Menu

4. Pediatrics MCQs

Practice Set 228 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 4541

Topic: 4. Pediatrics

A 2-week-old infant is being treated for congenital idiopathic clubfoot (talipes equinovarus) using the Ponseti method. According to this technique, what is the very first deformity that must be corrected through manipulation and casting?

. Ankle equinus
. Hindfoot varus
. Forefoot adductus
. Midfoot cavus
. Tibial internal torsion

Correct Answer & Explanation

. Midfoot cavus

Explanation

The Ponseti method follows the acronym CAVE (Cavus, Adductus, Varus, Equinus) for the order of correction. The first step is to correct the midfoot cavus by elevating the first ray to align the forefoot with the hindfoot.

Question 4542

Topic: Pediatric Upper Extremity & Spine
A 5-year-old boy presents after falling from the monkey bars with a significantly swollen, deformed elbow. Radiographs show an extension-type Gartland III supracondylar humerus fracture. Which of the following physical exam findings indicates the most commonly injured nerve in this fracture pattern?
. Inability to make the "A-OK" sign
. Loss of sensation over the dorsal first web space
. Inability to cross the index and middle fingers
. Weakness with elbow flexion and supination
. Loss of sensation over the volar tip of the small finger

Correct Answer & Explanation

. Inability to make the "A-OK" sign

Explanation

The anterior interosseous nerve (AIN), a branch of the median nerve, is the most commonly injured nerve in extension-type supracondylar humerus fractures. Injury to the AIN results in weakness of the flexor pollicis longus and flexor digitorum profundus to the index finger, presenting as an inability to form the "A-OK" sign.

Question 4543

Topic: Pediatric Hip

A 12-year-old obese male undergoes in-situ percutaneous pinning for a stable slipped capital femoral epiphysis (SCFE). Postoperatively, he develops severe hip pain and restriction of all hip movements. Radiographs show joint space narrowing without a joint effusion. What is the most likely diagnosis?

. Avascular necrosis
. Chondrolysis
. Septic arthritis
. Implant failure
. Labral tear

Correct Answer & Explanation

. Chondrolysis

Explanation

Chondrolysis is a devastating complication of SCFE characterized by acute loss of articular cartilage and diffuse joint space narrowing. It presents with severe stiffness and pain, often linked to unrecognized intra-articular hardware penetration.

Question 4544

Topic: Pediatric Hip
The lateral pillar classification (Herring) is widely used for prognostication in Legg-Calvé-Perthes disease. In a Herring Group C hip, what is the radiographic appearance of the lateral pillar of the femoral head?
. No radiolucency in the lateral pillar
. Greater than 50% maintenance of lateral pillar height
. Exactly 50% maintenance of lateral pillar height
. Less than 50% maintenance of lateral pillar height
. Complete extrusion of the lateral pillar

Correct Answer & Explanation

. Less than 50% maintenance of lateral pillar height

Explanation

The Herring classification evaluates the height of the lateral portion of the femoral head on an AP radiograph during the fragmentation phase. Group C is defined as less than 50% maintenance of normal lateral pillar height, and it carries the worst prognosis.

Question 4545

Topic: Pediatric Hip

A 4-month-old infant with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a follow-up visit, the infant exhibits decreased spontaneous extension of the knee on the treated side. What is the most likely cause?

. Avascular necrosis of the femoral head
. Inferior dislocation of the hip
. Femoral nerve palsy due to excessive hip flexion
. Obturator nerve palsy due to excessive hip abduction
. Sciatic nerve palsy due to excessive hip extension

Correct Answer & Explanation

. Femoral nerve palsy due to excessive hip flexion

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment, classically caused by hyperflexion of the hip. It presents with decreased active knee extension. The harness must be adjusted (decreasing flexion) or temporarily discontinued to allow nerve recovery. Excessive abduction is linked to avascular necrosis.

Question 4546

Topic: Pediatric Hip

A 12-year-old boy is diagnosed with a unilateral slipped capital femoral epiphysis (SCFE). Which of the following is an accepted indication for prophylactic in situ pinning of the contralateral asymptomatic hip?

. Patient age over 15 years
. Male gender
. Presence of an underlying endocrine disorder (e.g., hypothyroidism)
. An initial slip angle of less than 30 degrees
. Presence of a closed triradiate cartilage

Correct Answer & Explanation

. Presence of an underlying endocrine disorder (e.g., hypothyroidism)

Explanation

Prophylactic pinning of the contralateral hip in SCFE is recommended for patients at high risk of bilateral disease. High-risk factors include underlying endocrine/metabolic disorders (e.g., hypothyroidism, renal osteodystrophy, panhypopituitarism), prior radiation, or very young age (open triradiate cartilage). Older age and closed triradiate cartilage are lower risk.

Question 4547

Topic: Pediatric Hip

A 13-year-old obese male presents with an acute-on-chronic slipped capital femoral epiphysis (SCFE) and is unable to bear weight. He is scheduled for in-situ pinning. What is the primary proposed advantage of performing an incidental hip capsulotomy during the surgical fixation of this unstable SCFE?

. To directly visualize and anatomically reduce the slipped epiphysis.
. To repair the torn labrum commonly associated with acute SCFE.
. To reduce intracapsular tamponade pressure and theoretically decrease the risk of avascular necrosis (AVN).
. To promote faster fusion of the physis by introducing inflammatory mediators.
. To retrieve loose chondral fragments from the joint space.

Correct Answer & Explanation

. To reduce intracapsular tamponade pressure and theoretically decrease the risk of avascular necrosis (AVN).

Explanation

In unstable SCFE (defined by the inability to bear weight), the risk of avascular necrosis (AVN) is significantly higher (up to 50%). Performing an anterior capsulotomy decompresses the intracapsular hematoma, reducing tamponade effect on the delicate retinacular vessels, thereby theoretically decreasing the risk of AVN.

Question 4548

Topic: Pediatric Hip

A 4-month-old female with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a follow-up visit, she demonstrates an inability to actively extend the knee on the treated side. Which of the following harness positioning errors is the most likely cause?

. Excessive hip flexion
. Excessive hip abduction
. Inadequate hip flexion
. Excessive knee flexion
. Excessive hip adduction

Correct Answer & Explanation

. Excessive hip flexion

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness and is typically caused by excessive hip flexion, which stretches or compresses the femoral nerve. Excessive hip abduction, on the other hand, is associated with a higher risk of avascular necrosis (AVN) of the femoral head.

Question 4549

Topic: Pediatric Hip
The Herring lateral pillar classification is used to predict the prognosis in Legg-Calvé-Perthes disease. This classification relies on assessing the height of the lateral pillar on an AP pelvic radiograph. During which stage of the disease must this assessment be made for it to be prognostically valid?
. Initial (Necrosis) stage
. Fragmentation stage
. Reossification stage
. Healed (Residual) stage
. Pre-symptomatic stage

Correct Answer & Explanation

. Fragmentation stage

Explanation

The Herring lateral pillar classification evaluates the height of the lateral portion of the capital femoral epiphysis. To be prognostically accurate, it must be determined during the early fragmentation stage of Legg-Calvé-Perthes disease, when the extent of epiphyseal involvement is maximally apparent.

Question 4550

Topic: Pediatric Hip
A 4-month-old female is evaluated for asymmetric thigh folds. Ultrasound of the hip reveals an alpha angle of 40 degrees and a beta angle of 80 degrees. According to the Graf classification for Developmental Dysplasia of the Hip (DDH), what is the appropriate interpretation and recommended next step?
. Graf Type I: Normal hip, no treatment needed
. Graf Type IIa: Physiologic immaturity, repeat ultrasound in 4 weeks
. Graf Type IIb: Mild dysplasia, observe
. Graf Type III: Subluxated hip, initiate Pavlik harness treatment
. Graf Type IV: Dislocated hip, requires immediate open reduction

Correct Answer & Explanation

. Graf Type III: Subluxated hip, initiate Pavlik harness treatment

Explanation

According to the Graf classification, a Type III hip (subluxated) is characterized by an alpha angle of less than 43 degrees and a beta angle greater than 77 degrees, indicating no cartilaginous roof coverage. The appropriate next step in a 4-month-old is conservative treatment with an abduction orthosis, such as a Pavlik harness.

Question 4551

Topic: Pediatric Hip

A 12-year-old obese boy undergoes in-situ percutaneous single screw fixation for a stable slipped capital femoral epiphysis (SCFE). Which of the following screw positions on fluoroscopy places the hip at the highest risk for unrecognized joint penetration and subsequent chondrolysis?

. Anterior-superior quadrant of the femoral head
. Anterior-inferior quadrant of the femoral head
. Posterior-superior quadrant of the femoral head
. Posterior-inferior quadrant of the femoral head
. Direct central position

Correct Answer & Explanation

. Anterior-superior quadrant of the femoral head

Explanation

The primary cause of chondrolysis following SCFE fixation is unrecognized pin/screw penetration into the joint space. The 'blind spot' during fluoroscopic imaging (AP and frog-leg lateral) is the anterior-superior quadrant of the femoral head. Screws placed in this quadrant can appear to be within bone on standard views despite actually penetrating the articular cartilage.

Question 4552

Topic: Pediatric Hip

A 12-year-old obese male presents with an acute-on-chronic Slipped Capital Femoral Epiphysis (SCFE). Which of the following is considered an absolute indication for prophylactic pinning of the contralateral asymptomatic hip?

. Age greater than 14 years
. Female gender
. Presence of an endocrine disorder
. Body mass index > 95th percentile
. Bilateral hip pain on presentation

Correct Answer & Explanation

. Presence of an endocrine disorder

Explanation

The presence of an endocrinopathy (such as hypothyroidism or renal osteodystrophy) is an absolute indication for prophylactic pinning of the contralateral hip due to the high risk of bilateral involvement.

Question 4553

Topic: Pediatric Hip

A 4-month-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). Hyperflexion of the hips in the harness puts the patient at highest risk for which complication?

. Avascular necrosis of the femoral head
. Femoral nerve palsy
. Sciatic nerve palsy
. Inferior dislocation of the hip
. Acetabular dysplasia

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Hyperflexion of the hips in a Pavlik harness can compress the femoral nerve against the inguinal ligament, causing a transient femoral nerve palsy. Excessive abduction increases the risk of avascular necrosis.

Question 4554

Topic: Pediatric Hip

A 13-year-old obese boy presents with 3 weeks of insidious onset left groin and thigh pain. He walks with a limp and exhibits an externally rotated foot progression angle. On examination, as the left hip is flexed, it obligately externally rotates. Radiographs confirm a stable slipped capital femoral epiphysis (SCFE). Which of the following represents the primary mechanism of displacement?

. The epiphysis displaces anteriorly and superiorly relative to the metaphysis
. The metaphysis displaces anteriorly and superiorly relative to the epiphysis
. The epiphysis displaces anteriorly and inferiorly relative to the metaphysis
. The metaphysis displaces posteriorly and inferiorly relative to the epiphysis
. The epiphysis displaces posteriorly and superiorly relative to the metaphysis

Correct Answer & Explanation

. The metaphysis displaces anteriorly and superiorly relative to the epiphysis

Explanation

In SCFE, the epiphysis actually remains relatively tethered within the acetabulum while the femoral neck (metaphysis) displaces anteriorly and superiorly relative to the epiphysis.

Question 4555

Topic: 4. Pediatrics

A 6-year-old girl sustains a displaced extension-type supracondylar humerus fracture. On presentation, her hand is pale with an absent radial pulse. After rapid closed reduction and percutaneous pinning, her hand becomes pink and capillary refill is less than 2 seconds, but the radial pulse remains unpalpable. What is the most appropriate next step in management?

. Immediate vascular exploration
. Doppler ultrasound of the brachial artery
. Observation and admission for close neurovascular monitoring
. Removal of the pins and open reduction
. Administration of intravenous heparin

Correct Answer & Explanation

. Observation and admission for close neurovascular monitoring

Explanation

A 'pink, pulseless' hand following reduction and stabilization of a pediatric supracondylar humerus fracture indicates adequate collateral circulation. Current orthopedic guidelines recommend close observation for 24-48 hours rather than immediate vascular exploration, provided the hand remains well-perfused with brisk capillary refill.

Question 4556

Topic: Pediatric Upper Extremity & Spine

A 12-year-old premenarchal female presents with a right thoracic scoliosis curve of 35 degrees. Her Risser stage is 0. Which combination of factors indicates the highest risk for curve progression in adolescent idiopathic scoliosis?

. Male gender, mature skeletal age, single lumbar curve
. Female gender, premenarchal status, single thoracic curve
. Female gender, premenarchal status, double curve pattern
. Male gender, postmenarchal equivalent status, double curve pattern
. Female gender, mature skeletal age, single thoracic curve

Correct Answer & Explanation

. Female gender, premenarchal status, double curve pattern

Explanation

Risk factors for progression in adolescent idiopathic scoliosis (AIS) include female gender (females are up to 10 times more likely to have curves progress to surgical magnitude), substantial remaining skeletal growth (premenarchal status, open triradiate cartilage, Risser 0), and double curve patterns.

Question 4557

Topic: 4. Pediatrics

An infant born with idiopathic congenital talipes equinovarus (clubfoot) is undergoing serial casting using the Ponseti method. Which of the following represents the correct sequence of deformity correction?

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

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus

Explanation

The mnemonic CAVE dictates the correct physiological sequence of correction in the Ponseti method: Cavus (corrected by supinating the forefoot to align with the hindfoot), Adductus, Varus, and finally Equinus (which often requires a percutaneous Achilles tenotomy as the final step).

Question 4558

Topic: 4. Pediatrics

According to the Hueter-Volkmann law, which of the following biomechanical principles explains the progressive genu varum deformity seen in infantile Blount's disease?

. Increased tensile forces stimulate physeal growth on the medial side
. Increased compressive forces inhibit physeal growth on the medial side
. Decreased compressive forces accelerate physeal growth on the lateral side
. Shear forces completely arrest the entire proximal tibial physis
. Asymmetric muscular pull causes lateral physeal hypertrophy

Correct Answer & Explanation

. Increased compressive forces inhibit physeal growth on the medial side

Explanation

The Hueter-Volkmann law states that increased compressive forces across a physis inhibit growth, while tensile forces stimulate growth. In Blount's disease, pathological compressive forces on the medial proximal tibial physis inhibit its growth, leading to a progressive varus deformity.

Question 4559

Topic: Pediatric Hip

In a 12-year-old male presenting with a unilateral slipped capital femoral epiphysis (SCFE), which of the following is an established indication for prophylactic in situ pinning of the asymptomatic contralateral hip?

. Body mass index greater than the 95th percentile
. Male gender
. Diagnosis of an underlying endocrine disorder (e.g., hypothyroidism)
. Initial slip angle greater than 50 degrees
. Presentation with an acute-on-chronic slip

Correct Answer & Explanation

. Diagnosis of an underlying endocrine disorder (e.g., hypothyroidism)

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended in patients with an underlying endocrinopathy (such as hypothyroidism or panhypopituitarism), renal osteodystrophy, or prior radiation therapy, due to a significantly elevated risk of developing bilateral disease compared to idiopathic SCFE.

Question 4560

Topic: Pediatric Hip

A 3-month-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the parents note that the infant has stopped kicking her left leg. Examination reveals active hip flexion is absent, but hip adduction and ankle movements are intact. Which of the following is the most likely cause of this complication?

. Excessive abduction of the hip in the harness
. Excessive flexion of the hip in the harness
. Inadequate flexion of the hip leading to re-dislocation
. Ischemic necrosis of the capital femoral epiphysis
. Entrapment of the sciatic nerve

Correct Answer & Explanation

. Excessive flexion of the hip in the harness

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness and presents with decreased active hip flexion and knee extension. It is typically caused by excessive hip flexion in the harness, and management involves adjusting the straps to reduce flexion or temporarily discontinuing the harness.

Test Yourself

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

On this Page