Menu

4. Pediatrics MCQs

Practice Set 149 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 2961

Topic: Pediatric Hip

Following closed reduction of a dysplastic hip in a 9-month-old, the surgeon applies a spica cast. To minimize the risk of avascular necrosis of the femoral head, the hip should NOT be placed in which of the following positions?

. Flexion of 100 degrees
. Abduction > 60 degrees
. Internal rotation of 10 degrees
. Abduction of 40 degrees
. Flexion of 90 degrees

Correct Answer & Explanation

. Flexion of 100 degrees

Explanation

Excessive abduction (>60 degrees) during spica casting for DDH significantly increases the risk of avascular necrosis. The safe zone of Ramsey limits abduction to avoid compressing the medial circumflex femoral vessels.

Question 2962

Topic: Pediatric Upper Extremity & Spine

A 12-year-old girl presents with adolescent idiopathic scoliosis. She has a 20-degree right thoracic curve. She has not reached menarche. Which of the following radiographic parameters indicates the highest risk for curve progression?

. Closed triradiate cartilage
. Risser grade 0
. Risser grade 4
. Apical vertebral rotation of Grade 1
. Curve magnitude of 15 degrees

Correct Answer & Explanation

. Closed triradiate cartilage

Explanation

A Risser grade of 0 indicates that ossification of the iliac apophysis has not yet begun, implying significant remaining spinal growth. This is the strongest radiographic predictor for curve progression in adolescent idiopathic scoliosis.

Question 2963

Topic: Pediatric Upper Extremity & Spine

A 13-year-old girl is evaluated for scoliosis. Radiographs show a 32-degree right thoracic curve. She is premenarchal, and her Risser grade is 1.

What is the most appropriate management?

. Physical therapy and observation
. Thoracolumbosacral orthosis (TLSO)
. Posterior spinal fusion
. Anterior spinal tethering
. Nighttime bending brace only

Correct Answer & Explanation

. Physical therapy and observation

Explanation

Bracing is indicated for skeletally immature patients (Risser 0-2) presenting with curve magnitudes between 25 and 45 degrees. A TLSO brace aims to halt curve progression during the adolescent growth spurt.

Question 2964

Topic: Pediatric Hip

A 4-week-old infant is treated with a Pavlik harness for a dislocated left hip. After 3 weeks of strict compliance, ultrasound reveals the hip remains completely dislocated. What is the most appropriate next step in management?

. Continue the harness for an additional 3 weeks
. Discontinue the harness and proceed to closed reduction and spica casting
. Switch to a Denis Browne splint
. Perform an immediate open reduction via a medial approach
. Observe without treatment until 6 months of age

Correct Answer & Explanation

. Continue the harness for an additional 3 weeks

Explanation

Continuing a Pavlik harness beyond 3-4 weeks in a persistently dislocated hip increases the risk of 'Pavlik harness disease' and acetabular posterior lip damage. The most appropriate next step is to transition to a rigid abduction orthosis or proceed with closed reduction and spica casting.

Question 2965

Topic: Pediatric Upper Extremity & Spine

In the Lenke classification system for Adolescent Idiopathic Scoliosis, a proximal thoracic curve is defined as structural if the residual Cobb angle on a side-bending radiograph is at least:

. 10 degrees
. 15 degrees
. 20 degrees
. 25 degrees
. 30 degrees

Correct Answer & Explanation

. 10 degrees

Explanation

The Lenke classification defines a structural curve as one having a residual Cobb angle of 25 degrees or greater on lateral side-bending radiographs, or a regional kyphosis of 20 degrees or more.

Question 2966

Topic: 4. Pediatrics

A 12-year-old boy sustains a completely displaced Salter-Harris type II fracture of the distal femur. Which of the following factors is most strongly predictive of subsequent premature physeal closure?

. Age of the patient at the time of injury
. Initial degree of fracture displacement
. Time elapsed from injury to surgical stabilization
. Use of smooth transphyseal K-wire fixation
. Postoperative immobilization duration

Correct Answer & Explanation

. Age of the patient at the time of injury

Explanation

Distal femoral physeal fractures carry a very high rate of growth arrest (up to 50%). The initial severity of the trauma, as indicated by the initial degree of displacement, is the most significant prognostic factor for premature physeal closure.

Question 2967

Topic: Pediatric Hip

On an anteroposterior pelvis radiograph of a 6-month-old female, the ossific nucleus of the right femoral head is located in the superolateral quadrant formed by Hilgenreiner's and Perkin's lines. What is the diagnosis?

. Normal hip joint development
. Developmental dysplasia of the hip
. Congenital coxa vara
. Slipped capital femoral epiphysis
. Legg-Calvรฉ-Perthes disease

Correct Answer & Explanation

. Normal hip joint development

Explanation

In a normal pediatric pelvis radiograph, the ossific nucleus of the femoral head sits in the inferomedial quadrant. A superolateral position relative to Hilgenreiner's and Perkin's lines is diagnostic of developmental dysplasia of the hip (DDH).

Question 2968

Topic: 4. Pediatrics

A 9-year-old girl develops a localized physeal bar in the distal radius following a previous trauma. Advanced imaging shows the bar comprises 25% of the cross-sectional area of the physis, and she has roughly 3 cm of anticipated growth remaining. What is the most appropriate management?

. Observation and sequential radiographic follow-up
. Resection of the physeal bar with interposition material
. Complete ipsilateral distal radius epiphysiodesis
. Contralateral distal radius epiphysiodesis
. Corrective extra-articular distal radius osteotomy

Correct Answer & Explanation

. Observation and sequential radiographic follow-up

Explanation

Physeal bar resection with interposition (e.g., fat or cranioplast) is indicated if the bar involves less than 50% of the cross-sectional area and the child has at least 2 years or 2 cm of remaining growth. If greater than 50% is involved, completion epiphysiodesis is preferred.

Question 2969

Topic: Pediatric Hip

A newborn with arthrogryposis multiplex congenita presents with rigid, bilateral dislocated hips. What is the generally recommended initial management for these hip dislocations?

. Immediate Pavlik harness application
. Serial hip casting starting at birth
. Observation until 6 months of age followed by open reduction
. Immediate open reduction via a medial approach
. Bilateral proximal femoral shortening osteotomies at 3 months

Correct Answer & Explanation

. Immediate Pavlik harness application

Explanation

Teratologic hip dislocations, such as those seen in arthrogryposis, are notoriously rigid. Pavlik harnesses are contraindicated as they frequently fail and can cause iatrogenic fractures or cartilage damage. Observation until roughly 6 months of age followed by single-stage open reduction is standard.

Question 2970

Topic: 4. Pediatrics

A 13-year-old boy sustains a juvenile Tillaux fracture. This fracture pattern is primarily the result of the specific sequence of closure of the distal tibial physis. In what predictable sequence does the distal tibial physis normally close?

. Central, followed by anteromedial, posteromedial, and finally lateral
. Lateral, followed by central, and finally medial
. Anterior, followed by central, and finally posterior
. Medial, followed by lateral, and finally central
. Posterior, followed by anterior, and finally lateral

Correct Answer & Explanation

. Central, followed by anteromedial, posteromedial, and finally lateral

Explanation

The distal tibial physis typically closes from central to anteromedial, then posteromedial, and finally lateral. This late closure of the lateral portion leaves it vulnerable to avulsion by the anterior inferior tibiofibular ligament, resulting in a Tillaux fracture.

Question 2971

Topic: Pediatric Hip

A 4-year-old girl is undergoing surgical treatment for late-presenting developmental dysplasia of the hip. The surgeon plans a redirectional pelvic osteotomy that hinges at the symphysis pubis to provide primarily anterolateral coverage. Which osteotomy is being described?

. Pemberton osteotomy
. Salter innominate osteotomy
. Dega osteotomy
. Chiari osteotomy
. Shelf arthroplasty

Correct Answer & Explanation

. Pemberton osteotomy

Explanation

The Salter innominate osteotomy is a complete, trans-iliac redirectional osteotomy that hinges on the symphysis pubis to provide anterolateral head coverage. The Pemberton and Dega osteotomies are incomplete osteotomies that hinge at the triradiate cartilage.

Question 2972

Topic: Pediatric Upper Extremity & Spine

A 12-year-old premenarchal girl (Risser 0) is diagnosed with Adolescent Idiopathic Scoliosis. Her standing radiographs reveal a right thoracic curve of 32 degrees. Neurologic exam is normal. What is the most appropriate management?

. Observation with 6-month radiographic follow-up
. Initiation of physical therapy and Schroth exercises alone
. Thoracolumbosacral orthosis (TLSO) bracing
. Posterior spinal instrumentation and fusion
. Anterior vertebral body tethering

Correct Answer & Explanation

. Observation with 6-month radiographic follow-up

Explanation

In a growing child (Risser 0-2) with an adolescent idiopathic scoliosis curve measuring between 25 and 45 degrees, TLSO bracing is indicated to halt curve progression. A landmark trial (BrAIST) showed bracing significantly decreases the likelihood of progression to surgery.

Question 2973

Topic: 4. Pediatrics

A 14-year-old boy sustains a triplane fracture of the distal ankle. Which of the following Salter-Harris fracture patterns best describes the radiographic appearance in the sagittal and coronal planes, respectively?

. SH I in the sagittal plane, SH IV in the coronal plane
. SH II in the sagittal plane, SH III in the coronal plane
. SH III in the sagittal plane, SH II in the coronal plane
. SH IV in the sagittal plane, SH II in the coronal plane
. SH II in the sagittal plane, SH IV in the coronal plane

Correct Answer & Explanation

. SH I in the sagittal plane, SH IV in the coronal plane

Explanation

A triplane fracture typically appears as a Salter-Harris III fracture (vertical epiphyseal separation) on an AP (coronal) radiograph, and a Salter-Harris II fracture (posterior metaphyseal spike) on a lateral (sagittal) radiograph.

Question 2974

Topic: 4. Pediatrics

You are evaluating a 6-week-old infant who has been in a Pavlik harness for 2 weeks for DDH. The parents report the infant has stopped kicking the left leg. On examination, the infant demonstrates absent active knee extension on the left side. What is the most likely diagnosis and appropriate initial management?

. Sciatic nerve palsy; continue harness but adjust posterior straps
. Obturator nerve palsy; loosen anterior straps immediately
. Femoral nerve palsy; discontinue harness temporarily and observe
. Femoral nerve palsy; continue harness but add rigid knee extension splints
. Peroneal nerve palsy; switch to a rigid abduction orthosis

Correct Answer & Explanation

. Sciatic nerve palsy; continue harness but adjust posterior straps

Explanation

Absent active knee extension in a Pavlik harness indicates a femoral nerve palsy, which is typically caused by excessive hip flexion compressing the nerve against the pelvis. The standard management is to temporarily discontinue the harness until quadriceps function fully recovers.

Question 2975

Topic: Pediatric Hip

A 6-week-old female infant, born breech, undergoes a screening ultrasound of the hips. The alpha angle is measured at 48 degrees and the beta angle at 65 degrees. Dynamic stress views show subluxation. What is the most appropriate initial management?

. Reassurance and repeat ultrasound in 6 weeks
. Pavlik harness application
. Rigid hip abduction orthosis
. Closed reduction and spica casting
. Open reduction

Correct Answer & Explanation

. Reassurance and repeat ultrasound in 6 weeks

Explanation

An alpha angle less than 60 degrees at 6 weeks with instability indicates Developmental Dysplasia of the Hip (DDH). A Pavlik harness is the gold standard first-line treatment for reducible DDH in infants under 6 months of age.

Question 2976

Topic: 4. Pediatrics

A 13-year-old boy presents with an ankle injury after a twisting mechanism while playing soccer. CT imaging reveals a fracture with a sagittal component through the epiphysis, a coronal component through the posterior metaphysis, and a transverse component through the physis. Which mechanism of injury is most classically associated with this fracture pattern?

. Pronation-abduction
. Supination-inversion
. Supination-external rotation
. Pronation-external rotation
. Axial loading

Correct Answer & Explanation

. Pronation-abduction

Explanation

This describes a triplane fracture, which is a Salter-Harris IV equivalent. It is classically caused by a supination-external rotation force in a child nearing skeletal maturity.

Question 2977

Topic: 4. Pediatrics

A 14-year-old girl sustains a juvenile Tillaux fracture (Salter-Harris III of the anterolateral distal tibial epiphysis). What underlying anatomic phenomenon explains why the fracture occurs specifically in this anterolateral location?

. The distal tibial physis closes starting from lateral to medial.
. The distal tibial physis closes starting centrally, progressing medially, and closing laterally last.
. The anterior talofibular ligament is the strongest ligament in the ankle.
. The syndesmosis is completely ossified in adolescents.
. The medial malleolus fails to ossify completely until age 16.

Correct Answer & Explanation

. The distal tibial physis closes starting from lateral to medial.

Explanation

The distal tibial physis closes in an asymmetric pattern: it starts centrally, progresses medially, and finally closes laterally. The open anterolateral physis remains vulnerable to avulsion forces from the anterior inferior tibiofibular ligament.

Question 2978

Topic: Pediatric Upper Extremity & Spine

A 14-year-old girl is diagnosed with a 45-degree right thoracic scoliosis. She is premenarcheal, Risser 0, and has open triradiate cartilages on pelvic radiographs. Without treatment, what is the estimated risk of her curve progressing to greater than 50 degrees?

. < 10%
. 20 - 30%
. 40 - 50%
. 60 - 70%
. > 90%

Correct Answer & Explanation

. < 10%

Explanation

Curve progression risk is based on remaining growth and curve magnitude. A premenarcheal, Risser 0 patient with a curve already at 45 degrees has an extremely high risk (approaching 100%) of progressing beyond surgical thresholds.

Question 2979

Topic: Pediatric Hip

A 3-month-old infant is being treated for DDH with a Pavlik harness. During a follow-up visit, you notice the infant lacks active knee extension on the treated side, though the harness is holding the hips in 110 degrees of flexion. What is the most likely cause of this finding?

. Avascular necrosis of the femoral head
. Femoral nerve palsy due to hyperflexion
. Obturator nerve palsy due to hyperabduction
. Inferior dislocation of the hip
. Sciatic nerve compression

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Excessive hip flexion in a Pavlik harness can compress the femoral nerve against the inguinal ligament, leading to a temporary femoral nerve palsy (manifesting as decreased active knee extension). This requires immediate adjustment or temporary removal of the harness.

Question 2980

Topic: 4. Pediatrics

A 10-year-old boy falls from monkey bars and sustains a distal radius fracture. Radiographs demonstrate a fracture line that passes through the metaphysis, traverses the physis, and exits through the epiphysis into the radiocarpal joint. What Salter-Harris classification does this represent?

. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type I

Explanation

A Salter-Harris Type IV fracture involves the metaphysis, physis, and epiphysis. Because it crosses the articular surface and the growth plate vertically, precise anatomic reduction is critical to prevent physeal arrest and joint incongruity.

Test Yourself

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

On this Page