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4. Pediatrics MCQs

Practice Set 183 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 3641

Topic: Pediatric Lower Extremity
A 4-year-old girl presents with progressive bilateral genu varum. Radiographs show Langenskiold stage III changes of the proximal medial tibia with a metaphyseal-diaphyseal angle of 18 degrees. What is the recommended treatment?
. Reassurance and observation
. Knee-ankle-foot orthosis (KAFO) bracing
. Proximal tibial valgus osteotomy
. Medial tibial epiphysiodesis
. Lateral tibial hemiepiphysiodesis

Correct Answer & Explanation

. Proximal tibial valgus osteotomy

Explanation

In infantile Blount disease, children older than 3 years with advanced Langenskiold stages (II or III) and severe deformity require surgical correction via a proximal tibial valgus osteotomy. Bracing is generally ineffective after age 3.

Question 3642

Topic: 4. Pediatrics
A 14-year-old boy twists his ankle while playing soccer. X-rays show a Salter-Harris III fracture of the anterolateral distal tibia (Tillaux fracture). This fracture pattern is primarily determined by which of the following mechanisms of distal tibial physeal closure?
. Central to lateral to medial
. Central to medial to lateral
. Medial to lateral to central
. Lateral to central to medial
. Anterior to posterior

Correct Answer & Explanation

. Central to medial to lateral

Explanation

The distal tibial physis closes in a predictable sequence: central, then medial, and finally lateral. The open anterolateral physis remains vulnerable to avulsion by the anterior inferior tibiofibular ligament, resulting in a Tillaux fracture.

Question 3643

Topic: 4. Pediatrics

A 2-year-old child presents with an anterolateral bow of the tibia and a pseudarthrosis visible on radiographs. This condition is most strongly associated with which of the following genetic disorders?

. Osteogenesis Imperfecta
. Neurofibromatosis Type 1
. Marfan Syndrome
. Ehlers-Danlos Syndrome
. Achondroplasia

Correct Answer & Explanation

. Neurofibromatosis Type 1

Explanation

Congenital pseudarthrosis of the tibia (CPT) is characterized by anterolateral bowing and has a strong clinical association with Neurofibromatosis Type 1 (NF1), which is present in over 50% of these patients.

Question 3644

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy presents with a Gartland type III supracondylar humerus fracture. The hand is pink but pulseless. After closed reduction and percutaneous pinning, the hand remains pink and pulseless. What is the most appropriate next step in management?
. Immediate vascular exploration
. Observation with close monitoring
. Administration of IV heparin
. Removal of the pins and open reduction
. Angiography

Correct Answer & Explanation

. Observation with close monitoring

Explanation

In a pediatric supracondylar humerus fracture with a pink, pulseless hand after anatomical reduction and pinning, observation for 24-48 hours is indicated. The collateral circulation is adequate to perfuse the hand, and vascular exploration is not immediately required.

Question 3645

Topic: Pediatric Hip

A 4-year-old child presents with untreated unilateral developmental dysplasia of the hip. Which of the following surgical interventions is most commonly required to achieve and maintain a stable reduction?

. Closed reduction and spica cast
. Open reduction and spica casting only
. Open reduction, femoral shortening derotation osteotomy, and pelvic osteotomy
. Varus derotation osteotomy alone
. Shelf arthroplasty

Correct Answer & Explanation

. Open reduction, femoral shortening derotation osteotomy, and pelvic osteotomy

Explanation

In children older than 3 years with untreated DDH, open reduction alone is associated with a high risk of avascular necrosis and redislocation. Femoral shortening osteotomy is necessary to decompress the joint, combined with a pelvic osteotomy to provide adequate anterolateral coverage.

Question 3646

Topic: Pediatric Hip

A 12-year-old obese boy presents with left knee pain and an antalgic gait. Radiographs reveal a severe slipped capital femoral epiphysis (SCFE) with a slip angle of 60 degrees. After in situ pinning of the left hip, which of the following is the most accepted indication for prophylactic pinning of the contralateral asymptomatic hip?

. All patients regardless of age or endocrine status
. Male gender and obesity alone
. Endocrine disorders, radiation therapy, or age less than 10 years
. Family history of SCFE
. A slip angle greater than 50 degrees on the affected side

Correct Answer & Explanation

. Endocrine disorders, radiation therapy, or age less than 10 years

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with endocrine disorders, prior radiation therapy, or those presenting at an atypically young age (girls <10, boys <12). These patients have a significantly higher risk of sequential bilateral involvement.

Question 3647

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvรฉ-Perthes disease. Radiographs demonstrate >50% loss of lateral pillar height. According to the Herring lateral pillar classification, what is the expected outcome without surgical intervention?
. Excellent outcome with full remodeling
. Good outcome with minimal residual deformity
. Fair outcome but no increased risk of early osteoarthritis
. Poor outcome with a high risk of early-onset osteoarthritis
. Spontaneous fusion of the hip joint

Correct Answer & Explanation

. Poor outcome with a high risk of early-onset osteoarthritis

Explanation

Loss of more than 50% of the lateral pillar height corresponds to Herring Group C. This group has a poor prognosis with a high likelihood of significant residual deformity (coxa magna, severe flattening) and early-onset osteoarthritis.

Question 3648

Topic: Pediatric Lower Extremity

During the initial casting for an infant with a rigid idiopathic clubfoot using the Ponseti method, what is the first deformity that must be corrected?

. Equinus
. Cavus
. Varus
. Adduction
. Tibial torsion

Correct Answer & Explanation

. Cavus

Explanation

The Ponseti method corrects the deformities of clubfoot in a specific sequence summarized by the acronym CAVE. Cavus is corrected first by elevating the first ray to align the forefoot with the hindfoot.

Question 3649

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy falls from monkey bars and sustains a Gartland Type III supracondylar humerus fracture. On examination, the radial pulse is absent, but the hand is warm, pink, and has a capillary refill of less than 2 seconds. After prompt closed reduction and percutaneous pinning, the pulse remains absent but the hand remains well-perfused. What is the most appropriate next step?
. Immediate open exploration of the brachial artery
. Angiography to localize the arterial injury
. Observation and admission for neurovascular monitoring
. Removal of the pins and open reduction
. Administration of thrombolytics

Correct Answer & Explanation

. Observation and admission for neurovascular monitoring

Explanation

A "pulseless but pink" hand following reduction and pinning of a supracondylar fracture indicates adequate collateral circulation. Current guidelines recommend close observation and monitoring rather than immediate surgical exploration.

Question 3650

Topic: 4. Pediatrics

A 2-year-old child presents with bilateral genu varum. Radiographs reveal medial metaphyseal beaking of the proximal tibia. Which of the following radiographic measurements most reliably differentiates infantile Blount disease from physiologic bowing?

. Mechanical axis deviation
. Tibiofemoral angle
. Metaphyseal-diaphyseal angle of Drennan
. Anatomic axis of the femur
. Joint line convergence angle

Correct Answer & Explanation

. Metaphyseal-diaphyseal angle of Drennan

Explanation

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

Question 3651

Topic: 4. Pediatrics

A 3-year-old boy with multiple recurrent fractures, blue sclerae, and dentinogenesis imperfecta is diagnosed with osteogenesis imperfecta. This condition is most commonly caused by a mutation affecting which of the following?

. Type II collagen
. Type I collagen
. Fibroblast growth factor receptor 3 (FGFR3)
. Fibrillin-1
. Cartilage oligomeric matrix protein (COMP)

Correct Answer & Explanation

. Type I collagen

Explanation

Osteogenesis imperfecta is primarily caused by autosomal dominant mutations in the COL1A1 or COL1A2 genes, which encode the chains of Type I collagen. This leads to brittle bones, blue sclerae, and abnormal dentition.

Question 3652

Topic: 4. Pediatrics

A 6-year-old child with spastic quadriplegic cerebral palsy has a migration percentage of 45% on an AP pelvis radiograph. He has pain with hip range of motion and limited abduction. What is the most appropriate surgical management?

. Adductor tenotomy alone
. Bilateral selective dorsal rhizotomy
. Varus derotational osteotomy (VDRO) of the proximal femur with pelvic osteotomy
. Total hip arthroplasty
. Proximal femoral resection arthroplasty

Correct Answer & Explanation

. Varus derotational osteotomy (VDRO) of the proximal femur with pelvic osteotomy

Explanation

In a child with cerebral palsy and significant hip subluxation (migration percentage >40%), a bony reconstruction consisting of a proximal femoral varus derotational osteotomy (VDRO) and a pelvic osteotomy is the gold standard.

Question 3653

Topic: Pediatric Lower Extremity
A 3-year-old boy treated for idiopathic clubfoot with the Ponseti method presents with a recurrence of the deformity. Examination reveals dynamic supination of the foot during the swing phase of gait. Passive range of motion demonstrates fully correctable deformities. What is the most appropriate next step in management?
. Posteromedial release
. Split anterior tibial tendon transfer (SPLATT)
. Talonavicular arthrodesis
. Tibialis posterior tendon transfer
. Achilles tendon lengthening alone

Correct Answer & Explanation

. Split anterior tibial tendon transfer (SPLATT)

Explanation

Dynamic supination in a relapsed Ponseti-treated clubfoot with a flexible deformity is typically managed with a split anterior tibial tendon transfer (SPLATT) to the lateral cuneiform. This is often combined with an Achilles tendon lengthening if equinus is present.

Question 3654

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy sustains a completely displaced posterolateral supracondylar humerus fracture. Upon presentation, he has a pulseless but well-perfused (pink) hand. Closed reduction and percutaneous pinning are performed, achieving an anatomic reduction. Postoperatively, the hand remains pink but the radial pulse is still absent. What is the most appropriate management?

. Immediate open exploration of the brachial artery
. Observation and hospital admission for close neurovascular monitoring
. Color duplex ultrasound of the brachial artery
. CT angiography of the upper extremity
. Removal of pins and open reduction

Correct Answer & Explanation

. Observation and hospital admission for close neurovascular monitoring

Explanation

In a pulseless, pink hand following anatomic reduction and pinning of a supracondylar fracture, observation is the standard of care. Collateral circulation provides adequate perfusion; open exploration is indicated only for a pulseless, pale (ischemic) hand after reduction.

Question 3655

Topic: Pediatric Hip

A 6-week-old female is undergoing treatment with a Pavlik harness for developmental dysplasia of the hip (DDH). During the follow-up visit, the parents report that the child has stopped moving her left leg. Examination reveals decreased active knee extension and an absent patellar reflex on the left side. What is the most likely cause of this finding?

. Avascular necrosis of the femoral head
. Excessive hip flexion in the harness causing femoral nerve palsy
. Excessive hip abduction in the harness causing obturator nerve palsy
. Septic arthritis of the hip
. Transient synovitis

Correct Answer & Explanation

. Excessive hip flexion in the harness causing femoral nerve palsy

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment due to excessive hip flexion. The initial management is to temporarily remove or adjust the harness to decrease the flexion, which usually leads to spontaneous recovery.

Question 3656

Topic: Pediatric Hip

An 11-year-old boy presents with a 4-week history of left groin pain and a limp. Radiographs confirm a mild, stable slipped capital femoral epiphysis (SCFE) of the left hip. The right hip is radiographically normal. Which of the following is the strongest indication for prophylactic pinning of the contralateral (right) hip?

. Patient age of 11 years
. Presence of a positive Drehmann sign on the right
. Endocrinopathy such as hypothyroidism
. Family history of SCFE
. Body mass index in the 90th percentile

Correct Answer & Explanation

. Endocrinopathy such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is strongly indicated in patients with underlying endocrinopathies (e.g., hypothyroidism, renal osteodystrophy) or prior radiation therapy. These conditions significantly increase the risk of bilateral involvement.

Question 3657

Topic: 4. Pediatrics
A 7-year-old boy with spastic diplegic cerebral palsy with GMFCS level III presents with a progressive crouch gait. Physical examination reveals fixed knee flexion contractures of 15 degrees bilaterally. Which of the following interventions is most appropriate to address this specific deformity?
. Hamstring lengthening and ground reaction ankle-foot orthoses
. Selective dorsal rhizotomy
. Distal femoral extension osteotomies and patellar tendon advancements
. Bilateral Achilles tendon lengthenings
. Intrathecal baclofen pump placement

Correct Answer & Explanation

. Distal femoral extension osteotomies and patellar tendon advancements

Explanation

Fixed knee flexion contractures (>10-15 degrees) in a crouch gait are best treated with bony procedures such as distal femoral extension osteotomies, often combined with patellar tendon advancement. Soft tissue lengthening alone is insufficient for fixed bony/capsular deformities.

Question 3658

Topic: 4. Pediatrics
A 6-year-old boy with Sillence Type III osteogenesis imperfecta presents with progressive anterolateral bowing of his bilateral femurs, leading to an inability to ambulate. He has been receiving IV pamidronate for 2 years. Which of the following surgical strategies is most appropriate?
. Application of bilateral guided growth plates (8-plates)
. Multi-level osteotomies and placement of rigid intramedullary nails
. Multi-level osteotomies and placement of telescopic intramedullary nails
. External fixation for gradual deformity correction
. Bilateral long leg bracing

Correct Answer & Explanation

. Multi-level osteotomies and placement of telescopic intramedullary nails

Explanation

In a growing child with severe bowing from osteogenesis imperfecta, the standard surgical treatment is multi-level "shish kebab" osteotomies with telescopic (growing) intramedullary nails. This accommodates future growth and prevents recurrent deformities.

Question 3659

Topic: 4. Pediatrics

A newborn male is noted to have unilateral foreshortening of the right lower extremity. Radiographs reveal complete absence of the fibula, a shortened tibia with anterior bowing, and a 3-ray foot. Which of the following knee anomalies is most commonly associated with this presentation?

. Anterior cruciate ligament (ACL) deficiency
. Posterior cruciate ligament (PCL) deficiency
. Congenital dislocation of the patella
. Bipartite patella
. Discoid lateral meniscus

Correct Answer & Explanation

. Anterior cruciate ligament (ACL) deficiency

Explanation

Fibular hemimelia is frequently associated with an absent or deficient anterior cruciate ligament (ACL), leading to anteroposterior instability of the knee. Other common findings include a ball-and-socket ankle, tarsal coalitions, and absent lateral rays.

Question 3660

Topic: 4. Pediatrics

A 3-year-old boy presents to the emergency department with a spiral fracture of the midshaft femur. He was reportedly running and tripped over a rug. The parents delayed bringing him in for two days. Upon examination, there are multiple bruises in various stages of healing on his back. What is the next most appropriate step in management regarding the mechanism of injury?

. Report suspected child abuse to child protective services immediately
. Obtain a DEXA scan to rule out osteogenesis imperfecta
. Consult hematology for a bleeding disorder workup
. Accept the history as a common mechanism for spiral fractures in toddlers
. Obtain a skeletal survey and defer reporting until abuse is confirmed radiographically

Correct Answer & Explanation

. Report suspected child abuse to child protective services immediately

Explanation

A femur fracture in a non-ambulatory child or one with a suspicious mechanism/delay in care, combined with bruises in varied stages of healing, is highly indicative of non-accidental trauma. The physician is legally obligated to report suspected abuse immediately.

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