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2. Trauma MCQs

Practice Set 620 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 12381

Topic: 2. Trauma

A 32-year-old male sustains a severely comminuted tibial plateau fracture. Six hours later, he reports intractable pain out of proportion to the injury. Compartment pressures are measured. What is the currently accepted clinical threshold for diagnosing acute compartment syndrome requiring fasciotomy?

. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 30 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

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

A delta pressure (diastolic blood pressure minus absolute compartment pressure) of less than 30 mmHg is considered the most reliable threshold for diagnosing acute compartment syndrome. Absolute pressure alone is less accurate as it fails to account for the patient's systemic perfusion pressure.

Question 12382

Topic: 2. Trauma

A 28-year-old male sustains a closed tibial shaft fracture. Clinical suspicion for acute compartment syndrome is high. Which of the following pressure measurements is the most reliable threshold for emergent fasciotomy?

. Absolute compartment pressure greater than 15 mmHg
. Absolute compartment pressure greater than 20 mmHg
. Delta pressure (Diastolic blood pressure minus compartment pressure) less than 30 mmHg
. Delta pressure (Mean arterial pressure minus compartment pressure) less than 40 mmHg
. Delta pressure (Systolic blood pressure minus compartment pressure) less than 30 mmHg

Correct Answer & Explanation

. Delta pressure (Diastolic blood pressure minus compartment pressure) less than 30 mmHg

Explanation

Delta pressure (diastolic blood pressure minus compartment pressure) is the most accurate indicator for compartment syndrome. A delta pressure of less than 30 mmHg is the widely accepted threshold indicating the need for emergent fasciotomy.

Question 12383

Topic: 2. Trauma
A 45-year-old farmer sustains a severe open tibia fracture with extensive soft tissue stripping and soil contamination (Gustilo-Anderson IIIB). In addition to a first-generation cephalosporin and an aminoglycoside, which antibiotic is most critical to add to the regimen?
. Vancomycin
. Ciprofloxacin
. Doxycycline
. Azithromycin
. High-dose Penicillin

Correct Answer & Explanation

. High-dose Penicillin

Explanation

Farm injuries or wounds heavily contaminated with soil or standing water have a high risk of Clostridium perfringens infection. High-dose penicillin should be added to the standard open fracture antibiotic regimen to provide adequate anaerobic coverage.

Question 12384

Topic: 2. Trauma

A 30-year-old male sustains a closed tibia fracture. Several hours later, he develops severe pain out of proportion to the injury, exacerbated by passive stretch of the toes. His diastolic blood pressure is 80 mm Hg, and an intra-compartmental pressure monitor reads 55 mm Hg. What is the most appropriate next step in management?

. Observation with frequent neurological checks
. Bivalving the cast and elevating the leg above heart level
. Emergent four-compartment fasciotomy of the leg
. Emergent single-compartment fasciotomy of the anterior compartment
. Administration of intravenous fluids and strong analgesics

Correct Answer & Explanation

. Emergent four-compartment fasciotomy of the leg

Explanation

A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mm Hg is an absolute indication for emergent fasciotomy. A four-compartment release is the standard of care for acute compartment syndrome of the leg.

Question 12385

Topic: 2. Trauma

When utilizing a locking plate to fix a severely comminuted diaphyseal fracture in osteoporotic bone, what is the primary biomechanical advantage of the fixed-angle construct?

. It generates high frictional forces between the plate and the bone surface.
. It relies on absolute stability to promote primary bone healing.
. It acts as a single-beam construct, reducing the risk of screw pull-out.
. It provides dynamic axial compression across the fracture site.
. It necessitates precise contouring of the plate to match the bone anatomy.

Correct Answer & Explanation

. It acts as a single-beam construct, reducing the risk of screw pull-out.

Explanation

Locking plates utilize a threaded interface between the screw head and the plate, creating a fixed-angle construct that functions as a single load-bearing beam. They do not rely on plate-to-bone friction, which preserves periosteal blood supply and prevents screw toggle or pull-out in osteoporotic bone.

Question 12386

Topic: Pelvic & Acetabular Trauma
A 35-year-old male involved in a high-speed motor vehicle collision presents with an unstable pelvic ring injury classified as an APC III (anteroposterior compression type III). He is hemodynamically unstable despite initial resuscitation efforts. What is the most critical immediate management step after addressing life-threatening injuries and initial fluid resuscitation?
. Placement of a C-clamp or external fixator for pelvic stabilization.
. Emergent angiography and embolization for ongoing hemorrhage.
. Open reduction and internal fixation of the sacroiliac joint.
. Application of skeletal traction to reduce posterior displacement.
. Transfusion of packed red blood cells and plasma.

Correct Answer & Explanation

. Placement of a C-clamp or external fixator for pelvic stabilization.

Explanation

In an APC III pelvic fracture, especially with hemodynamic instability, the pelvic ring is often widely disrupted, leading to significant volume loss within the pelvic cavity due to venous and arterial bleeding. While transfusion is critical, and angiography may be needed, the most critical immediate orthopedic intervention after initial resuscitation is mechanical stabilization of the pelvic ring using a C-clamp or external fixator. This reduces the pelvic volume, tamponades bleeding, and reduces ongoing hemorrhage. Angiography is typically performed after mechanical stabilization if the patient remains hemodynamically unstable, indicating persistent arterial bleeding. ORIF and traction are definitive treatment steps, not immediate life-saving measures.

Question 12387

Topic: 2. Trauma

A 24-year-old male sustains a comminuted tibia fracture and subsequently develops severe leg pain out of proportion to the injury, worsening with passive toe extension. The clinical suspicion for acute compartment syndrome is high. Which of the following intracompartmental pressure measurements confirms the diagnosis?

. Absolute pressure > 15 mmHg
. Absolute pressure > 20 mmHg
. Delta P (Diastolic BP minus Compartment Pressure) < 30 mmHg
. Delta P (Systolic BP minus Compartment Pressure) < 30 mmHg
. MAP (Mean Arterial Pressure) minus Compartment Pressure < 10 mmHg

Correct Answer & Explanation

. Delta P (Diastolic BP minus Compartment Pressure) < 30 mmHg

Explanation

Acute compartment syndrome is diagnosed when the Delta P (diastolic blood pressure minus the intracompartmental pressure) drops below 30 mmHg. This dynamic measurement is more reliable than absolute pressure as it accounts for the patient's systemic tissue perfusion pressure.

Question 12388

Topic: 2. Trauma
A 32-year-old motorcyclist sustains a Gustilo-Anderson Type IIIB open fracture of the distal third of the tibia. Following aggressive debridement, bone stabilization, and appropriate antibiotic therapy, a large soft tissue defect with exposed bone remains. What is the most appropriate option for soft tissue coverage?
. Split-thickness skin graft
. Soleus rotational muscle flap
. Gastrocnemius rotational muscle flap
. Free tissue transfer (e.g., anterolateral thigh flap)
. Local V-Y advancement flap

Correct Answer & Explanation

. Free tissue transfer (e.g., anterolateral thigh flap)

Explanation

Soft tissue defects in the distal third of the tibia lack adequate local muscle bulk for rotational coverage. They necessitate free tissue transfer (such as an anterolateral thigh or latissimus dorsi flap) to provide durable coverage over exposed bone or hardware.

Question 12389

Topic: Pelvic & Acetabular Trauma

A 45-year-old man sustains an anteroposterior compression (APC) Type II pelvic ring injury in a high-speed motor vehicle collision. Which of the following accurately describes the ligamentous disruption associated with this specific injury pattern?

. Anterior sacroiliac ligaments disrupted; posterior sacroiliac ligaments intact
. Both anterior and posterior sacroiliac ligaments completely disrupted
. Sacrotuberous ligaments intact; sacrospinous ligaments disrupted
. Posterior sacroiliac ligaments disrupted; anterior sacroiliac ligaments intact
. Complete disruption of the pubic symphysis with a concomitant sacral fracture

Correct Answer & Explanation

. Anterior sacroiliac ligaments disrupted; posterior sacroiliac ligaments intact

Explanation

An APC II pelvic injury is characterized by pubic symphysis diastasis and tearing of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. The strong posterior sacroiliac ligaments remain intact, rendering the pelvis rotationally unstable but vertically stable.

Question 12390

Topic: 2. Trauma

A 35-year-old male is brought to the emergency department intubated after a motorcycle collision. He has a closed, comminuted midshaft tibia fracture. His blood pressure is 90/60 mmHg. Intracompartmental pressure of the anterior compartment is measured at 45 mmHg. What is the most appropriate next step in management?

. Observation and elevate the leg
. Administer intravenous mannitol
. Immediate four-compartment fasciotomy
. Apply a long leg cast
. Perform closed reduction and re-measure pressures

Correct Answer & Explanation

. Immediate four-compartment fasciotomy

Explanation

The patient has a delta pressure (diastolic BP minus compartment pressure) of 15 mmHg. A delta pressure of less than 30 mmHg is an absolute indication for immediate fasciotomy to prevent irreversible muscle and nerve ischemia.

Question 12391

Topic: 2. Trauma

A 32-year-old male sustains a Hawkins Type II fracture of the talar neck. At his 8-week follow-up, radiographs reveal subchondral radiolucency in the talar dome. What does this radiographic finding indicate?

. Onset of avascular necrosis
. Osteomyelitis of the talus
. Intact vascularity to the talar body
. Nonunion of the talar neck
. Post-traumatic osteoarthritis

Correct Answer & Explanation

. Intact vascularity to the talar body

Explanation

The Hawkins sign is a subchondral radiolucent band seen in the talar dome 6 to 8 weeks post-injury, indicating subchondral bone resorption. This process requires an intact blood supply, thereby prognosticating a low risk of avascular necrosis.

Question 12392

Topic: 2. Trauma

A 28-year-old male sustains a closed midshaft tibia fracture. Four hours post-injury, he complains of severe leg pain out of proportion to the injury, not relieved by opioids. Passive stretch of the toes elicits excruciating pain. Compartment pressure monitoring reveals an anterior compartment pressure of 45 mmHg and a diastolic blood pressure of 65 mmHg. What is the most appropriate management?

. Elevate the leg above the level of the heart
. Administer intravenous analgesia and reassess in 2 hours
. Perform a diagnostic ultrasound for deep vein thrombosis
. Perform an emergent four-compartment fasciotomy
. Apply a long leg cast to stabilize the fracture and reduce swelling

Correct Answer & Explanation

. Perform an emergent four-compartment fasciotomy

Explanation

The patient demonstrates classic clinical signs of acute compartment syndrome, confirmed by a delta P (diastolic BP minus compartment pressure) of 20 mmHg, which is well below the 30 mmHg threshold. Emergent four-compartment fasciotomy is indicated to prevent irreversible muscle and nerve necrosis.

Question 12393

Topic: 2. Trauma
A 45-year-old male sustains a severe open tibia fracture with a 12 cm laceration, extensive muscle stripping, and massive contamination after a motorcycle accident. Following initial debridement, bone is exposed requiring flap coverage. According to the Gustilo-Anderson classification, what type of fracture is this and what is the optimal timing for initial antibiotic administration?
. Type IIIA; within 24 hours
. Type IIIB; as soon as possible, ideally within 1 hour
. Type IIIC; post-operatively
. Type IIIB; only after intraoperative cultures are taken
. Type IIIA; only if signs of infection develop

Correct Answer & Explanation

. Type IIIB; as soon as possible, ideally within 1 hour

Explanation

This is a Gustilo-Anderson Type IIIB fracture due to the extensive soft tissue injury requiring a flap for coverage. Early administration of broad-spectrum systemic antibiotics, ideally within 1 hour of injury, is the most critical factor in reducing infection rates in open fractures.

Question 12394

Topic: 2. Trauma
A 28-year-old male sustains a severe open tibia fracture (Gustilo-Anderson IIIB) after a motorcycle collision. After initial thorough surgical debridement and external fixation, a soft tissue defect with exposed bone remains. According to Godina's principles, to minimize the risk of flap failure and deep infection, a definitive free tissue transfer should ideally be performed within what timeframe from injury?
. 24 hours
. 72 hours
. 7 days
. 14 days
. 21 days

Correct Answer & Explanation

. 72 hours

Explanation

Classic literature by Godina demonstrates significantly reduced infection and failure rates when free flap coverage is achieved within 72 hours of injury. Early coverage prevents bacterial colonization of exposed bone and desiccation of surrounding tissues.

Question 12395

Topic: 2. Trauma

A 24-year-old male falls onto an outstretched hand. Immediate radiographs are negative, but an MRI obtained 1 week later reveals a non-displaced fracture of the proximal pole of the scaphoid. What is the most appropriate management for this specific fracture pattern?

. Short-arm cast for 4 weeks
. Long-arm thumb spica cast for 6 weeks
. Percutaneous headless compression screw fixation
. Proximal row carpectomy
. Vascularized bone graft

Correct Answer & Explanation

. Percutaneous headless compression screw fixation

Explanation

Proximal pole scaphoid fractures have a tenuous retrograde blood supply and a high risk of nonunion and avascular necrosis. Operative fixation with a headless compression screw is generally recommended even for non-displaced fractures to promote healing and allow early mobilization.

Question 12396

Topic: 2. Trauma

A 24-year-old man sustains bilateral closed femoral shaft fractures. 24 hours post-admission, he develops petechiae over his axillae, confusion, and tachypnea. Which of the following is the most effective prophylactic measure against this syndrome?

. Administration of prophylactic corticosteroids
. Early definitive internal fixation of the fractures
. Prophylactic systemic heparinization
. Inferior vena cava filter placement
. High-dose vitamin C supplementation

Correct Answer & Explanation

. Early definitive internal fixation of the fractures

Explanation

The patient is presenting with Fat Embolism Syndrome (FES). Early stabilization of long bone fractures (typically within the first 24 hours) is the most proven and effective method to reduce the incidence and severity of FES.

Question 12397

Topic: 2. Trauma

The diagnosis of acute compartment syndrome of the leg is heavily reliant on clinical suspicion and intra-compartmental pressure monitoring. Which pressure threshold relative to the patient's diastolic blood pressure (Delta P) is generally considered an absolute indication for fasciotomy?

. Delta P < 10 mm Hg
. Delta P < 30 mm Hg
. Delta P > 30 mm Hg
. Delta P > 45 mm Hg
. Absolute compartment pressure > 20 mm Hg

Correct Answer & Explanation

. Delta P < 30 mm Hg

Explanation

A Delta P (Diastolic BP minus compartment pressure) of less than 30 mm Hg indicates critically impaired tissue perfusion and is widely accepted as the threshold for emergent fasciotomy to prevent irreversible muscle and nerve necrosis.

Question 12398

Topic: 2. Trauma

In the pathophysiology of acute compartment syndrome, what is the primary initial microvascular event that initiates the cascade leading to tissue ischemia?

. Arterial vasospasm
. Capillary endothelial damage
. Venous outflow obstruction
. Arteriovenous shunting
. Lymphatic obstruction

Correct Answer & Explanation

. Venous outflow obstruction

Explanation

The cascade of acute compartment syndrome begins with an increase in intracompartmental pressure that first exceeds the venous pressure. This results in venous outflow obstruction, leading to further fluid transudation, increased tissue pressure, and eventually collapse of the arteriolar supply, which results in tissue ischemia.

Question 12399

Topic: 2. Trauma

In a polytraumatized patient, which of the following inflammatory markers is considered the most reliable indicator of the magnitude of the systemic inflammatory response and can help guide the timing of definitive fracture fixation?

. Interleukin-1 (IL-1)
. Interleukin-6 (IL-6)
. Interleukin-10 (IL-10)
. Tumor Necrosis Factor-alpha (TNF-a)
. C-Reactive Protein (CRP)

Correct Answer & Explanation

. Interleukin-6 (IL-6)

Explanation

Interleukin-6 (IL-6) levels correlate most closely with the severity of tissue injury, magnitude of the systemic inflammatory response syndrome (SIRS), and mortality in polytrauma patients. It is heavily utilized in clinical parameters for determining the 'window of opportunity' for transitioning from Damage Control Orthopedics (DCO) to Early Total Care (ETC).

Question 12400

Topic: 2. Trauma

According to Perren's strain theory of fracture healing, primary bone healing (direct osteonal remodeling without callus formation) can only occur if the interfragmentary strain at the fracture gap is maintained below what maximum threshold?

. Less than 2%
. Between 2% and 10%
. Between 10% and 30%
. Between 30% and 50%
. Greater than 50%

Correct Answer & Explanation

. Less than 2%

Explanation

Perren's strain theory dictates the type of tissue that can form in a fracture gap based on the strain (deformation). Primary bone healing (osteonal cutting cones crossing the gap) requires absolute stability with interfragmentary strain < 2%. Strain between 2% and 10% permits secondary healing (cartilage/callus formation). Strains >10% result in granulation tissue and potential nonunion.

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