Menu

4. Pediatrics MCQs

Practice Set 243 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 4841

Topic: Pediatric Hip

A 3-year-old girl presents with a painless limp. Examination reveals a positive Galeazzi sign and asymmetric thigh folds. Radiographs reveal a dislocated left hip with a broken Shenton's line and an acetabular index of 40 degrees. The right hip is normal. What is the most appropriate primary surgical treatment?

. Closed reduction and spica casting
. Open reduction and spica casting
. Open reduction, femoral shortening osteotomy, and pelvic osteotomy
. Pavlik harness application
. Shelf acetabuloplasty

Correct Answer & Explanation

. Closed reduction and spica casting

Explanation

In a child older than 2 to 3 years presenting with a completely dislocated hip (Developmental Dysplasia of the Hip), closed reduction is rarely successful and carries a high risk of avascular necrosis. The standard of care is an open reduction combined with a femoral shortening osteotomy (to relieve tension on the reduced hip and decrease AVN risk) and a pelvic osteotomy (e.g., Pemberton or Dega) to address the significant acetabular dysplasia (acetabular index of 40 degrees).

Question 4842

Topic: 4. Pediatrics
A 2-year-old boy presents with anterolateral bowing of the tibia. Radiographs demonstrate a pseudarthrosis of the middle third of the tibia. Examination reveals six café-au-lait spots. Which of the following surgical treatments provides the most reliable long-term outcome for achieving and maintaining union?
. Observation and bracing until skeletal maturity
. Resection of the pseudarthrosis, intramedullary rodding, and autogenous bone grafting
. Closed reduction and long leg casting
. Syme amputation
. Ilizarov bone transport without resection of the hamartomatous tissue

Correct Answer & Explanation

. Resection of the pseudarthrosis, intramedullary rodding, and autogenous bone grafting

Explanation

Congenital pseudarthrosis of the tibia (CPT) is strongly associated with Neurofibromatosis type 1 (NF-1). The pseudarthrosis site contains dense, hamartomatous fibrous tissue that inhibits healing. The standard surgical treatment involves complete resection of this tissue, stabilization with an intramedullary device (e.g., Williams rod or Fassier-Duval rod) that crosses the ankle to prevent recurrent deformity, and copious autogenous bone grafting. Cross-union procedures to the fibula or vascularized fibular grafts are also options.

Question 4843

Topic: 4. Pediatrics

A 4-year-old obese girl presents with bilateral severe genu varum. Standing radiographs demonstrate a metaphyseal-diaphyseal angle (Drennan angle) of 22 degrees bilaterally, with prominent medial metaphyseal beaking. Which of the following is the most appropriate management?

. Observation and parental reassurance
. Knee-ankle-foot orthosis (KAFO) bracing
. Proximal tibial valgus osteotomy
. Guided growth with tension band plates on the lateral proximal tibia
. Epiphyseodesis of the lateral proximal tibia

Correct Answer & Explanation

. Observation and parental reassurance

Explanation

The patient has infantile Blount's disease. A Drennan angle >16 degrees is highly predictive of progression. By age 4, the likelihood of success with bracing is very low, and irreversible damage to the medial physis may occur. A proximal tibial valgus osteotomy, often combined with a fibular osteotomy or release, is indicated to acutely correct the deformity and unload the medial physis before permanent physeal arrest occurs. Guided growth (lateral hemiepiphysiodesis) has higher failure rates in severe, early-onset Blount's, particularly in obese patients.

Question 4844

Topic: 4. Pediatrics

A 12-year-old boy sustains a displaced Salter-Harris type II fracture of the distal femur. He is treated with closed reduction and percutaneous crossed-pin fixation. Due to the specific anatomy and biomechanics of the distal femoral physis, which of the following complications is most frequently encountered with this injury?

. Nonunion
. Growth arrest resulting in limb length discrepancy or angular deformity
. Acute compartment syndrome
. Popliteal artery laceration
. Chronic osteomyelitis

Correct Answer & Explanation

. Nonunion

Explanation

The distal femoral physis is highly undulated and relies heavily on its structural interlocking for stability. Salter-Harris II fractures here are notorious for causing significant physeal injury during the initial trauma. The incidence of growth arrest (resulting in limb length discrepancy or angular deformity) is extremely high, reported to be up to 40-50%, even with anatomic reduction and appropriate fixation.

Question 4845

Topic: 4. Pediatrics
A 14-year-old boy sustains a twisting ankle injury. Radiographs show a Salter-Harris III fracture of the anterolateral portion of the distal tibial epiphysis. What anatomical characteristic explains this specific fracture pattern?
. The anterolateral physis is the last portion to close during skeletal maturation
. The medial physis is the last portion to close during skeletal maturation
. The anterior inferior tibiofibular ligament (AITFL) is weaker than the physis
. The deltoid ligament avulses the medial malleolus before the syndesmosis fails
. The syndesmosis completely ruptures prior to physeal failure

Correct Answer & Explanation

. The anterolateral physis is the last portion to close during skeletal maturation

Explanation

A juvenile Tillaux fracture is a Salter-Harris III avulsion of the anterolateral distal tibial epiphysis by the anterior inferior tibiofibular ligament (AITFL). This occurs because the distal tibial physis closes in an asymmetrical pattern: central, then medial, then posterior, and finally anterolateral. During this specific window of adolescence, the anterolateral physis remains open and is the weakest link when external rotation forces are applied.

Question 4846

Topic: Pediatric Upper Extremity & Spine
A newborn presents with a severe right radial clubhand. Examination shows an absent thumb and radial deviation of the wrist. An echocardiogram reveals an atrial septal defect (ASD). Which of the following syndromes best fits this clinical picture?
. Fanconi anemia
. Holt-Oram syndrome
. Thrombocytopenia-Absent Radius (TAR) syndrome
. VACTERL association
. Klippel-Trenaunay syndrome

Correct Answer & Explanation

. Holt-Oram syndrome

Explanation

Holt-Oram syndrome is an autosomal dominant condition characterized by upper extremity anomalies (often radial ray deficiencies, including absent thumb) and congenital heart defects, most commonly an ASD or VSD. In contrast, TAR syndrome features an absent radius but a PRESENT thumb. Fanconi anemia involves bone marrow failure and requires chromosomal breakage testing. VACTERL includes vertebral, anal, cardiac, tracheoesophageal, renal, and limb anomalies, but Holt-Oram is specifically defined by the heart-hand connection.

Question 4847

Topic: 4. Pediatrics

A 3-year-old girl is brought in for a waddling gait and noticeable 'bow legs'. Standing radiographs reveal bilateral genu varum. Which of the following radiographic parameters is the most reliable for differentiating infantile Blount's disease from resolving physiologic genu varum?

. Presence of medial metaphyseal beaking alone
. Metaphyseal-diaphyseal angle (Drennan angle) greater than 16 degrees
. Tibiofemoral angle of 15 degrees varus
. Thickening of the medial tibial cortices
. Widening of the entire proximal tibial physis

Correct Answer & Explanation

. Presence of medial metaphyseal beaking alone

Explanation

The metaphyseal-diaphyseal angle (MDA), or Drennan angle, is the most reliable radiographic tool to differentiate physiologic bowing from infantile Blount's disease. An MDA greater than 16 degrees has a high positive predictive value for progression to Blount's disease, while an angle less than 10 degrees suggests physiologic bowing that will likely resolve.

Question 4848

Topic: 4. Pediatrics

A 5-year-old boy presents with a painless limp. Examination reveals a positive Trendelenburg sign on the right. Radiographs show a right neck-shaft angle of 95 degrees, a vertical proximal femoral physis, and an inverted Y-shaped radiolucency in the inferior femoral neck. What radiographic measurement is the primary indication to perform a valgus-producing subtrochanteric osteotomy?

. Neck-shaft angle less than 120 degrees
. Hilgenreiner-epiphyseal angle (HEA) greater than 60 degrees
. Articulotrochanteric distance (ATD) less than 0 mm
. Limb length discrepancy greater than 1 cm
. Center-edge (CE) angle of Wiberg less than 20 degrees

Correct Answer & Explanation

. Neck-shaft angle less than 120 degrees

Explanation

The diagnosis is developmental coxa vara. The Hilgenreiner-epiphyseal angle (HEA) is used to predict progression and guide treatment. An HEA > 60 degrees indicates a high likelihood of progression and is a clear indication for surgical intervention (valgus subtrochanteric osteotomy). An HEA < 45 degrees usually resolves spontaneously. Angles between 45 and 60 degrees require close observation.

Question 4849

Topic: 4. Pediatrics

A 4-year-old girl presents with a unilaterally elevated left shoulder. Physical exam reveals restricted abduction of the left shoulder and a noticeably smaller left scapula. Radiographs confirm an elevated scapula with an omovertebral bone connecting the cervical spine to the superior angle of the scapula. Which of the following conditions is most commonly associated with this congenital deformity?

. Diastematomyelia
. Klippel-Feil syndrome
. Cleidocranial dysplasia
. Holt-Oram syndrome
. Larsen syndrome

Correct Answer & Explanation

. Diastematomyelia

Explanation

Sprengel's deformity is a congenital failure of descent of the scapula. The most common associated condition is Klippel-Feil syndrome (congenital cervical spine fusion), seen in up to 30% of cases. The omovertebral bone is a fibrous, cartilaginous, or osseous connection found in roughly 30% of Sprengel patients.

Question 4850

Topic: Pediatric Lower Extremity

A newborn male is noted to have a limb length discrepancy and deformity of the right lower extremity. Radiographs reveal partial absence of the fibula, anteromedial bowing of the tibia, and a foot with three digits. Which of the following foot deformities is most characteristically associated with this condition?

. Equinovarus
. Equinovalgus
. Calcaneovalgus
. Calcaneovarus
. Cavovarus

Correct Answer & Explanation

. Equinovarus

Explanation

Fibular hemimelia is the most common congenital long bone deficiency. It is characterized by partial or complete absence of the fibula, anteromedial bowing of the tibia, absence of lateral rays of the foot, and an equinovalgus foot deformity. Associated findings include femoral shortening (PFFD), cruciate ligament deficiency, and a ball-and-socket ankle joint.

Question 4851

Topic: 4. Pediatrics

A 6-year-old boy with spastic quadriplegic cerebral palsy is evaluated for hip instability. An AP pelvis radiograph is obtained and the Reimers migration percentage is calculated. At what migration percentage is surgical intervention (e.g., adductor/iliopsoas release or reconstructive osteotomy) generally indicated to prevent frank hip dislocation?

. > 10%
. > 15%
. > 30%
. > 60%
. > 80%

Correct Answer & Explanation

. > 10%

Explanation

The Reimers migration percentage (MP) measures the percentage of the femoral head outside of the acetabulum (lateral to Perkins line). An MP > 30% is a critical threshold in children with cerebral palsy, indicating significant hip subluxation. It generally prompts surgical intervention such as soft tissue release or varus derotational osteotomy (VDRO) with pelvic osteotomy depending on the patient's age and degree of dysplasia.

Question 4852

Topic: 4. Pediatrics

A 5-year-old boy falls from monkey bars and sustains a widely displaced extension-type supracondylar humerus fracture. On presentation, the hand is pink but the radial pulse is absent. After urgent closed reduction and percutaneous pinning, the hand remains well-perfused (pink and warm with brisk capillary refill) but the radial pulse remains absent. What is the most appropriate next step in management?

. Immediate vascular surgery consultation for brachial artery exploration
. Remove pins, re-reduce, and repin the fracture
. Perform an anterior approach to release the aponeurosis and explore the artery
. Observe and admit for serial neurovascular checks
. Perform a computed tomography angiogram (CTA) of the upper extremity

Correct Answer & Explanation

. Immediate vascular surgery consultation for brachial artery exploration

Explanation

In a pediatric supracondylar humerus fracture presenting with a 'pink, pulseless' hand, the initial step is closed reduction and pinning. If the hand remains pink and well-perfused with an absent radial pulse after adequate reduction and stabilization, the standard of care is close observation. The collateral circulation is sufficient to maintain limb viability, and the pulse typically returns over days to weeks. Surgical exploration is indicated for a 'white, pulseless' hand that does not improve after reduction.

Question 4853

Topic: 4. Pediatrics
A 13-year-old girl sustains an ankle injury while playing soccer. Radiographs reveal a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis. What is the mechanism of injury and the anatomic structure responsible for avulsing this fragment?
. Plantarflexion and inversion; anterior talofibular ligament (ATFL)
. Dorsiflexion and eversion; deltoid ligament
. External rotation; anterior inferior tibiofibular ligament (AITFL)
. Internal rotation; posterior inferior tibiofibular ligament (PITFL)
. Axial loading; interosseous membrane

Correct Answer & Explanation

. External rotation; anterior inferior tibiofibular ligament (AITFL)

Explanation

A juvenile Tillaux fracture is a Salter-Harris type III fracture of the anterolateral distal tibial epiphysis. It occurs in adolescents due to the asymmetric closure pattern of the distal tibial physis (closing centrally first, then medially, then laterally). An external rotation force causes the anterior inferior tibiofibular ligament (AITFL) to avulse the unfused anterolateral epiphysis.

Question 4854

Topic: 4. Pediatrics

A 10-month-old infant with achondroplasia is noted to have a persistent thoracolumbar kyphosis. Which of the following statements regarding the natural history and management of this deformity is most accurate?

. It typically progresses to severe structural kyphosis requiring early posterior spinal fusion.
. It is secondary to true vertebral body hemivertebrae formation.
. It usually resolves spontaneously with the onset of independent walking.
. It should be treated immediately with a rigid Boston brace.
. It requires anterior and posterior spinal fusion due to high risk of pseudoarthrosis.

Correct Answer & Explanation

. It typically progresses to severe structural kyphosis requiring early posterior spinal fusion.

Explanation

Thoracolumbar kyphosis is present in up to 90% of infants with achondroplasia. It is primarily positional, exacerbated by relative hypotonia and large head size, and typically resolves spontaneously once the child develops truncal muscle strength and begins to walk independently. Bracing or surgery is rarely indicated unless it persists and becomes a fixed structural deformity (wedged vertebrae) later in childhood.

Question 4855

Topic: 4. Pediatrics
A 2-year-old boy with multiple café-au-lait spots and axillary freckling presents with marked anterolateral bowing of his left tibia. Radiographs demonstrate diaphyseal narrowing and cystic changes. What is the most appropriate surgical management to prevent or treat pseudoarthrosis in this condition once indicated?
. Observation until skeletal maturity
. Serial casting into a rectus alignment
. Prophylactic above-knee amputation
. Excision of the pseudoarthrosis, bone grafting, and intramedullary rodding
. Percutaneous drilling and injection of bone marrow aspirate

Correct Answer & Explanation

. Excision of the pseudoarthrosis, bone grafting, and intramedullary rodding

Explanation

Congenital anterolateral bowing of the tibia is highly associated with Neurofibromatosis type 1 (NF1) and frequently progresses to a recalcitrant pseudoarthrosis due to abnormal hamartomatous tissue in the periosteum. The standard surgical treatment involves radical excision of the diseased periosteum and pseudoarthrosis, autologous bone grafting, and intramedullary rodding (often combined with an external fixator to maximize stability).

Question 4856

Topic: 4. Pediatrics

A 6-month-old infant is brought to the clinic with bilateral femur fractures and blue sclerae. Genetic testing confirms a diagnosis of Osteogenesis Imperfecta (OI). This condition is primarily caused by a mutation affecting the synthesis of which of the following proteins?

. Type II collagen
. Fibrillin-1
. Fibroblast growth factor receptor 3
. Type I collagen
. Cartilage oligomeric matrix protein (COMP)

Correct Answer & Explanation

. Type II collagen

Explanation

Osteogenesis Imperfecta is a group of genetic disorders that mainly affect the formation of Type I collagen, the major structural protein in bone, skin, and sclerae. The mutations typically occur in the COL1A1 or COL1A2 genes, leading to decreased production or abnormal structure of collagen, resulting in brittle bones, blue sclerae, and dentinogenesis imperfecta.

Question 4857

Topic: Pediatric Hip
An 8-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Which of the following radiographic findings is considered a 'head at risk' sign, portending a poorer prognosis and a higher risk of femoral head deformation?
. Medial subluxation of the femoral head
. Gage sign
. Presence of the crescent sign in the anterior 25% of the head
. Delayed skeletal age
. Decreased medial joint space

Correct Answer & Explanation

. Gage sign

Explanation

Catterall described 'head at risk' signs in Legg-Calvé-Perthes disease, which indicate a high risk for progressive subluxation and a poorer outcome. These include: Gage sign (a V-shaped radiolucency in the lateral portion of the epiphysis and adjacent metaphysis), lateral (not medial) subluxation of the femoral head, calcification lateral to the epiphysis, diffuse metaphyseal reaction, and a horizontal physis.

Question 4858

Topic: 4. Pediatrics
A 1-year-old child is evaluated for a markedly shortened right lower extremity. Radiographs show a shortened femur, an absent femoral head, and no bony connection between the proximal femur and the acetabulum. The tibia is relatively normal in length, but the fibula is absent. What classification system is most commonly used for this specific femoral condition?
. Aitken classification
. Langenskiöld classification
. Gartland classification
. Herring lateral pillar classification
. Dimon-Hughston classification

Correct Answer & Explanation

. Aitken classification

Explanation

The Aitken classification is used for Proximal Focal Femoral Deficiency (PFFD). It evaluates the presence of the femoral head, the continuity of the femoral shaft with the neck/head, and the severity of the deficiency (Classes A through D). Langenskiöld is for Blount disease. Herring is for Perthes disease. Gartland is for supracondylar humerus fractures.

Question 4859

Topic: 4. Pediatrics

A 4-year-old, significantly overweight boy presents with progressive bowing of both legs. Standing radiographs reveal bilateral genu varum, metaphyseal-diaphyseal angles of 20 degrees, and medial physeal beaking of the proximal tibiae. What is the primary pathophysiologic mechanism underlying this condition?

. Genetic mutation in COL10A1
. Vitamin D deficiency leading to impaired mineralization
. Asymmetric mechanical suppression of physeal growth
. Premature fusion of the entire proximal tibial physis
. Hypervascularity of the medial epiphysis

Correct Answer & Explanation

. Genetic mutation in COL10A1

Explanation

Blount disease (tibia vara) is an acquired condition resulting from mechanical overload of the posteromedial aspect of the proximal tibial physis. According to the Hueter-Volkmann principle, excessive compressive forces inhibit physeal growth. This leads to progressive varus, flexion, and internal rotation deformity of the tibia.

Question 4860

Topic: 4. Pediatrics

A 4-week-old infant is brought to the clinic for a right-sided neck mass and a head tilt. The infant's head is tilted to the right and rotated to the left. Palpation reveals a firm, non-tender 'olive-like' mass in the right sternocleidomastoid muscle. What is the most appropriate initial management?

. Surgical release of the sternocleidomastoid muscle
. Botulinum toxin injection into the affected muscle
. Physical therapy focusing on passive stretching and positioning
. MRI of the cervical spine and brainstem
. Casting in a neutral position

Correct Answer & Explanation

. Surgical release of the sternocleidomastoid muscle

Explanation

The clinical presentation is classic for congenital muscular torticollis with a sternocleidomastoid (SCM) tumor (fibromatosis colli). Initial management consists of parental education, repositioning, and physical therapy for passive stretching of the affected SCM muscle. Over 90% of cases resolve with conservative management. Surgery is reserved for cases refractory to at least 6-12 months of dedicated therapy.

Test Yourself

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

On this Page