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2. Trauma MCQs

Practice Set 127 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 2521

Topic: 2. Trauma
A 30-year-old male sustains a vertically oriented (Pauwels Type III) femoral neck fracture. Biomechanically, what is the primary mode of failure for this specific fracture pattern if treated with three parallel cannulated screws alone?
. Superior screw cut-out
. Inferior screw back-out
. Varus collapse with inferior shear
. Valgus impaction
. Nonunion from hyper-compression

Correct Answer & Explanation

. Varus collapse with inferior shear

Explanation

Pauwels Type III femoral neck fractures have a vertical fracture line (angle > 50 degrees) that experiences high shear forces. The primary mode of failure when treated with parallel screws alone is varus collapse and inferior shear displacement.

Question 2522

Topic: 2. Trauma

A 28-year-old motorcyclist sustains a high-energy midshaft femur fracture. According to standard trauma protocols, which imaging modality is considered the gold standard to rule out an ipsilateral associated fracture in this scenario?

. AP and lateral plain radiographs of the hip
. Dedicated fine-cut CT scan of the femoral neck
. MRI of the pelvis
. Bone scan
. Intraoperative fluoroscopy post-nailing

Correct Answer & Explanation

. Dedicated fine-cut CT scan of the femoral neck

Explanation

Between 2% and 9% of femoral shaft fractures have an associated ipsilateral femoral neck fracture, which is often nondisplaced and easily missed. A dedicated fine-cut CT protocol of the femoral neck is the gold standard for screening in these high-energy injuries.

Question 2523

Topic: 2. Trauma

A 45-year-old male sustains a medial tibial plateau fracture with significant displacement (Schatzker IV) following a varus-directed force. What is the most appropriate surgical approach for optimal buttress plating of this specific fracture pattern?

. Anterolateral
. Direct lateral
. Posteromedial
. Anterior midline with parapatellar arthrotomy
. Extensile lateral

Correct Answer & Explanation

. Posteromedial

Explanation

Schatzker IV fractures involve the medial plateau and are often associated with high-energy varus forces. A posteromedial approach allows for direct visualization and optimal placement of an anti-glide or buttress plate to counteract the deforming forces.

Question 2524

Topic: 2. Trauma
A 38-year-old male sustains a Gustilo-Anderson Type IIIB open tibial shaft fracture. Following serial debridements, he requires soft tissue coverage with a free flap. According to the Godina principles, within what timeframe should the free flap ideally be performed to minimize infection and flap failure rates?
. Within 24 hours
. Within 72 hours
. Between 7 and 10 days
. Between 2 and 3 weeks
. After 4 weeks

Correct Answer & Explanation

. Within 72 hours

Explanation

Godina's classic principles advocate for early free flap coverage of Type IIIB open fractures, ideally within 72 hours. This early coverage has been shown to significantly reduce the rates of deep infection and flap failure compared to delayed coverage.

Question 2525

Topic: 2. Trauma

A 50-year-old female sustains a distal femur fracture. CT scan reveals a coronal plane fracture of the lateral femoral condyle. What is the optimal direction of screw placement to achieve the most biomechanically stable fixation for this specific fragment?

. Medial to lateral
. Lateral to medial
. Anterior to posterior (AP)
. Posterior to anterior (PA)
. Inferior to superior

Correct Answer & Explanation

. Posterior to anterior (PA)

Explanation

A coronal plane fracture of the femoral condyle is known as a Hoffa fracture. Biomechanical studies have shown that posterior-to-anterior (PA) lag screw placement is stronger than AP placement due to the trajectory crossing the fracture line closer to 90 degrees and engaging thicker anterior cortex.

Question 2526

Topic: 2. Trauma

A 68-year-old male sustains a high-energy distal femur fracture. CT imaging reveals a coronal plane fracture of the lateral femoral condyle. What is the most appropriate fixation strategy for this specific fracture pattern?

. Lateral locked plating alone
. Retrograde intramedullary nailing
. Anterior-to-posterior directed lag screws
. Posterior-to-anterior directed lag screws
. Distal femoral replacement

Correct Answer & Explanation

. Anterior-to-posterior directed lag screws

Explanation

A coronal plane fracture of the femoral condyle is a Hoffa fracture. It is best stabilized with anterior-to-posterior directed lag screws placed perpendicular to the fracture line to provide optimal interfragmentary compression.

Question 2527

Topic: 2. Trauma
A 29-year-old motorcyclist sustains a Gustilo-Anderson Type IIIB open tibial shaft fracture. After initial debridement, external fixation, and appropriate systemic antibiotic initiation, what is the current guideline for the duration of prophylactic antibiotics in this setting?
. 24 hours from the time of injury
. 72 hours from the time of injury or 24 hours after soft tissue coverage, whichever comes first
. 7 days from the time of injury or until the external fixator is removed
. Until definitive intramedullary nailing is performed
. 48 hours post-injury regardless of coverage status

Correct Answer & Explanation

. 72 hours from the time of injury or 24 hours after soft tissue coverage, whichever comes first

Explanation

For severe open fractures (Type III), current guidelines recommend continuing antibiotics for 72 hours from the time of injury or 24 hours after a successful soft-tissue coverage procedure, whichever occurs first.

Question 2528

Topic: 2. Trauma

A 22-year-old male complains of severe leg pain out of proportion to examination 6 hours after undergoing intramedullary nailing for a closed tibial shaft fracture. His blood pressure is 110/70 mmHg. Compartment pressures are measured. At what absolute pressure or Delta P threshold is fasciotomy definitively indicated?

. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 25 mmHg
. Delta P (Diastolic BP minus compartment pressure) < 30 mmHg
. Delta P (Systolic BP minus compartment pressure) < 40 mmHg
. Delta P (Mean Arterial Pressure minus compartment pressure) < 30 mmHg

Correct Answer & Explanation

. Delta P (Diastolic BP minus compartment pressure) < 30 mmHg

Explanation

Compartment syndrome is a clinical diagnosis, but when utilizing pressures, a Delta P (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is considered the definitive threshold for performing a fasciotomy.

Question 2529

Topic: 2. Trauma

An 18-year-old female presents with a displaced talar neck fracture following a snowboarding accident. She undergoes open reduction and internal fixation. Six weeks postoperatively, a subchondral radiolucent band is visible in the talar dome on the AP radiograph (Hawkins sign). What does this finding indicate?

. Impending nonunion of the fracture
. Development of post-traumatic osteoarthritis
. Intact vascularity to the body of the talus
. Early avascular necrosis of the talar dome
. Infection of the talonavicular joint

Correct Answer & Explanation

. Intact vascularity to the body of the talus

Explanation

The Hawkins sign is a subchondral radiolucent band seen in the talar dome 6-8 weeks post-injury. It represents subchondral atrophy from disuse and implies intact vascularity to the talar body, effectively ruling out avascular necrosis.

Question 2530

Topic: 2. Trauma

A 45-year-old male falls from a roof and sustains a displaced intra-articular calcaneus fracture. The surgeon utilizes the Sanders classification for preoperative planning. On which specific imaging view is this classification system based?

. Harris axial radiograph of the heel
. Sagittal CT reconstruction of the subtalar joint
. Axial CT view at the level of the sustentaculum tali
. Coronal CT view at the widest portion of the posterior facet
. Broden's view radiograph

Correct Answer & Explanation

. Coronal CT view at the widest portion of the posterior facet

Explanation

The Sanders classification for calcaneus fractures is based on the number and location of articular fracture lines seen on the coronal CT image at the widest portion of the posterior facet.

Question 2531

Topic: 2. Trauma
A 26-year-old male sustains a high-energy femoral neck fracture with a vertical fracture line (Pauwels Type III). What is the primary biomechanical rationale for utilizing a fixed-angle device (e.g., sliding hip screw or cephalomedullary nail) rather than multiple cancellous screws for this injury?
. To increase the rotational stability of the head fragment
. To convert excessive shear forces into compressive forces
. To prevent avascular necrosis by preserving the lateral epiphyseal vessels
. To minimize the risk of intra-articular screw penetration
. To allow for early full weight-bearing

Correct Answer & Explanation

. To convert excessive shear forces into compressive forces

Explanation

Pauwels Type III fractures have a highly vertical orientation, resulting in dominant shear forces that increase the risk of varus collapse and nonunion. A fixed-angle device is preferred because it better resists these shear forces and can convert them into compressive forces.

Question 2532

Topic: 2. Trauma

A polytrauma patient presents with a femur fracture, bilateral pulmonary contusions, and a Glasgow Coma Scale of 7.

His initial serum lactate is 4.5 mmol/L and pH is 7.21. According to the principles of Damage Control Orthopedics (DCO), what is the most appropriate initial management of the femur fracture?

. Immediate reamed intramedullary nailing
. Immediate unreamed intramedullary nailing
. Skeletal traction with delayed definitive fixation
. Temporary external fixation
. Open reduction and internal fixation with a locking plate

Correct Answer & Explanation

. Temporary external fixation

Explanation

This patient is borderline/unstable with a high lactate (>2.5 mmol/L), severe head injury, and chest trauma. Damage Control Orthopedics dictates rapid temporary stabilization with external fixation to minimize the 'second hit' of systemic inflammation caused by definitive surgery.

Question 2533

Topic: 2. Trauma

A 50-year-old male is involved in a motor vehicle collision and sustains a complex acetabular fracture.

An obturator oblique radiograph demonstrates the classic 'spur sign'. Which Letournel fracture pattern is pathognomonic for this finding?

. Transverse fracture
. Anterior column with posterior hemitransverse
. T-type fracture
. Both-column fracture
. Posterior wall fracture

Correct Answer & Explanation

. Both-column fracture

Explanation

The 'spur sign' on an obturator oblique radiograph represents the intact portion of the ilium attached to the axial skeleton while the entire articular surface is displaced. It is pathognomonic for an associated both-column acetabular fracture.

Question 2534

Topic: 2. Trauma

A 60-year-old female sustains a split-depression fracture of the lateral tibial plateau (Schatzker Type II) following a valgus stress injury. During surgical approach and articular elevation, which intra-articular structure is most commonly found incarcerated within the fracture site?

. Anterior cruciate ligament
. Medial meniscus
. Lateral meniscus
. Popliteus tendon
. Posterior cruciate ligament

Correct Answer & Explanation

. Lateral meniscus

Explanation

In Schatzker Type II (split-depression) tibial plateau fractures, the peripheral rim of the lateral meniscus is frequently torn or incarcerated within the articular split, requiring careful elevation and repair during fracture fixation.

Question 2535

Topic: 2. Trauma

A 28-year-old snowboarder sustains a high-energy talar neck fracture. Six weeks post-operatively, an anteroposterior radiograph of the ankle reveals a subchondral lucency spanning the talar dome. What does this radiographic finding indicate?

. Avascular necrosis of the talar body
. Infection of the talonavicular joint
. Resorption of subchondral bone secondary to intact vascularity
. Nonunion of the talar neck fracture
. Early post-traumatic osteoarthritis

Correct Answer & Explanation

. Resorption of subchondral bone secondary to intact vascularity

Explanation

Hawkins sign is a subchondral lucent band visible on the AP radiograph of the talus 6-8 weeks after injury. It indicates subchondral osteopenia resulting from hyperemia and an intact vascular supply, suggesting that avascular necrosis is unlikely.

Question 2536

Topic: 2. Trauma
A 25-year-old male sustains a vertically oriented femoral neck fracture (Pauwels Type III) after a high-speed motorcycle accident. Biomechanically, which of the following best explains the high rate of failure and nonunion associated with this specific fracture pattern?
. Predominance of compressive forces across the fracture line
. Disruption of the ligamentum teres arterial supply
. High shear forces across the fracture site
. Inability to achieve anatomic reduction using closed methods
. Poor bone quality in young adult males

Correct Answer & Explanation

. High shear forces across the fracture site

Explanation

Pauwels Type III fractures (>50 degrees to the horizontal) have a vertical orientation that converts joint reactive forces into high shear forces across the fracture site. This mechanical environment significantly increases the risk of varus collapse, fixation failure, and nonunion.

Question 2537

Topic: 2. Trauma

A 32-year-old male is admitted with a closed midshaft tibia fracture. Six hours later, he complains of severe leg pain out of proportion to the injury, significantly worsened by passive toe extension. Which of the following absolute or delta pressure criteria is widely accepted as an indication for emergency fasciotomy?

. Absolute compartment pressure > 20 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Mean arterial pressure minus compartment pressure < 40 mmHg
. Systolic blood pressure minus compartment pressure < 30 mmHg
. Absolute compartment pressure > 15 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

Acute compartment syndrome is definitively diagnosed and treated with fasciotomy when the delta pressure (diastolic blood pressure minus intracompartmental pressure) is less than 30 mmHg. This measure accounts for varying systemic perfusion pressures better than absolute compartment pressure alone.

Question 2538

Topic: 2. Trauma
A 29-year-old farmer sustains an open tibial shaft fracture with massive soft tissue stripping and gross soil contamination (Gustilo-Anderson Type IIIA) from a tractor rollover. In addition to a first-generation cephalosporin and an aminoglycoside, which of the following antibiotics is strongly indicated?
. Clindamycin
. High-dose Penicillin
. Vancomycin
. Doxycycline
. Azithromycin

Correct Answer & Explanation

. High-dose Penicillin

Explanation

In farm-related injuries or injuries with heavy soil contamination, there is a high risk of anaerobic infection, particularly Clostridium perfringens. High-dose Penicillin (or metronidazole for allergic patients) should be added to the antibiotic regimen to cover this pathogen.

Question 2539

Topic: 2. Trauma

A 55-year-old female presents with a Schatzker II (split-depression) lateral tibial plateau fracture following a fall. She is scheduled for open reduction and internal fixation. Preoperative MRI is most likely to reveal an associated injury to which of the following structures?

. Lateral meniscus
. Medial meniscus
. Posterior cruciate ligament
. Medial collateral ligament
. Patellar tendon

Correct Answer & Explanation

. Lateral meniscus

Explanation

Schatzker II fractures (lateral split-depression) are frequently associated with soft tissue injuries. A lateral meniscal tear is the most common associated intra-articular injury, often trapped within the fracture site or preventing reduction.

Question 2540

Topic: 2. Trauma

A 35-year-old male undergoes intramedullary nailing of a comminuted femoral shaft fracture on a fracture table. Postoperatively, he complains of numbness in his perineal region. What is the primary etiology of this complication?

. Direct injury to the sciatic nerve during reaming
. Compression of the common peroneal nerve by the knee holder
. Injury to the superior gluteal nerve during the piriformis start
. Pudendal nerve neurapraxia from the perineal traction post
. Femoral nerve stretch from prolonged traction

Correct Answer & Explanation

. Pudendal nerve neurapraxia from the perineal traction post

Explanation

Use of a perineal post on a fracture table provides countertraction but can lead to pudendal nerve neurapraxia. Patients typically present with perineal numbness, and sometimes transient erectile dysfunction, which generally resolves spontaneously.

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