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4. Pediatrics MCQs

Practice Set 53 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 1041

Topic: 4. Pediatrics

A 6-year-old boy crushes his finger in a door, presenting with a clinically flexed distal phalanx, a laceration at the nail fold, and the proximal nail plate resting superficial to the eponychium. Radiographs show a widening of the distal phalanx physis. What is the most appropriate management?

. Closed reduction and buddy taping
. Oral antibiotics and outpatient follow-up
. Splinting in hyperextension for 6 weeks
. Nail removal, I&D, anatomic reduction, and repair of the nail bed
. Percutaneous pinning without soft tissue exploration

Correct Answer & Explanation

. Nail removal, I&D, anatomic reduction, and repair of the nail bed

Explanation

This presentation describes a Seymour fracture, which is an open Salter-Harris fracture of the distal phalanx. It requires meticulous irrigation and debridement, reduction of the fracture, and repair of the nail bed to prevent osteomyelitis and growth arrest.

Question 1042

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy sustains an extension-type Gartland III supracondylar humerus fracture. Post-reduction, he is unable to flex the interphalangeal joint of his thumb and the distal interphalangeal joint of his index finger. Which nerve is most likely injured?
. Ulnar nerve
. Posterior interosseous nerve
. Anterior interosseous nerve
. Superficial radial nerve
. Recurrent motor branch of the median nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar humerus fractures. It presents clinically as an inability to make the "OK" sign due to weakness of the FPL and the FDP to the index finger.

Question 1043

Topic: 4. Pediatrics

Which of the following is considered an acceptable radiographic parameter for nonoperative management of a diaphyseal both-bone forearm fracture in an 8-year-old child?

. 30 degrees of mid-shaft angulation
. Complete lack of bayonet apposition without any cortical contact
. 15 degrees of angulation and 45 degrees of malrotation
. 10 degrees of angulation and complete bayonet apposition
. 20 degrees of volar angulation in the proximal third

Correct Answer & Explanation

. 15 degrees of angulation and 45 degrees of malrotation

Explanation

In children under 9 years old, complete bayonet apposition is acceptable if angulation is less than 15 degrees and malrotation is less than 45 degrees. This is due to the significant remodeling potential of the pediatric forearm, particularly near the distal physis.

Question 1044

Topic: 4. Pediatrics

A 6-month-old infant is brought to the emergency department with swelling and decreased spontaneous movement of the right leg. Radiographs reveal a spiral fracture of the midshaft femur. What is the most critical next step in management?

. Immediate closed reduction and spica casting in the ER
. Consultation with the child protection team and skeletal survey
. Flexible intramedullary nailing
. Pavlik harness application
. Reassurance and close outpatient follow-up

Correct Answer & Explanation

. Consultation with the child protection team and skeletal survey

Explanation

Femur fractures in non-ambulatory infants are highly suspicious for non-accidental trauma (child abuse). A full skeletal survey and consultation with child protective services are mandatory prior to finalizing definitive orthopedic management.

Question 1045

Topic: Pediatric Upper Extremity & Spine
A 5-year-old boy presents with a displaced Gartland III supracondylar humerus fracture. The hand is pink but the radial pulse is absent. After closed reduction and percutaneous pinning, the hand remains pink and well-perfused with a capillary refill of 2 seconds, but the radial pulse remains unpalpable. What is the most appropriate next step?
. Immediate open vascular exploration via an anterior approach
. Observation and hospital admission for serial neurovascular checks
. Administration of intra-arterial vasodilators
. Removal of pins and transition to open reduction
. Immediate CT angiography of the upper extremity

Correct Answer & Explanation

. Observation and hospital admission for serial neurovascular checks

Explanation

A "pink, pulseless" hand after anatomic reduction and pinning of a supracondylar humerus fracture generally indicates adequate collateral perfusion. The standard of care is close observation and admission for serial clinical checks rather than immediate vascular exploration.

Question 1046

Topic: 4. Pediatrics

A 4-year-old child sustains a phalangeal neck fracture of the index finger with 90 degrees of dorsal angulation. Attempted closed reduction is unsuccessful due to soft tissue interposition. Which structure is most commonly interposed, blocking reduction in this specific pediatric fracture?

. Flexor digitorum profundus tendon
. Volar plate
. Collateral ligament
. Extensor central slip
. Lateral band

Correct Answer & Explanation

. Volar plate

Explanation

In pediatric phalangeal neck fractures with severe dorsal angulation, the proximal phalanx head can buttonhole through palmar structures. The volar plate or collateral ligaments typically interpose and block reduction, necessitating open reduction.

Question 1047

Topic: 4. Pediatrics
A 13-year-old boy presents with a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis (Tillaux fracture). Which ligamentous structure is responsible for avulsing this fragment?
. Anterior talofibular ligament
. Anterior inferior tibiofibular ligament
. Posterior inferior tibiofibular ligament
. Calcaneofibular ligament
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament

Explanation

The Tillaux fracture is an avulsion of the anterolateral distal tibial epiphysis caused by tension from the anterior inferior tibiofibular ligament (AITFL). This occurs in adolescents because the medial portion of the distal tibial physis closes before the lateral portion.

Question 1048

Topic: 4. Pediatrics

A 5-year-old presents with a severely displaced supracondylar humerus fracture. The radial pulse is absent, but the hand is warm, pink, and has a brisk capillary refill. Following closed reduction and percutaneous pinning, the hand remains 'pink and pulseless.' What is the next best step in management?

. Immediate open exploration of the brachial artery
. Perform an intraoperative angiogram
. Remove the pins and attempt an open reduction
. Observation and careful monitoring
. Prophylactic forearm fasciotomy

Correct Answer & Explanation

. Observation and careful monitoring

Explanation

A 'pink, pulseless' hand following stable reduction and pinning of a pediatric supracondylar humerus fracture indicates adequate collateral perfusion. The standard of care is close observation rather than immediate vascular exploration.

Question 1049

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy falls on an outstretched hand and sustains an extension-type supracondylar humerus fracture. Upon examination, he cannot actively flex the interphalangeal joint of his thumb. Which nerve is most likely injured?

. Ulnar nerve
. Radial nerve
. Posterior interosseous nerve
. Anterior interosseous nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar humerus fractures. AIN palsy presents with the inability to flex the IP joint of the thumb (flexor pollicis longus) and the distal IP joint of the index finger (flexor digitorum profundus), preventing the "A-OK" sign.

Question 1050

Topic: 4. Pediatrics

A 9-year-old girl is evaluated for a lateral condyle fracture of the humerus. Which of the following accurately describes a Milch Type II fracture?

. The fracture line exits lateral to the trochlear groove.
. The fracture line exits into the joint through the trochlear groove.
. The fracture involves the medial epicondyle.
. It is an extra-articular fracture.
. It represents a Salter-Harris Type I injury.

Correct Answer & Explanation

. The fracture line exits into the joint through the trochlear groove.

Explanation

A Milch Type II lateral condyle fracture extends through the apophysis and exits into the joint through the trochlear groove, creating potential radioulnar instability as it violates the lateral wall of the trochlea. Milch Type I exits lateral to the trochlear groove through the capitulotrochlear groove.

Question 1051

Topic: 4. Pediatrics

A 7-year-old child presents with a pink, pulseless hand following a closed reduction and percutaneous pinning of a displaced supracondylar humerus fracture. Capillary refill is brisk and the child is comfortable. What is the next most appropriate step in management?

. Immediate exploration of the brachial artery
. Removal of pins and open reduction
. Observation and hospital admission for serial monitoring
. Emergent angiogram
. Fasciotomy of the forearm

Correct Answer & Explanation

. Observation and hospital admission for serial monitoring

Explanation

In the setting of a pink, pulseless hand after successful anatomic reduction and pinning of a supracondylar fracture, observation is indicated if tissue perfusion is excellent. The collateral circulation is sufficient, and the radial pulse often returns within a few days as vasospasm resolves.

Question 1052

Topic: 4. Pediatrics

An 8-year-old boy presents with a crush injury to his distal middle finger. Radiographs demonstrate a displaced Salter-Harris I fracture of the distal phalanx. The proximal nail plate sits outside the eponychial fold. What is the most appropriate management?

. Closed reduction and splinting in extension
. Splinting and prophylactic antibiotics without reduction
. Removal of the nail plate, copious irrigation, fracture reduction, and nail bed repair
. Terminal Syme amputation
. Percutaneous pinning strictly avoiding the nail bed

Correct Answer & Explanation

. Removal of the nail plate, copious irrigation, fracture reduction, and nail bed repair

Explanation

This is a classic Seymour fracture, an open Salter-Harris I or II fracture of the distal phalanx. It requires nail plate removal, extensive irrigation, anatomic reduction, and repair of the nail bed to prevent osteomyelitis and premature physeal closure.

Question 1053

Topic: 4. Pediatrics

A 6-year-old boy presents with a completely displaced extension-type supracondylar humerus fracture.

On examination, he is unable to actively flex the interphalangeal joint of his thumb. Which nerve is most likely injured?

. Radial nerve
. Ulnar nerve
. Anterior interosseous nerve (AIN)
. Posterior interosseous nerve (PIN)
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve (AIN)

Explanation

The Anterior Interosseous Nerve (AIN) is the most commonly injured nerve in extension-type pediatric supracondylar humerus fractures. Injury presents with the inability to flex the IP joint of the thumb and DIP joint of the index finger, resulting in a loss of the 'OK' sign.

Question 1054

Topic: Pediatric Upper Extremity & Spine

A 5-year-old girl falls on an outstretched hand and sustains a Milch Type II lateral condyle fracture of the humerus with 3 mm of displacement. What is the standard management for this injury?

. Long arm cast in supination for 4 weeks
. Closed reduction and percutaneous pinning (CRPP)
. Open reduction and internal fixation (ORIF)
. Excision of the fragment and lateral collateral ligament repair
. Non-weight bearing in a sling

Correct Answer & Explanation

. Open reduction and internal fixation (ORIF)

Explanation

Pediatric lateral condyle fractures displaced more than 2 mm generally require open reduction and internal fixation (ORIF). Closed reduction is often inadequate due to soft tissue interposition and rotation, carrying a high risk of nonunion.

Question 1055

Topic: 4. Pediatrics

A 12-year-old male presents with gradually worsening left hip pain and a limp for 3 months. Physical examination reveals limited internal rotation and abduction of the left hip. Radiographs show a widened physis and posterior and inferior displacement of the epiphysis relative to the metaphysis. Which of the following is the most appropriate immediate management?

. Non-weight bearing and urgent in situ pinning
. Traction and observation
. Open reduction and internal fixation
. Core decompression
. Anti-inflammatory medications and protected weight-bearing

Correct Answer & Explanation

. Non-weight bearing and urgent in situ pinning

Explanation

Correct Answer: AThis clinical presentation and radiographic findings are classic for Slipped Capital Femoral Epiphysis (SCFE). The priority is to prevent further slippage and stabilize the physis. This is achieved by immediate non-weight bearing and urgent in situ pinning with a single screw to prevent further slip and allow physeal closure. Open reduction is generally reserved for unstable or severe slips, or failed in situ pinning. Traction is not standard treatment for SCFE. Core decompression is for avascular necrosis. Protected weight-bearing allows for continued slippage.

Question 1056

Topic: 4. Pediatrics

Which of the following conditions is characterized by a deficiency in Type I collagen synthesis, leading to brittle bones, blue sclerae, and often hearing loss?

. Achondroplasia
. Marfan syndrome
. Ehlers-Danlos syndrome
. Osteogenesis Imperfecta
. Fibrous dysplasia

Correct Answer & Explanation

. Osteogenesis Imperfecta

Explanation

Correct Answer: DOsteogenesis Imperfecta (OI) is a genetic disorder caused by mutations in genes encoding Type I collagen (COL1A1 or COL1A2). This leads to defective collagen, resulting in brittle bones (recurrent fractures), blue sclerae, hearing loss, dentinogenesis imperfecta, and joint laxity. Achondroplasia is a form of dwarfism due to FGFR3 mutation affecting endochondral ossification. Marfan syndrome affects fibrillin-1 (connective tissue) with ocular, cardiovascular, and skeletal manifestations. Ehlers-Danlos syndrome involves various collagen defects leading to hyperelastic skin and hypermobile joints. Fibrous dysplasia is a developmental anomaly where normal bone is replaced by fibrous tissue and immature woven bone.

Question 1057

Topic: 4. Pediatrics

An obese 13-year-old boy presents with left knee pain and a limp for three weeks. Physical examination reveals an obligatory external rotation of the left lower extremity when the hip is passively flexed. Radiographs show posterior and inferior displacement of the proximal femoral epiphysis. What is the most appropriate initial management?

. Closed reduction and spica casting
. In situ fixation with a single partially threaded screw
. Core decompression of the femoral head
. Subtrochanteric derotational osteotomy
. Open reduction and internal fixation with multiple pins

Correct Answer & Explanation

. In situ fixation with a single partially threaded screw

Explanation

This patient has a slipped capital femoral epiphysis (SCFE) characterized by obligatory external rotation with hip flexion. The gold standard for initial management is stable in situ fixation, typically with a single cannulated screw placed centrally across the physis.

Question 1058

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy falls from monkey bars and sustains a displaced extension-type supracondylar humerus fracture (Gartland Type III). On physical examination, he is unable to flex the interphalangeal joint of his thumb and the distal interphalangeal joint of his index finger. Which nerve is most likely injured?
. Radial nerve
. Ulnar nerve
. Anterior interosseous nerve
. Posterior interosseous nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar humerus fractures. Injury leads to an inability to make the "A-OK" sign due to paralysis of the flexor pollicis longus and the flexor digitorum profundus to the index finger.

Question 1059

Topic: Pediatric Hip

A 13-year-old obese male presents with a stable slipped capital femoral epiphysis (SCFE) on the left side. Which of the following factors is the strongest predictor for the subsequent development of a contralateral slip?

. High body mass index alone
. Lower modified Oxford bone age score
. High Southwick slip angle on the ipsilateral side
. Symptom duration greater than 3 months
. Failure of Klein's line to intersect the epiphysis

Correct Answer & Explanation

. Lower modified Oxford bone age score

Explanation

A lower modified Oxford bone age score indicates more remaining skeletal growth, which is a strong, validated predictor for a subsequent contralateral slipped capital femoral epiphysis.

Question 1060

Topic: 4. Pediatrics

A 7-year-old child has an Aneurysmal Bone Cyst involving the distal femoral physis. Surgical treatment is planned. Which complication is a particular concern given the lesion's proximity to the growth plate?

. Pathological fracture post-surgery.
. Articular cartilage damage.
. Angular deformity or limb length discrepancy.
. Vascular compromise in the popliteal fossa.
. Nerve palsy of the sciatic nerve.

Correct Answer & Explanation

. Angular deformity or limb length discrepancy.

Explanation

Correct Answer: CIn children, an Aneurysmal Bone Cyst involving or closely adjacent to the physis (growth plate) poses a significant risk of iatrogenic damage to the growth plate during surgery or due to the lesion's growth itself. This can lead to serious complications such as angular deformity (e.g., genu valgum/varum) or limb length discrepancy due to partial or complete physeal arrest. While other complications are possible, physeal damage is a specific concern in this anatomical location and age group.

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