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4. Pediatrics MCQs

Practice Set 172 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 3421

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy sustains a completely displaced extension-type supracondylar humerus fracture. After anatomic closed reduction and percutaneous pinning in the operating room, the hand is pink and capillary refill is brisk, but the radial pulse remains absent. What is the most appropriate next step in management?

. Immediate exploration of the brachial artery
. Observation and admission for close clinical monitoring
. Stat Doppler ultrasound of the radial artery
. Emergent upper extremity arteriography
. Removal of the pins and immediate re-reduction

Correct Answer & Explanation

. Observation and admission for close clinical monitoring

Explanation

A pulseless but pink and well-perfused hand following adequate reduction and pinning of a supracondylar humerus fracture is an indication for close clinical observation and admission. Vascular exploration is only indicated if the hand remains white, cool, and poorly perfused after reduction.

Question 3422

Topic: 4. Pediatrics

A 3-year-old girl presents with progressive bowing of her left leg. A clinical radiograph demonstrates medial physeal sloping and metaphyseal beaking.

Which radiographic measurement is most predictive of progression in this condition?

. Metaphyseal-diaphyseal angle (Drennan's angle)
. Tibiofemoral angle
. Lateral distal femoral angle
. Posterior tibial slope angle
. Alpha angle

Correct Answer & Explanation

. Metaphyseal-diaphyseal angle (Drennan's angle)

Explanation

The clinical scenario and imaging suggest infantile Blount's disease. A metaphyseal-diaphyseal angle (Drennan's angle) greater than 16 degrees on AP radiographs is highly predictive of progressive infantile tibia vara requiring treatment.

Question 3423

Topic: 4. Pediatrics
A 3-year-old boy with a history of idiopathic clubfoot successfully treated with the Ponseti method presents with a recurrent deformity. Gait analysis reveals dynamic supination of the foot during the swing phase, but passive hindfoot range of motion is normal. What is the most appropriate treatment?
. Repeat serial casting followed by a repeat Achilles tenotomy
. Split anterior tibial tendon transfer (SPLATT)
. Transfer of the whole anterior tibial tendon to the lateral cuneiform
. Calcaneocuboid fusion
. Cuboid decancellation osteotomy

Correct Answer & Explanation

. Transfer of the whole anterior tibial tendon to the lateral cuneiform

Explanation

Dynamic supination in a previously treated clubfoot with a supple hindfoot is best managed by transferring the entire anterior tibial tendon to the lateral cuneiform. A split transfer (SPLATT) is less effective for this specific condition and is usually reserved for neuromuscular disorders like cerebral palsy.

Question 3424

Topic: Pediatric Hip

A 13-year-old obese male presents with acute-on-chronic left groin pain after a minor fall. He is completely unable to bear weight on the affected extremity. Radiographs reveal a slipped capital femoral epiphysis (SCFE). Compared to a patient who is able to bear weight, this patient is at the highest risk for developing which of the following complications?

. Chondrolysis
. Avascular necrosis
. Femoroacetabular impingement
. Slipped capital femoral epiphysis of the contralateral hip
. Premature physeal closure

Correct Answer & Explanation

. Avascular necrosis

Explanation

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

Question 3425

Topic: Pediatric Hip

A 4-month-old female infant is undergoing treatment with a Pavlik harness for developmental dysplasia of the hip (DDH). After 3 weeks of strict full-time wear, an ultrasound reveals that the hip remains dislocated. What is the most appropriate next step in management?

. Continue the Pavlik harness for an additional 3 weeks
. Transition to a rigid abduction orthosis
. Perform an immediate open reduction
. Perform a varus derotational osteotomy
. Wait until skeletal maturity for surgical reconstruction

Correct Answer & Explanation

. Transition to a rigid abduction orthosis

Explanation

Failure to achieve reduction in a Pavlik harness after 3 to 4 weeks necessitates abandoning the harness to prevent 'Pavlik disease' (posterior acetabular wear). The next appropriate step is typically a trial of a rigid abduction orthosis or proceeding to closed reduction with spica casting.

Question 3426

Topic: Pediatric Upper Extremity & Spine
A 5-year-old girl sustains a Gartland type III supracondylar humerus fracture. Following closed reduction and percutaneous pinning, the radial pulse is not palpable, but her hand is warm and pink with a capillary refill time of 2 seconds. What is the most appropriate next step?
. Immediate exploration of the brachial artery
. Removal of all pins and open reduction
. Perform an upper extremity angiogram
. Observation and hospital admission
. Fasciotomy of the forearm

Correct Answer & Explanation

. Observation and hospital admission

Explanation

A 'pink, pulseless' hand after reduction and pinning of a supracondylar fracture indicates adequate collateral perfusion. Current AAOS guidelines recommend close observation for 24-48 hours rather than routine surgical exploration.

Question 3427

Topic: Pediatric Lower Extremity

An infant with idiopathic clubfoot is undergoing serial casting using the Ponseti method. After sequential correction of the cavus, adductus, and varus deformities, the foot remains in 15 degrees of equinus. What is the most appropriate next step?

. Perform an extensive posteromedial release
. Perform a percutaneous Achilles tenotomy
. Continue weekly casting until equinus resolves naturally
. Apply an ankle-foot orthosis (AFO)
. Perform an anterior tibial tendon transfer

Correct Answer & Explanation

. Perform a percutaneous Achilles tenotomy

Explanation

The Ponseti method addresses deformities in the CAVE sequence: Cavus, Adductus, Varus, and Equinus. Once the midfoot score is 1 or less and only equinus remains, a percutaneous Achilles tenotomy is indicated to safely correct the equinus.

Question 3428

Topic: 4. Pediatrics

A 7-year-old child with spastic quadriplegic cerebral palsy (GMFCS Level V) has bilateral hip pain. Anteroposterior pelvic radiographs demonstrate a Reimers migration percentage of 65% bilaterally with early acetabular dysplasia. What is the most appropriate treatment?

. Bilateral adductor and iliopsoas releases
. Bilateral botulinum toxin injections to the adductors
. Bilateral proximal femoral varus derotational osteotomies (VDRO) and pelvic osteotomies
. Observation and wheelchair modifications
. Bilateral proximal femoral resection (Girdlestone procedure)

Correct Answer & Explanation

. Bilateral proximal femoral varus derotational osteotomies (VDRO) and pelvic osteotomies

Explanation

In a child with CP, a migration percentage greater than 50% indicates hip dislocation with significant dysplasia. Soft tissue releases alone are insufficient; osseous reconstruction with VDRO and pelvic osteotomy is required.

Question 3429

Topic: Pediatric Upper Extremity & Spine

A 13-year-old premenarchal girl presents with adolescent idiopathic scoliosis. Radiographs demonstrate a right thoracic curve of 32 degrees. Her Risser stage is 0. What is the most appropriate management?

. Observation with radiographs every 6 months
. Thoracolumbosacral orthosis (TLSO) for 18 hours per day
. Nighttime-only bending brace
. Posterior spinal fusion
. Anterior vertebral body tethering

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) for 18 hours per day

Explanation

Bracing is indicated for skeletally immature patients (Risser 0-2, premenarchal) with an idiopathic scoliotic curve between 25 and 45 degrees. A TLSO worn for at least 18 hours per day has been shown to significantly decrease the risk of progression to surgery.

Question 3430

Topic: Pediatric Lower Extremity

A newborn is diagnosed with severe unilateral fibular hemimelia. Which of the following knee anomalies is most commonly associated with this condition?

. Anterior cruciate ligament deficiency
. Discoid lateral meniscus
. Bipartite patella
. Posterior cruciate ligament deficiency
. Congenital patellar dislocation

Correct Answer & Explanation

. Anterior cruciate ligament deficiency

Explanation

Fibular hemimelia is a longitudinal deficiency characterized by partial or complete absence of the fibula. It is highly associated with anterior cruciate ligament (ACL) deficiency, absent lateral rays, and tarsal coalitions.

Question 3431

Topic: Pediatric Hip

An 8-year-old boy is diagnosed with Legg-Calve-Perthes disease. Radiographs show greater than 50% collapse of the lateral pillar. According to the Herring lateral pillar classification, what is his prognosis and recommended treatment?

. Pillar A, excellent prognosis, observation only
. Pillar B, fair prognosis, symptomatic treatment
. Pillar C, poor prognosis, surgical containment
. Pillar C, poor prognosis, immediate total hip arthroplasty
. Pillar B/C border, good prognosis, abduction bracing

Correct Answer & Explanation

. Pillar C, poor prognosis, surgical containment

Explanation

This patient has Lateral Pillar C disease (>50% collapse). Children older than 8 years at the time of onset with Pillar B/C or C involvement have a poorer prognosis and generally benefit from surgical containment (femoral or pelvic osteotomy).

Question 3432

Topic: 4. Pediatrics
A 14-year-old boy sustains an ankle injury while playing soccer. Radiographs show a Salter-Harris type III fracture of the anterolateral aspect of the distal tibial epiphysis. What is the mechanism of injury for this specific fracture pattern?
. Hyperplantarflexion
. Axial loading with inversion
. External rotation of the foot
. Direct blow to the lateral malleolus
. Internal rotation with dorsiflexion

Correct Answer & Explanation

. External rotation of the foot

Explanation

This is a Tillaux fracture, caused by an avulsion of the anterolateral tibial epiphysis by the anterior inferior tibiofibular ligament (AITFL). The mechanism is external rotation in an adolescent whose distal tibial physis is closing centrally and medially but remains open laterally.

Question 3433

Topic: 4. Pediatrics

A 3-year-old girl is evaluated for multiple long bone fractures following minimal trauma. Clinical exam reveals blue sclerae and mild dentinogenesis imperfecta. Genetic testing is most likely to reveal a mutation affecting the synthesis of which of the following proteins?

. Type I collagen
. Type II collagen
. Type X collagen
. Fibroblast growth factor receptor 3 (FGFR3)
. Cartilage oligomeric matrix protein (COMP)

Correct Answer & Explanation

. Type I collagen

Explanation

The clinical picture describes Osteogenesis Imperfecta (OI), which is predominantly caused by autosomal dominant mutations in the COL1A1 or COL1A2 genes. These mutations result in quantitative or qualitative defects in Type I collagen.

Question 3434

Topic: Pediatric Hip

An 18-month-old girl presents with a painless limp and a positive Trendelenburg sign. Pelvic radiographs show a unilaterally dislocated left hip with an acetabular index of 40 degrees. What is the most appropriate management?

. Pavlik harness trial
. Rigid hip abduction orthosis
. Closed reduction and spica cast
. Open reduction and spica cast with possible pelvic osteotomy
. Observation until skeletal maturity

Correct Answer & Explanation

. Open reduction and spica cast with possible pelvic osteotomy

Explanation

In a child older than 18 months presenting with DDH and significant dysplasia (acetabular index >30-35), closed reduction has a high failure and AVN rate. Open reduction, often combined with a pelvic osteotomy (e.g., Salter or Pemberton) and capsulorrhaphy, is typically required.

Question 3435

Topic: 4. Pediatrics

A 2-year-old boy is brought to the clinic for anterolateral bowing of the right tibia. Radiographs demonstrate diaphyseal narrowing and sclerosis. The parents are counseled regarding the high risk of fracture and congenital pseudarthrosis. This condition is most strongly associated with which of the following underlying disorders?

. Achondroplasia
. Neurofibromatosis type 1
. Osteogenesis imperfecta
. Multiple hereditary exostoses
. McCune-Albright syndrome

Correct Answer & Explanation

. Neurofibromatosis type 1

Explanation

Anterolateral bowing of the tibia in a young child is a classic presentation of impending congenital pseudarthrosis of the tibia (CPT). Approximately 50% to 90% of children with CPT have an underlying diagnosis of Neurofibromatosis type 1 (NF-1).

Question 3436

Topic: Pediatric Hip

A 5-month-old girl has been treated with a Pavlik harness for an initially irreducible, dislocated right hip for 4 weeks. Repeat ultrasound shows the hip remains persistently dislocated. What is the next best step in management?

. Continue Pavlik harness for 2 more weeks
. Transition to a rigid abduction orthosis (e.g., Rhino cruiser)
. Closed reduction and spica casting
. Immediate open reduction
. Observation until skeletal maturity

Correct Answer & Explanation

. Closed reduction and spica casting

Explanation

Continued use of a Pavlik harness for a dislocated hip after 3-4 weeks without successful reduction leads to 'Pavlik harness disease', which causes posterior wear of the acetabulum. Transitioning to a rigid orthosis is indicated for residual dysplasia but not for a dislocated hip, which requires closed (or open) reduction and spica casting.

Question 3437

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy falls from monkey bars and sustains a significantly displaced extension-type supracondylar humerus fracture. On presentation, his hand is pink but the radial pulse is absent. The fracture is closed reduced and pinned, and the hand remains pink, but the radial pulse remains absent. Capillary refill is brisk. What is the most appropriate next step?

. Immediate exploration of the brachial artery
. CT angiography of the upper extremity
. Release of the pins and repositioning of the fracture
. Observation and admission for neurovascular checks
. Open reduction via an anterior approach

Correct Answer & Explanation

. Observation and admission for neurovascular checks

Explanation

A 'pink, pulseless hand' following closed reduction and pinning of a supracondylar humerus fracture with good capillary refill indicates adequate collateral perfusion. Observation is the standard of care, as most pulses return within a few days and ischemic complications in this setting are exceedingly rare.

Question 3438

Topic: Pediatric Hip

A 12-year-old obese boy presents with right thigh pain and inability to bear weight after a minor trip 2 days ago. Radiographs reveal a severe, unstable right slipped capital femoral epiphysis (SCFE). During management, what is the most significant clinical risk associated with this specific type of injury?

. Chondrolysis
. Avascular necrosis of the femoral head
. Femoroacetabular impingement
. Premature hip osteoarthritis
. Nonunion of the proximal femoral physis

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Unstable SCFE is defined by the inability to bear weight even with crutches and carries a high risk of avascular necrosis (AVN), ranging from 10-50%. Prompt, gentle reduction and stabilization are crucial to minimize capsular tension and preserve the tenuous blood supply.

Question 3439

Topic: Pediatric Hip
A 7-year-old boy presents with a painless limp of 3 months duration. Radiographs show fragmentation of the capital femoral epiphysis consistent with Legg-Calvé-Perthes disease. According to the Herring lateral pillar classification, which radiographic feature is most predictive of the final functional outcome?
. Extent of the subchondral fracture (Crescent sign)
. Degree of metaphyseal cysts
. Height of the lateral portion of the capital femoral epiphysis
. Amount of epiphyseal extrusion
. Premature closure of the capital femoral physis

Correct Answer & Explanation

. Height of the lateral portion of the capital femoral epiphysis

Explanation

The Herring lateral pillar classification divides the femoral head into three pillars. The height of the lateral pillar on an AP radiograph during the fragmentation stage is the most reliable prognostic indicator for long-term outcome in Legg-Calvé-Perthes disease.

Question 3440

Topic: 4. Pediatrics

A 4-year-old boy with spastic diplegic cerebral palsy presents for routine hip surveillance. His Reimer's migration percentage is 25% bilaterally. Physical exam shows limited hip abduction to 30 degrees bilaterally. What is the recommended prophylactic surgical treatment to prevent progressive hip subluxation?

. Varus derotational osteotomy (VDRO) of the proximal femur
. Adductor and iliopsoas tendon lengthening
. Pemberton pelvic osteotomy
. Shelf arthroplasty
. Botulinum toxin injection to the hamstrings

Correct Answer & Explanation

. Varus derotational osteotomy (VDRO) of the proximal femur

Explanation

In children with cerebral palsy, soft-tissue releases (adductor and psoas lengthening) are indicated when the hip migration percentage is between 25% and 30% with decreasing abduction. Once the migration index exceeds 40%, bony reconstruction (VDRO) is typically required.

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