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4. Pediatrics MCQs

Practice Set 254 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 5061

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy falls from monkey bars and sustains a Gartland Type III extension-type supracondylar humerus fracture. On arrival, his hand is pale, cool, and pulseless. After closed reduction and percutaneous pinning, the hand becomes pink and capillary refill is less than 2 seconds, but the radial pulse remains absent. What is the next most appropriate step in management?
. Immediate vascular surgery consultation for brachial artery exploration and repair
. Perform an intra-operative angiogram
. Observation and hospital admission for close monitoring
. Remove the pins, perform open reduction, and explore the artery
. Administer intravenous heparin

Correct Answer & Explanation

. Observation and hospital admission for close monitoring

Explanation

In the setting of a poorly perfused hand ('pulseless, pinkless') prior to reduction of a pediatric supracondylar humerus fracture, reduction and pinning should be performed urgently. If the hand becomes well-perfused (pink, warm, good capillary refill) after reduction, even if the radial pulse remains absent (a 'pulseless, pink' hand), the standard of care is close clinical observation. Immediate exploration is only indicated if the hand remains ischemic after anatomic reduction.

Question 5062

Topic: 4. Pediatrics

An 18-year-old rugby player presents to the emergency department with dyspnea, dysphagia, and an apparent posterior sternoclavicular (SC) joint dislocation. When considering closed reduction versus surgical intervention, the surgeon must remember that the medial clavicular epiphysis typically fuses at what age?

. 12-14 years
. 16-18 years
. 22-25 years
. 28-30 years
. 8-10 years

Correct Answer & Explanation

. 12-14 years

Explanation

The medial epiphysis of the clavicle is the last physis to close in the human body, typically fusing between 22 and 25 years of age. Therefore, apparent SC dislocations in young adults under 25 are often Salter-Harris physeal fractures.

Question 5063

Topic: 4. Pediatrics

A 6-year-old child presents with a pulseless, pink hand following a displaced extension-type supracondylar humerus fracture. After closed reduction and percutaneous pinning, the hand remains pink but the radial pulse is absent. What is the next best step in management?

. Immediate exploration of the brachial artery
. Angiography
. Observation and admission for 24-48 hours
. Removal of pins and open reduction
. Fasciotomy of the forearm

Correct Answer & Explanation

. Immediate exploration of the brachial artery

Explanation

A "pulseless but pink" (well-perfused) hand after stable reduction of a supracondylar fracture typically indicates adequate collateral circulation. The standard of care is close clinical observation rather than immediate vascular exploration.

Question 5064

Topic: Pediatric Lower Extremity

A 16-year-old gymnast presents with chronic anterior knee pain. Examination shows a prominent and tender tibial tubercle. Radiographs demonstrate fragmentation of the tibial tubercle apophysis. The condition is caused by repetitive traction forces from which of the following structures?

. Medial patellofemoral ligament
. Quadriceps tendon
. Patellar tendon
. Anterior cruciate ligament
. Iliotibial band

Correct Answer & Explanation

. Medial patellofemoral ligament

Explanation

The clinical presentation describes Osgood-Schlatter disease, which is a traction apophysitis of the tibial tubercle. It is caused by repetitive microtrauma and traction forces exerted by the patellar tendon on the unossified or partially ossified tibial tubercle apophysis in growing adolescents.

Question 5065

Topic: Pediatric Upper Extremity & Spine

A 12-year-old Little League baseball pitcher presents with acute medial elbow pain and swelling. Radiographs reveal widening and partial avulsion of the medial epicondyle apophysis. Which phase of the throwing motion generates the highest valgus stress on the elbow, directly contributing to this pathophysiology?

. Wind-up
. Early cocking
. Late cocking and early acceleration
. Deceleration
. Follow-through

Correct Answer & Explanation

. Wind-up

Explanation

The late cocking and early acceleration phases of throwing generate the maximum valgus torque across the medial elbow. In skeletally immature athletes, the medial epicondyle apophysis is the weak link, and repetitive valgus stress leads to apophysitis or avulsion ('Little League Elbow'). In adults, this force typically injures the ulnar collateral ligament.

Question 5066

Topic: Pediatric Hip

A 25-year-old hockey player presents with chronic groin pain exacerbated by hip flexion and internal rotation. AP pelvis and Dunn lateral radiographs demonstrate an alpha angle of 68 degrees and a positive crossover sign. Which of the following morphologic abnormalities is most likely present?

. Isolated Cam impingement
. Isolated Pincer impingement
. Mixed Cam and Pincer impingement
. Developmental dysplasia of the hip (DDH)
. Slipped capital femoral epiphysis (SCFE)

Correct Answer & Explanation

. Isolated Cam impingement

Explanation

The patient has imaging signs of both Cam (alpha angle greater than 50-55 degrees on a Dunn lateral) and Pincer (positive crossover sign on an AP pelvis, indicating focal or global acetabular retroversion) impingement. Most cases of femoroacetabular impingement (FAI) represent a mixed morphology rather than isolated Cam or Pincer impingement.

Question 5067

Topic: Pediatric Hip

A 25-year-old ice hockey goalie complains of deep, activity-related groin pain. An AP pelvis radiograph demonstrates a "crossover sign" and prominent ischial spines. Which of the following diagnoses best explains these radiographic findings?

. Cam impingement due to a decreased alpha angle
. Pincer impingement due to acetabular retroversion
. Cam impingement secondary to an old slipped capital femoral epiphysis
. Pincer impingement due to excessive acetabular anteversion
. Ischiofemoral impingement

Correct Answer & Explanation

. Cam impingement due to a decreased alpha angle

Explanation

A crossover sign (anterior rim crossing the posterior rim) and prominent ischial spines on an AP pelvis radiograph are classic indicators of focal or global acetabular retroversion, a primary cause of Pincer-type FAI.

Question 5068

Topic: Pediatric Hip

A 13-year-old obese boy presents with left thigh pain and a limp for 3 weeks. Examination reveals an obligate external rotation of the left hip with passive flexion. Radiographs show a mild slipped capital femoral epiphysis (SCFE). Which of the following is the most appropriate definitive management for the affected hip?

. Spica casting in internal rotation
. Open reduction and internal fixation to restore anatomic alignment
. In situ fixation with a single cannulated screw
. Observation and non-weight bearing with crutches
. Proximal femoral corrective osteotomy

Correct Answer & Explanation

. Spica casting in internal rotation

Explanation

The standard of care for a stable, mild to moderate SCFE is in situ fixation using a single cannulated screw placed in the center of the epiphysis. Open reduction increases the risk of avascular necrosis and is generally reserved for severe, unstable slips in specialized centers using specific surgical exposures (e.g., modified Dunn approach).

Question 5069

Topic: 4. Pediatrics

In the Ponseti method for correcting idiopathic congenital talipes equinovarus (clubfoot), which component of the deformity must be addressed and corrected first during serial casting?

. Equinus
. Hindfoot varus
. Forefoot adductus
. Cavus
. Internal tibial torsion

Correct Answer & Explanation

. Equinus

Explanation

The sequence of correction in the Ponseti method follows the mnemonic CAVE: Cavus, Adductus, Varus, Equinus. The very first step is to correct the Cavus deformity by supinating the forefoot and elevating the first ray to align the forefoot with the hindfoot.

Question 5070

Topic: Pediatric Hip

A 4-month-old female infant is being evaluated for developmental dysplasia of the hip (DDH). She has been treated with a properly applied Pavlik harness for 4 weeks; however, follow-up clinical examination and ultrasound show no improvement, and the hip remains dislocated. What is the next most appropriate step in management?

. Continue Pavlik harness treatment for an additional 4 weeks
. Transition to a rigid abduction orthosis (e.g., Ilfeld splint)
. Closed reduction and spica casting under anesthesia
. Open reduction through an anterior approach
. Varus derotational osteotomy of the proximal femur

Correct Answer & Explanation

. Continue Pavlik harness treatment for an additional 4 weeks

Explanation

Failure of Pavlik harness treatment for DDH is typically defined if the hip remains dislocated after 3-4 weeks of proper wear. Continuing the harness in a persistently dislocated hip places the infant at high risk for 'Pavlik harness disease' (erosion of the posterior acetabular wall). The next most appropriate step for an infant of this age is a closed reduction and spica casting under general anesthesia, usually confirmed with an intraoperative arthrogram.

Question 5071

Topic: Pediatric Lower Extremity

What is the final deformity corrected in the serial casting phase of the Ponseti method for idiopathic clubfoot?

. Cavus
. Adductus
. Varus
. Equinus
. Supination

Correct Answer & Explanation

. Cavus

Explanation

The sequence of correction in Ponseti casting follows the acronym CAVE: Cavus, Adductus, Varus, and finally Equinus. The equinus deformity is typically the last to be addressed and often requires a percutaneous Achilles tenotomy to achieve adequate dorsiflexion.

Question 5072

Topic: Pediatric Hip

When utilizing a Pavlik harness for the treatment of Developmental Dysplasia of the Hip (DDH), hyperflexion of the hips most commonly places the infant at risk for which complication?

. Femoral nerve palsy
. Sciatic nerve palsy
. Avascular necrosis of the femoral head
. Inferior dislocation of the hip
. Transient synovitis

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Femoral nerve palsy is the most common nerve injury associated with the Pavlik harness and is typically caused by excessive hip flexion. Avascular necrosis is a devastating complication usually associated with extreme hyperabduction rather than hyperflexion.

Question 5073

Topic: Pediatric Hip

In the treatment of severe Slipped Capital Femoral Epiphysis (SCFE), an intracapsular cuneiform osteotomy of the femoral neck is performed. This aggressive over-correction most significantly increases the risk of which devastating complication?

. Chondrolysis
. Avascular necrosis (AVN)
. Femoral nerve palsy
. Premature physeal closure
. Nonunion of the greater trochanter

Correct Answer & Explanation

. Chondrolysis

Explanation

Avascular necrosis (AVN) is the most severe and devastating complication of SCFE treatment. Intracapsular base-of-neck or cuneiform osteotomies aggressively stretch or transect the retinacular vessels (branches of the MFCA), leading to a high rate of AVN compared to in-situ pinning or extracapsular osteotomies.

Question 5074

Topic: Pediatric Hip

A 6-week-old female is treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At her 2-week follow-up visit, the parents report she has stopped spontaneously kicking her affected leg. Physical examination reveals an absence of active knee extension. Which of the following is the most appropriate next step in management?

. Adjust the anterior straps to increase hip flexion
. Adjust the posterior straps to decrease hip abduction
. Discontinue the harness temporarily until neurologic function returns
. Transition immediately to a rigid hip spica cast
. Obtain an emergent ultrasound to evaluate for a septic hip

Correct Answer & Explanation

. Adjust the anterior straps to increase hip flexion

Explanation

The patient has developed a femoral nerve palsy, a known complication of the Pavlik harness typically caused by excessive hip flexion. The standard management is to remove the harness or significantly relax the straps until spontaneous active knee extension returns, after which the harness can often be carefully reapplied or an alternative brace considered.

Question 5075

Topic: Pediatric Hip

A 12-year-old obese male presents with a unilateral slipped capital femoral epiphysis (SCFE) of the left hip. Which of the following patient profiles is a strongly accepted indication for prophylactic in situ pinning of the contralateral, asymptomatic right hip?

. All male patients presenting with unilateral SCFE
. Patients with an underlying endocrine disorder or metabolic bone disease
. Patients presenting with a chronic, stable SCFE
. Patients older than 14 years of age
. Patients with a slip angle greater than 50 degrees on the affected side

Correct Answer & Explanation

. All male patients presenting with unilateral SCFE

Explanation

Prophylactic pinning of the contralateral hip in SCFE is generally indicated for patients at high risk for a future contralateral slip. These include patients with underlying endocrinopathies (e.g., hypothyroidism, growth hormone deficiency), metabolic bone disease, prior pelvic radiation, and very young age (typically < 10 years).

Question 5076

Topic: 4. Pediatrics

A 2-week-old infant with congenital talipes equinovarus (clubfoot) is undergoing the Ponseti casting method. What is the correct sequence of deformity correction utilizing this technique?

. Cavus, Adductus, Varus, Equinus (CAVE)
. Equinus, Varus, Adductus, Cavus
. Varus, Cavus, Equinus, Adductus
. Adductus, Varus, Cavus, Equinus
. Cavus, Equinus, Varus, Adductus

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus (CAVE)

Explanation

The Ponseti method follows a strict sequence of deformity correction summarized by the mnemonic CAVE: Cavus (corrected by supinating the forefoot to align with the hindfoot), Adductus, Varus, and finally Equinus (which often requires a percutaneous Achilles tenotomy).

Question 5077

Topic: Pediatric Hip

A 4-month-old infant has been treated with a Pavlik harness for 4 weeks for a completely dislocated left hip. Ultrasound evaluation today shows the hip remains persistently dislocated. What is the most appropriate next step in management?

. Continue Pavlik harness for an additional 4 weeks
. Switch to a rigid abduction orthosis (e.g., Ilfeld splint)
. Closed reduction and spica casting
. Open reduction and pelvic osteotomy
. Observation and re-evaluation at age 6 months

Correct Answer & Explanation

. Continue Pavlik harness for an additional 4 weeks

Explanation

Failure to achieve reduction after 3-4 weeks of Pavlik harness treatment requires cessation of the harness to prevent "Pavlik harness disease" (posterior acetabular wear). The next appropriate step is typically a closed reduction and spica casting under general anesthesia.

Question 5078

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy sustains a Gartland type III supracondylar humerus fracture with posteromedial displacement of the distal fragment. Which nerve is most at risk of injury in this specific displacement pattern?
. Median nerve
. Ulnar nerve
. Radial nerve
. Anterior interosseous nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Radial nerve

Explanation

In posteromedially displaced supracondylar humerus fractures, the proximal fragment goes anterolaterally, putting the radial nerve at the greatest risk of tethering or injury. Posterolateral displacement puts the median nerve (specifically AIN) at greatest risk.

Question 5079

Topic: Pediatric Hip
A 12-year-old boy with chronic renal failure presents with a unilateral slipped capital femoral epiphysis (SCFE) of the left hip. What is the most appropriate indication for prophylactic pinning of the contralateral right hip?
. Age greater than 14 years at presentation
. Presence of an underlying endocrine or metabolic disorder
. Grade III slip on the primarily affected left side
. Presence of a lateral slip angle greater than 50 degrees
. Male gender

Correct Answer & Explanation

. Presence of an underlying endocrine or metabolic disorder

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended in patients with endocrine or metabolic disorders (e.g., hypothyroidism, chronic renal failure, growth hormone therapy) due to a significantly increased risk (approaching 100%) of bilateral involvement. Age less than 10, not older, is also considered a relative indication.

Question 5080

Topic: Pediatric Hip

An infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At the 3-week follow-up, the infant exhibits decreased spontaneous movement of the affected leg and absent knee extension. What is the most likely cause of this physical finding?

. Avascular necrosis of the femoral head
. Obturator nerve palsy due to excessive abduction
. Femoral nerve palsy due to excessive hyperflexion
. Sciatic nerve palsy due to excessive adduction
. Transient synovitis secondary to brace wear

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by excessive hyperflexion of the hip. It presents with decreased active knee extension and diminished spontaneous leg movements. The harness should be temporarily removed or adjusted, and the palsy typically resolves spontaneously.

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