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2. Trauma MCQs

Practice Set 14 of 640

This practice set contains high-yield board review questions covering key concepts in 2. Trauma. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 261

Topic: 2. Trauma

When utilizing a rigid lateral entry intramedullary nail for a femur fracture in a 13-year-old, the starting point should be placed lateral to the tip of the greater trochanter primarily to avoid injury to which of the following structures?

. Ascending branch of the medial circumflex femoral artery
. Lateral circumflex femoral artery
. Sciatic nerve
. Piriformis tendon insertion
. Gluteus medius footprint

Correct Answer & Explanation

. Ascending branch of the medial circumflex femoral artery

Explanation

The ascending branch of the medial circumflex femoral artery provides the primary blood supply to the femoral head in adolescents. A starting point medial to the tip or in the piriformis fossa carries an unacceptably high risk of iatrogenic avascular necrosis.

Question 262

Topic: 2. Trauma

A 7-year-old girl is scheduled for Titanium Elastic Nailing (TENs) of a transverse midshaft femur fracture. What is the recommended formula for selecting the appropriate nail diameter?

. 20% of the narrowest canal diameter
. 40% of the narrowest canal diameter
. 60% of the narrowest canal diameter
. 80% of the narrowest canal diameter
. 100% of the narrowest canal diameter

Correct Answer & Explanation

. 40% of the narrowest canal diameter

Explanation

The proper nail size is typically 40% of the narrowest medullary canal diameter. Two nails of the exact same size should be used to provide balanced three-point fixation and prevent asymmetric deforming forces.

Question 263

Topic: 2. Trauma
A 9-year-old boy sustains a traumatic proximal femur fracture. Radiographs reveal a transepiphyseal fracture with dislocation of the femoral head. What is the Delbet classification and the associated risk of avascular necrosis (AVN)?
. Type I, nearly 90% risk of AVN
. Type II, nearly 50% risk of AVN
. Type III, nearly 25% risk of AVN
. Type IV, nearly 10% risk of AVN
. Type I, nearly 20% risk of AVN

Correct Answer & Explanation

. Type I, nearly 90% risk of AVN

Explanation

Delbet Type I is a transepiphyseal fracture. When accompanied by a dislocation of the femoral head, it carries the highest risk of avascular necrosis among pediatric femoral neck fractures, nearing 90%.

Question 264

Topic: 2. Trauma

A 9-year-old boy weighing 45 kg (99 lbs) sustains a highly comminuted, length-unstable midshaft femur fracture resulting in 4 cm of shortening. What is the most appropriate surgical treatment?

. Spica casting
. Flexible intramedullary nailing
. Submuscular bridge plating
. External fixation
. Rigid trochanteric entry intramedullary nail

Correct Answer & Explanation

. Submuscular bridge plating

Explanation

Submuscular bridge plating is ideal for length-unstable, comminuted femur fractures in school-aged children. This is especially true for older children nearing the weight limit (usually 50kg) for flexible nails, which might telescope in comminuted patterns.

Question 265

Topic: 2. Trauma

In a 6-month-old pre-ambulatory infant presenting with an isolated femur fracture, which of the following fracture patterns is most specific for non-accidental trauma (child abuse)?

. Spiral midshaft
. Transverse midshaft
. Oblique proximal third
. Classic metaphyseal lesion (corner fracture)
. Distal physeal separation

Correct Answer & Explanation

. Classic metaphyseal lesion (corner fracture)

Explanation

While spiral and transverse diaphyseal fractures are the most common patterns seen in child abuse, the classic metaphyseal lesion (corner or bucket-handle fracture) is highly specific for non-accidental trauma.

Question 266

Topic: 2. Trauma

A 6-year-old boy underwent Titanium Elastic Nailing for a femur fracture 6 months ago. The fracture has healed well, but he complains of localized pain and a palpable mass near the medial and lateral knee. What is the most likely cause?

. Septic arthritis of the knee
. Distal femoral physeal arrest
. Prominent nail ends at the insertion site
. Heterotopic ossification
. Deep vein thrombosis

Correct Answer & Explanation

. Prominent nail ends at the insertion site

Explanation

The most common complication of flexible intramedullary nailing in pediatric femur fractures is soft-tissue irritation and pain. This occurs due to prominent nail ends left at the distal insertion sites near the metaphysis.

Question 267

Topic: 2. Trauma

A 16-year-old water skier presents with acute buttock pain after a forced hyperflexion of the hip with the knee extended. Radiographs reveal an ischial tuberosity avulsion fracture. Surgical fixation is generally indicated if the displacement exceeds:

. 0.5 cm
. 1.0 cm
. 2.0 cm
. 4.0 cm
. 5.0 cm

Correct Answer & Explanation

. 2.0 cm

Explanation

Surgical fixation of an ischial tuberosity avulsion is typically indicated for displacement > 1.5 to 2.0 cm. Operative management prevents symptomatic nonunion, exostosis formation, and chronic hamstring weakness.

Question 268

Topic: 2. Trauma



A 7-year-old boy presents with a significantly displaced subtrochanteric femur fracture. Treatment with flexible intramedullary nails is considered. What is the most common malalignment complication seen when treating this specific fracture pattern with flexible nails?

. Varus and procurvatum
. Valgus and recurvatum
. Limb lengthening
. Rotational malalignment
. Coxa breva

Correct Answer & Explanation

. Varus and procurvatum

Explanation

Subtrochanteric fractures treated with flexible nails are highly prone to varus and procurvatum deformities. This occurs due to the strong deforming forces of the iliopsoas and hip abductors pulling on the short proximal fragment.

Question 269

Topic: 2. Trauma

In a 7-year-old child treated non-operatively for a diaphyseal femur fracture, what is the maximum acceptable varus/valgus angulation?

. 5 degrees
. 10 degrees
. 15 degrees
. 20 degrees
. 30 degrees

Correct Answer & Explanation

. 10 degrees

Explanation

For children aged 6 to 10 years, acceptable alignment criteria for femur fractures include < 10 degrees of varus/valgus, < 15 degrees of anteroposterior angulation, and < 1.5 cm of shortening.

Question 270

Topic: 2. Trauma

A 6-year-old boy weighing 35 kg sustains a highly comminuted, length-unstable fracture of the femoral diaphysis after a fall from a tree. What is the most appropriate surgical intervention?

. Spica casting
. Flexible titanium intramedullary nailing
. Submuscular bridge plating
. Rigid antegrade intramedullary nailing via piriformis fossa
. External fixation

Correct Answer & Explanation

. Submuscular bridge plating

Explanation

For pediatric femur fractures that are length-unstable (highly comminuted or long spiral), submuscular bridge plating is the preferred treatment. Flexible intramedullary nails lack the stability to maintain length in comminuted patterns, leading to unacceptable shortening.

Question 271

Topic: 2. Trauma

When planning flexible titanium intramedullary nailing for a pediatric transverse femur fracture, what is the optimal diameter sizing for each nail?

. 20% of the narrowest medullary canal diameter
. 30% of the narrowest medullary canal diameter
. 40% of the narrowest medullary canal diameter
. 60% of the narrowest medullary canal diameter
. 80% of the narrowest medullary canal diameter

Correct Answer & Explanation

. 40% of the narrowest medullary canal diameter

Explanation

To achieve optimal three-point fixation and construct stability, two flexible nails should be used, with each nail diameter occupying approximately 40% of the narrowest portion of the medullary canal.

Question 272

Topic: 2. Trauma

A 7-year-old child undergoes flexible intramedullary nailing for a femoral shaft fracture. What is the most common complication associated with this procedure?

. Deep surgical site infection
. Nonunion
. Pain and soft tissue irritation at the insertion site
. Avascular necrosis of the femoral head
. Premature physeal closure

Correct Answer & Explanation

. Pain and soft tissue irritation at the insertion site

Explanation

The most frequent complication of flexible intramedullary nailing is soft tissue irritation and pain at the distal insertion site. This occurs in up to 15% of cases and often necessitates removal of the implants after fracture consolidation.

Question 273

Topic: 2. Trauma

A 4-year-old girl sustains an isolated, closed midshaft femur fracture. Non-operative management with a spica cast is elected. What is the maximum acceptable varus/valgus angulation in this age group?

. 5 degrees
. 10 degrees
. 15 degrees
. 20 degrees
. 25 degrees

Correct Answer & Explanation

. 15 degrees

Explanation

In children aged 2 to 10 years treated in a spica cast, acceptable alignment parameters are less than 15 degrees of varus/valgus angulation, less than 20 degrees of anteroposterior angulation, and less than 2 cm of shortening.

Question 274

Topic: 2. Trauma

A 13-year-old boy requires a rigid intramedullary nail for a midshaft femur fracture. To minimize the risk of iatrogenic avascular necrosis, the optimal starting point for nail insertion is:

. The piriformis fossa
. The tip of the greater trochanter or slightly lateral
. The lesser trochanter
. The intertrochanteric line
. The base of the femoral neck

Correct Answer & Explanation

. The tip of the greater trochanter or slightly lateral

Explanation

Piriformis fossa entry in adolescents is associated with an unacceptably high risk of avascular necrosis due to disruption of the ascending branch of the medial femoral circumflex artery. A greater trochanteric or lateral entry point is required.

Question 275

Topic: 2. Trauma

In a 6-year-old child treated non-operatively for a diaphyseal femur fracture, longitudinal overgrowth is expected. At what age range does this overgrowth phenomenon peak?

. 0 to 2 years
. 2 to 10 years
. 10 to 12 years
. 12 to 14 years
. 14 to 16 years

Correct Answer & Explanation

. 2 to 10 years

Explanation

Femoral overgrowth after a fracture occurs secondary to local hyperemia stimulating the physes. It is most pronounced in children aged 2 to 10 years, averaging 1.5 to 2.0 cm of overgrowth.

Question 276

Topic: 2. Trauma

An 11-year-old boy sustains a Salter-Harris Type II fracture of the distal femur following a football tackle. Which of the following complications is most highly associated with this specific injury?

. Atrophic nonunion
. Physeal growth arrest
. Acute compartment syndrome of the thigh
. Avascular necrosis of the femoral condyles
. Chronic osteomyelitis

Correct Answer & Explanation

. Physeal growth arrest

Explanation

Distal femur physeal fractures have an exceptionally high rate of growth arrest (up to 50%), due to the undulating, complex shape of the physis and the high-energy trauma typically required to fracture it.

Question 277

Topic: 2. Trauma

A 13-year-old boy sustains a diaphyseal femur fracture. A rigid intramedullary nail is selected for fixation. To minimize the risk of iatrogenic avascular necrosis (AVN) of the femoral head, which of the following is the recommended starting point?

. Piriformis fossa
. Tip of the greater trochanter
. Lateral to the tip of the greater trochanter
. Medial to the greater trochanteric apophysis
. Lesser trochanter

Correct Answer & Explanation

. Lateral to the tip of the greater trochanter

Explanation

In adolescents, a starting point lateral to the tip of the greater trochanter avoids the medial circumflex femoral artery anastomosis. Piriformis entry carries an unacceptably high risk of AVN in this age group.

Question 278

Topic: 2. Trauma

A 15-year-old boy presents with a posterior hip dislocation following a high-speed motor vehicle collision. Which of the following factors is the most significant predictor for the development of avascular necrosis (AVN)?

. Patient age at the time of injury
. Mechanism of injury
. Time elapsed until closed reduction
. Direction of the dislocation
. Presence of an associated posterior wall fracture

Correct Answer & Explanation

. Time elapsed until closed reduction

Explanation

The risk of AVN following pediatric and adolescent traumatic hip dislocation is most closely associated with the time to reduction. Delays greater than 6 hours significantly increase the incidence of AVN.

Question 279

Topic: 2. Trauma

Which of the following factors is an accepted relative contraindication to the use of titanium elastic nails (TENs) for the treatment of a pediatric diaphyseal femur fracture?

. Patient age of 7 years
. Transverse fracture pattern
. Patient weight greater than 50 kg (110 lbs)
. Midshaft fracture location
. Concomitant closed head injury

Correct Answer & Explanation

. Patient weight greater than 50 kg (110 lbs)

Explanation

TENs biomechanically rely on three-point bending. Patients weighing over 50 kg or those older than 11 years have a significantly higher risk of loss of fixation, shortening, and angular deformity.

Question 280

Topic: 2. Trauma

A 4-year-old child sustains an isolated midshaft femur fracture. The child is placed in a one-and-a-half spica cast. What is the maximum acceptable amount of initial shortening in this patient?

. 0 mm
. 5 mm
. 15 mm
. 30 mm
. 40 mm

Correct Answer & Explanation

. 15 mm

Explanation

In children aged 2 to 10 years, femoral overgrowth typically occurs following a fracture due to post-traumatic hyperemia. Therefore, 15 to 20 mm of initial shortening is acceptable and often desired to equalize leg lengths at maturity.

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