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2. Trauma MCQs

Practice Set 400 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 7981

Topic: 2. Trauma

A 33-year-old farmer sustains a Gustilo-Anderson Type IIIA open radius/ulna fracture severely contaminated with manure and soil. Based on current evidence-based guidelines, which initial intravenous antibiotic regimen is most appropriate?

. Cefazolin alone
. Cefazolin and gentamicin
. Cefazolin, gentamicin, and high-dose penicillin
. Ceftriaxone and clindamycin
. Vancomycin and piperacillin-tazobactam

Correct Answer & Explanation

. Cefazolin alone

Explanation

Heavily contaminated agricultural or soil-related open fractures carry a high risk of Clostridium perfringens infection. Guidelines recommend a first-generation cephalosporin, an aminoglycoside, and high-dose penicillin to provide adequate coverage.

Question 7982

Topic: 2. Trauma

A 35-year-old man is found unresponsive after a drug overdose, with his right leg pinned beneath his body for approximately 30 hours. The lower leg is woody, rigid, and completely insensate, with absent distal pulses. Doppler signals are absent. What is the most appropriate orthopedic management?

. Emergent four-compartment fasciotomy
. Elevation of the limb and application of ice
. Intra-arterial thrombolysis
. Observation of the leg with delayed amputation if necessary
. Immediate application of a negative pressure wound therapy device

Correct Answer & Explanation

. Emergent four-compartment fasciotomy

Explanation

This is a classic presentation of a "missed" or late compartment syndrome (>24 hours) where the muscle is already irreversibly necrotic. Performing a fasciotomy in this setting exposes dead tissue to bacteria, drastically increasing the risk of life-threatening sepsis; observation or amputation is preferred.

Question 7983

Topic: Pelvic & Acetabular Trauma

A 50-year-old male sustains a posterior wall acetabular fracture with a concomitant posterior hip dislocation. To optimally visualize the posterior wall and the anterior column of the acetabulum preoperatively, which specific radiographic view is required?

. AP Pelvis view
. Iliac oblique view
. Obturator oblique view
. Pelvic inlet view
. Pelvic outlet view

Correct Answer & Explanation

. AP Pelvis view

Explanation

The Judet obturator oblique view (the pelvis rotated 45 degrees away from the affected hip) profiles the anterior column and the posterior wall of the acetabulum. The iliac oblique view profiles the posterior column and anterior wall.

Question 7984

Topic: 2. Trauma

A surgeon is using a lateral locked plating construct to treat a comminuted supracondylar femur fracture in an osteoporotic patient. How does intentionally decreasing the working length of the plate (placing screws very close to the fracture site) alter the biomechanics of the construct?

. It decreases construct stiffness, promoting secondary bone healing
. It increases construct stiffness, increasing the risk of nonunion
. It allows for dynamic compression across the comminuted segment
. It increases fracture site micromotion, leading to hypertrophic callus
. It shields the distal locking screws from pullout forces

Correct Answer & Explanation

. It decreases construct stiffness, promoting secondary bone healing

Explanation

Decreasing the working length makes a locking plate construct overly stiff. In bridge plating of comminuted fractures, a construct that is too stiff prevents the crucial micromotion needed for secondary bone healing (callus formation), drastically increasing the risk of nonunion.

Question 7985

Topic: 2. Trauma

A 24-year-old hemodynamically stable male presents with a "floating knee" consisting of ipsilateral closed diaphyseal fractures of the femur and tibia. To optimize alignment and facilitate the surgical procedure, what is the generally recommended sequence of fixation?

. Intramedullary nailing of the tibia followed by the femur
. Intramedullary nailing of the femur followed by the tibia
. External fixation of the tibia followed by plating of the femur
. Simultaneous intramedullary nailing using a single combined approach
. Plating of the tibia followed by intramedullary nailing of the femur

Correct Answer & Explanation

. Intramedullary nailing of the tibia followed by the femur

Explanation

In a floating knee injury, stabilizing the femur first is recommended. This restores the mechanical axis of the lower extremity, simplifies patient positioning, and provides a stable counter-force for the subsequent reduction and nailing of the tibia.

Question 7986

Topic: 2. Trauma

A 25-year-old man sustains a closed Pauwels type III femoral neck fracture. Which of the following fixation constructs provides the most biomechanically stable fixation for this specific fracture pattern?

. Three parallel cancellous screws
. A sliding hip screw with a derotation screw
. A fixed-angle blade plate
. Two crossed cannulated screws
. A fully threaded 7.3 mm screw alone

Correct Answer & Explanation

. Three parallel cancellous screws

Explanation

Pauwels type III fractures have a vertical orientation resulting in high shear forces. A sliding hip screw with a derotation screw provides a fixed-angle construct that better resists these vertical shear forces compared to parallel cancellous screws.

Question 7987

Topic: 2. Trauma

A 40-year-old farmer sustains a highly contaminated Type IIIb open tibial shaft fracture from a tractor rollover. According to evidence-based guidelines, what is the most appropriate initial intravenous antibiotic regimen?

. Cefazolin alone
. Cefazolin and gentamicin
. Ceftriaxone and clindamycin
. Ceftriaxone, gentamicin, and high-dose penicillin
. Vancomycin and piperacillin-tazobactam

Correct Answer & Explanation

. Cefazolin alone

Explanation

For severe, highly contaminated open fractures with a risk of Clostridium (such as farm injuries), standard guidelines recommend a first-generation cephalosporin, an aminoglycoside, and high-dose penicillin. This provides broad-spectrum coverage and specific prophylaxis against gas gangrene.

Question 7988

Topic: 2. Trauma

A 32-year-old man presents with a closed midshaft humeral fracture after a fall. On examination, he is unable to extend his wrist or fingers, though sensation is intact. What is the most appropriate initial management?

. Immediate surgical exploration of the radial nerve
. Electromyography (EMG) and nerve conduction studies
. Functional bracing and clinical observation
. Open reduction and internal fixation with nerve exploration
. External fixation to restore length

Correct Answer & Explanation

. Immediate surgical exploration of the radial nerve

Explanation

A primary radial nerve palsy in the setting of a closed humeral shaft fracture is managed non-operatively with a functional brace and observation. Over 85% of these injuries represent neurapraxia and will recover spontaneously within 3 to 4 months.

Question 7989

Topic: 2. Trauma

A 28-year-old polytrauma patient presents with a severe closed femoral shaft fracture, multiple rib fractures, and bilateral pulmonary contusions. Initial labs reveal a serum lactate of 4.5 mmol/L and a base deficit of -8. What is the optimal surgical management of the femur fracture?

. Early total care with immediate reamed intramedullary nailing
. Early total care with unreamed intramedullary nailing
. Damage control orthopedics with spanning external fixation
. Skeletal traction for 2 weeks followed by intramedullary nailing
. Open reduction and internal fixation with a locking plate

Correct Answer & Explanation

. Early total care with immediate reamed intramedullary nailing

Explanation

This patient exhibits signs of physiologic exhaustion (elevated lactate, high base deficit) and significant thoracic trauma, making him borderline or unstable. Damage control orthopedics with rapid external fixation is indicated to stabilize the fracture while minimizing the 'second hit' of a major surgery.

Question 7990

Topic: 2. Trauma

A 38-year-old man presents with severe pain out of proportion to clinical findings 12 hours after a closed tibial shaft fracture. His diastolic blood pressure is 65 mm Hg. A needle manometer measures his anterior compartment pressure at 40 mm Hg. What is the most appropriate next step?

. Administer intravenous analgesics and elevate the leg
. Remove the splint and recheck pressure in 2 hours
. Perform a single-incision fasciotomy of the anterior compartment only
. Perform a four-compartment fasciotomy of the lower leg
. Apply ice and arrange for urgent intramedullary nailing

Correct Answer & Explanation

. Administer intravenous analgesics and elevate the leg

Explanation

The delta pressure (diastolic BP minus compartment pressure) is 25 mm Hg. A delta pressure of less than 30 mm Hg in the setting of clinical signs is diagnostic for acute compartment syndrome, requiring emergent four-compartment fasciotomy.

Question 7991

Topic: 2. Trauma

A 21-year-old male sustains a completely displaced midshaft clavicle fracture. Which of the following radiographic or clinical findings represents the strongest relative indication for operative fixation over non-operative management?

. Presence of a small butterfly fragment
. Fracture shortening of 2.5 cm
. Patient age greater than 20 years
. Medial third fracture location
. Associated non-displaced scapular body fracture

Correct Answer & Explanation

. Presence of a small butterfly fragment

Explanation

Shortening of greater than 2 cm (or 100% displacement) in midshaft clavicle fractures is a strong relative indication for surgical fixation. Operative treatment in this setting significantly decreases the risk of nonunion and symptomatic malunion.

Question 7992

Topic: 2. Trauma

A 25-year-old male sustains an isolated closed midshaft tibia fracture after a motorcycle crash. He is obtunded due to a concomitant severe traumatic brain injury. His current blood pressure is 80/50 mm Hg. The orthopedic surgeon suspects acute compartment syndrome and measures the intracompartmental pressure of the anterior leg compartment at 35 mm Hg. Which of the following is the most appropriate next step in management?

. Immediate four-compartment fasciotomy
. Observation and repeat pressure measurement in 2 hours
. Application of a long-leg cast and limb elevation
. Administration of intravenous mannitol and furosemide
. Immediate external fixation of the tibia without fasciotomy

Correct Answer & Explanation

. Immediate four-compartment fasciotomy

Explanation

Acute compartment syndrome is a clinical diagnosis, but in obtunded patients, intracompartmental pressure monitoring is required. A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mm Hg is an absolute indication for immediate fasciotomy. In this hypotensive patient, a compartment pressure of 35 mm Hg yields a delta pressure of 15 mm Hg (50 - 35), necessitating emergent surgical release.

Question 7993

Topic: 2. Trauma

A 32-year-old male sustains a Hawkins type III talar neck fracture following a fall from a height. He undergoes urgent open reduction and internal fixation. At 8 weeks postoperatively, an anteroposterior radiograph of the ankle demonstrates a subchondral radiolucent band in the talar dome. What does this radiographic finding indicate regarding the prognosis of his talus?

. Impending avascular necrosis of the talar body
. Intact vascularity to the talar body
. Nonunion of the talar neck
. Early post-traumatic osteoarthritis
. Post-traumatic osteomyelitis

Correct Answer & Explanation

. Impending avascular necrosis of the talar body

Explanation

The presence of a subchondral radiolucent band in the talar dome at 6 to 8 weeks post-injury is known as the Hawkins sign. It represents subchondral atrophy and osteopenia resulting from active hyperemia, which indicates that the vascular supply to the talar body remains intact. This reassuring finding suggests that the development of avascular necrosis is highly unlikely.

Question 7994

Topic: 2. Trauma

A 28-year-old male is brought to the trauma bay after a severe motor vehicle collision. Radiographs reveal a displaced, vertically oriented (Pauwels type III) femoral neck fracture. What is the most appropriate biomechanical construct for definitive surgical fixation of this injury to minimize the risk of varus collapse and nonunion?

. Three parallel cancellous lag screws
. A sliding hip screw (dynamic hip screw) with an anti-rotation screw
. Bipolar hemiarthroplasty
. Total hip arthroplasty
. Cephalomedullary nail with a single lag screw

Correct Answer & Explanation

. Three parallel cancellous lag screws

Explanation

Pauwels type III femoral neck fractures are characterized by a vertically oriented fracture line, creating high shear forces and a significant risk of varus displacement. In young adults, a fixed-angle construct such as a sliding hip screw with an anti-rotation screw provides superior biomechanical stability against shear forces compared to parallel cancellous screws. This approach promotes fracture compression and significantly lowers the rate of fixation failure.

Question 7995

Topic: 2. Trauma

A 28-year-old man sustains a closed right tibial shaft fracture. Two hours after admission, he complains of severe leg pain exacerbated by passive toe stretch. His blood pressure is 110/70 mm Hg. The anterior compartment pressure is measured at 45 mm Hg. Which of the following is the most appropriate next step in management?

. Elevate the leg above heart level and observe
. Administer intravenous analgesics and recheck in 2 hours
. Perform an urgent four-compartment fasciotomy
. Apply a long leg cast
. Perform closed reduction and intramedullary nailing

Correct Answer & Explanation

. Elevate the leg above heart level and observe

Explanation

The patient has a delta P (diastolic BP minus compartment pressure) of 25 mm Hg, which is highly diagnostic for acute compartment syndrome (threshold < 30 mm Hg). Urgent four-compartment fasciotomy is required to prevent irreversible muscle and nerve necrosis.

Question 7996

Topic: 2. Trauma

Which of the following fracture characteristics is the most reliable predictor of humeral head ischemia following a proximal humerus fracture?

. Metaphyseal head extension (calcar length) less than 8 mm
. Varus angulation of the surgical neck
. Greater tuberosity displacement > 1 cm
. Displacement of the lesser tuberosity
. Humeral shaft spiral extension

Correct Answer & Explanation

. Metaphyseal head extension (calcar length) less than 8 mm

Explanation

Hertel's criteria for predicting humeral head ischemia include an anatomical neck fracture, a disrupted medial hinge, and a metaphyseal head extension (calcar length) of less than 8 mm. These factors compromise the blood supply from the anterior and posterior humeral circumflex arteries.

Question 7997

Topic: 2. Trauma

A 35-year-old man is brought to the trauma bay with an APC-III pelvic ring injury and hemodynamic instability. The trauma team decides to place a circumferential pelvic binder. To be most effective, the binder should be centered over which of the following anatomic landmarks?

. Anterior superior iliac spines
. Greater trochanters
. Iliac crests
. Pubic symphysis
. Sacral promontory

Correct Answer & Explanation

. Anterior superior iliac spines

Explanation

Circumferential pelvic binders are most effective at reducing pelvic volume and stabilizing the pelvis when centered over the greater trochanters. Placement over the iliac crests is incorrect and can exacerbate certain fracture patterns.

Question 7998

Topic: 2. Trauma

A 40-year-old patient presents with a severe knee injury following a motor vehicle collision. Lateral knee radiographs reveal a coronal shear fracture of the lateral femoral condyle. Which of the following best describes this fracture pattern and its optimal fixation?

. Barton fracture; dorsal buttress plate
. Hoffa fracture; anterior-to-posterior (AP) or posterior-to-anterior (PA) interfragmentary screws
. Schatzker type IV fracture; medial buttress plate
. Chauffeur's fracture; percutaneous pinning
. Tillaux fracture; anterior syndesmotic screw

Correct Answer & Explanation

. Barton fracture; dorsal buttress plate

Explanation

A coronal shear fracture of the femoral condyle is known as a Hoffa fracture. It is inherently unstable and typically requires open reduction and internal fixation using AP or PA lag screws to compress the articular surface.

Question 7999

Topic: 2. Trauma

A 45-year-old man sustains a Gustilo-Anderson Type IIIB open tibial shaft fracture. According to recent literature, which of the following interventions has the greatest impact on reducing his risk of deep infection?

. Time to initial surgical debridement < 6 hours
. Time to administration of systemic intravenous antibiotics
. Application of negative pressure wound therapy in the emergency department
. Immediate definitive intramedullary nailing
. Use of high-pressure pulsatile lavage

Correct Answer & Explanation

. Time to initial surgical debridement < 6 hours

Explanation

The most critical factor in reducing the risk of infection in open fractures is the early administration of systemic antibiotics, ideally within 1 hour of injury. The '6-hour rule' for surgical debridement is less supported by current evidence compared to prompt antibiotic delivery.

Question 8000

Topic: 2. Trauma

When stabilizing an intertrochanteric femur fracture with a cephalomedullary nail, the concept of the tip-apex distance (TAD) is critical to prevent hardware failure. A TAD greater than which of the following thresholds is associated with a significantly increased risk of lag screw cut-out?

. 10 mm
. 15 mm
. 20 mm
. 25 mm
. 35 mm

Correct Answer & Explanation

. 10 mm

Explanation

A tip-apex distance (TAD) greater than 25 mm is a strong predictor of lag screw cut-out in the treatment of intertrochanteric hip fractures. The measurement is the sum of the distance from the tip of the screw to the apex of the femoral head on both AP and lateral radiographs.

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