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2. Trauma MCQs

Practice Set 518 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 10341

Topic: 2. Trauma
According to the latest guidelines for the management of open fractures, what is the recommended prophylactic antibiotic regimen for a Gustilo-Anderson Type III open tibia fracture in a patient with no known allergies?
. First-generation cephalosporin alone
. First-generation cephalosporin and an aminoglycoside
. First-generation cephalosporin and a fluoroquinolone
. First-generation cephalosporin and metronidazole
. Broad-spectrum penicillin alone

Correct Answer & Explanation

. First-generation cephalosporin and an aminoglycoside

Explanation

For Gustilo-Anderson Type III open fractures, current guidelines typically recommend adding Gram-negative coverage to standard Gram-positive prophylaxis. This is most commonly achieved with a first-generation cephalosporin combined with an aminoglycoside.

Question 10342

Topic: 2. Trauma

Which of the following types of fracture fixation provides absolute stability and promotes primary bone healing rather than secondary bone healing via callus formation?

. Intramedullary nailing of a femur fracture
. Bridge plating of a comminuted tibia fracture
. Compression plating of a transverse radius fracture
. External fixation of a highly comminuted pilon fracture
. Cast immobilization of a non-displaced humeral shaft fracture

Correct Answer & Explanation

. Compression plating of a transverse radius fracture

Explanation

Primary bone healing requires conditions of absolute stability and minimal interfragmentary strain, which is achieved through techniques like compression plating or lag screw fixation. Methods like intramedullary nailing provide relative stability and heal via secondary callus formation.

Question 10343

Topic: 2. Trauma

A 32-year-old male presents with a closed tibial shaft fracture. Which of the following continuous compartment pressure measurements is the most reliable threshold for diagnosing acute compartment syndrome and indicating fasciotomy?

. Absolute pressure greater than 30 mm Hg
. Absolute pressure greater than 45 mm Hg
. Delta pressure (diastolic blood pressure minus compartment pressure) less than 30 mm Hg
. Delta pressure (mean arterial pressure minus compartment pressure) less than 40 mm Hg
. Absolute pressure greater than 20 mm Hg

Correct Answer & Explanation

. Delta pressure (diastolic blood pressure minus compartment pressure) less than 30 mm Hg

Explanation

A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mm Hg is the most reliable indicator for acute compartment syndrome. Absolute pressure thresholds can lead to over-diagnosis, especially in hypotensive patients.

Question 10344

Topic: Pelvic & Acetabular Trauma
A 28-year-old male sustains an anteroposterior compression type III (APC-III) pelvic ring injury. Initial resuscitation includes a pelvic binder. Where is the most appropriate anatomical location to center the pelvic binder to effectively reduce pelvic volume?
. Over the iliac crests
. Over the anterior superior iliac spines (ASIS)
. Directly over the greater trochanters
. Over the umbilicus
. At the level of the ischial tuberosities

Correct Answer & Explanation

. Directly over the greater trochanters

Explanation

A pelvic binder should be centered directly over the greater trochanters to effectively close the pelvic ring and reduce volume. Placement higher, such as over the iliac crests or ASIS, is less effective and can paradoxically exacerbate the deformity.

Question 10345

Topic: 2. Trauma

A 40-year-old smoker presents with a 9-month-old midshaft humeral fracture that has failed to heal following conservative management with a functional brace. Radiographs show a hypertrophic nonunion with an "elephant shoe" appearance. Which of the following best describes the primary underlying cause of this specific type of nonunion?

. Inadequate blood supply to the fracture site
. Chronic low-grade infection
. Inadequate mechanical stability
. Poor nutritional status
. Systemic nicotine toxicity

Correct Answer & Explanation

. Inadequate mechanical stability

Explanation

A hypertrophic nonunion ("elephant shoe" appearance) is characterized by abundant callus formation, indicating excellent biological potential and blood supply. The primary cause of failure to unite in this scenario is inadequate mechanical stability.

Question 10346

Topic: 2. Trauma

A 25-year-old patient suffers a severe crush injury to the hand. Clinical evaluation raises suspicion for compartment syndrome of the hand. How many distinct fascial compartments are recognized in the hand that may require release during fasciotomy?

. 4
. 7
. 10
. 12
. 14

Correct Answer & Explanation

. 10

Explanation

There are 10 recognized distinct fascial compartments in the hand that must be evaluated and potentially released during a hand fasciotomy for compartment syndrome. These are: 4 dorsal interosseous compartments, 3 volar interosseous compartments, the hypothenar compartment, the thenar compartment, and the adductor pollicis compartment.

Question 10347

Topic: 2. Trauma

A 27-year-old male presents with an isolated closed rupture of the extensor pollicis longus (EPL) tendon. Which of the following conditions or prior injuries is classically associated with this specific delayed tendon rupture?

. Scaphoid waist fracture
. Nondisplaced distal radius fracture
. Lunate dislocation
. Hook of hamate fracture
. Trapezium fracture

Correct Answer & Explanation

. Scaphoid waist fracture

Explanation

EPL rupture is a well-known complication of distal radius fractures, classically associated with nondisplaced or minimally displaced distal radius fractures. The rupture is thought to be secondary to relative ischemia in the tightly enclosed third dorsal extensor compartment due to hematoma and localized increased pressure, or mechanical attrition from fracture callus/hardware.

Question 10348

Topic: 2. Trauma

A 28-year-old industrial painter presents to the emergency room 2 hours after accidentally injecting his non-dominant index finger with a high-pressure paint gun. The entry wound is a tiny 2 mm puncture on the volar tip of the digit. The finger is swollen, pale, and mildly painful. What is the most appropriate next step in management?

. Tetanus prophylaxis, oral antibiotics, and discharge with close outpatient follow-up
. Local incision and drainage in the emergency department
. Immediate surgical exploration and wide debridement in the operating room
. Non-operative management with elevation, intravenous antibiotics, and corticosteroids
. Application of a warm compress and observation for compartment syndrome

Correct Answer & Explanation

. Immediate surgical exploration and wide debridement in the operating room

Explanation

High-pressure injection injuries are acute surgical emergencies. The injected material (such as solvents or oil-based paint) causes severe chemical irritation, tissue necrosis, and acute compartment syndrome. The entry wound is deceptive; extensive spread often occurs along flexor tendon sheaths. Prompt surgical decompression and extensive wide debridement in the OR are required to maximize the chance of digit salvage.

Question 10349

Topic: Lower Extremity Trauma

During a primary total knee arthroplasty, the surgeon evaluates the gaps and finds the knee is tight in extension and symmetrical in flexion. Which of the following is the most appropriate next step in management?

. Recut the proximal tibia with more posterior slope
. Resect more distal femur
. Upsize the femoral component
. Release the posterior cruciate ligament
. Recut the distal femur with more valgus

Correct Answer & Explanation

. Resect more distal femur

Explanation

A tight extension gap with a balanced flexion gap is treated by resecting more distal femur. This increases the extension gap without affecting the flexion gap. Recutting the tibia would affect both gaps simultaneously. Upsizing the femoral component would decrease the flexion gap. Releasing the PCL primarily affects the flexion gap (increases it).

Question 10350

Topic: 2. Trauma

A 78-year-old female sustains a periprosthetic femur fracture 10 years after a THA. Radiographs show a spiral fracture around the tip of a cemented polished taper slip stem. The stem has subsided 3 cm. The proximal femur demonstrates severe comminution and osteopenia, rendering it unsupportive. Distal bone stock is excellent. What is the most appropriate classification and treatment plan?

. Vancouver B1; ORIF with cerclage cables and locked plating
. Vancouver B2; revision to a standard length cementless porous stem
. Vancouver B2; ORIF with locked plating and allograft struts
. Vancouver B3; revision to a fully porous-coated cylindrical or fluted tapered diaphyseal-fitting stem
. Vancouver C; ORIF with locked plating distal to the stem

Correct Answer & Explanation

. Vancouver B3; revision to a fully porous-coated cylindrical or fluted tapered diaphyseal-fitting stem

Explanation

This is a Vancouver B3 fracture. The fracture is around the stem (Type B), the stem is loose as evidenced by subsidence (B2 or B3), and there is severe proximal bone loss/comminution (making it B3 rather than B2). The gold standard treatment for B3 fractures is revision bypassing the deficient proximal bone, typically using a long fluted tapered diaphyseal-engaging stem.

Question 10351

Topic: 2. Trauma

A patient presents with a periprosthetic femur fracture occurring around a loose, polished tapered slip stem, with adequate remaining bone stock. According to the Vancouver classification, what is the most appropriate management?

. Open reduction internal fixation (ORIF) with a locking plate
. Revision to a long, fully porous coated or fluted stem
. Cortical strut allograft alone
. Nonoperative management in a long leg cast
. Cerclage wiring alone

Correct Answer & Explanation

. Revision to a long, fully porous coated or fluted stem

Explanation

This is a Vancouver B2 fracture (fracture around the stem, loose stem, good bone stock). The gold standard treatment is stem revision using a long extensively porous-coated or fluted tapered modular stem that bypasses the fracture by at least two cortical diameters.

Question 10352

Topic: 2. Trauma

A 28-year-old male sustains an isolated, high-energy closed midshaft tibia fracture. He is obtunded due to a concurrent closed head injury. Which of the following parameters is widely considered the most reliable threshold to diagnose acute compartment syndrome requiring emergent fasciotomy?

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

Correct Answer & Explanation

. Absolute compartment pressure > 30 mmHg

Explanation

The delta pressure (Diastolic BP minus absolute compartment pressure) of less than 30 mmHg is the most reliable objective indicator for acute compartment syndrome. Absolute pressures can be misleading, especially in hypotensive or hypertensive patients, making delta pressure the standard indication for fasciotomy, particularly in obtunded patients.

Question 10353

Topic: 2. Trauma
According to the Gustilo-Anderson classification, a highly contaminated open diaphyseal tibia fracture presenting with extensive soft tissue stripping, but maintaining adequate local soft tissue coverage for the bone without requiring a flap, is classified as which of the following?
. Type II
. Type IIIA
. Type IIIB
. Type IIIC
. Type IV

Correct Answer & Explanation

. Type IIIA

Explanation

A Type IIIA open fracture involves extensive soft tissue laceration or stripping, often associated with high-energy trauma or severe contamination, but the bone is adequately covered by local soft tissue, precluding the need for a local or free flap. Type IIIB requires a rotational or free flap for coverage, and Type IIIC involves an arterial injury requiring repair.

Question 10354

Topic: 2. Trauma
A 35-year-old male arrives hemodynamically unstable following a motorcycle crash. Pelvic radiographs demonstrate an Anteroposterior Compression Type III (APC-III) pelvic ring disruption with a completely widened symphysis and completely disrupted sacroiliac joints. What is statistically the most common anatomical source of the massive retroperitoneal hemorrhage in this injury pattern?
. Superior gluteal artery
. Internal pudendal artery
. Posterior venous plexus and cancellous bone bleeding
. Common iliac vein laceration
. Obturator artery

Correct Answer & Explanation

. Posterior venous plexus and cancellous bone bleeding

Explanation

Despite the dramatic nature of arterial bleeding, approximately 80-90% of massive hemorrhage in severe pelvic fractures is venous in origin, primarily arising from the disrupted presacral venous plexus and the large surfaces of exposed cancellous bone at the fracture sites. Arterial bleeding accounts for the minority of cases.

Question 10355

Topic: 2. Trauma

When utilizing the 'delta pressure' concept to diagnose acute compartment syndrome, which of the following calculations is used to determine the threshold for fasciotomy?

. Systolic Blood Pressure minus Compartment Pressure
. Mean Arterial Pressure minus Compartment Pressure
. Diastolic Blood Pressure minus Compartment Pressure
. Compartment Pressure minus Venous Pressure
. Systolic Blood Pressure minus Diastolic Blood Pressure

Correct Answer & Explanation

. Systolic Blood Pressure minus Compartment Pressure

Explanation

The delta pressure is calculated as the Diastolic Blood Pressure minus the Compartment Pressure. A delta pressure of 30 mmHg or less is highly indicative of acute compartment syndrome and is a standard indication for emergent fasciotomy.

Question 10356

Topic: Pelvic & Acetabular Trauma

In the acute management of a hemodynamically unstable patient with an anteroposterior compression (APC) pelvic ring injury, what is the anatomically correct placement level for a circumferential pelvic binder?

. Anterior superior iliac spines
. Anterior inferior iliac spines
. Greater trochanters
. Iliac crests
. Pubic symphysis strictly

Correct Answer & Explanation

. Anterior superior iliac spines

Explanation

Pelvic binders must be centered over the greater trochanters to effectively reduce the pelvic volume and stabilize the fracture. Placement over the iliac crests or ASIS can paradoxically open the pelvic ring.

Question 10357

Topic: 2. Trauma
A 25-year-old male sustains a vertically oriented (Pauwels Type III) basicervical femoral neck fracture. To maximize biomechanical stability and reduce the risk of shear-induced nonunion, which of the following fixation constructs is biomechanically superior?
. Three parallel cancellous cannulated screws
. A dynamic hip screw (sliding hip screw) with a derotation screw
. Two cross-threaded cannulated screws
. An intramedullary nail with single head/neck fixation
. A unipolar hemiarthroplasty

Correct Answer & Explanation

. A dynamic hip screw (sliding hip screw) with a derotation screw

Explanation

Vertical femoral neck fractures (Pauwels Type III) experience high shear forces. A fixed-angle device like a sliding hip screw provides superior biomechanical resistance to shear and varus collapse compared to multiple cancellous screws.

Question 10358

Topic: 2. Trauma
According to the Gustilo-Anderson classification, a highly comminuted open tibia fracture resulting from a high-velocity gunshot wound with a 2-cm soft tissue laceration and adequate periosteal coverage is best classified as:
. Type I
. Type II
. Type IIIA
. Type IIIB
. Type IIIC

Correct Answer & Explanation

. Type IIIA

Explanation

High-energy injuries, highly comminuted fractures, and high-velocity gunshot wounds are automatically classified as Type III injuries regardless of the size of the wound. Because it has adequate periosteal coverage, it is classified as Type IIIA.

Question 10359

Topic: 2. Trauma

A 24-year-old male sustains bilateral closed femur fractures. On post-injury day 2, he acutely develops confusion, profound hypoxia, and a petechial rash over his axillae. Which of the following is the most appropriate initial management strategy?

. Emergent administration of high-dose systemic corticosteroids
. Intravenous heparin infusion
. Supportive care with aggressive oxygenation and mechanical ventilation
. Immediate placement of an inferior vena cava filter
. Administration of broad-spectrum antibiotics

Correct Answer & Explanation

. Emergent administration of high-dose systemic corticosteroids

Explanation

The classic triad of hypoxemia, neurologic compromise, and petechial rash strongly indicates Fat Embolism Syndrome (FES). The mainstay of treatment is supportive care, prioritizing the maintenance of adequate oxygenation and hemodynamics.

Question 10360

Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable patient with an anteroposterior compression type III (APC III) pelvic ring injury is brought to the trauma bay. A pelvic binder is applied. What is the next most appropriate orthopedic intervention if the patient remains persistently hypotensive despite fluid resuscitation?
. Application of an external fixator
. Retrograde urethrogram
. Preperitoneal pelvic packing
. Open reduction internal fixation of the symphysis
. Emergent bilateral internal iliac artery embolization

Correct Answer & Explanation

. Preperitoneal pelvic packing

Explanation

Preperitoneal pelvic packing (PPP) or pelvic angiography are the appropriate next steps for persistent hemodynamic instability. PPP is increasingly favored for rapid control of venous bleeding, which is the most common source of pelvic hemorrhage.

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