenskiold stage III. What is the most appropriate management?
. Reassurance as this is physiologic bowing
. Knee-ankle-foot orthosis (KAFO) bracing
. Proximal tibial valgus osteotomies
. High-dose Vitamin D supplementation
. Guided growth via medial hemiepiphysiodesis alone

Correct Answer & Explanation

. Proximal tibial valgus osteotomies

Explanation

In infantile Blount disease, children older than 3 years or those with a metaphyseal-diaphyseal angle > 16 degrees and Langenskiold stage III or higher are unlikely to respond to bracing. Proximal tibial corrective osteotomy is the standard of care to prevent permanent joint deformity.

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