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4. Pediatrics MCQs

Practice Set 52 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 1021

Topic: 4. Pediatrics

Fibular deficiency (fibular hemimelia) is the most common congenital long bone deficiency. When examining a child with this condition, which of the following knee anomalies is most frequently encountered?

. Posterior cruciate ligament (PCL) absence
. Anterior cruciate ligament (ACL) hypoplasia or absence
. Medial meniscus discoid variant
. Patella alta with quadriceps contracture
. Congenital knee dislocation

Correct Answer & Explanation

. Anterior cruciate ligament (ACL) hypoplasia or absence

Explanation

Fibular deficiency is strongly associated with anterior cruciate ligament (ACL) absence or hypoplasia. Patients also frequently present with genu valgum and lateral femoral condyle hypoplasia.

Question 1022

Topic: 4. Pediatrics

A 10-month-old infant is diagnosed with severe Achterman and Kalamchi Type II fibular hemimelia. The limb length discrepancy is projected to be 22 cm at skeletal maturity. The foot has three rays and is fixed in severe equinovalgus. What is the most appropriate management?

. Early Syme amputation
. Serial casting to correct equinovalgus followed by observation
. Early epiphyseodesis of the contralateral limb
. Ilizarov limb lengthening at age 2
. Supramalleolar osteotomy and Achilles lengthening

Correct Answer & Explanation

. Early Syme amputation

Explanation

In severe fibular hemimelia with a projected leg length discrepancy >20 cm and a non-functional foot (absent rays, severe deformity), early Syme or Boyd amputation followed by prosthetic fitting provides the best functional outcome.

Question 1023

Topic: 4. Pediatrics

A newborn infant is evaluated for a right lower extremity deformity. Clinical examination reveals a significantly shortened lower leg and a foot with only three toes. Radiographs confirm complete absence of the right fibula. Which of the following associated lower extremity anomalies is most classically expected in this patient?

. Anterolateral tibial bowing
. Posteromedial tibial bowing
. Cruciate ligament deficiency
. Medial column foot ray deficiency
. Varus hindfoot deformity

Correct Answer & Explanation

. Anterolateral tibial bowing

Explanation

Fibular hemimelia is classically associated with anterior cruciate ligament (ACL) deficiency, anteromedial tibial bowing, absent lateral foot rays, and an equinovalgus foot deformity. Anterolateral bowing is associated with congenital pseudarthrosis of the tibia, while posteromedial bowing typically resolves and is associated with calcaneovalgus foot.

Question 1024

Topic: Pediatric Lower Extremity

The understanding and surgical management of tarsal coalitions have been significantly influenced by foundational studies. Which of the following statements accurately attributes a key contribution to the specified researcher or group?

. Cowell's work established the critical threshold of 50% posterior facet involvement for talocalcaneal coalitions, dictating primary arthrodesis for larger lesions.
. Mubarak and colleagues emphasized the necessity of a wide, rectangular resection and EDB interposition for calcaneonavicular coalitions.
. Wilde et al. detailed the medial approach for middle facet talocalcaneal coalitions and the importance of preserving the FHL tendon and neurovascular bundle.
. Modern literature primarily advocates for simple resection without interposition grafts to minimize donor site morbidity.
. Current guidelines recommend immediate surgical intervention for all newly diagnosed tarsal coalitions, regardless of symptoms or arthrosis.

Correct Answer & Explanation

. Wilde et al. detailed the medial approach for middle facet talocalcaneal coalitions and the importance of preserving the FHL tendon and neurovascular bundle.

Explanation

Correct Answer: CThe "Summary of Key Literature and Guidelines" section directly attributes the following: Wilde et al. "contributed significantly to the understanding of the middle facet's role in TC coalitions, detailing the medial approach and the importance of preserving the FHL tendon and the neurovascular bundle."Option A is incorrect: Mubarak and colleagues established the 50% posterior facet involvement rule for TC coalitions. Cowell's work focused on CN coalitions.Option B is incorrect: Cowell's seminal work established the lateral approach and EDB interposition for CN coalitions.Option D is incorrect: Modern literature supports the use of interposition grafts (EDB, fat, FHL) to prevent recurrence. Simple resection alone is associated with higher recurrence rates.Option E is incorrect: Current guidelines recommend an initial trial of non-operative management for all newly diagnosed, non-arthritic tarsal coalitions.

Question 1025

Topic: Pediatric Hip
A 4-year-old child presents with a painless limp. Examination reveals limited abduction and internal rotation of the hip. Radiographs show increased density and flattening of the femoral epiphysis. What is the most likely diagnosis?
. Developmental dysplasia of the hip (DDH)
. Septic arthritis of the hip
. Slipped capital femoral epiphysis (SCFE)
. Legg-Calvé-Perthes disease
. Transient synovitis

Correct Answer & Explanation

. Legg-Calvé-Perthes disease

Explanation

The clinical picture of a painless limp in a 4-year-old with limited hip abduction and internal rotation, coupled with radiographic findings of increased density (sclerosis) and flattening (fragmentation/collapse) of the femoral epiphysis, is characteristic of Legg-Calvé-Perthes disease. This condition is idiopathic avascular necrosis of the femoral head. SCFE typically occurs in older, often obese adolescents. DDH presents earlier and with different radiographic findings. Septic arthritis and transient synovitis are acute painful conditions.

Question 1026

Topic: Pediatric Hip

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

. Adjust the anterior straps to increase flexion
. Adjust the posterior straps to decrease abduction
. Discontinue the harness immediately
. Schedule an urgent MRI of the lumbar spine
. Transition to a rigid hip spica cast

Correct Answer & Explanation

. Discontinue the harness immediately

Explanation

The patient has developed a femoral nerve palsy, a known complication of hyperflexion in a Pavlik harness. The most appropriate immediate step is to discontinue the harness to allow for nerve recovery before attempting alternative treatments.

Question 1027

Topic: Pediatric Lower Extremity

When treating a 2-week-old infant with idiopathic clubfoot using the Ponseti method, what is the correct sequence of deformity correction?

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

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus

Explanation

The Ponseti method corrects the components of clubfoot in a specific sequence summarized by the acronym CAVE: Cavus, Adductus, Varus, and finally Equinus. The cavus is corrected first by elevating the first ray to supinate the forefoot.

Question 1028

Topic: Pediatric Hip

An obese 13-year-old male presents with right knee pain and an antalgic limp. Examination reveals obligate external rotation of the right hip with passive flexion. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Which of the following is the most recognized complication of in-situ percutaneous pinning of a stable SCFE?

. Chondrolysis
. Avascular necrosis
. Femoral nerve palsy
. Leg length discrepancy > 3 cm
. Heterotopic ossification

Correct Answer & Explanation

. Chondrolysis

Explanation

Chondrolysis is a severe complication associated with SCFE treatment, often linked to unrecognized intra-articular hardware penetration during in-situ pinning. AVN is much more commonly associated with unstable SCFE or aggressive reduction attempts rather than standard pinning of a stable slip.

Question 1029

Topic: Pediatric Hip

A 12-year-old obese male presents with a stable left slipped capital femoral epiphysis (SCFE). Which of the following is the strongest indication for prophylactic in situ pinning of the asymptomatic right hip?

. Male sex
. Age greater than 14 years
. Weight greater than 95th percentile
. Underlying endocrinopathy
. Family history of SCFE

Correct Answer & Explanation

. Underlying endocrinopathy

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with an underlying endocrinopathy (e.g., hypothyroidism) or prior pelvic radiation, as their risk for bilateral involvement is significantly elevated.

Question 1030

Topic: Pediatric Hip

A 6-month-old female with developmental dysplasia of the hip has failed 4 weeks of Pavlik harness treatment. Ultrasound demonstrates continued posterior dislocation of the femoral head. What is the most appropriate next step in management?

. Continue Pavlik harness for an additional 4 weeks
. Switch to a rigid abduction orthosis
. Closed reduction and spica casting under anesthesia
. Open reduction and pelvic osteotomy
. Observation until 1 year of age

Correct Answer & Explanation

. Closed reduction and spica casting under anesthesia

Explanation

If a Pavlik harness fails to achieve reduction within 3-4 weeks, it should be discontinued to prevent Pavlik harness disease (damage to the posterior acetabular wall). The next appropriate step is closed reduction and spica casting under general anesthesia with an arthrogram.

Question 1031

Topic: Pediatric Hip

A 6-month-old female with developmental dysplasia of the hip (DDH) has failed treatment with a Pavlik harness. Ultrasound confirms persistent dislocation. What is the next most appropriate step in management?

. Observation until age 1
. Switch to an abduction orthosis without confirmation of reduction
. Closed reduction with hip spica casting
. Open reduction with femoral shortening osteotomy
. Salter innominate osteotomy

Correct Answer & Explanation

. Closed reduction with hip spica casting

Explanation

For infants between 6 and 18 months, or those who fail Pavlik harness treatment, closed reduction under anesthesia followed by spica casting is the standard next step. An intraoperative arthrogram is typically performed to assess the adequacy of reduction.

Question 1032

Topic: Pediatric Hip

A 4-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 child is no longer actively extending her left knee. Which nerve is most likely affected by incorrect harness positioning?

. Sciatic nerve
. Femoral nerve
. Obturator nerve
. Common peroneal nerve
. Tibial nerve

Correct Answer & Explanation

. Femoral nerve

Explanation

Excessive hyperflexion in a Pavlik harness can cause compression of the femoral nerve against the inguinal ligament, leading to transient femoral nerve palsy (loss of active knee extension). Treatment involves altering the harness to reduce flexion.

Question 1033

Topic: Pediatric Hip

A 12-year-old obese male presents with acute severe hip pain and inability to bear weight. Radiographs show a severe slipped capital femoral epiphysis (SCFE). Which of the following treatments is associated with the highest risk of iatrogenic avascular necrosis (AVN) of the femoral head?

. In situ pinning with a single cannulated screw
. In situ pinning with two cannulated screws
. Closed reduction with forceful manipulation prior to pinning
. Prophylactic pinning of the contralateral hip
. Open subcapital realignment (modified Dunn procedure) by an experienced surgeon

Correct Answer & Explanation

. Closed reduction with forceful manipulation prior to pinning

Explanation

Forceful closed reduction or overzealous manipulation of an acute or unstable SCFE severely compromises the already tenuous epiphyseal blood supply. This drastically increases the rate of avascular necrosis and is strictly contraindicated.

Question 1034

Topic: 4. Pediatrics

During the Ponseti method of serial casting for a congenital clubfoot, the sequence of deformity correction is critical. Which component of the deformity is corrected last, typically requiring a surgical intervention to fully resolve?

. Cavus
. Adductus
. Varus
. Equinus
. Supination

Correct Answer & Explanation

. Equinus

Explanation

The Ponseti method corrects the deformities in the order of CAVE: Cavus, Adductus, Varus, and finally Equinus. The equinus deformity is corrected last and requires a percutaneous Achilles tenotomy in approximately 80-90% of cases.

Question 1035

Topic: 4. Pediatrics
A 10-year-old child presents to the emergency department after jamming his finger during a soccer game. Radiographs of the affected finger reveal an epiphyseal fracture involving the distal phalanx. According to the Doyle classification, which type of mallet injury is this, and what is its corresponding Salter-Harris classification?
. Type I; Salter-Harris Type I
. Type II; Salter-Harris Type II
. Type III; Salter-Harris Type III
. Type IV; Salter-Harris Type I or II
. Type IV; Salter-Harris Type III or IV

Correct Answer & Explanation

. Type IV; Salter-Harris Type I or II

Explanation

Correct Answer: D. The case explicitly defines Doyle Type IV as: 'Epiphyseal fracture in children (Salter-Harris type I or II).' The patient is a 10-year-old child with an epiphyseal fracture, directly matching this description. Incorrect Options: Type I; Salter-Harris Type I: Type I is a soft tissue avulsion, not an epiphyseal fracture. Type II; Salter-Harris Type II: Type II is a bony avulsion fracture involving less than 30% of the articular surface in adults, not specifically an epiphyseal fracture in children. Type III; Salter-Harris Type III: Type III is a bony avulsion fracture involving more than 30% of the articular surface, often with subluxation, in adults. Type IV; Salter-Harris Type III or IV: While Type IV is an epiphyseal fracture, the case specifically states it's Salter-Harris Type I or II, not III or IV.

Question 1036

Topic: 4. Pediatrics

A 10-year-old boy presents to the emergency department after a basketball struck his right long finger. Examination reveals an open wound at the proximal nail fold with the nail plate positioned superficial to the eponychium, and the fingertip rests in flexion. Radiographs demonstrate a Salter-Harris I fracture of the distal phalanx. What is the most appropriate definitive management?

. Closed reduction and external continuous extension splinting for 6 weeks
. Nail bed repair, fracture reduction, and K-wire fixation
. Amputation of the distal phalanx
. Non-weight bearing and observation
. Primary arthrodesis of the DIP joint

Correct Answer & Explanation

. Nail bed repair, fracture reduction, and K-wire fixation

Explanation

This is a Seymour fracture, which is an open physeal fracture of the distal phalanx associated with a nail bed laceration. Appropriate management requires nail removal, thorough irrigation and debridement, fracture reduction, nail bed repair, and often K-wire fixation to prevent osteomyelitis and growth arrest.

Question 1037

Topic: 4. Pediatrics

A 10-year-old boy presents with a mallet-like deformity of his right long finger after a crush injury in a door. Clinically, the DIP joint is flexed, and the proximal edge of the nail plate is avulsed from the eponychial fold. Radiographs show a widening of the dorsal distal phalanx physis. What is the most appropriate management?

. Continuous extension splinting for 6 weeks
. Closed reduction and extension block pinning
. Removal of the nail plate, irrigation, reduction of the physeal fracture, and nailbed repair
. DIP joint arthrodesis
. Observation with buddy taping

Correct Answer & Explanation

. Removal of the nail plate, irrigation, reduction of the physeal fracture, and nailbed repair

Explanation

This is a Seymour fracture, characterized by a Salter-Harris I or II fracture of the distal phalanx with an associated nailbed laceration. It is an open fracture requiring removal of the nail plate, thorough irrigation, nailbed repair, and reduction of the fracture.

Question 1038

Topic: 4. Pediatrics
Which of the following specific histological findings differentiates the vascular pathology of Hypothenar Hammer Syndrome from an atherosclerotic arterial occlusion?
. Presence of lipid-laden macrophages forming a necrotic core
. Transmural inflammation with giant cells
. Intimal hyperplasia with fragmentation of the internal elastic lamina and organizing thrombus
. Medial calcific sclerosis (Mönckeberg's sclerosis)
. Congenital absence of the tunica media

Correct Answer & Explanation

. Intimal hyperplasia with fragmentation of the internal elastic lamina and organizing thrombus

Explanation

HHS is a traumatic mechanism leading to intimal disruption, fragmentation of the internal elastic lamina, and reactive intimal hyperplasia with subsequent thrombosis. It lacks the lipid cores of atherosclerosis or the giant cells of arteritis.

Question 1039

Topic: 4. Pediatrics
A 13-year-old male presents with a left ankle injury sustained during a soccer match. Radiographs, including the AP and lateral views shown below, are obtained. Based on the available imaging, which of the following best describes the classic radiographic appearance of this injury?
. Triplane fracture; Salter–Harris III on sagittal view; Salter–Harris II on anteroposterior (AP) view
. Triplane fracture; Salter–Harris II on sagittal view; Salter–Harris III on anteroposterior (AP) view
. Triplane fracture; Salter–Harris III on sagittal view; Salter–Harris III on anteroposterior (AP) view
. Tillaux fracture; Salter–Harris III on sagittal view; Salter–Harris II on anteroposterior (AP) view
. Tillaux fracture; Salter–Harris II on sagittal view; Salter–Harris III on anteroposterior (AP) view

Correct Answer & Explanation

. Triplane fracture; Salter–Harris II on sagittal view; Salter–Harris III on anteroposterior (AP) view

Explanation

Correct Answer: Triplane fracture; Salter–Harris II on sagittal view; Salter–Harris III on anteroposterior (AP) view. The images depict a triplane fracture of the distal tibia, a complex transitional ankle fracture occurring during physeal closure. The characteristic radiographic appearance of a triplane fracture is a Salter–Harris II fracture pattern on the lateral view (sagittal plane) and a Salter–Harris III fracture pattern on the anteroposterior (AP) or coronal view. This is because the fracture involves the epiphysis, physis, and metaphysis in multiple planes. Salter–Harris III on sagittal view; Salter–Harris II on anteroposterior (AP) view: This reverses the classic appearance. Salter–Harris III on sagittal view; Salter–Harris III on anteroposterior (AP) view: This would imply a Salter-Harris III in both planes, which is not the classic description of a triplane fracture. Tillaux fracture: A Tillaux fracture is a Salter-Harris III fracture of the anterolateral distal tibial epiphysis only, without a metaphyseal component, and is typically seen as a Salter-Harris III on AP/coronal views. It does not have the Salter-Harris II component on the lateral view.

Question 1040

Topic: 4. Pediatrics

Nine months after his initial presentation and treatment for a triplane ankle fracture, a 13-year-old male returns for follow-up. You inform him about the most likely long-term sequela of his injury. Which of the following is the most probable outcome at this point?

. Posttraumatic physeal closure of the distal tibia that does not require additional treatment
. Posttraumatic physeal closure of the distal tibia that requires corrective valgus osteotomy
. Posttraumatic physeal closure of the distal tibia that requires corrective varus osteotomy
. Posttraumatic physeal closure of the distal tibia that requires corrective extension osteotomy
. Nonunion of the Thurston–Holland fragment

Correct Answer & Explanation

. Posttraumatic physeal closure of the distal tibia that does not require additional treatment

Explanation

Correct Answer: Posttraumatic physeal closure of the distal tibia that does not require additional treatmentTransitional ankle fractures, such as Tillaux and triplane fractures, occur during the period of physiological physeal closure. By the time these injuries occur, a significant portion of the growth plate has already fused. Therefore, while some degree of posttraumatic physeal closure may occur, it is typically not clinically significant and does not lead to substantial limb length discrepancy or angular deformity requiring corrective osteotomy. The remaining growth potential is usually minimal.Posttraumatic physeal closure of the distal tibia that requires corrective valgus/varus/extension osteotomy:These are unlikely because significant growth arrest leading to angular deformity or limb length discrepancy is rare with transitional fractures due to the timing of the injury during natural physeal closure.Nonunion of the Thurston–Holland fragment:The Thurston–Holland fragment is associated with Salter-Harris II fractures (a component of triplane fractures). While nonunion is a theoretical complication of any fracture, it is exceedingly rare in pediatric physeal fractures, especially with appropriate treatment, and has not been reported as a common sequela for triplane fractures.

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