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2. Trauma MCQs

Practice Set 512 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 10221

Topic: 2. Trauma

A 28-year-old male sustains a coronal shear fracture of the lateral femoral condyle (Hoffa fracture) following a motorcycle crash. Operative intervention is planned. What is the optimal surgical approach and mechanical fixation strategy for this fracture pattern?

. Medial parapatellar approach with anterior-to-posterior (AP) screws
. Lateral approach with posterior-to-anterior (PA) directed lag screws
. Anterolateral approach with a medially applied buttress plate
. Posterior approach with a lateral neutralizing plate
. Arthroscopic excision of the fractured fragment

Correct Answer & Explanation

. Lateral approach with posterior-to-anterior (PA) directed lag screws

Explanation

Hoffa fractures are coronal plane shear fractures usually of the lateral condyle. They are optimally fixed via a lateral approach using posterior-to-anterior (PA) lag screws, which biomechanically better resist shear and pullout forces.

Question 10222

Topic: 2. Trauma

A 45-year-old male presents with a posterior hip dislocation and an associated posterior wall acetabular fracture after a dashboard injury. The hip is closed reduced in the trauma bay. Which of the following is an absolute indication for operative fixation of this posterior wall fracture?

. A fracture involving 10% of the posterior wall
. A roof arc angle of greater than 45 degrees
. The presence of marginal impaction of the articular cartilage
. A concentric joint space on the post-reduction AP pelvis radiograph
. Patient age greater than 40 years

Correct Answer & Explanation

. The presence of marginal impaction of the articular cartilage

Explanation

Operative indications for a posterior wall acetabular fracture include a fragment size >20%, joint instability, and marginal impaction. Marginal impaction must be operatively elevated and grafted to prevent rapid post-traumatic osteoarthritis.

Question 10223

Topic: 2. Trauma
A 35-year-old male sustains a posterior hip dislocation with an associated fracture of the femoral head that extends into the weight-bearing zone, along with an acetabular posterior wall fracture. Which Pipkin classification best describes this injury?
. Pipkin I
. Pipkin II
. Pipkin III
. Pipkin IV
. Pipkin V

Correct Answer & Explanation

. Pipkin IV

Explanation

Pipkin IV fractures involve a posterior hip dislocation with a femoral head fracture and an associated acetabular fracture. Management typically requires surgical fixation of both the acetabulum and femoral head to restore joint stability.

Question 10224

Topic: 2. Trauma

A 28-year-old female sustains a severe twisting injury to her ankle. Radiographs show a fracture-dislocation with the proximal fibular shaft fragment trapped behind the posterolateral ridge of the tibia. Closed reduction in the ED is unsuccessful. What is the most likely diagnosis?

. Maisonneuve fracture
. Bosworth fracture-dislocation
. Tillaux fracture
. Pilon fracture
. Dupuytren fracture

Correct Answer & Explanation

. Bosworth fracture-dislocation

Explanation

A Bosworth fracture is a rare fracture-dislocation of the ankle where the proximal fibular fragment becomes entrapped behind the posterior tubercle of the distal tibia. It is characteristically irreducible by closed means and requires open reduction.

Question 10225

Topic: Pelvic & Acetabular Trauma

A 34-year-old male arrives in the trauma bay in hemorrhagic shock after a crush injury to the pelvis. AP pelvis radiograph demonstrates complete disruption of the pubic symphysis (5 cm diastasis) and widened sacroiliac joints bilaterally. A pelvic binder is to be applied. What is the correct anatomical landmark for the optimal placement of the binder?

. Iliac crests
. Greater trochanters
. Anterior superior iliac spines
. Pubic symphysis
. Umbilicus

Correct Answer & Explanation

. Greater trochanters

Explanation

To effectively reduce pelvic volume and control venous hemorrhage in an 'open book' pelvic fracture, a pelvic binder must be centered directly over the greater trochanters. Placement over the iliac crests is ineffective and can exacerbate the deformity.

Question 10226

Topic: 2. Trauma

A 50-year-old roofer falls from a ladder, sustaining a closed, displaced intra-articular calcaneus fracture. Computed tomography (CT) is obtained. According to the Sanders classification, which anatomical structure is evaluated in the coronal plane to determine the severity and type of fracture?

. Anterior facet
. Middle facet
. Posterior facet
. Calcaneocuboid joint
. Sustentaculum tali

Correct Answer & Explanation

. Posterior facet

Explanation

The Sanders classification for intra-articular calcaneus fractures is based on the number and location of articular fracture lines through the posterior facet as seen on coronal CT imaging.

Question 10227

Topic: 2. Trauma

A 28-year-old female falls from a horse and presents with saddle anesthesia and bowel/bladder dysfunction. CT of the pelvis shows a transverse fracture through the S2 neural foramina connecting bilateral longitudinal sacral fractures. What is the most likely diagnosis?

. Denis Zone I fracture
. APC II pelvic injury
. Spinopelvic dissociation (U-type fracture)
. LC I pelvic injury
. Sacral ala fracture

Correct Answer & Explanation

. Spinopelvic dissociation (U-type fracture)

Explanation

A U-type sacral fracture represents spinopelvic dissociation, characterized by bilateral longitudinal sacral fractures joined by a transverse fracture. Patients typically present with significant neurological deficits and require lumbopelvic fixation.

Question 10228

Topic: 2. Trauma

Which of the following measurements is considered the most reliable threshold for diagnosing acute compartment syndrome in a trauma patient?

. Absolute compartment pressure > 30 mmHg
. Absolute compartment pressure > 45 mmHg
. Diastolic blood pressure minus compartment pressure (Delta P) < 30 mmHg
. Mean arterial pressure minus compartment pressure < 30 mmHg
. Systolic blood pressure minus compartment pressure < 40 mmHg

Correct Answer & Explanation

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

Explanation

The delta P, defined as the diastolic blood pressure minus the compartment pressure, of less than 30 mmHg is the most reliable clinical indicator for diagnosing acute compartment syndrome. It minimizes false positives that can occur when relying solely on absolute compartment pressures.

Question 10229

Topic: Pelvic & Acetabular Trauma

To effectively reduce pelvic volume and stabilize an 'open book' pelvic ring injury in the emergency department, a pelvic binder should be anatomically centered over the:

. Iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Symphysis pubis
. Ischial tuberosities

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders are biomechanically most effective at closing the pelvic volume when centered directly over the greater trochanters. Placement higher over the iliac crests or ASIS may fail to close the symphysis or paradoxically worsen the deformity.

Question 10230

Topic: Lower Extremity Trauma

A patient sustains a Schatzker type II tibial plateau fracture (split-depression). Which surgical approach is generally most appropriate for direct visualization and internal fixation of this specific injury pattern?

. Medial approach
. Posteromedial approach
. Anterolateral approach
. Direct posterior approach
. Ilioinguinal approach

Correct Answer & Explanation

. Anterolateral approach

Explanation

Schatzker type II fractures involve a split and depression of the lateral tibial plateau. The standard anterolateral approach provides excellent visualization of the lateral articular surface and allows for appropriate application of a lateral buttress plate.

Question 10231

Topic: 2. Trauma

In the management of a severely polytraumatized orthopaedic patient, which of the following laboratory parameters is recognized as the most reliable indicator for successful completion of systemic tissue resuscitation and adequate oxygen delivery?

. Arterial pH normalization
. Serum lactate clearance
. Hemoglobin > 10 g/dL
. Mixed venous oxygen saturation > 90%
. Systolic blood pressure > 100 mmHg

Correct Answer & Explanation

. Serum lactate clearance

Explanation

Serum lactate level and its clearance (the rate at which lactate levels return to normal) are among the most reliable indicators of adequate global tissue perfusion and oxygenation in trauma resuscitation. While base deficit and pH are also useful, lactate clearance strictly correlates with restoration of aerobic metabolism. Normalizing blood pressure or hemoglobin does not guarantee adequate cellular perfusion (occult hypoperfusion).

Question 10232

Topic: 2. Trauma

A 24-year-old male sustains a closed comminuted femoral shaft fracture. Forty-eight hours later, he develops acute confusion, an axillary petechial rash, and hypoxemia. Which of the following is the most likely pathophysiologic mechanism triggering his respiratory distress?

. Bacterial colonization of the alveolar spaces
. Thromboembolism from deep pelvic veins
. Release of marrow fat droplets triggering a systemic inflammatory cascade
. Aspiration of gastric contents during the initial trauma
. Donor antibody reaction via Transfusion-related acute lung injury (TRALI)

Correct Answer & Explanation

. Release of marrow fat droplets triggering a systemic inflammatory cascade

Explanation

The patient demonstrates Gurd's classic triad for Fat Embolism Syndrome (FES). FES is triggered when intravasation of marrow fat droplets causes mechanical pulmonary obstruction and a severe inflammatory response via the breakdown of fats into toxic free fatty acids.

Question 10233

Topic: 2. Trauma

In a polytrauma patient undergoing damage control orthopedics, which of the following serum markers peaks early and correlates most strongly with the severity of the systemic inflammatory response syndrome (SIRS)?

. Interleukin-1 (IL-1)
. Interleukin-6 (IL-6)
. Tumor necrosis factor-alpha (TNF-alpha)
. C-reactive protein (CRP)
. Erythrocyte sedimentation rate (ESR)

Correct Answer & Explanation

. Interleukin-6 (IL-6)

Explanation

Interleukin-6 (IL-6) levels peak early after severe injury. It is considered the most accurate marker for evaluating the magnitude of the systemic inflammatory response and predicting multi-organ failure.

Question 10234

Topic: Pelvic & Acetabular Trauma
A 35-year-old trauma patient presents with an unstable anteroposterior compression (APC-III) pelvic ring injury and hemodynamic instability. When applying a circumferential pelvic binder, where should it be anatomically centered to correctly maximize reduction?
. At the level of the iliac crests
. Centered over the umbilicus
. At the level of the greater trochanters
. Directly over the anterior superior iliac spines (ASIS)
. Around the proximal thighs below the lesser trochanters

Correct Answer & Explanation

. At the level of the greater trochanters

Explanation

A pelvic binder must be centered precisely over the greater trochanters to effectively compress the pelvic ring. Placing it higher over the iliac crests is ineffective and can paradoxically widen the true pelvis.

Question 10235

Topic: 2. Trauma
A 35-year-old farmer sustains a Gustilo-Anderson Type IIIA open tibia fracture heavily contaminated with soil. Which of the following is the most appropriate initial empiric antibiotic regimen?
. First-generation cephalosporin alone
. First-generation cephalosporin and an aminoglycoside
. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin
. Vancomycin and piperacillin-tazobactam
. Ciprofloxacin alone

Correct Answer & Explanation

. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin

Explanation

For severe open fractures (Type III) occurring in farm or heavily contaminated environments, anaerobic coverage (specifically for Clostridium) is necessary. The classic recommendation is a first-generation cephalosporin, an aminoglycoside, and high-dose penicillin.

Question 10236

Topic: Pelvic & Acetabular Trauma
A 25-year-old male sustains a high-energy trauma resulting in an APC-III (anteroposterior compression) pelvic ring injury. Which of the following ligamentous complexes is completely disrupted in this injury pattern?
. Anterior sacroiliac ligament only
. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments only
. Sacrotuberous and sacrospinous ligaments only
. Anterior sacroiliac, posterior sacroiliac, sacrotuberous, and sacrospinous ligaments
. Posterior sacroiliac ligament only

Correct Answer & Explanation

. Anterior sacroiliac, posterior sacroiliac, sacrotuberous, and sacrospinous ligaments

Explanation

An APC-III injury represents complete disruption of the pelvic ring both anteriorly and posteriorly. It involves the tearing of the anterior and posterior sacroiliac ligaments, as well as the sacrotuberous and sacrospinous ligaments, rendering the pelvis globally unstable.

Question 10237

Topic: 2. Trauma

A surgeon is utilizing a locked plating construct for a comminuted diaphyseal femur fracture to promote secondary bone healing. To purposefully decrease the stiffness of the construct and increase interfragmentary strain at the fracture site, which of the following technical modifications is most appropriate?

. Decrease the plate working length by placing screws in holes immediately adjacent to the fracture
. Increase the plate working length by leaving empty holes near the fracture site
. Use a plate made of stainless steel instead of titanium
. Utilize unlocking screws in the diaphyseal segment to compress the plate to the bone
. Place lag screws through the plate into the comminuted fragments

Correct Answer & Explanation

. Increase the plate working length by leaving empty holes near the fracture site

Explanation

Increasing the working length of a locked plate (the distance between the innermost screws on either side of the fracture) acts to decrease the construct stiffness. This allows for greater micromotion (interfragmentary strain) at the fracture site, which is optimal for secondary bone healing via callus formation. Placing screws closer to the fracture or using stainless steel makes the construct stiffer.

Question 10238

Topic: 2. Trauma

In the systemic response to major orthopedic trauma, the 'second hit' phenomenon refers to an exaggerated systemic inflammatory response following early total care surgical intervention. Which of the following cytokines is most widely recognized as the primary marker for the magnitude of this initial systemic inflammatory response?

. Interleukin-1 (IL-1)
. Interleukin-6 (IL-6)
. Interleukin-10 (IL-10)
. Transforming Growth Factor-beta (TGF-beta)
. Interferon-gamma

Correct Answer & Explanation

. Interleukin-6 (IL-6)

Explanation

Interleukin-6 (IL-6) is established as the best clinical marker for the magnitude of the systemic inflammatory response syndrome (SIRS) following major trauma and surgery. IL-6 levels correlate directly with the severity of tissue injury, blood loss, risk of multi-organ failure (MOF), and overall mortality. IL-10 is primarily an anti-inflammatory cytokine that attempts to regulate this response.

Question 10239

Topic: 2. Trauma

A 24-year-old male is admitted after a motorcycle collision resulting in a closed tibial shaft fracture. He complains of severe, progressively worsening pain. Which of the following pressure measurements is generally considered the threshold for performing a four-compartment fasciotomy?

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

Correct Answer & Explanation

. Delta pressure (Diastolic blood pressure minus compartment pressure) < 30 mmHg.

Explanation

The delta pressure, defined as the diastolic blood pressure minus the absolute compartment pressure, is the most reliable indicator for acute compartment syndrome. A delta pressure of less than 30 mmHg is the widely accepted threshold that indicates the need for emergent fasciotomy. Relying solely on absolute pressure can lead to unnecessary fasciotomies or missed diagnoses in hypotensive patients.

Question 10240

Topic: Pelvic & Acetabular Trauma
A 45-year-old pedestrian is struck by a vehicle and sustains a pelvic ring injury. Imaging shows a 3 cm diastasis of the pubic symphysis. The anterior sacroiliac ligaments are disrupted, but the posterior sacroiliac ligaments are intact. According to the Young and Burgess classification, this injury is classified as:
. Anteroposterior Compression (APC) I
. Anteroposterior Compression (APC) II
. Anteroposterior Compression (APC) III
. Lateral Compression (LC) I
. Lateral Compression (LC) II

Correct Answer & Explanation

. Anteroposterior Compression (APC) II

Explanation

An Anteroposterior Compression (APC) type II injury involves a symphyseal diastasis > 2.5 cm with rupture of the anterior sacroiliac (SI), sacrotuberous, and sacrospinous ligaments. Crucially, the posterior SI ligaments remain intact, providing vertical stability but resulting in rotational instability (an "open book" pelvis). APC I is diastasis < 2.5 cm. APC III involves complete disruption of both anterior and posterior SI ligaments, causing complete rotational and vertical instability.

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