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2. Trauma MCQs

Practice Set 316 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 6301

Topic: 2. Trauma

A 28-year-old motorcyclist presents to the trauma bay with an avulsed, flail, and pulseless upper extremity. Radiographs show a massively laterally displaced scapula, an intact clavicle, and complete acromioclavicular separation. What is the most common vascular injury associated with this diagnosis?

. Axillary artery disruption
. Subclavian artery disruption
. Brachial artery thrombosis
. Suprascapular artery avulsion
. Internal mammary artery transection

Correct Answer & Explanation

. Subclavian artery disruption

Explanation

Scapulothoracic dissociation is a devastating, high-energy injury characterized by complete disruption of the scapulothoracic articulation, marked by lateral displacement of the scapula. It is highly associated with severe neurovascular injuries, most notably complete avulsion of the brachial plexus and disruption of the subclavian artery or vein. Early vascular imaging and intervention are critical.

Question 6302

Topic: 2. Trauma

A 38-year-old unrestrained driver presents with a severely swollen knee after a motor vehicle collision. CT scan reveals a supracondylar distal femur fracture with an associated intra-articular coronal plane fracture of the lateral femoral condyle. Which of the following accurately describes the biomechanically optimal fixation for this coronal plane component?

. Anterior-to-posterior oriented fully threaded cortical screws
. Posterior-to-anterior oriented fully threaded cortical screws
. Anterior-to-posterior oriented partially threaded cancellous lag screws
. Medial-to-lateral oriented fully threaded cortical screws
. Lateral-to-medial oriented partially threaded cancellous lag screws

Correct Answer & Explanation

. Anterior-to-posterior oriented partially threaded cancellous lag screws

Explanation

A coronal plane fracture of the femoral condyle is known as a Hoffa fracture, most commonly involving the lateral condyle. Biomechanical studies have demonstrated that anterior-to-posterior directed partially threaded cancellous lag screws provide the strongest fixation. They allow compression perpendicular to the fracture plane and have significantly greater pull-out strength compared to posterior-to-anterior directed screws.

Question 6303

Topic: 2. Trauma

A 24-year-old man sustains a closed comminuted tibial shaft fracture. Two hours after presentation, he complains of severe pain out of proportion to the injury that is not relieved by intravenous narcotics. His leg is swollen and tense. Compartment pressures are measured. What pressure differential (Delta P) is considered the absolute threshold for performing an emergency four-compartment fasciotomy?

. Compartment pressure > 15 mm Hg
. Compartment pressure > 20 mm Hg above systolic blood pressure
. Compartment pressure within 30 mm Hg of diastolic blood pressure
. Compartment pressure > 45 mm Hg regardless of blood pressure
. Compartment pressure within 10 mm Hg of mean arterial pressure

Correct Answer & Explanation

. Compartment pressure within 30 mm Hg of diastolic blood pressure

Explanation

The diagnosis of acute compartment syndrome requires high clinical suspicion. When clinical signs are equivocal or in an unexaminable patient, compartment pressure monitoring is indicated. The widely accepted threshold for performing a fasciotomy is a Delta P (Diastolic Blood Pressure minus Compartment Pressure) of less than or equal to 30 mm Hg. Using absolute pressure values is less reliable and can lead to unnecessary fasciotomies, especially in hypotensive patients.

Question 6304

Topic: 2. Trauma

A 28-year-old man sustains a closed spiral fracture of the middle third of the humerus after an arm-wrestling match. On examination in the emergency department, he is unable to extend his wrist or fingers, and he has decreased sensation over the dorsal first web space. What is the most appropriate initial management?

. Immediate open reduction and internal fixation with radial nerve exploration
. Closed reduction, coaptation splinting, and clinical observation of nerve recovery
. Immediate electromyography (EMG) and nerve conduction studies
. Application of a shoulder spica cast and immediate nerve grafting
. External fixation and radial nerve transposition

Correct Answer & Explanation

. Closed reduction, coaptation splinting, and clinical observation of nerve recovery

Explanation

A radial nerve palsy associated with a closed humeral shaft fracture (often a Holstein-Lewis fracture in the distal third, but also common in midshaft spiral fractures) has a spontaneous recovery rate of over 85-90%. Initial management is non-operative, utilizing closed reduction and splinting or functional bracing. Operative exploration is reserved for open fractures, penetrating injuries, palsy developingafterclosed reduction, or failure of clinical or EMG recovery by 3 to 4 months.

Question 6305

Topic: 2. Trauma

A 45-year-old polytrauma patient is brought to the trauma bay after a high-speed motor vehicle collision. He presents with a severe head injury (Glasgow Coma Scale score of 7) and a closed midshaft femur fracture. According to current guidelines for Damage Control Orthopedics (DCO), what is the most appropriate initial management of the femur fracture?

. Immediate reamed intramedullary nailing
. External fixation
. Skeletal traction
. Plate osteosynthesis
. Immediate unreamed intramedullary nailing

Correct Answer & Explanation

. External fixation

Explanation

In a polytrauma patient with a severe head injury and physiological instability, Damage Control Orthopedics (DCO) is indicated to avoid the 'second hit' phenomenon. External fixation allows for rapid stabilization of the fracture without the systemic inflammatory burden, potential for increased intracranial pressure, and prolonged surgical time associated with intramedullary nailing or plating.

Question 6306

Topic: 2. Trauma
A 28-year-old man sustains a Pauwels type III (vertical) femoral neck fracture after falling from a ladder. Which of the following fixation constructs provides the most biomechanically stable fixation against shear forces for this specific fracture pattern?
. Three parallel cancellous lag screws in an inverted triangle configuration
. A sliding hip screw (dynamic hip screw) combined with a derotational screw
. Two crossed cancellous screws
. An intramedullary nail with a single cephalomedullary interlocking screw
. A non-vascularized fibular strut graft alone

Correct Answer & Explanation

. A sliding hip screw (dynamic hip screw) combined with a derotational screw

Explanation

Pauwels type III femoral neck fractures have a highly vertical fracture line (angle >50 degrees), which subjects the fracture to high shear forces and increases the risk of varus collapse and nonunion. Biomechanical studies have consistently demonstrated that a fixed-angle construct, such as a sliding hip screw combined with an anti-rotation screw, provides superior stability and resistance to shear forces compared to multiple parallel cancellous screws.

Question 6307

Topic: 2. Trauma

A 35-year-old woman sustains a highly comminuted distal femur fracture following a high-energy trauma. Computed tomography (CT) imaging reveals an isolated coronal plane fracture of the lateral femoral condyle. What is the eponym for this specific fracture fragment?

. Die-punch fracture
. Hoffa fracture
. Chaput fracture
. Gosselin fracture
. Tillaux fracture

Correct Answer & Explanation

. Hoffa fracture

Explanation

A coronal plane fracture of the femoral condyle is known as a Hoffa fracture. It is a severe intra-articular injury that most commonly affects the lateral condyle. It requires anatomic reduction and stable internal fixation, typically with anterior-to-posterior or posterior-to-anterior directed lag screws, to prevent articular incongruity and post-traumatic arthritis.

Question 6308

Topic: 2. Trauma
A 30-year-old man sustains an open tibia fracture with massive soft tissue stripping and exposed bone (Gustilo-Anderson IIIB) after a motorcycle collision. After initial thorough surgical debridement and bony stabilization, what is the optimal timeframe for definitive soft tissue coverage to minimize the risk of deep infection and flap failure?
. Within 24 hours
. Within 72 hours
. Between 3 and 7 days
. Between 7 and 14 days
. After 14 days

Correct Answer & Explanation

. Within 72 hours

Explanation

Based on Godina's classic principles and subsequent supporting literature, early soft tissue coverage (optimally within 72 hours) of severe open tibia fractures with significant soft tissue loss (Gustilo IIIB) significantly reduces the rate of deep infection, flap failure, and nonunion compared to delayed coverage.

Question 6309

Topic: 2. Trauma

A 25-year-old man falls from a height of 20 feet, sustaining a displaced, intra-articular calcaneus fracture. The Sanders classification system is utilized to guide surgical management based on CT imaging. What is the primary anatomical landmark assessed on coronal CT to determine the Sanders classification?

. Sustentaculum tali
. Anterior process
. Posterior facet
. Calcaneocuboid joint
. Calcaneal tuberosity

Correct Answer & Explanation

. Posterior facet

Explanation

The Sanders classification system is the most widely used scheme for intra-articular calcaneus fractures. It is based on the number and location of primary fracture lines extending through the posterior facet of the calcaneus, as visualized on the widest coronal CT image.

Question 6310

Topic: 2. Trauma

Which of the following statements is most accurate regarding the initial management of a traumatic, hemodynamically unstable pelvic ring disruption?

. Pelvic binders should be placed at the level of the iliac crests for maximal effect.
. Angiography and embolization are most effective for major venous bleeding.
. Preperitoneal pelvic packing is a highly effective initial intervention for controlling venous and cancellous bone bleeding.
. External fixation reduces pelvic volume more effectively than a correctly applied pelvic binder.
. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is strictly contraindicated in pelvic trauma.

Correct Answer & Explanation

. Preperitoneal pelvic packing is a highly effective initial intervention for controlling venous and cancellous bone bleeding.

Explanation

Preperitoneal pelvic packing is a rapid and highly effective surgical method for controlling the life-threatening venous plexus and cancellous bone bleeding typically seen in unstable pelvic fractures. Pelvic binders must be centered over the greater trochanters, not the iliac crests. Angiography targets arterial (not venous) bleeding. Binders generally reduce pelvic volume as effectively or more effectively than external fixation in the acute setting.

Question 6311

Topic: 2. Trauma
A 55-year-old man presents with a closed, highly comminuted tibial shaft fracture. His diastolic blood pressure is 60 mm Hg. What absolute intra-compartmental pressure would meet the widely accepted delta pressure threshold for performing an immediate four-compartment fasciotomy?
. 15 mm Hg
. 20 mm Hg
. 25 mm Hg
. 35 mm Hg
. 50 mm Hg only

Correct Answer & Explanation

. 25 mm Hg

Explanation

The delta pressure (ΔP) is calculated as the diastolic blood pressure minus the intra-compartmental pressure. A ΔP of less than 30 mm Hg is a widely accepted threshold indicating inadequate tissue perfusion and mandating an immediate fasciotomy. With a diastolic BP of 60 mm Hg, an absolute compartment pressure of 35 mm Hg results in a ΔP of 25 mm Hg (which is <30 mm Hg).

Question 6312

Topic: 2. Trauma

A 22-year-old male sustains a severe pelvic trauma. Radiographs and CT imaging reveal a transverse fracture of the acetabulum combined with a posterior wall fracture. According to the Letournel and Judet classification of acetabular fractures, which of the following categories best describes this injury?

. Elementary fracture
. Associated fracture
. Occult fracture
. Simple fracture
. Non-articular fracture

Correct Answer & Explanation

. Associated fracture

Explanation

The Letournel and Judet classification system divides acetabular fractures into 5 elementary types (anterior wall, anterior column, posterior wall, posterior column, transverse) and 5 associated types (posterior column/posterior wall, transverse/posterior wall, T-shaped, anterior column/posterior hemitransverse, both columns). A transverse plus posterior wall fracture falls under the associated fracture category.

Question 6313

Topic: 2. Trauma
A 35-year-old man sustains a severe open tibia fracture (Gustilo-Anderson IIIB) in a motorcycle crash. He is hemodynamically stable. Which of the following factors has been shown in the literature to be the most critical independent predictor for reducing the risk of deep infection in this patient?
. Time to surgical debridement of less than 6 hours
. Time to systemic antibiotic administration
. Use of high-pressure pulsatile lavage
. Early use of negative pressure wound therapy
. Definitive soft tissue coverage within 24 hours

Correct Answer & Explanation

. Time to systemic antibiotic administration

Explanation

The most critical and consistently proven factor in reducing infection rates in open fractures is the early administration of systemic antibiotics (ideally within 1 hour of injury). The traditional '6-hour rule' for surgical debridement has been largely disproven as an independent predictor of infection risk, provided adequate debridement occurs within the first 24 hours.

Question 6314

Topic: 2. Trauma

A 28-year-old male is admitted with a closed midshaft tibia fracture. Overnight, he develops increasing pain out of proportion to his injury that is poorly responsive to IV opioids. Pain is elicited with passive stretch of his hallux. You measure his compartment pressures. Which of the following parameters represents an absolute indication for emergency fasciotomy?

. Absolute compartment pressure > 30 mmHg
. Absolute compartment pressure > 45 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Mean arterial pressure minus compartment pressure < 30 mmHg
. Systolic blood pressure minus compartment pressure < 45 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

Delta P (diastolic blood pressure minus compartment pressure) < 30 mmHg is the most reliable threshold for diagnosing acute compartment syndrome and is an absolute indication for fasciotomy. This measurement accounts for the tissue perfusion gradient, making it far more accurate than absolute pressure alone, especially in hypotensive patients.

Question 6315

Topic: 2. Trauma
A 25-year-old female presents with a high-energy Pauwels type III (vertical shear) femoral neck fracture. Which of the following internal fixation constructs provides the most biomechanical stability for this specific fracture pattern?
. Three parallel partially threaded cancellous screws
. Dynamic hip screw (DHS) with an anti-rotation screw
. Cephalomedullary nail with a single head screw
. Cannulated screws placed in an inverted triangle
. Two divergent fully threaded screws

Correct Answer & Explanation

. Dynamic hip screw (DHS) with an anti-rotation screw

Explanation

Pauwels type III fractures are highly unstable due to the vertical orientation of the fracture line, creating immense shear forces. Biomechanical studies have demonstrated that a fixed-angle device, such as a dynamic hip screw (DHS) combined with a derotational screw, provides superior stability and higher failure loads compared to multiple cancellous screws in high-shear, vertical femoral neck fractures.

Question 6316

Topic: 2. Trauma

In a polytrauma patient with bilateral femur fractures and a pulmonary contusion, 'Damage Control Orthopedics' (DCO) with temporary external fixation is being considered over Early Total Care (ETC) with intramedullary nailing. Which of the following physiological parameters classifies the patient as 'borderline' and supports the use of DCO?

. Initial serum lactate of 1.5 mmol/L
. Base deficit > 8 mmol/L
. Platelet count of 150,000/uL
. Injury Severity Score (ISS) of 16
. Core temperature of 36.5°C

Correct Answer & Explanation

. Base deficit > 8 mmol/L

Explanation

According to Pape et al., 'borderline' polytrauma patients are at high risk of ARDS and multiple organ failure if subjected to early total care (e.g., prolonged reaming and intramedullary nailing). Indicators supporting DCO include a base deficit > 8 mmol/L, initial lactate > 2.5 mmol/L, pH < 7.25, hypothermia (< 35°C), and significant bilateral pulmonary contusions.

Question 6317

Topic: 2. Trauma
A 45-year-old roofer falls 15 feet, sustaining a displaced, intra-articular calcaneus fracture. You review his imaging to determine the Sanders classification. Which specific imaging modality and view dictates the Sanders classification for calcaneus fractures?
. The number of articular fragments on a sagittal CT reconstruction
. The number and location of fracture lines through the posterior facet on a coronal CT image
. The degree of Böhler's angle depression on a lateral radiograph
. The presence of anterior process extension on an axial CT image
. The degree of comminution of the calcaneal tuberosity on a Harris axial radiograph

Correct Answer & Explanation

. The number and location of fracture lines through the posterior facet on a coronal CT image

Explanation

The Sanders classification is strictly based on coronal CT images through the widest portion of the posterior facet of the calcaneus. It categorizes the fracture based on the number and location of the primary fracture lines dividing the posterior facet, which correlates with surgical prognosis.

Question 6318

Topic: 2. Trauma
A 32-year-old male is brought to the trauma bay after a motorcycle crash. He has an 'open book' pelvic ring injury (APC III) and is hemodynamically unstable. In severe pelvic fractures with massive volume expansion, what is the primary anatomical source of the life-threatening hemorrhage?
. Arterial bleeding from the superior gluteal artery
. Venous bleeding from the pre-sacral plexus and exposed cancellous bone
. Arterial bleeding from a ruptured internal iliac artery trunk
. Hemorrhage from an avulsed corona mortis
. Extravasation from an associated extraperitoneal bladder rupture

Correct Answer & Explanation

. Venous bleeding from the pre-sacral plexus and exposed cancellous bone

Explanation

In severe pelvic ring injuries with massive retroperitoneal volume expansion, approximately 80-90% of the hemorrhage is venous in origin (primarily from the pre-sacral venous plexus) combined with bleeding from the expansive, raw cancellous bone surfaces. While arterial bleeding (such as from the superior gluteal or pudendal arteries) can be catastrophic, it accounts for a much smaller percentage of overall pelvic hemorrhage cases.

Question 6319

Topic: 2. Trauma

An 82-year-old man presents with a hip injury after a mechanical fall. Radiographs and CT scan show an anterior column and posterior hemitransverse acetabular fracture with severe superomedial dome impaction (the "gull sign"). Which of the following factors most strongly predicts early failure if open reduction and internal fixation alone is chosen?

. Patient age over 80 years
. Superomedial dome impaction
. Medialization of the femoral head
. Presence of an associated posterior wall fracture
. Delay to surgery > 48 hours

Correct Answer & Explanation

. Superomedial dome impaction

Explanation

Superomedial dome impaction (the 'gull sign') in osteopenic patients represents a poor prognostic factor for open reduction and internal fixation (ORIF) alone. It involves severe crushing of the osteoporotic subchondral bone of the acetabular roof. Attempted ORIF in the presence of this sign carries a very high rate of early mechanical failure and progression to post-traumatic arthritis. Thus, acute total hip arthroplasty (often combined with column stabilization) is frequently indicated in this population.

Question 6320

Topic: 2. Trauma

A 30-year-old man with a closed midshaft tibia fracture complains of severe leg pain out of proportion to his injury, worsening with passive toe stretch. His blood pressure is 110/60 mm Hg. Intracompartmental pressure monitoring reveals an anterior compartment pressure of 40 mm Hg. What is the most appropriate next step in management?

. Observation and re-evaluation in 2 hours
. Elevate the leg above heart level
. Four-compartment fasciotomies
. Intravenous corticosteroids
. Immediate intramedullary nailing without fasciotomy

Correct Answer & Explanation

. Four-compartment fasciotomies

Explanation

This patient has acute compartment syndrome. The delta pressure (diastolic blood pressure minus intracompartmental pressure) is 60 - 40 = 20 mm Hg. A delta pressure of less than 30 mm Hg, combined with clinical signs of severe pain with passive stretch, is an absolute indication for emergent four-compartment fasciotomies of the leg.

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