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2. Trauma MCQs

Practice Set 416 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 8301

Topic: 2. Trauma

A 25-year-old male is admitted with a severe closed midshaft tibia fracture. Twelve hours later, he reports severe, escalating leg pain that is unresponsive to intravenous opioids and is exacerbated by passive stretch of his great toe. His compartment pressures are measured. Which of the following parameters represents an absolute indication for emergency four-compartment fasciotomy?

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

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The differential pressure (Delta P), calculated as the diastolic blood pressure minus the absolute compartment pressure, is the most reliable diagnostic metric for acute compartment syndrome. A Delta P of less than 30 mmHg strongly indicates impaired capillary perfusion and represents an absolute indication for emergent fasciotomy.

Question 8302

Topic: 2. Trauma
A 25-year-old healthy male sustains a vertically oriented basicervical femoral neck fracture (Pauwels type III) after a fall from a roof. The fracture is successfully closed reduced. Which of the following internal fixation constructs offers the highest biomechanical stability against vertical shear forces for this specific fracture pattern?
. Three parallel cancellous lag screws in an inverted triangle configuration
. A sliding hip screw (dynamic hip screw) with an anti-rotation screw
. Two parallel cancellous lag screws
. A cephalomedullary nail utilizing a single proximal lag screw
. A fully threaded cannulated screw construct

Correct Answer & Explanation

. A sliding hip screw (dynamic hip screw) with an anti-rotation screw

Explanation

Pauwels type III (vertically oriented) femoral neck fractures in young adults are subjected to massive vertical shear forces, leading to a high rate of nonunion and varus collapse. Biomechanical studies demonstrate that fixed-angle devices, such as a sliding hip screw (DHS), offer superior resistance to these shear forces compared to multiple cancellous screws. An anti-rotation screw is often added to control rotational forces.

Question 8303

Topic: 2. Trauma

A 45-year-old male with poorly controlled type 2 diabetes presents with a highly comminuted, displaced tibial pilon fracture (OTA/AO 43-C3). On presentation, he has severe soft tissue swelling, skin tension, and fracture blisters. He undergoes initial spanning external fixation with fibular stabilization. What is the optimal clinical indicator that dictates the appropriate timing for definitive open reduction and internal fixation (ORIF) of the pilon?

. Definitive fixation within 24 hours to prevent soft tissue contracture
. When the fracture blisters have ruptured and begun to re-epithelialize
. Resolution of edema indicated by the return of skin wrinkles
. After 6 weeks of external fixation to allow for early soft callus formation
. After a negative wound culture is obtained from blister fluid

Correct Answer & Explanation

. Resolution of edema indicated by the return of skin wrinkles

Explanation

High-energy pilon fractures are fraught with severe soft-tissue complications, including catastrophic wound dehiscence and deep infection. The standard of care is staged management. Definitive ORIF should be delayed until the soft-tissue envelope has sufficiently recovered, which is clinically indicated by the resolution of edema and the appearance of the "wrinkle sign" (return of normal skin wrinkles), typically taking 10 to 21 days.

Question 8304

Topic: 2. Trauma
A 45-year-old male is brought to the trauma bay following a high-speed motorcycle collision. He is diagnosed with an APC III (anteroposterior compression type III) pelvic ring injury. Despite the application of a pelvic binder, 2 liters of warmed crystalloid, and 2 units of uncrossmatched packed red blood cells, his blood pressure remains 80/50 mm Hg with a heart rate of 130 bpm. A FAST (Focused Assessment with Sonography for Trauma) exam is negative. What is the most appropriate next step in the management of this patient?
. CT scan of the abdomen and pelvis
. Retrograde urethrogram to rule out urethral injury
. Preperitoneal pelvic packing and/or pelvic angiography
. Exploratory laparotomy
. Application of an anterior supra-acetabular external fixator

Correct Answer & Explanation

. Preperitoneal pelvic packing and/or pelvic angiography

Explanation

This patient has a hemodynamically unstable pelvic ring injury with a negative FAST exam, ruling out major intra-abdominal hemorrhage as the primary cause of shock. According to advanced trauma life support (ATLS) and orthopedic trauma protocols, after mechanical stabilization with a binder (or sheet), patients who remain hemodynamically unstable require immediate hemorrhage control. This is best achieved through preperitoneal pelvic packing (PPP) and/or pelvic angiography with embolization. CT scanning is contraindicated in a hemodynamically unstable patient. Exploratory laparotomy is not indicated with a negative FAST, as entering the peritoneum can release the tamponade effect on a retroperitoneal pelvic hematoma.

Question 8305

Topic: 2. Trauma
A 28-year-old female sustains a vertical, displaced femoral neck fracture (Pauwels type III) during a fall from a height. She is taken to the operating room for definitive fixation. Which of the following fixation constructs provides the greatest biomechanical stability and highest load-to-failure for this specific fracture pattern?
. Three parallel cancellous screws in an inverted triangle configuration
. Three parallel cancellous screws in a standard triangle configuration
. A sliding hip screw (fixed-angle device) with a derotational screw
. A standard trochanteric entry cephalomedullary nail
. Unipolar hemiarthroplasty

Correct Answer & Explanation

. A sliding hip screw (fixed-angle device) with a derotational screw

Explanation

Pauwels type III femoral neck fractures are characterized by a highly vertical fracture line (angle > 50 degrees), which subjects the fracture site to tremendous shear forces during weight-bearing. Biomechanical studies have consistently demonstrated that a fixed-angle construct, such as a sliding hip screw (SHS), provides superior biomechanical stability against vertical shear compared to multiple cancellous screws. To prevent rotation of the femoral head during insertion and load-bearing, a supplemental derotational screw is typically placed proximal to the SHS. Cancellous screws alone have a high rate of failure in vertical fracture patterns.

Question 8306

Topic: 2. Trauma

A 78-year-old independent female with a 15-year history of severe rheumatoid arthritis falls onto her flexed elbow. Radiographs reveal a highly comminuted, intra-articular distal humerus fracture (OTA/AO type 13C3) with severe osteopenia. What is the most appropriate definitive management to maximize early function and minimize the need for revision surgery?

. Hinged external fixation of the elbow
. Open reduction and internal fixation with dual orthogonal plates
. Open reduction and internal fixation with dual parallel plates
. Total elbow arthroplasty
. Hemiarthroplasty of the elbow

Correct Answer & Explanation

. Total elbow arthroplasty

Explanation

In elderly patients with poor bone stock (osteopenia/osteoporosis) and pre-existing inflammatory arthritis (such as rheumatoid arthritis), highly comminuted distal humerus fractures (OTA/AO 13C3) are notoriously difficult to reconstruct securely with Open Reduction and Internal Fixation (ORIF). Total Elbow Arthroplasty (TEA) is the treatment of choice in this demographic. Evidence shows that TEA in this specific patient population provides more predictable clinical outcomes, allows for immediate postoperative mobilization, and has a lower rate of reoperation and failure compared to ORIF.

Question 8307

Topic: 2. Trauma

A 40-year-old pedestrian is struck by a vehicle and sustains a severe, high-energy bicondylar tibial plateau fracture with metaphyseal-diaphyseal dissociation (Schatzker VI). Clinical examination reveals tense, severe swelling and extensive fracture blisters over the proximal leg. What is the most appropriate initial management?

. Immediate single-incision ORIF with a lateral locked plate
. Immediate dual-incision ORIF with medial and lateral plates
. Knee-spanning external fixation and delayed definitive ORIF
. Primary amputation due to the high risk of acute compartment syndrome
. Application of a well-molded long leg cast

Correct Answer & Explanation

. Knee-spanning external fixation and delayed definitive ORIF

Explanation

High-energy tibial plateau fractures (Schatzker VI) are associated with massive soft-tissue trauma. Early definitive open reduction and internal fixation (ORIF) through compromised soft tissues (swelling, fracture blisters) is associated with an unacceptably high rate of catastrophic complications, including deep infection and wound dehiscence. The standard 'damage control orthopedics' approach is the application of a knee-spanning external fixator to restore length, alignment, and joint distraction. Definitive ORIF is delayed until the soft tissue envelope recovers, which is typically indicated by the resolution of swelling and the appearance of skin wrinkling (often 10 to 21 days later).

Question 8308

Topic: 2. Trauma
A 25-year-old farmer sustains a severe open tibia fracture after a tractor rollover. The wound is 12 cm long with extensive muscle damage, heavy soil contamination, and exposed bone stripped of periosteum requiring a rotational flap for coverage (Gustilo-Anderson IIIB). Upon arrival in the emergency department, which of the following prophylactic antibiotic regimens is most traditionally appropriate?
. A first-generation cephalosporin alone
. A first-generation cephalosporin and an aminoglycoside
. A first-generation cephalosporin, an aminoglycoside, and high-dose penicillin
. Vancomycin alone
. Ciprofloxacin and clindamycin

Correct Answer & Explanation

. A first-generation cephalosporin, an aminoglycoside, and high-dose penicillin

Explanation

For severe open fractures (Gustilo-Anderson type III), coverage for both Gram-positive and Gram-negative organisms is required, typically achieved with a first-generation cephalosporin (e.g., cefazolin) and an aminoglycoside (e.g., gentamicin). Because this injury occurred in a farm environment and involves heavy soil contamination and devitalized muscle, there is a high risk of anaerobic infection, specifically Clostridium perfringens. Therefore, the addition of high-dose penicillin is required for anaerobic coverage. While contemporary guidelines sometimes utilize ceftriaxone in place of the aminoglycoside, the classic triad of a cephalosporin, aminoglycoside, and penicillin remains the gold standard for farm-related/highly contaminated type III open fractures on board examinations.

Question 8309

Topic: 2. Trauma

A 35-year-old construction worker falls from a height of 15 feet, sustaining a closed, displaced, intra-articular calcaneus fracture (Sanders Type II). He is scheduled for ORIF via an extensile lateral approach. Which of the following strategies is most critical for decreasing the risk of postoperative wound complications?

. Performing the surgery within 24 hours of the initial injury
. Delaying surgery until the 'wrinkle sign' is present on the lateral heel
. Making the vertical limb of the incision anterior to the fibula
. Using a tourniquet for the entire duration of the procedure
. Creating a thin skin flap to avoid subperiosteal dissection

Correct Answer & Explanation

. Delaying surgery until the 'wrinkle sign' is present on the lateral heel

Explanation

Wound complications (dehiscence, infection) are the most frequent major complications associated with the extensile lateral approach for calcaneus fractures, occurring in up to 10-25% of cases. The most critical factor in minimizing this risk is appropriate surgical timing. Surgery must be delayed until the severe soft tissue swelling has subsided, which is clinically indicated by the return of normal skin creases or the 'wrinkle sign' (often 1 to 3 weeks post-injury). The flap created should be a full-thickness, 'no-touch' subperiosteal flap to preserve the precarious vascular supply (calcaneal branches of the peroneal and posterior tibial arteries) to the L-shaped corner.

Question 8310

Topic: 2. Trauma

A 55-year-old male presents with a pelvic injury following a motor vehicle collision. Standard AP and Judet views of the pelvis are obtained. On the obturator oblique radiograph, an intact segment of the ilium attached to the axial skeleton is visible, while the articular surface of the acetabulum is completely separated from it, creating a classic 'spur sign'. This radiographic finding is pathognomonic for which type of acetabular fracture?

. Anterior column posterior hemitransverse fracture
. Transverse fracture
. T-type fracture
. Both column fracture
. Posterior column fracture

Correct Answer & Explanation

. Both column fracture

Explanation

The 'spur sign' is a pathognomonic radiographic sign seen on the obturator oblique view of the pelvis in 'Both Column' acetabular fractures (a type of associated fracture in the Judet-Letournel classification). It represents the inferior-most aspect of the intact ilium that remains attached to the axial skeleton (the 'spur'), while the entire articular surface of the acetabulum (both anterior and posterior columns) is fractured and medially displaced. In a both column fracture, no part of the articular surface remains attached to the intact axial skeleton.

Question 8311

Topic: 2. Trauma

A 24-year-old male undergoes intramedullary nailing of a closed diaphyseal tibia fracture. Six hours postoperatively, he complains of agonizing leg pain requiring rapidly escalating doses of IV narcotics. The pain is severely exacerbated by passive extension of the hallux. His blood pressure is 110/75 mm Hg. Intracompartmental pressure monitoring of the anterior compartment reveals a pressure of 55 mm Hg. What is the most appropriate definitive management?

. Elevate the leg above the level of the heart to decrease swelling
. Administer a bolus of IV mannitol to decrease compartment edema
. Remove the intramedullary nail and place a spanning external fixator
. Perform immediate four-compartment fasciotomies of the leg
. Observe closely and repeat pressure measurements in 4 hours

Correct Answer & Explanation

. Perform immediate four-compartment fasciotomies of the leg

Explanation

This patient exhibits classic signs of acute compartment syndrome: pain out of proportion to the injury, increasing narcotic requirement, pain with passive stretch (hallux extension stretches the extensor hallucis longus in the anterior compartment), and a dangerous Delta pressure. The Delta pressure (Diastolic BP minus compartment pressure) is 75 - 55 = 20 mm Hg. A Delta pressure of less than 30 mm Hg is an absolute indication for surgical decompression. The definitive treatment is immediate four-compartment fasciotomy. Leg elevation is contraindicated as it further decreases arterial perfusion pressure to the ischemic compartment.

Question 8312

Topic: 2. Trauma
A 32-year-old male sustains a closed, isolated Pauwels type III (vertical shear) femoral neck fracture following a high-energy fall. You are planning definitive surgical intervention. Which of the following internal fixation constructs provides the greatest biomechanical stability for this specific fracture pattern?
. Three parallel cannulated cancellous screws in an inverted triangle configuration
. Three parallel cannulated cancellous screws in a standard triangle configuration
. A sliding hip screw (SHS) combined with a derotation screw
. Two fully threaded cortical lag screws
. A dynamic condylar screw (DCS)

Correct Answer & Explanation

. A sliding hip screw (SHS) combined with a derotation screw

Explanation

Pauwels type III femoral neck fractures are characterized by a vertically oriented fracture line (typically >50 degrees from the horizontal). This vertical orientation subjects the fracture to immense shear forces and a high risk of varus collapse, nonunion, and fixation failure. Biomechanical studies have consistently shown that fixed-angle constructs, such as a sliding hip screw (SHS) combined with a derotation screw to control rotational forces, provide superior biomechanical stability and a higher load-to-failure rate compared to multiple parallel cancellous screws for vertically oriented femoral neck fractures.

Question 8313

Topic: 2. Trauma
A 42-year-old construction worker sustains an open middle-third tibia fracture (Gustilo-Anderson IIIB) after being struck by heavy machinery. Following serial thorough surgical debridements, the wound is clean and free of necrotic tissue, but there remains a 7 cm by 5 cm anterior soft tissue defect with exposed tibial bone devoid of periosteum. What is the most appropriate method for providing soft-tissue coverage of this specific defect?
. Medial gastrocnemius rotational muscle flap
. Lateral gastrocnemius rotational muscle flap
. Soleus rotational muscle flap
. Free latissimus dorsi muscle flap
. Split-thickness skin grafting directly over the bone

Correct Answer & Explanation

. Soleus rotational muscle flap

Explanation

Soft-tissue coverage for exposed tibial bone (Gustilo-Anderson type IIIB injuries) is dictated by the anatomic zone of the defect. The lower extremity is traditionally divided into thirds for flap selection. Proximal-third tibial defects are classically covered using a medial (or lateral) gastrocnemius rotational flap. Middle-third defects are optimally managed with a soleus muscle rotational flap. Distal-third defects generally lack adequate local muscle bulk and therefore typically require a free tissue transfer (e.g., free latissimus dorsi or anterolateral thigh flap). Split-thickness skin grafts require a vascularized bed and cannot survive on bare bone without periosteum.

Question 8314

Topic: 2. Trauma

A 72-year-old female with a 20-year history of severe rheumatoid arthritis presents to the emergency department after a mechanical fall onto her left arm. Radiographs demonstrate a closed, severely comminuted intra-articular fracture of the distal humerus (OTA/AO type 13C3) with profound osteopenia.

Given the patient's age, bone quality, and medical comorbidities, what is the most appropriate definitive surgical intervention?

. Open reduction and internal fixation with orthogonal locking plates
. Open reduction and internal fixation with parallel locking plates
. Total elbow arthroplasty
. Closed reduction and percutaneous pinning
. Olecranon osteotomy and spanning external fixation

Correct Answer & Explanation

. Total elbow arthroplasty

Explanation

While open reduction and internal fixation (ORIF) with dual plating (parallel or orthogonal) remains the standard of care for most displaced distal humerus fractures in younger patients, total elbow arthroplasty (TEA) is the treatment of choice for elderly patients with severe intra-articular comminution (such as OTA 13C3), severely osteoporotic bone, or pre-existing inflammatory arthritis (e.g., rheumatoid arthritis). In this specific demographic, TEA provides a more predictable recovery, allows for immediate postoperative weight-bearing and range of motion, and demonstrates a lower rate of reoperation for fixation failure compared to ORIF, which struggles to obtain adequate purchase in osteoporotic, rheumatoid bone.

Question 8315

Topic: Pelvic & Acetabular Trauma

A 35-year-old male is brought to the ED after a motorcycle collision. He is hypotensive with a systolic BP of 70 mmHg. Primary survey reveals an unstable pelvis. Radiographs show a widened pubic symphysis of 4 cm and disruption of the anterior and posterior sacroiliac ligaments. A pelvic binder is to be applied to temporarily stabilize the pelvis. To achieve optimal reduction of pelvic volume and mechanical stability, where should the pelvic binder be centered?

. Over the iliac crests
. Over the greater trochanters
. Over the anterior superior iliac spines
. Over the lumbar spine
. Directly over the pubic symphysis

Correct Answer & Explanation

. Over the greater trochanters

Explanation

To optimally reduce pelvic volume and control hemorrhage in anterior-posterior compression (APC) pelvic ring injuries, a pelvic binder or sheet must be centered directly over the greater trochanters. Placement over the iliac crests is a common error and can paradoxically increase the pelvic volume by pushing the iliac wings inward at the top and outward at the bottom, worsening bleeding.

Question 8316

Topic: 2. Trauma

A 28-year-old man sustains a closed midshaft tibia fracture. Four hours post-injury, he complains of worsening leg pain out of proportion to the injury, not relieved by intravenous opioids. On examination, there is severe pain with passive stretch of the hallux. The most reliable diagnostic parameter for acute compartment syndrome is:

. Absolute compartment pressure greater than 30 mmHg
. Absolute compartment pressure greater than 45 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 40 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure less than 30 mmHg

Explanation

The most reliable parameter for diagnosing acute compartment syndrome is a delta pressure (diastolic blood pressure minus absolute compartment pressure) of less than 30 mmHg. Relying on an absolute pressure threshold (e.g., 30 mmHg) can lead to overdiagnosis and unnecessary fasciotomies, especially in hypertensive or hypotensive patients.

Question 8317

Topic: 2. Trauma
A 25-year-old man sustains a high-energy Pauwels type III (vertical shear) femoral neck fracture. To maximize biomechanical stability and minimize the risk of varus collapse, which of the following fixation constructs is most appropriate?
. Three parallel cancellous lag screws in an inverted triangle configuration
. Sliding hip screw (SHS) with an anti-rotation screw
. Fully threaded cancellous screws placed parallel to the femoral neck
. Flexible intramedullary nails
. Bipolar hemiarthroplasty

Correct Answer & Explanation

. Sliding hip screw (SHS) with an anti-rotation screw

Explanation

Pauwels type III femoral neck fractures in young adults are characterized by a vertically oriented fracture line, predisposing the hip to high shear forces and varus collapse. Biomechanical studies have consistently shown that a fixed-angle construct, such as a sliding hip screw (often supplemented with an anti-rotation screw), provides superior construct stiffness and resistance to vertical shear forces compared to multiple parallel cancellous screws.

Question 8318

Topic: 2. Trauma
A 42-year-old construction worker sustains a Gustilo-Anderson IIIB open tibia fracture with a 10 cm soft tissue defect over the middle third of the tibia, exposing the bone devoid of periosteum. Following serial debridement, skeletal stabilization, and negative pressure wound therapy, definitive soft-tissue coverage is planned. The most appropriate local flap choice for this specific defect is:
. Gastrocnemius rotational flap
. Soleus rotational flap
. Reverse superficial sural artery flap
. Fibularis brevis rotational flap
. Gracilis free flap

Correct Answer & Explanation

. Soleus rotational flap

Explanation

For soft tissue coverage of the lower extremity, the leg is classically divided into thirds. The proximal third is typically covered by a gastrocnemius rotational flap. The middle third is best covered by a soleus rotational flap. The distal third generally requires a free tissue transfer or a reverse sural artery flap, as local muscle bellies do not provide adequate distal reach.

Question 8319

Topic: 2. Trauma

A 45-year-old male sustains a distal femur fracture following a motor vehicle collision. CT imaging reveals an isolated coronal plane fracture of the lateral femoral condyle. Which surgical approach provides the best visualization to anatomically reduce this specific articular fracture fragment?

. Standard medial parapatellar approach
. Direct lateral approach to the distal femur
. Posterior approach to the popliteal fossa
. Swashbuckler approach
. Medial subvastus approach

Correct Answer & Explanation

. Swashbuckler approach

Explanation

A coronal plane fracture of the femoral condyle is known as a Hoffa fracture, with the lateral condyle being the most commonly affected. To adequately visualize the intra-articular surface and ensure anatomic reduction of the lateral Hoffa fragment, the "Swashbuckler" approach (a modified lateral approach involving reflection of the vastus lateralis from the lateral intermuscular septum) is utilized. A standard direct lateral approach is insufficient for viewing the complex intra-articular reduction.

Question 8320

Topic: 2. Trauma

A 68-year-old woman with a 10-year history of alendronate therapy presents with progressively worsening right thigh pain for 3 months. Radiographs demonstrate focal cortical thickening of the lateral cortex of the subtrochanteric right femur with a transverse radiolucent "dreaded black line." The patient denies any trauma. What is the most appropriate next step in management?

. Discontinue alendronate, begin protected weight-bearing, and obtain radiographs of the contralateral femur
. Continue alendronate and schedule for isolated plate osteosynthesis
. Discontinue alendronate and switch to teriparatide exclusively without surgical intervention
. Discontinue alendronate, schedule for prophylactic full-length intramedullary nailing, and obtain radiographs of the contralateral femur
. Discontinue alendronate and perform a core decompression of the symptomatic lesion

Correct Answer & Explanation

. Discontinue alendronate, schedule for prophylactic full-length intramedullary nailing, and obtain radiographs of the contralateral femur

Explanation

This patient presents with a symptomatic impending atypical femur fracture (AFF) associated with long-term bisphosphonate use. The "dreaded black line" indicates a stress fracture. Due to the high risk of completion, symptomatic impending AFFs should be treated with prophylactic full-length intramedullary nailing. Alendronate must be discontinued, and because these lesions are frequently bilateral, imaging of the contralateral femur is absolutely mandatory.

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