Menu

4. Pediatrics MCQs

Practice Set 182 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 3621

Topic: Pediatric Hip
A 9-year-old boy presents with a 4-month history of right hip pain and a painless limp. Radiographs reveal fragmentation of the right capital femoral epiphysis. The lateral pillar maintains 40% of its normal height. According to the Herring classification, what is the most appropriate treatment?
. Observation and activity restriction
. Petrie cast application
. Proximal femoral varus derotational osteotomy
. Shelf acetabuloplasty
. Hip arthrodesis

Correct Answer & Explanation

. Proximal femoral varus derotational osteotomy

Explanation

This patient has Herring Group C (less than 50% lateral pillar height) Legg-Calvรฉ-Perthes disease. In children older than 8 years of age with Group B or B/C borderline disease, surgical containment via proximal femoral osteotomy has been shown to yield better outcomes than nonoperative management.

Question 3622

Topic: Pediatric Hip

A 6-week-old female infant is undergoing treatment for developmental dysplasia of the left hip with a Pavlik harness. After 4 weeks of strict full-time harness wear, a follow-up ultrasound reveals that the left hip remains completely dislocated. What is the most appropriate next step?

. Continue the Pavlik harness for an additional 4 weeks
. Add an abduction wedge to the Pavlik harness
. Discontinue the harness and proceed to closed reduction and spica casting
. Discontinue the harness and observe until the child is 6 months old
. Perform an immediate open reduction

Correct Answer & Explanation

. Add an abduction wedge to the Pavlik harness

Explanation

Continued use of a Pavlik harness in a persistently dislocated hip beyond 3 to 4 weeks significantly increases the risk of "Pavlik harness disease," which involves damage to the posterior acetabular wall. The harness should be discontinued, and the patient transitioned to a rigid orthosis or closed reduction.

Question 3623

Topic: Pediatric Hip

A 13-year-old obese boy presents with 3 weeks of vague groin pain and a limp. Radiographs confirm a stable slipped capital femoral epiphysis (SCFE). He undergoes in situ percutaneous pinning with a single screw. Which of the following screw positions carries the highest risk of accelerating chondrolysis?

. Anterosuperior to the center of the epiphysis
. Center-center in the epiphysis
. Posteroinferior to the center of the epiphysis
. Anteroinferior to the center of the epiphysis
. Directly through the anterior femoral neck cortex

Correct Answer & Explanation

. Posteroinferior to the center of the epiphysis

Explanation

Screws placed in the anterosuperior quadrant of the femoral head frequently have unrecognized joint penetration, which is the leading cause of chondrolysis in SCFE pinning. The ideal position is center-center or slightly posteroinferior.

Question 3624

Topic: Pediatric Lower Extremity

A 3-year-old child who was successfully treated for idiopathic clubfoot using the Ponseti method presents with recurrent dynamic supination of the foot during the swing phase of gait. Passive range of motion reveals full dorsiflexion and neutral heel valgus. What is the most appropriate next step in management?

. Repeat serial casting
. Posterior medial release
. Tibialis anterior tendon transfer to the lateral cuneiform
. Split tibialis posterior tendon transfer
. Achilles tendon lengthening

Correct Answer & Explanation

. Tibialis anterior tendon transfer to the lateral cuneiform

Explanation

Dynamic supination in a previously corrected clubfoot indicates a muscle imbalance. A full passive range of motion with dynamic supination is best treated with a tibialis anterior tendon transfer to the lateral cuneiform.

Question 3625

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy falls from monkey bars and sustains a Gartland type III supracondylar humerus fracture. On presentation, his hand is warm and pink, but the radial pulse is absent. After urgent closed reduction and percutaneous pinning, the hand remains pink and well-perfused, but the pulse is still absent by Doppler. What is the most appropriate next step?
. Immediate vascular exploration
. Observe with close admission monitoring
. Perform a CT angiogram
. Remove the pins and perform open reduction
. Perform a forearm fasciotomy

Correct Answer & Explanation

. Observe with close admission monitoring

Explanation

A "pulseless pink" hand after anatomic reduction and pinning of a supracondylar humerus fracture indicates adequate collateral perfusion. Observation is the standard of care, as the pulse often returns within 24 to 48 hours.

Question 3626

Topic: 4. Pediatrics

A 4-year-old girl with spastic quadriplegic cerebral palsy (GMFCS level V) undergoes screening pelvis radiographs. Her migration percentage is calculated at 45% bilaterally. She has 30 degrees of hip abduction bilaterally with knees extended. What is the most appropriate intervention?

. Botulinum toxin injections to the adductors
. Bilateral adductor tenotomies
. Varus derotational osteotomies (VDRO) of the proximal femurs with pelvic osteotomies
. Observation and repeat radiograph in 6 months
. Bilateral soft tissue releases and obturator neurectomies

Correct Answer & Explanation

. Varus derotational osteotomies (VDRO) of the proximal femurs with pelvic osteotomies

Explanation

In a child with CP and a migration percentage over 40%, soft tissue releases alone have an unacceptably high failure rate. Bony reconstruction with VDRO and possible pelvic osteotomy is the most reliable treatment to prevent further subluxation.

Question 3627

Topic: Pediatric Hip

A 6-week-old female infant is diagnosed with a dislocated but reducible left hip. She is placed in a Pavlik harness. After 3 weeks of compliant harness wear, ultrasound demonstrates the left 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 closed reduction and spica casting
. Perform open reduction and spica casting
. Wait until 6 months of age for closed reduction

Correct Answer & Explanation

. Transition to a rigid abduction orthosis

Explanation

Failure to reduce a dislocated hip after 3 to 4 weeks of Pavlik harness treatment requires discontinuation of the harness to prevent Pavlik harness disease. The next standard non-operative step is a rigid abduction orthosis, such as an Ilfeld or Rhino brace.

Question 3628

Topic: 4. Pediatrics

A 7-year-old boy is diagnosed with Legg-Calve-Perthes disease. Which of the following radiographic findings represents the classic "head-at-risk" sign described by Catterall?

. Lateral subluxation of the femoral head
. Decreased teardrop distance
. Medial calcification of the epiphysis
. Anterior metaphyseal cysts
. Premature closure of the physis

Correct Answer & Explanation

. Lateral subluxation of the femoral head

Explanation

Catterall's "head-at-risk" signs include lateral subluxation, Gage's sign, metaphyseal cysts, and a horizontal physis. Lateral subluxation strongly predicts poor outcomes due to the risk of hinge abduction.

Question 3629

Topic: 4. Pediatrics

A 10-month-old infant with homozygous achondroplasia presents with recent episodes of sleep apnea and delayed motor milestones. Examination shows exaggerated reflexes in the lower extremities. What is the best initial diagnostic study?

. CT scan of the lower extremities
. Polysomnography
. MRI of the craniocervical junction
. Radiographs of the thoracolumbar spine
. Genetic testing for FGFR3 mutation

Correct Answer & Explanation

. MRI of the craniocervical junction

Explanation

Infants with achondroplasia are at high risk for foramen magnum stenosis causing cervicomedullary compression, manifesting as central sleep apnea and hyperreflexia. Urgent MRI of the craniocervical junction is essential to evaluate the need for decompression.

Question 3630

Topic: Pediatric Upper Extremity & Spine

A 14-year-old girl with adolescent idiopathic scoliosis (AIS) has a right thoracic curve of 48 degrees and a Risser stage of 0. She has not reached menarche. What is the most appropriate recommendation?

. Observation with repeat radiographs in 6 months
. Thoracolumbosacral orthosis (TLSO) bracing for 18 hours a day
. Nighttime bending brace
. Posterior spinal fusion
. Anterior vertebral body tethering

Correct Answer & Explanation

. Posterior spinal fusion

Explanation

This patient has a curve approaching 50 degrees and has significant remaining growth potential (Risser 0, premenarchal). Surgery (posterior spinal fusion) is indicated for curves greater than 45-50 degrees to prevent continued progression into adulthood.

Question 3631

Topic: Pediatric Lower Extremity

An infant is born with Aitken Class C proximal focal femoral deficiency (PFFD) on the right. The acetabulum is severely dysplastic, the femoral head is absent, and there is a severe limb length discrepancy. What knee finding is most consistently associated with PFFD?

. Medial collateral ligament deficiency
. Cruciate ligament deficiency
. Patellar aplasia
. Genu varum
. Proximal tibiofibular synostosis

Correct Answer & Explanation

. Cruciate ligament deficiency

Explanation

PFFD is strongly associated with absence or hypoplasia of the cruciate ligaments, leading to anteroposterior knee instability. Fibular hemimelia is another extremely common concurrent finding.

Question 3632

Topic: 4. Pediatrics

A 3-year-old obese girl presents with progressive bilateral genu varum. Standing radiographs reveal a diaphyseal-metaphyseal angle (Drennan angle) of 22 degrees and medial metaphyseal beaking. What is the most appropriate initial treatment?

. Observation and reassurance
. Knee-ankle-foot orthoses (KAFO) during weight-bearing
. Proximal tibial valgus osteotomy
. Guided growth with lateral eight-plates
. Epiphysiodesis of the medial proximal tibia

Correct Answer & Explanation

. Knee-ankle-foot orthoses (KAFO) during weight-bearing

Explanation

Infantile Blount's disease in a child under 3-4 years with Langenskiold stage I or II is initially treated with orthotics (KAFOs) to offload the medial physis. Surgical intervention is reserved for older children, brace failure, or advanced stages.

Question 3633

Topic: Pediatric Hip

A 4-week-old female with a history of breech presentation is diagnosed with developmental dysplasia of the hip (DDH). Ultrasound shows an alpha angle of 45 degrees, a beta angle of 75 degrees, and 40% femoral head coverage. Treatment with a Pavlik harness is initiated. What is the most common iatrogenic nerve complication associated with this treatment?

. Femoral nerve palsy
. Sciatic nerve palsy
. Obturator nerve palsy
. Superior gluteal nerve palsy
. Tibial nerve palsy

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

The most common nerve complication of a Pavlik harness is femoral nerve palsy, typically caused by excessive hyperflexion of the hips. It usually resolves completely after temporarily removing or adjusting the harness.

Question 3634

Topic: Pediatric Hip

A 13-year-old obese boy presents with 2 days of severe right hip pain after a minor fall and is completely unable to bear weight. Radiographs show a posterior and inferior slip of the proximal femoral epiphysis. What is the most appropriate management for this acute, unstable slipped capital femoral epiphysis (SCFE)?

. Immediate forceful closed reduction and spica casting
. Urgent gentle closed reduction and multiple screw fixation
. Urgent in situ single screw fixation
. Delayed in situ single screw fixation after 1 week of traction
. Subtrochanteric derotational osteotomy

Correct Answer & Explanation

. Urgent in situ single screw fixation

Explanation

Unstable SCFE requires urgent in situ fixation, typically with a single screw, to decompress the joint capsule and stabilize the slip. Forceful closed reduction is contraindicated as it significantly increases the risk of avascular necrosis.

Question 3635

Topic: Pediatric Hip

A 7-year-old boy presents with a painless limp. Radiographs demonstrate fragmentation of the capital femoral epiphysis consistent with Legg-Calve-Perthes disease. According to the Herring lateral pillar classification, a hip that maintains 60% of its lateral pillar height is classified into which group, and what is the generally expected outcome?

. Group A - excellent outcome regardless of age
. Group B - good outcome if the patient is under 8 years old
. Group B - poor outcome regardless of age
. Group C - good outcome if the patient is over 8 years old
. Group C - poor outcome regardless of age

Correct Answer & Explanation

. Group B - good outcome if the patient is under 8 years old

Explanation

Group B involves maintenance of >50% lateral pillar height. Patients under 8 years of age at the onset of Group B LCPD generally have good outcomes with containment treatment, whereas older children may have less favorable results.

Question 3636

Topic: Pediatric Lower Extremity

A 3-month-old infant treated with the Ponseti method for idiopathic clubfoot has undergone five serial casts. The midfoot is now fully corrected and abducted to 70 degrees, but severe equinus persists. What is the next most appropriate step in management?

. Continue casting for 3 more weeks
. Percutaneous Achilles tenotomy
. Posterior capsulotomy of the ankle
. Tibialis anterior tendon transfer
. Extensive posteromedial release

Correct Answer & Explanation

. Percutaneous Achilles tenotomy

Explanation

Once the cavus, adductus, and varus deformities are fully corrected via serial casting in the Ponseti method, residual equinus is treated with a percutaneous Achilles tenotomy followed by a final cast for 3 weeks.

Question 3637

Topic: Pediatric Upper Extremity & Spine
A 5-year-old boy falls from the monkey bars and sustains a Gartland type III extension supracondylar humerus fracture. Examination shows weakness in flexing the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which nerve is most likely injured?
. Radial nerve
. Ulnar nerve
. Anterior interosseous nerve
. Posterior interosseous nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN), a branch of the median nerve, is the most commonly injured nerve in extension-type supracondylar humerus fractures. It innervates the flexor pollicis longus and the flexor digitorum profundus to the index finger.

Question 3638

Topic: Pediatric Lower Extremity

A 14-year-old boy with a history of recurrent ankle sprains presents with rigid, painful flatfeet and peroneal spasticity. A CT scan of the hindfoot is ordered to evaluate for a tarsal coalition. If a talocalcaneal coalition is present, which facet is most commonly involved?

. Anterior facet
. Middle facet
. Posterior facet
. Lateral facet
. Medial facet

Correct Answer & Explanation

. Middle facet

Explanation

The middle facet is the most commonly involved facet in talocalcaneal coalitions. It is best visualized on coronal CT scans of the hindfoot and is a frequent cause of rigid flatfoot in adolescents.

Question 3639

Topic: Pediatric Upper Extremity & Spine

A 13-year-old premenarchal female (Risser 0) presents with right thoracic adolescent idiopathic scoliosis. Standing radiographs reveal a Cobb angle of 32 degrees. What is the most appropriate recommended treatment?

. Observation with follow-up radiographs in 6 months
. Intensive physical therapy utilizing the Schroth method alone
. Thoracolumbosacral orthosis (TLSO) bracing
. Posterior spinal fusion
. Anterior vertebral body tethering

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) bracing

Explanation

TLSO bracing is indicated for skeletally immature patients (Risser 0-2) with an AIS curve of 25 to 45 degrees. Bracing has been proven to significantly decrease the risk of curve progression to the surgical threshold.

Question 3640

Topic: 4. Pediatrics

A 6-year-old boy with spastic quadriplegic cerebral palsy (GMFCS Level V) is evaluated during routine hip surveillance. He is currently pain-free, but AP pelvis radiographs reveal a bilateral migration percentage of 45%. What is the most appropriate management?

. Continued observation and radiographic follow-up in 1 year
. Adductor and psoas tendon lengthenings
. Bilateral varus derotational osteotomies (VDRO) with pelvic osteotomies
. Bilateral total hip arthroplasties
. Proximal femoral resection (Castle procedure)

Correct Answer & Explanation

. Bilateral varus derotational osteotomies (VDRO) with pelvic osteotomies

Explanation

In a spastic CP patient, a hip migration percentage >40% typically requires bony reconstruction, including VDRO and often a pelvic osteotomy (like a Dega), to provide stable joint coverage. Soft tissue releases alone have a high failure rate at this degree of subluxation.

Test Yourself

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

On this Page