Menu

4. Pediatrics MCQs

Practice Set 231 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 4601

Topic: Pediatric Hip

A 12-year-old boy with a BMI of 32 presents with a left slipped capital femoral epiphysis (SCFE). Prophylactic pinning of the contralateral asymptomatic hip is most strongly indicated in which of the following scenarios?

. The patient is an African American male
. The patient presents with a chronic SCFE rather than an acute one
. The patient has underlying renal osteodystrophy
. The patient has a closed triradiate cartilage on the AP pelvis radiograph
. The patient has a positive family history of SCFE

Correct Answer & Explanation

. The patient is an African American male

Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial for idiopathic cases but is strongly indicated in patients with underlying endocrinopathies or metabolic bone diseases (e.g., renal osteodystrophy, hypothyroidism, panhypopituitarism) and in patients receiving radiation therapy, because the risk of contralateral slip approaches 50-100% in these populations.

Question 4602

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 4603

Topic: 4. Pediatrics

A 7-year-old with spastic quadriplegic cerebral palsy has progressive hip subluxation with a Reimer's migration index of 45%. The primary deforming forces responsible for this progressive subluxation are spasticity of which muscle groups?

. Abductors and extensors
. Adductors and flexors
. Adductors and internal rotators
. Abductors and external rotators
. Hamstrings and quadriceps

Correct Answer & Explanation

. Abductors and extensors

Explanation

In cerebral palsy, progressive hip subluxation and dislocation are driven by the muscle imbalance caused by spasticity. The spastic adductors and hip flexors (iliopsoas) overpower the relatively weaker abductors and extensors, driving the femoral head posteromedially and causing a progressive valgus and anteverted proximal femur, which leads to superolateral uncovering and eventual dislocation.

Question 4604

Topic: Pediatric Upper Extremity & Spine

A 4-year-old boy undergoes open reduction and internal fixation of a displaced Milch Type II lateral condyle fracture of the humerus. Which of the following is the most common complication associated with this injury and its treatment?

. Avascular necrosis of the trochlea
. Cubitus varus
. Nonunion
. Lateral spur formation (lateral condylar overgrowth)
. Ulnar nerve palsy

Correct Answer & Explanation

. Avascular necrosis of the trochlea

Explanation

Lateral spur formation, or lateral condylar overgrowth, is the most common complication of a lateral condyle fracture, occurring in up to 50-70% of cases. It causes a cosmetic bump on the lateral elbow but rarely restricts motion or causes functional deficits. While nonunion and tardy ulnar nerve palsy (due to cubitus valgus) are classic severe complications of a missed or poorly treated lateral condyle fracture, lateral overgrowth is far more frequent.

Question 4605

Topic: 4. Pediatrics
A 3-year-old girl with a BMI in the 98th percentile presents with bilateral severe bowing of the lower extremities. Radiographs reveal an abrupt varus angulation at the proximal tibial metaphysis with medial beaking. The metaphyseal-diaphyseal (Drennan) angle is 20 degrees. What is the most appropriate initial management?
. Reassurance and annual observation
. Bilateral knee-ankle-foot orthoses (KAFOs)
. Proximal tibial valgus osteotomies
. Eight-plate guided growth (hemiepiphysiodesis) of the lateral proximal tibia
. Epiphysiodesis of the medial proximal tibia

Correct Answer & Explanation

. Bilateral knee-ankle-foot orthoses (KAFOs)

Explanation

The patient has infantile Blount's disease (tibia vara), characterized by medial metaphyseal beaking and a Drennan angle >16 degrees (which distinguishes it from physiologic bowing). For children under the age of 4 with Langenskiöld Stage I or II, bracing with KAFOs during weight-bearing hours is the standard initial treatment. Surgery (osteotomy) is indicated if bracing fails, or if the child is over age 4 at presentation.

Question 4606

Topic: Pediatric Hip
In Legg-Calvé-Perthes disease, which of the following clinical factors is considered the most significant prognostic factor for long-term hip joint survival and prevention of early osteoarthritis?
. Age at clinical presentation
. Gender of the patient
. Presence of a Gage sign on radiographs
. Degree of metaphyseal cyst formation
. Amount of initial limb length discrepancy

Correct Answer & Explanation

. Age at clinical presentation

Explanation

Age at clinical presentation is universally recognized as the most critical prognostic factor in Legg-Calvé-Perthes disease. Children who present at less than 6 to 8 years of age have a significant remodeling potential and generally fare better. Those over age 8 at presentation have a much higher rate of poor outcomes and early secondary osteoarthritis. The Lateral Pillar classification is the most significant radiographic prognostic factor.

Question 4607

Topic: 4. Pediatrics
A 13-year-old girl sustains an ankle injury while playing soccer. Radiographs demonstrate a Salter-Harris III fracture of the anterolateral distal tibia. Which of the following describes the mechanism of injury and the anatomic structure responsible for avulsing this fragment?
. Supination-inversion; Calcaneofibular ligament
. Pronation-eversion; Deltoid ligament
. External rotation; Anterior inferior tibiofibular ligament (AITFL)
. Internal rotation; Posterior inferior tibiofibular ligament (PITFL)
. Plantarflexion; Anterior talofibular ligament (ATFL)

Correct Answer & Explanation

. External rotation; Anterior inferior tibiofibular ligament (AITFL)

Explanation

This is a juvenile Tillaux fracture, which is a Salter-Harris III fracture of the anterolateral distal tibial epiphysis. It occurs in adolescents due to the asymmetric closure of the distal tibial physis (central, then medial, then lateral). An external rotation force placed on the foot causes the strong Anterior Inferior Tibiofibular Ligament (AITFL) to avulse the unfused anterolateral epiphysis.

Question 4608

Topic: Pediatric Upper Extremity & Spine

A 12-year-old premenarchal female (Risser 0) presents with a right thoracic adolescent idiopathic scoliosis. Her curve measures 22 degrees on a standing PA radiograph. What is the approximate risk of curve progression to greater than 30 degrees?

. 10%
. 20%
. 40%
. 68%
. 95%

Correct Answer & Explanation

. 10%

Explanation

According to the Lonstein and Carlson progression formula and established general guidelines for Adolescent Idiopathic Scoliosis, a patient who is highly immature (Risser 0-2, premenarchal) with a curve measuring between 20-29 degrees has approximately a 68% risk of curve progression. This warrants close observation or initiation of bracing.

Question 4609

Topic: 4. Pediatrics

A 5-year-old child with a history of multiple fractures, blue sclerae, and dentinogenesis imperfecta is diagnosed with Osteogenesis Imperfecta Type I. This condition is most commonly caused by a mutation in which of the following genes?

. FGFR3
. COMP
. COL1A1
. COL2A1
. RUNX2

Correct Answer & Explanation

. FGFR3

Explanation

Osteogenesis Imperfecta (OI) is a genetic disorder of connective tissue primarily affecting Type I collagen. It is most commonly inherited in an autosomal dominant pattern and is caused by mutations in the COL1A1 or COL1A2 genes. FGFR3 is associated with achondroplasia; COMP with pseudoachondroplasia and multiple epiphyseal dysplasia; COL2A1 with spondyloepiphyseal dysplasia (SED); and RUNX2 with cleidocranial dysplasia.

Question 4610

Topic: Pediatric Hip

A 13-year-old boy presents to the emergency department unable to bear weight on his right leg after a minor fall 2 days ago. He has a history of vague right groin pain for 3 months. Radiographs demonstrate a severe, unstable slipped capital femoral epiphysis (SCFE). Which of the following best describes the rationale for performing a capsulotomy during surgical fixation?

. To assist with anatomic closed reduction
. To reduce intracapsular pressure and minimize the risk of avascular necrosis
. To prevent chondrolysis
. To facilitate removal of loose bodies
. To allow for placement of a second stabilizing screw

Correct Answer & Explanation

. To assist with anatomic closed reduction

Explanation

Unstable SCFE (defined by the inability to bear weight) carries a high risk of avascular necrosis (AVN), reportedly up to 50%. The primary rationale for performing an anterior capsulotomy during surgical treatment of an unstable SCFE is to evacuate the fracture hematoma, thereby decompressing the joint and reducing intracapsular pressure, which theoretically improves perfusion to the femoral head and decreases the risk of AVN.

Question 4611

Topic: 4. Pediatrics

A 2-year-old boy presents with anterolateral bowing of the left tibia and a newly developed midshaft fracture. Radiographs reveal a narrowed, sclerotic medullary canal with a pseudarthrosis. This clinical presentation is most strongly associated with which of the following systemic conditions?

. Osteogenesis Imperfecta
. Neurofibromatosis type 1 (NF1)
. Achondroplasia
. Marfan syndrome
. Ehlers-Danlos syndrome

Correct Answer & Explanation

. Osteogenesis Imperfecta

Explanation

Congenital pseudarthrosis of the tibia (CPT) classically presents with anterolateral bowing of the tibia that fractures and fails to heal due to abnormal periosteum. It is strongly associated with Neurofibromatosis type 1 (NF1); approximately 50% of children with CPT have NF1. Conversely, posteromedial bowing is generally benign and resolves spontaneously.

Question 4612

Topic: Pediatric Hip

An 11-year-old girl with a body mass index (BMI) in the 99th percentile is diagnosed with a unilateral slipped capital femoral epiphysis (SCFE).

Which of the following is considered an absolute indication for prophylactic in situ pinning of the contralateral, asymptomatic hip?

. A modified Southwick angle greater than 50 degrees on the symptomatic side
. Patient age younger than 12 years at the time of presentation
. The presence of an underlying endocrine or metabolic disorder (e.g., hypothyroidism)
. A patient BMI exceeding the 95th percentile
. Female sex

Correct Answer & Explanation

. A modified Southwick angle greater than 50 degrees on the symptomatic side

Explanation

While factors such as young age, obesity, and open triradiate cartilage are relative indications that surgeons consider when discussing prophylactic pinning, the presence of an underlying endocrine or metabolic disorder (such as hypothyroidism, panhypopituitarism, or renal osteodystrophy) is universally considered an absolute indication for prophylactic pinning of the contralateral hip due to the extremely high risk of a subsequent slip.

Question 4613

Topic: 4. Pediatrics
A 3-and-a-half-year-old child presents with worsening bilateral genu varum. Radiographs demonstrate a prominent metaphyseal beak and depression of the medial proximal tibial physis consistent with Langenskiöld Stage III infantile Blount disease. What is the most appropriate management for this patient?
. Observation with serial clinical examinations every 6 months
. Full-time use of a Knee-Ankle-Foot Orthosis (KAFO)
. Proximal tibial valgus osteotomy and concomitant fibular osteotomy
. Guided growth via lateral hemi-epiphysiodesis
. Asymmetric guided growth utilizing tension band plates medially

Correct Answer & Explanation

. Proximal tibial valgus osteotomy and concomitant fibular osteotomy

Explanation

Infantile Blount disease management is dependent on age and Langenskiöld stage. Bracing (KAFO) is generally indicated for children under 3 years old with Stage I or II disease. For a child over the age of 3 presenting with Stage III disease or higher, conservative management is unlikely to succeed. The standard of care is surgical realignment, typically through a proximal tibial valgus osteotomy combined with a fibular osteotomy to prevent recurrence and correct the mechanical axis.

Question 4614

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy falls from the monkey bars and sustains a Gartland Type III supracondylar humerus fracture. Upon initial evaluation, his hand is pale and pulseless. After prompt closed reduction and percutaneous pinning in the operating room, the hand becomes warm and pink, with a capillary refill of less than 2 seconds, but the radial pulse remains unpalpable. What is the next best step in management?
. Immediate open vascular exploration of the brachial artery
. Removal of the pins, extension of the elbow to 30 degrees, and re-evaluation
. Admit the patient for close inpatient observation and neurovascular monitoring
. Administration of intra-arterial vasodilators (e.g., papaverine)
. Perform an immediate forearm fasciotomy

Correct Answer & Explanation

. Admit the patient for close inpatient observation and neurovascular monitoring

Explanation

The management of the 'pink, pulseless hand' following reduction of a supracondylar humerus fracture is a well-established algorithm. If the hand is well-perfused (pink, warm, good capillary refill) after adequate reduction and stabilization, collateral circulation is sufficient. The standard of care is to admit the patient for close neurovascular monitoring (observation) rather than pursuing immediate vascular exploration, as the brachial artery is often in spasm and recanalizes over time.

Question 4615

Topic: 4. Pediatrics

A 3-month-old infant is undergoing treatment for Developmental Dysplasia of the Hip (DDH) using a Pavlik harness. During a follow-up visit, the mother notes that the infant has stopped kicking the affected leg. On examination, the infant exhibits absent knee extension but normal ankle dorsiflexion and plantarflexion.

Which nerve injury is most likely, and what specific mechanical factor in the harness caused it?

. Femoral nerve palsy; caused by excessive hip flexion
. Obturator nerve palsy; caused by excessive hip abduction
. Sciatic nerve palsy; caused by excessive hip extension
. Femoral nerve palsy; caused by excessive hip abduction
. Sciatic nerve palsy; caused by excessive knee flexion

Correct Answer & Explanation

. Femoral nerve palsy; caused by excessive hip flexion

Explanation

Femoral nerve palsy is the most common nerve injury associated with the use of a Pavlik harness for DDH. It is caused by excessive hip flexion, which tethers the femoral nerve against the inguinal ligament. The clinical presentation is an infant who stops kicking and loses active knee extension. Treatment consists of temporarily loosening or discontinuing the flexion straps or the harness entirely until function returns.

Question 4616

Topic: Pediatric Hip
An 8-year-old boy presents with a painful limp and limited hip abduction. Radiographs reveal fragmentation of the proximal femoral epiphysis with maintained height of the lateral pillar (>50% of original height), classifying it as Herring Lateral Pillar Group B Legg-Calvé-Perthes disease (LCPD). According to the multicenter prospective study by Herring et al., which intervention provides the best radiographic outcome for this specific patient profile?
. Non-weight-bearing strictly enforced with crutches
. Scottish Rite abduction bracing
. Surgical containment via a proximal femoral varus osteotomy or pelvic osteotomy
. Core decompression of the femoral head
. Total hip arthroplasty

Correct Answer & Explanation

. Surgical containment via a proximal femoral varus osteotomy or pelvic osteotomy

Explanation

According to the landmark multicenter prospective LCPD study by Herring et al., surgical containment (proximal femoral varus osteotomy or pelvic osteotomy) provides significantly better radiographic outcomes (Stulberg classification) compared to nonoperative treatment for children who are 8 years of age or older at the time of onset and who have Lateral Pillar Group B or B/C border disease.

Question 4617

Topic: 4. Pediatrics

A 6-year-old boy with spastic quadriplegic cerebral palsy (GMFCS level V) presents for routine hip surveillance. Anteroposterior pelvic radiograph reveals a Reimers migration percentage (migration index) of 45% in the right hip and 30% in the left hip. The patient experiences pain during diapering.

What is the most appropriate surgical management for the right hip?

. Adductor longus tenotomy alone
. Proximal femoral varus derotation osteotomy (VDRO) with a pelvic osteotomy
. Intrathecal baclofen pump insertion
. Total hip arthroplasty
. Observation with repeat radiograph in 6 months

Correct Answer & Explanation

. Adductor longus tenotomy alone

Explanation

In children with cerebral palsy, a Reimers migration percentage greater than 40-50% indicates significant subluxation with a high risk of progression to dislocation. Adductor tenotomy alone is generally reserved for lower migration indices (<30%) in younger patients. For a migration index of 45% in a 6-year-old, bony reconstruction utilizing a proximal femoral varus derotation osteotomy (VDRO) combined with a pelvic osteotomy (such as a Dega or Pemberton) is the gold standard to provide definitive coverage and containment.

Question 4618

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 4619

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 4620

Topic: 4. Pediatrics

A 2-month-old infant is brought to the clinic due to a consistent head posture. The mother notes the baby's head is tilted toward the right shoulder, and the chin is rotated toward the left. On examination, a firm, non-tender, olive-shaped mass is palpable in the lower third of the right sternocleidomastoid muscle.

What is the most appropriate initial management for this condition?

. Immediate MRI of the cervical spine to rule out congenital vertebral anomalies
. Surgical unipolar release of the sternocleidomastoid muscle
. Initiation of a physical therapy program focused on gentle stretching exercises
. Botulinum toxin A injection into the affected muscle mass
. Application of a cervical collar to force the head into a neutral position

Correct Answer & Explanation

. Immediate MRI of the cervical spine to rule out congenital vertebral anomalies

Explanation

The clinical presentation is classic for Congenital Muscular Torticollis (CMT) with an SCM pseudo-tumor (fibromatosis colli). The initial management for CMT is conservative, consisting of a physical therapy program emphasizing gentle, sustained passive stretching of the affected sternocleidomastoid muscle, as well as positioning techniques. This resolves the condition in over 90% of cases if initiated early (<1 year of age). Surgical release is reserved for recalcitrant cases persisting beyond 12-18 months of age.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page