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2. Trauma MCQs

Practice Set 517 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 10321

Topic: Pelvic & Acetabular Trauma
A 38-year-old male is brought to the trauma bay after a motorcycle collision. He has a heart rate of 130 bpm and blood pressure of 75/40 mmHg. Pelvic radiographs show an anteroposterior compression type III (APC III) injury. After initiating massive transfusion protocols, what is the most appropriate initial mechanical intervention?
. Immediate open reduction and internal fixation of the pubic symphysis
. Application of a pelvic binder centered over the iliac crests
. Application of a pelvic binder centered over the greater trochanters
. Bilateral internal iliac artery embolization
. Placement of a resuscitative endovascular balloon occlusion of the aorta (REBOA)

Correct Answer & Explanation

. Application of a pelvic binder centered over the greater trochanters

Explanation

In a hemodynamically unstable patient with an open-book pelvic ring injury, the initial mechanical intervention is the application of a pelvic binder to reduce pelvic volume and promote tamponade. The binder must be centered over the greater trochanters, not the iliac crests, to effectively close the pelvic ring.

Question 10322

Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the ED after a motorcycle crash. Pelvic radiographs show an APC-III pelvic ring injury. He remains hemodynamically unstable despite a pelvic binder and massive transfusion protocols. What is the most appropriate next step in surgical management?
. Bilateral internal iliac artery embolization
. Exploratory laparotomy
. Preperitoneal pelvic packing
. Application of a supra-acetabular external fixator
. Sacroiliac screw fixation

Correct Answer & Explanation

. Preperitoneal pelvic packing

Explanation

In a hemodynamically unstable patient with a mechanically stabilized pelvic ring injury, preperitoneal pelvic packing or angioembolization is indicated. Hemorrhage in APC injuries is most commonly venous from the presacral plexus, making packing highly effective.

Question 10323

Topic: 2. Trauma

A 30-year-old man sustains a closed high-energy tibial shaft fracture. Eight hours later, he develops excruciating pain out of proportion to the injury. Which of the following is the most sensitive and earliest clinical finding for acute compartment syndrome?

. Loss of distal pulses
. Paresthesias in the first web space
. Pain with passive stretch of the toes
. Pallor of the foot
. Motor paralysis

Correct Answer & Explanation

. Pain with passive stretch of the toes

Explanation

Pain with passive stretch of the muscles in the involved compartment is the most sensitive and earliest clinical indicator of acute compartment syndrome. Pulselessness and paralysis are late, often irreversible signs.

Question 10324

Topic: 2. Trauma

A 32-year-old male sustains a closed tibia fracture and develops worsening leg pain. Compartment pressures are measured. What pressure threshold is most universally accepted as an absolute indication for emergency fasciotomy?

. Absolute compartment pressure greater than 30 mmHg
. Absolute compartment pressure greater than 40 mmHg
. Diastolic blood pressure minus compartment pressure less than 30 mmHg
. Mean arterial pressure minus compartment pressure less than 30 mmHg
. Systolic blood pressure minus compartment pressure less than 30 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure less than 30 mmHg

Explanation

A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the most reliable threshold and indication for fasciotomy in acute compartment syndrome.

Question 10325

Topic: Pelvic & Acetabular Trauma
A 40-year-old hypotensive male presents with an anteroposterior compression type III (APC-III) pelvic ring injury. To be most effective in reducing pelvic volume and venous bleeding, a pelvic binder must be centered directly over which anatomic landmarks?
. Iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Pubic symphysis
. L5-S1 junction

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders provide the most effective mechanical reduction of pelvic volume when centered directly over the greater trochanters. Placing them higher (e.g., over the iliac crests) is less effective and may exacerbate the injury.

Question 10326

Topic: 2. Trauma
A 28-year-old male sustains a Gustilo-Anderson type IIIB open tibia fracture in a motorcycle collision. According to established trauma guidelines, what is the single most critical modifiable factor in reducing the risk of deep infection?
. Time to initial surgical debridement
. Time to first dose of intravenous antibiotics
. Use of high-pressure pulsatile lavage
. Choice of internal fixation method
. Time to definitive soft tissue coverage

Correct Answer & Explanation

. Time to first dose of intravenous antibiotics

Explanation

Extensive literature demonstrates that the time to the first dose of systemic intravenous antibiotics is the most important determinant in reducing infection rates in open fractures. Administration within 1 hour of injury is recommended.

Question 10327

Topic: 2. Trauma

In the management of polytraumatized patients, Damage Control Orthopedics (DCO) is often favored over Early Total Care (ETC) in 'borderline' or 'unstable' patients. Which of the following systemic inflammatory markers, typically peaking 24 to 48 hours post-injury, has been shown to correlate most closely with the development of multiorgan failure and is frequently used to monitor systemic inflammatory response?

. Erythrocyte Sedimentation Rate (ESR)
. Interleukin-1 (IL-1)
. Interleukin-6 (IL-6)
. Tumor Necrosis Factor alpha (TNF-alpha)
. C-reactive protein (CRP)

Correct Answer & Explanation

. Interleukin-6 (IL-6)

Explanation

Interleukin-6 (IL-6) is a key pro-inflammatory cytokine that peaks 24 to 48 hours after severe injury. Peak levels of IL-6 (especially >500 pg/mL) correlate strongly with injury severity, the magnitude of the surgical 'second hit', and the risk of developing acute respiratory distress syndrome (ARDS) and multiple organ dysfunction syndrome (MODS).

Question 10328

Topic: 2. Trauma

According to Perren's strain theory of bone healing, what is the maximum percentage of interfragmentary strain that allows for primary (direct) bone healing to occur across a fracture site?

. Less than 2%
. 2% to 10%
. 10% to 15%
. 15% to 20%
. Greater than 20%

Correct Answer & Explanation

. Less than 2%

Explanation

Perren's strain theory states that primary (direct) bone healing via cutting cones requires absolute stability, which is defined as an interfragmentary strain of less than 2%. Strain between 2% and 10% allows for secondary bone healing (callus formation), while strain greater than 10% generally prevents bone formation and leads to nonunion or fibrous tissue formation.

Question 10329

Topic: 2. Trauma

A 32-year-old male sustains a closed, high-energy tibial shaft fracture. Two hours post-injury, he complains of severe pain disproportionate to the injury. His systemic blood pressure is 120/80 mmHg. Intracompartmental pressure testing is performed. Which of the following pressure profiles is the most universally accepted absolute indication for a four-compartment fasciotomy?

. Absolute intracompartmental pressure > 20 mmHg
. Absolute intracompartmental pressure > 25 mmHg
. Diastolic blood pressure minus intracompartmental pressure (Delta P) < 30 mmHg
. Mean arterial pressure minus intracompartmental pressure < 45 mmHg
. Systolic blood pressure minus intracompartmental pressure < 40 mmHg

Correct Answer & Explanation

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

Explanation

The most reliable threshold for diagnosing acute compartment syndrome and indicating a fasciotomy is a Delta P (Diastolic BP minus Intracompartmental Pressure) of less than 30 mmHg. Relying strictly on absolute compartment pressure can lead to overtreatment in normotensive patients or undertreatment in hypotensive patients.

Question 10330

Topic: Pelvic & Acetabular Trauma

In a patient who sustains a highly unstable vertical shear or an anteroposterior compression (APC) pelvic ring fracture with severe posterior sacroiliac (SI) joint disruption, massive retroperitoneal hemorrhage is often encountered. When arterial bleeding is the primary source in the setting of a posterior ring injury, which artery is most frequently implicated?

. Obturator artery
. Superior gluteal artery
. Internal pudendal artery
. External iliac artery
. Inferior epigastric artery

Correct Answer & Explanation

. Superior gluteal artery

Explanation

While the majority of pelvic hemorrhage is venous (from the presacral venous plexus) or from cancellous bone surfaces, arterial hemorrhage can be life-threatening. In posterior pelvic ring injuries (SI joint disruptions and sacral fractures), the superior gluteal artery is the most commonly injured artery as it exits the pelvis through the greater sciatic notch in close proximity to the SI joint.

Question 10331

Topic: Pelvic & Acetabular Trauma
During the acute resuscitation of a hemodynamically unstable patient with an anteroposterior compression (APC) type III pelvic ring injury, a pelvic binder is applied. To optimally reduce pelvic volume and control venous hemorrhage, the binder should be centered directly over which of the following anatomic landmarks?
. The anterior superior iliac spines (ASIS)
. The iliac crests
. The greater trochanters
. The pubic symphysis
. The level of the umbilicus

Correct Answer & Explanation

. The greater trochanters

Explanation

Pelvic binders must be placed accurately at the level of the greater trochanters to effectively close the pelvic ring, internally rotate the hemipelvises, and maximally reduce pelvic volume. Placement higher up over the ASIS or iliac crests is less effective and can paradoxically open the pelvic ring further in certain fracture patterns.

Question 10332

Topic: 2. Trauma

In the evaluation of suspected acute compartment syndrome of the lower leg, utilizing the 'delta pressure' (Delta P) is considered a more accurate indicator for intervention than the absolute compartment pressure. Which of the following accurately defines the Delta P and the threshold that strongly indicates the need for a fasciotomy?

. Systolic Blood Pressure minus Compartment Pressure; < 30 mmHg
. Diastolic Blood Pressure minus Compartment Pressure; < 30 mmHg
. Mean Arterial Pressure minus Compartment Pressure; > 30 mmHg
. Compartment Pressure minus Venous Pressure; > 30 mmHg
. Diastolic Blood Pressure minus Compartment Pressure; > 45 mmHg

Correct Answer & Explanation

. Diastolic Blood Pressure minus Compartment Pressure; < 30 mmHg

Explanation

Delta P is defined as the Diastolic Blood Pressure minus the Compartment Pressure. A Delta P of less than or equal to 30 mmHg indicates inadequate tissue perfusion pressure, which strongly confirms acute compartment syndrome and the necessity for an emergent fasciotomy.

Question 10333

Topic: 2. Trauma
In young adults with high-energy femoral neck fractures, a Pauwels type III fracture pattern is notoriously difficult to treat due to high rates of nonunion and avascular necrosis. The Pauwels classification categorizes these fractures based on which of the following parameters?
. The degree of comminution of the posterior neck
. The location of the fracture line (subcapital, transcervical, basicervical)
. The angle of the fracture line relative to the horizontal plane
. The amount of displacement of the fracture fragments
. The degree of vascular disruption to the femoral head

Correct Answer & Explanation

. The angle of the fracture line relative to the horizontal plane

Explanation

The Pauwels classification is based on the angle of the femoral neck fracture line relative to the horizontal plane. Type I is <30 degrees, Type II is 30-50 degrees, and Type III is >50 degrees. Higher angles (more vertical fracture lines) experience exponentially greater shear forces, leading to poor biomechanical stability, higher rates of fixation failure, and nonunion.

Question 10334

Topic: 2. Trauma

A 24-year-old male presents with a scaphoid proximal pole fracture nonunion six months post-injury. The proximal pole's severe vulnerability to avascular necrosis is primarily due to its retrograde blood supply from branches of which vessel?

. Ulnar artery
. Anterior interosseous artery
. Radial artery
. Posterior interosseous artery
. Deep palmar arch

Correct Answer & Explanation

. Radial artery

Explanation

The scaphoid receives a retrograde blood supply primarily from dorsal branches of the radial artery, which enter the bone distally. This anatomic peculiarity leaves the proximal pole highly susceptible to ischemia and avascular necrosis following a fracture.

Question 10335

Topic: 2. Trauma

In an obtunded polytrauma patient with a comminuted tibial shaft fracture, continuous compartment pressure monitoring is utilized. What 'delta P' threshold is the most universally accepted indication for an emergent four-compartment fasciotomy?

. Absolute compartment pressure > 20 mm Hg
. Absolute compartment pressure > 30 mm Hg
. Diastolic blood pressure minus compartment pressure < 30 mm Hg
. Mean arterial pressure minus compartment pressure < 40 mm Hg
. Systolic blood pressure minus compartment pressure < 30 mm Hg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mm Hg

Explanation

A 'delta P' (diastolic blood pressure minus compartment pressure) of less than 30 mm Hg is the most reliable and validated indicator for acute compartment syndrome requiring fasciotomy. Relying solely on absolute compartment pressures can be misleading, especially in hypotensive trauma patients.

Question 10336

Topic: 2. Trauma

A 30-year-old male sustains a high-velocity gunshot wound to the thigh resulting in a comminuted midshaft femur fracture and an expanding pulsatile hematoma with absent distal pulses. In the operating room, what is the most appropriate sequence of operative management?

. Femur fixation, then vascular repair, then fasciotomy
. Vascular shunting, femur fixation, definitive vascular repair, fasciotomy
. Fasciotomy, femur fixation, vascular repair
. Definitive vascular repair, femur fixation, fasciotomy
. Femur fixation, fasciotomy, definitive vascular repair

Correct Answer & Explanation

. Vascular shunting, femur fixation, definitive vascular repair, fasciotomy

Explanation

In combined orthopedic and vascular extremity injuries with severe ischemia, temporary vascular shunting must be performed first to restore perfusion and minimize ischemia time. This is followed by skeletal stabilization, definitive vascular repair, and lastly prophylactic fasciotomies.

Question 10337

Topic: Pelvic & Acetabular Trauma
You are applying a commercial pelvic binder to a hemodynamically unstable patient with an APC-III open-book pelvic ring injury. For maximum biomechanical efficacy and optimal reduction of pelvic volume, the binder should be centered over which anatomical landmarks?
. Iliac crests
. Greater trochanters
. Anterior superior iliac spines
. Pubic symphysis
. Sacral promontory

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders are most effective at reducing pelvic volume and controlling life-threatening retroperitoneal hemorrhage when placed precisely at the level of the greater trochanters. Improper placement higher over the iliac crests is biomechanically inferior and frequently restricts critical abdominal access.

Question 10338

Topic: 2. Trauma

Perren's strain theory dictates the specific type of bone healing that will occur in a fracture environment. Secondary bone healing via endochondral ossification and callus formation is optimized in a mechanical environment with what percentage of strain?

. < 2%
. 2% to 10%
. 10% to 20%
. 20% to 30%
. > 30%

Correct Answer & Explanation

. 2% to 10%

Explanation

Secondary bone healing, characterized by robust callus formation, optimally occurs in a moderate strain environment of between 2% and 10%. Strain < 2% promotes absolute stability and primary bone healing, while strain > 10% heavily promotes fibrous nonunion.

Question 10339

Topic: 2. Trauma

In a hypotensive polytrauma patient with a tibial shaft fracture, which of the following is the most reliable threshold for diagnosing acute compartment syndrome using intracompartmental pressure monitoring?

. Absolute pressure > 30 mmHg
. Absolute pressure > 45 mmHg
. Delta pressure (Diastolic BP - Compartment Pressure) < 30 mmHg
. Delta pressure (Mean Arterial BP - Compartment Pressure) < 30 mmHg
. Delta pressure (Systolic BP - Compartment Pressure) < 40 mmHg

Correct Answer & Explanation

. Delta pressure (Diastolic BP - Compartment Pressure) < 30 mmHg

Explanation

The delta pressure, calculated as diastolic blood pressure minus intracompartmental pressure, is the most reliable indicator for compartment syndrome. A delta pressure of less than 30 mmHg strongly indicates the need for emergency fasciotomy.

Question 10340

Topic: Pelvic & Acetabular Trauma
An anteroposterior compression type III (APC III) pelvic ring injury is characterized by complete disruption of the symphysis pubis and which of the following posterior structures?
. Anterior sacroiliac ligaments only
. Sacrotuberous and sacrospinous ligaments only
. Anterior and posterior sacroiliac ligaments
. Iliolumbar ligament only
. Lumbosacral plexus

Correct Answer & Explanation

. Anterior and posterior sacroiliac ligaments

Explanation

An APC III injury involves a complete disruption of both the anterior and posterior sacroiliac ligaments, along with the sacrotuberous and sacrospinous ligaments. This extensive damage results in complete global instability of the hemipelvis.

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