Menu

4. Pediatrics MCQs

Practice Set 249 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 4961

Topic: 4. Pediatrics

In the Ponseti method for the conservative management of congenital talipes equinovarus (clubfoot), manipulation and serial casting follow a specific sequence. Which of the following represents the correct sequential order of deformity correction?

. Cavus, Adductus, Varus, Equinus
. Adductus, Varus, Cavus, Equinus
. Equinus, Varus, Adductus, Cavus
. Cavus, Varus, Adductus, Equinus
. Equinus, Cavus, Adductus, Varus

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus

Explanation

The Ponseti method uses the CAVE acronym to dictate the order of deformity correction: Cavus, Adductus, Varus, Equinus. The cavus is corrected first by elevating the first ray to align the forefoot with the hindfoot. Next, the adductus and varus are simultaneously corrected by abducting the forefoot with counter-pressure on the lateral aspect of the talar head. Equinus is addressed last, often requiring a percutaneous Achilles tenotomy.

Question 4962

Topic: Pediatric Hip

A 3-month-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At the two-week follow-up, the parents report the baby has stopped kicking the affected leg. On examination, the hip remains reduced, but there is an absence of active knee extension. Which of the following complications has most likely occurred?

. Sciatic nerve palsy due to excessive abduction
. Femoral nerve palsy due to excessive hyperflexion
. Obturator nerve palsy due to excessive adduction
. Inferior gluteal nerve palsy due to tightness of the posterior strap
. Peroneal nerve palsy due to compression from the foot stirrup

Correct Answer & Explanation

. Sciatic nerve palsy due to excessive abduction

Explanation

Femoral nerve palsy is the most common nerve injury associated with the Pavlik harness, occurring in roughly 2% of cases. It is typically caused by excessive flexion of the hip (anterior straps too tight), which compresses the femoral nerve against the inguinal ligament or the rim of the pelvis. Clinically, it presents as an inability to actively extend the knee. Management involves altering the harness settings or temporarily discontinuing it to allow nerve recovery.

Question 4963

Topic: Pediatric Hip

A 13-year-old obese male presents with left hip pain, an antalgic gait, and obligate external rotation upon hip flexion. Radiographs confirm a left-sided Slipped Capital Femoral Epiphysis (SCFE). The surgeon discusses in-situ pinning of the left hip and considers prophylactic pinning of the asymptomatic right hip. Which of the following is the most established indication for prophylactic fixation of the contralateral hip in SCFE?

. Male sex
. Chronologic age greater than 14 years
. An underlying endocrine disorder (e.g., hypothyroidism)
. A body mass index (BMI) > 95th percentile
. Presence of a slipped capital femoral epiphysis on the left side (side-specific risk)

Correct Answer & Explanation

. Male sex

Explanation

While prophylactic contralateral pinning in SCFE remains controversial for the idiopathic obese patient, it is strongly indicated and widely accepted in patients with underlying endocrinopathies (such as hypothyroidism, growth hormone deficiency, or panhypopituitarism) and in those with renal osteodystrophy. These systemic conditions place the patient at an exceptionally high risk (up to 100% in some series) for developing a contralateral slip. Younger age (e.g., girls < 10, boys < 12) or open triradiate cartilage are also relative indications, but endocrine disorders are the strongest and most universally accepted absolute indication.

Question 4964

Topic: Pediatric Hip

A 6-week-old infant is being treated with a Pavlik harness for developmental dysplasia of the left hip (DDH). At the 3-week ultrasound follow-up, the hip remains dislocated and cannot be reduced in the harness. What is the most appropriate next step in management?

. Continue Pavlik harness for an additional 3 weeks
. Switch to a rigid abduction orthosis (e.g., Ilfeld brace)
. Perform a closed reduction and application of a spica cast
. Perform an open reduction and application of a spica cast
. Botulinum toxin injection into the adductors

Correct Answer & Explanation

. Continue Pavlik harness for an additional 3 weeks

Explanation

If a Pavlik harness fails to achieve reduction within 3 to 4 weeks, continuing it increases the risk of 'Pavlik harness disease' (excoriation, nerve palsy, and persistent posterior wear of the acetabulum). Transitioning to a rigid abduction brace is the recommended next step before attempting closed reduction under anesthesia.

Question 4965

Topic: Pediatric Hip

A 12-year-old boy undergoes an uncomplicated in situ pinning for an unstable slipped capital femoral epiphysis (SCFE). Six months later, he develops acute, severe hip stiffness and a pronounced antalgic gait. Radiographs reveal a uniform and rapid narrowing of the joint space. What is the most likely diagnosis?

. Avascular necrosis of the femoral head
. Chondrolysis
. Septic arthritis
. Femoroacetabular impingement
. Unrecognized slipped contralateral hip

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Chondrolysis is a severe complication following SCFE, characterized by acute, painful stiffness and rapid, uniform loss of the articular cartilage space on radiographs. It is strongly associated with unrecognized hardware penetration into the joint space during pinning.

Question 4966

Topic: Pediatric Hip

A 4-month-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At the follow-up visit, the parents report the infant is no longer kicking the right leg actively. Examination reveals an inability to actively extend the right knee. Which of the following positioning errors is most likely responsible for this complication?

. Excessive hip abduction
. Excessive hip flexion
. Excessive hip extension
. Inadequate hip flexion
. Inadequate hip abduction

Correct Answer & Explanation

. Excessive hip abduction

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by excessive hip flexion. It generally resolves with temporary adjustment or removal of the harness.

Question 4967

Topic: Pediatric Hip

A 3-month-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At her 2-week follow-up, the mother notes the infant is no longer kicking her leg on the treated side. Examination reveals a lack of active knee extension. What is the most appropriate next step in management?

. Immediate closed reduction and spica casting
. Open reduction of the hip
. Adjust the anterior straps to increase hip flexion
. Remove the harness and observe for spontaneous recovery
. Switch immediately to a rigid abduction orthosis (e.g., Rhino cruiser)

Correct Answer & Explanation

. Immediate closed reduction and spica casting

Explanation

A lack of active knee extension in a Pavlik harness indicates a femoral nerve palsy caused by hyperflexion of the hip. The standard of care is to remove the harness to decompress the nerve, which typically results in spontaneous recovery.

Question 4968

Topic: Pediatric Hip



An 8-year-old boy presents with an antalgic gait and is diagnosed with Legg-Calve-Perthes disease. Radiographs are utilized to determine the Herring Lateral Pillar classification. A significantly poorer long-term prognosis is most strongly associated with involvement of what percentage of the lateral pillar height?

. < 25% depression of the lateral pillar
. 25-50% depression of the lateral pillar
. > 50% depression of the lateral pillar
. Complete sparing of the lateral pillar
. Isolated depression of the medial pillar

Correct Answer & Explanation

. < 25% depression of the lateral pillar

Explanation

The Herring Lateral Pillar classification is strongly prognostic in Legg-Calve-Perthes. Group C is defined by >50% loss of lateral pillar height and carries the poorest prognosis, with a high likelihood of asynchronous healing and early degenerative joint disease.

Question 4969

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy sustains a completely displaced extension-type supracondylar humerus fracture. Which associated nerve deficit is most characteristic of this specific injury pattern?

. Inability to abduct the fingers
. Inability to extend the wrist
. Inability to flex the interphalangeal joint of the thumb and distal interphalangeal joint of the index finger
. Inability to extend the metacarpophalangeal joints
. Decreased sensation over the anatomical snuffbox

Correct Answer & Explanation

. Inability to abduct the fingers

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar humerus fractures. Injury to the AIN manifests as motor weakness in the flexor pollicis longus and the flexor digitorum profundus to the index finger.

Question 4970

Topic: Pediatric Hip

A 12-year-old obese male presents with a limp and right anterior thigh pain for three weeks. Examination reveals an obligate external rotation of the right hip during passive flexion. What is the most appropriate definitive management for his right hip?

. Physical therapy focusing on abductor strengthening
. Application of a hip spica cast
. In situ percutaneous pinning
. Open reduction and internal fixation with a dynamic hip screw
. Proximal femoral corrective osteotomy

Correct Answer & Explanation

. Physical therapy focusing on abductor strengthening

Explanation

The clinical picture is classic for a Slipped Capital Femoral Epiphysis (SCFE). The gold standard for definitive management of a stable SCFE is in situ percutaneous pinning using a single large cannulated screw to prevent further slip.

Question 4971

Topic: Pediatric Lower Extremity

When utilizing the Ponseti method for the conservative management of idiopathic clubfoot, what is the anatomically correct sequence for correcting the components of the deformity?

. Cavus, Adductus, Varus, Equinus
. Equinus, Varus, Adductus, Cavus
. Varus, Adductus, Cavus, Equinus
. Adductus, Cavus, Equinus, Varus
. Cavus, Varus, Equinus, Adductus

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus

Explanation

The Ponseti method dictates a strict sequential correction of the clubfoot deformities, easily remembered by the acronym CAVE: Cavus (by supinating the forefoot), Adductus, Varus, and finally Equinus (usually requiring a percutaneous Achilles tenotomy).

Question 4972

Topic: Pediatric Upper Extremity & Spine
A 5-year-old child sustains a Gartland type III supracondylar humerus fracture. On presentation, the hand is pink but pulseless. Following closed reduction and percutaneous pinning, the hand remains pink and pulseless. What is the most appropriate next step in management?
. Observation and hospital admission
. Immediate CT angiogram
. Open exploration of the brachial artery
. Removal of the K-wires and open reduction
. Intra-arterial papaverine injection

Correct Answer & Explanation

. Observation and hospital admission

Explanation

In a pink, pulseless hand following adequate reduction and pinning of a supracondylar fracture, observation is recommended as collateral circulation is sufficient. Vascular exploration is indicated only if the hand becomes pale or ischemic.

Question 4973

Topic: Pediatric Hip

A 13-year-old boy undergoes in situ single-screw pinning for a stable Slipped Capital Femoral Epiphysis (SCFE). Six months later, he develops progressive loss of hip motion, severe pain, and marked joint space narrowing on radiographs. What is the most likely diagnosis?

. Osteonecrosis of the femoral head
. Chondrolysis
. Implant failure
. Deep surgical site infection
. Femoroacetabular impingement

Correct Answer & Explanation

. Osteonecrosis of the femoral head

Explanation

Chondrolysis is a severe complication of SCFE characterized by acute cartilage necrosis and profound joint space narrowing. It is strongly associated with unrecognized pin penetration into the hip joint during fixation.

Question 4974

Topic: Pediatric Hip

A 32-year-old female presents with symptomatic developmental dysplasia of the hip. Radiographs demonstrate an open triradiate cartilage, a lateral center-edge angle of 15 degrees, and minimal osteoarthritis (Toennis grade 1). Which pelvic osteotomy is most appropriate?

. Salter osteotomy
. Pemberton osteotomy
. Chiari osteotomy
. Bernese periacetabular osteotomy (PAO)
. Shelf arthroplasty

Correct Answer & Explanation

. Salter osteotomy

Explanation

The Bernese Periacetabular Osteotomy (PAO) is the treatment of choice for symptomatic adult DDH with closed triradiate cartilage and minimal osteoarthritis. It allows extensive multiplanar correction while preserving the posterior column.

Question 4975

Topic: Pediatric Hip
A 12-year-old boy with Legg-Calvรฉ-Perthes disease presents in the fragmentation stage. Radiographs reveal >50% collapse of the lateral pillar (Herring Lateral Pillar Type C). What is the expected outcome and recommended treatment approach?
. Excellent outcome with observation only
. Good outcome with abduction bracing
. Poor outcome regardless of surgical containment
. Excellent outcome with immediate hip arthroscopy
. Spontaneous resolution with minimal residual deformity

Correct Answer & Explanation

. Poor outcome regardless of surgical containment

Explanation

Lateral Pillar Type C (>50% collapse) in an older child (>8 years of age) carries a poor prognosis. Studies have shown that surgical containment in this specific high-risk group yields little clinical or radiographic improvement compared to non-operative treatment.

Question 4976

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy presents with a Gartland type III supracondylar humerus fracture. His hand is pink but the radial pulse is absent. Following closed reduction and percutaneous pinning, the hand remains pink and pulseless. What is the most appropriate next step in management?
. Immediate exploration of the brachial artery
. Observation and admission for serial neurovascular checks
. Angiography of the upper extremity
. Removal of pins and open reduction
. Perform a forearm fasciotomy

Correct Answer & Explanation

. Observation and admission for serial neurovascular checks

Explanation

A pink, pulseless hand after reduction and pinning of a supracondylar humerus fracture indicates it is well-perfused through collateral circulation. The standard of care is close observation, as the pulse often returns within 24 to 48 hours.

Question 4977

Topic: Pediatric Hip

A 4-month-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At a follow-up visit, the mother notes that the child is no longer kicking the affected leg. Examination reveals an inability to actively extend the knee. Which of the following is the most likely cause?

. Avascular necrosis of the femoral head
. Obturator nerve palsy
. Femoral nerve palsy
. Sciatic nerve palsy
. Ischemic contracture of the quadriceps

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Hyperflexion of the hip in a Pavlik harness can lead to compression and temporary paralysis of the femoral nerve. This typically resolves spontaneously once the harness is adjusted to reduce the degree of hip flexion or temporarily removed.

Question 4978

Topic: Pediatric Hip

An obese 13-year-old boy is diagnosed with a stable left slipped capital femoral epiphysis (SCFE). The surgeon is debating whether to prophylactically pin the contralateral, asymptomatic right hip. If prophylactic pinning is performed, which of the following is the most likely complication associated with this specific intervention?

. Avascular necrosis of the femoral head
. Chondrolysis
. Infection
. Subtrochanteric fracture
. Premature osteoarthritis

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial due to procedural risks. The most significant specific risk of the pinning itself, particularly if the start point is below the lesser trochanter, is creating a stress riser that leads to a subtrochanteric femur fracture.

Question 4979

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy sustains a completely displaced extension-type supracondylar humerus fracture. After closed reduction and percutaneous pinning, the hand remains pink and pulseless. What is the next best step in management?

. Immediate vascular exploration
. Doppler ultrasound of the brachial artery
. Observation and admission for 48 hours
. Administration of IV heparin
. Removal of pins and open reduction

Correct Answer & Explanation

. Immediate vascular exploration

Explanation

A pink, pulseless hand following adequate reduction and pinning of a supracondylar humerus fracture indicates sufficient collateral circulation. Observation for 24-48 hours is indicated as pulses often return; immediate exploration is reserved for a white, pulseless hand.

Question 4980

Topic: Pediatric Hip

In a 7-year-old boy diagnosed with Legg-Calve-Perthes disease, which of the following radiographic classifications is most prognostic for final hip outcome and guides surgical decision-making?

. Catterall classification
. Salter-Thompson classification
. Herring Lateral Pillar classification
. Waldenstrom stages
. Stulberg classification

Correct Answer & Explanation

. Catterall classification

Explanation

The Herring Lateral Pillar classification assesses the height of the lateral aspect of the capital femoral epiphysis during the fragmentation stage. It is the most reliable prognostic indicator for long-term hip sphericity.

Test Yourself

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

On this Page