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4. Pediatrics MCQs

Practice Set 26 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 501

Topic: Pediatric Lower Extremity

A 10-year-old boy presents to the emergency department after a forceful jumping injury. He has a massive knee effusion, a palpable defect at the inferior pole of the patella, and cannot perform a straight leg raise. Lateral radiographs show a high-riding patella with a tiny bony fleck distally. What is the most likely diagnosis?

. Osgood-Schlatter disease
. Sinding-Larsen-Johansson syndrome
. Bipartite patella
. Patellar sleeve fracture
. Tibial tubercle avulsion fracture

Correct Answer & Explanation

. Patellar sleeve fracture

Explanation

The presentation is classic for a patellar sleeve fracture, an avulsion of the unossified distal patellar cartilage along with a small bony fragment. It disrupts the extensor mechanism and requires surgical repair.

Question 502

Topic: Pediatric Lower Extremity

A newborn is evaluated for a shortened lower extremity. Radiographs show a shortened femur with a hypoplastic proximal segment and an absent fibula. This presentation is most consistent with Proximal Focal Femoral Deficiency (PFFD). Which of the following conditions is most commonly associated with PFFD?

. Fibular hemimelia
. Tibial hemimelia
. Radioulnar synostosis
. Developmental dysplasia of the hip
. Clubfoot

Correct Answer & Explanation

. Fibular hemimelia

Explanation

Fibular hemimelia is the most common associated anomaly in patients with Proximal Focal Femoral Deficiency (PFFD), occurring in 50% to 80% of cases. Cruciate ligament deficiency in the knee is also frequently seen.

Question 503

Topic: 4. Pediatrics

Which of the following describes the fundamental pathophysiology of Osgood-Schlatter disease in a 13-year-old athlete?

. Avascular necrosis of the patellar pole
. Inflammation of the prepatellar bursa
. Traction apophysitis of the tibial tubercle
. Osteochondral defect of the trochlea
. Physeal arrest of the proximal tibia

Correct Answer & Explanation

. Traction apophysitis of the tibial tubercle

Explanation

Osgood-Schlatter disease is a traction apophysitis of the tibial tubercle. It occurs due to repetitive microtrauma from the pull of the patellar tendon on the unossified or partially ossified tibial apophysis.

Question 504

Topic: 4. Pediatrics
A 14-year-old boy sustains an ankle injury while sliding into a base. Radiographs show a Salter-Harris III fracture of the anterolateral distal tibial epiphysis. What ligament avulsion is responsible for this fracture pattern?
. Anterior talofibular ligament
. Anterior inferior tibiofibular ligament
. Posterior inferior tibiofibular ligament
. Deltoid ligament
. Calcaneofibular ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament

Explanation

A juvenile Tillaux fracture is a Salter-Harris III fracture of the anterolateral tibial epiphysis. It is caused by an avulsion force from the anterior inferior tibiofibular ligament (AITFL) during external rotation.

Question 505

Topic: 4. Pediatrics
A triplane fracture of the distal tibia in a pediatric patient consists of fracture lines occurring in three distinct planes. Which of the following accurately describes the orientation of these fracture lines?
. Sagittal in epiphysis, axial in physis, coronal in metaphysis
. Coronal in epiphysis, axial in physis, sagittal in metaphysis
. Axial in epiphysis, sagittal in physis, coronal in metaphysis
. Sagittal in epiphysis, coronal in physis, axial in metaphysis
. Coronal in epiphysis, sagittal in physis, axial in metaphysis

Correct Answer & Explanation

. Sagittal in epiphysis, axial in physis, coronal in metaphysis

Explanation

A triplane fracture typically appears as a Salter-Harris III on AP views and a Salter-Harris II on lateral views. The fracture planes are sagittal in the epiphysis, axial (horizontal) through the physis, and coronal in the metaphysis.

Question 506

Topic: Pediatric Hip

A 12-year-old obese boy presents with an acute exacerbation of chronic right groin pain and an inability to bear weight. Radiographs show a severe slipped capital femoral epiphysis (SCFE). Which of the following intraoperative maneuvers is most strongly associated with the development of avascular necrosis (AVN)?

. Using a single cannulated screw for fixation
. Forceful closed reduction to restore anatomic alignment
. In situ pinning without reduction
. Capsulotomy for hematoma decompression
. Using a smooth wire instead of a threaded screw

Correct Answer & Explanation

. Forceful closed reduction to restore anatomic alignment

Explanation

Forceful closed reduction of a SCFE compromises the delicate retinacular vessels, significantly increasing the risk of avascular necrosis. Current gold-standard management involves gentle positioning and in situ pinning.

Question 507

Topic: Pediatric Hip
In Legg-Calvé-Perthes disease, the Herring lateral pillar classification is used to predict long-term outcomes. During which phase of the disease should the radiographs be evaluated to determine the lateral pillar grade?
. Initial phase
. Early fragmentation phase
. Late fragmentation phase
. Reossification phase
. Healed phase

Correct Answer & Explanation

. Late fragmentation phase

Explanation

The Herring lateral pillar classification is most accurately determined during the late fragmentation phase of Legg-Calvé-Perthes disease. This ensures the maximal extent of epiphyseal involvement is visible for prognostic accuracy.

Question 508

Topic: 4. Pediatrics

A 9-year-old boy presents with knee pain and swelling after forcefully jumping. He has a high-riding patella and an inability to actively extend the knee against gravity. Radiographs show a small, 2-mm bony fragment near the inferior pole of the patella. What is the most likely diagnosis?

. Osgood-Schlatter disease
. Sinding-Larsen-Johansson syndrome
. Patellar sleeve fracture
. Bipartite patella
. Tibial tubercle avulsion fracture

Correct Answer & Explanation

. Patellar sleeve fracture

Explanation

A patellar sleeve fracture is a pediatric injury involving the avulsion of a large cartilaginous cap from the patella, often with only a tiny osseous fleck visible on X-ray. It presents with an extensor lag and requires surgical repair to restore the extensor mechanism.

Question 509

Topic: Pediatric Hip

An infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). The mother notes that the child has stopped actively extending the knee on the treated side. Which of the following harness positioning errors most likely caused this complication?

. Excessive hip flexion
. Excessive hip extension
. Excessive hip abduction
. Excessive hip adduction
. Excessive knee flexion

Correct Answer & Explanation

. Excessive hip flexion

Explanation

Excessive hip flexion in a Pavlik harness (typically >120 degrees) can cause femoral nerve compression against the inguinal ligament, leading to quadriceps palsy and an inability to extend the knee. Excessive abduction leads to AVN.

Question 510

Topic: 4. Pediatrics

When correcting a congenital idiopathic clubfoot using the Ponseti method, the acronym CAVE dictates the order of correction. What is the very first step in the manipulation and casting sequence?

. Correct the equinus by dorsiflexing the ankle
. Correct the varus by abducting the midfoot
. Correct the cavus by elevating the first ray
. Correct the adductus by externally rotating the tibia
. Perform a percutaneous Achilles tenotomy

Correct Answer & Explanation

. Correct the cavus by elevating the first ray

Explanation

The first step in the Ponseti method is correcting the cavus deformity. This is achieved by elevating the first metatarsal to align the forefoot with the hindfoot, creating a stable fulcrum for subsequent abduction.

Question 511

Topic: Pediatric Hip

A 13-year-old boy presents with left hip pain and an antalgic gait. During physical examination, as the affected hip is passively flexed, the thigh obligatorily rotates externally. This clinical finding is known as:

. Galeazzi sign
. Drehmann sign
. Ortolani test
. Barlow maneuver
. Trendelenburg sign

Correct Answer & Explanation

. Drehmann sign

Explanation

The Drehmann sign describes the obligatory external rotation and abduction of the hip during passive flexion. It is a classic physical examination finding in slipped capital femoral epiphysis (SCFE).

Question 512

Topic: Pediatric Lower Extremity

Which of the following is a principle of the Ponseti technique for correction of a clubfoot:

. Avoid use of casts
. Avoid use of braces
. Perform a comprehensive release
. Osteotomies produce correction
. Minimize surgery to bones and joints

Correct Answer & Explanation

. Minimize surgery to bones and joints

Explanation

The Ponseti technique, which was developed and tested by Ignacio Ponseti, MD, involves slow, gradual correction of a clubfoot using casts, a tenotomy if necessary to release the Achilles tendon, and maintenance of correction using braces (foot abduction orthoses) for several years. The technique avoids dissection of the growing bones and joints of a childs foot because of the associated risks of stiffness and growth disturbance.

Question 513

Topic: 4. Pediatrics

Which of the following pulse sequences is best for imaging the pediatric growth plate:

. T1-weighted images
. T2-weighted images
. Proton density images
. Fat-suppressed T2-weighted images
. Gradient echo sequence

Correct Answer & Explanation

. Gradient echo sequence

Explanation

The gradient echo sequence involves a short relaxation and excitation time. It shows both fat and water as intermediate signals. The gradient echo sequence is excellent for imaging physeal and articular cartilage. When imaging for a physeal bar, the physician ordering the magnetic resonance imaging should specify this sequence.

Question 514

Topic: 4. Pediatrics

Ehlers-Danlos syndrome is caused by a defect in which of the following:

. Elastin
. C ollagen
. Dermatan sulfate
. Proteoglycan
. Fibroblast growth factor

Correct Answer & Explanation

. C ollagen

Explanation

There are 11 subtypes of Ehlers-Danlos syndrome. Each of the subtypes is caused by defects in collagen types 1, 3, or 5, or their processing. Defects in a component of elastic microfibrils (fibrillin) are responsible for Marfan syndrome. Defects in dermatan sulfate processing cause Hurler syndrome. Defects in fibroblast growth factor cause achondroplasia. Defects in proteoglycan processing cause diastrophic dysplasia.

Question 515

Topic: Pediatric Hip
A 14-year-old girl is kicking a soccer ball when she feels a "pop" in her hip. The most likely diagnosis is:
. Slipped sacroiliac joint
. Slipped capital femoral epiphysis
. Pathologic hip fracture
. Avulsion of the anterior inferior iliac spine
. Ligamentum teres avulsion

Correct Answer & Explanation

. Avulsion of the anterior inferior iliac spine

Explanation

This is a classic description of avulsion of the anterior inferior iliac spine. When this patient hyperextended her hip and flexed her knee simultaneously to kick a ball, the rectus femoris was stretched at both joints. In a skeletally immature patient, this apophysis is not fully ossified and is vulnerable to avulsion. Treatment is symptomatic, with return to sports in about 6 weeks.

Question 516

Topic: 4. Pediatrics
Hip subluxation is most commonly seen in which type of cerebral palsy:
. Spastic hemiplegia
. Spastic diplegia
. Spastic triplegia
. Total involvement
. Athetoid

Correct Answer & Explanation

. Total involvement

Explanation

Neuromuscular subluxation of the hips is caused by muscle imbalance over time. It is most common in patients with greatest imbalance - total body involvement. Hip subluxation is rare in patients with spastic hemiplegia.

Question 517

Topic: 4. Pediatrics

Which group of cerebral palsy patients is most likely to sustain a pathologic fracture:

. Spastic hemiplegic
. Spastic diplegic
. Spastic triplegic
. Total involvement
. Athetoid

Correct Answer & Explanation

. Total involvement

Explanation

Pathologic fracture is most common in cerebral palsy patients with total involvement, presumably because they have little stress on the bone from either muscle tone or standing.

Question 518

Topic: 4. Pediatrics

Which is the most common location of pathologic fracture in patients with cerebral palsy:

. Radius
. Femur
. Humerus
. Tibia
. Calcaneus

Correct Answer & Explanation

. Femur

Explanation

Pathologic fracture is a common problem in patients with cerebral palsy. Pathologic fracture most commonly involves the femur, especially the shaft and distal metaphysis. This should be the first diagnostic consideration in a nonambulatory patient with a warm or swollen knee.

Question 519

Topic: Pediatric Hip

In which of the following scenarios is prophylactic percutaneous pinning of the contralateral hip most strongly indicated in a patient with a unilateral slipped capital femoral epiphysis (SCFE)?

. A 14-year-old male with an acute, unstable SCFE
. A 10-year-old female with an endocrine disorder
. A 15-year-old male with a chronic, stable SCFE
. A 13-year-old male with a BMI in the 85th percentile
. A 12-year-old female with an isolated slipped epiphysis and normal thyroid function

Correct Answer & Explanation

. A 10-year-old female with an endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip is highly recommended for patients with SCFE who have underlying endocrine disorders (e.g., hypothyroidism) or are younger than 10 years old, due to a significantly elevated risk of bilateral involvement.

Question 520

Topic: Pediatric Lower Extremity

During the Ponseti method of serial casting for idiopathic clubfoot, what is the first deformity that must be actively corrected?

. Equinus
. Hindfoot varus
. Forefoot adduction
. Cavus
. Tibial torsion

Correct Answer & Explanation

. Cavus

Explanation

The cavus deformity must be corrected first by elevating the first ray to align the forefoot with the hindfoot. Correction of the remaining deformities (adduction, varus, and finally equinus) follows sequentially in subsequent casts.

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