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2. Trauma MCQs

Practice Set 312 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 6221

Topic: Pelvic & Acetabular Trauma
A 45-year-old man is brought to the emergency department after falling from a 20-foot scaffold. He is hemodynamically unstable with a blood pressure of 80/40 mm Hg. Radiographs reveal an APC-III pelvic ring injury. A pelvic binder is to be applied. What is the most appropriate anatomical landmark for the optimal placement of the pelvic binder to effectively reduce pelvic volume?
. Iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Symphysis pubis
. Umbilicus

Correct Answer & Explanation

. Greater trochanters

Explanation

The optimal placement of a pelvic binder or sheet is centered over the greater trochanters. Biomechanical and clinical studies have shown that placing the binder at the level of the greater trochanters most effectively closes the pelvic ring and reduces pelvic volume. Placement higher, such as over the iliac crests or ASIS, is less effective and may paradoxically widen the pelvis in certain fracture patterns.

Question 6222

Topic: Upper Extremity Trauma

A 22-year-old motorcycle rider is ejected and sustains a massive traction injury to his right upper extremity. Physical examination reveals a completely flail, anesthetic right arm, and severe swelling over the shoulder girdle. Radiographs show significant lateral displacement of the scapula relative to the spinous processes, an intact clavicle, and disruption of the acromioclavicular joint. What is the most likely associated limb-threatening vascular injury?

. Axillary artery transection
. Subclavian artery disruption
. Brachial artery thrombosis
. Thoracoacromial trunk avulsion
. Internal thoracic artery rupture

Correct Answer & Explanation

. Subclavian artery disruption

Explanation

Scapulothoracic dissociation is a high-energy closed traction injury characterized by complete disruption of the scapulothoracic articulation. It is often accompanied by devastating injuries to the brachial plexus and the subclavian or axillary vessels. The subclavian artery is particularly vulnerable as it is tethered over the first rib and under the clavicle, making it the most common critical vascular injury associated with this pattern.

Question 6223

Topic: 2. Trauma
A 35-year-old man sustains a completely displaced, vertically oriented (Pauwels Type III) femoral neck fracture after a fall from a roof. Which of the following fixation constructs offers the greatest biomechanical stability and highest rate of union for this specific fracture pattern?
. Three parallel cannulated cancellous screws
. A sliding hip screw with an anti-rotation screw
. Two fully threaded cortical screws
. Bipolar hemiarthroplasty
. Total hip arthroplasty

Correct Answer & Explanation

. A sliding hip screw with an anti-rotation screw

Explanation

Young patients with displaced, high-shear (Pauwels Type III) femoral neck fractures require rigid fixation to prevent shear displacement at the fracture site. Biomechanical studies have shown that fixed-angle constructs, such as a sliding hip screw with a derotational screw, provide superior biomechanical stability compared to three parallel cannulated screws for vertical fracture patterns, leading to lower rates of nonunion and displacement.

Question 6224

Topic: 2. Trauma

A 27-year-old man sustains a closed midshaft tibia fracture treated with intramedullary nailing. Postoperatively, he develops severe pain out of proportion to the injury, significantly worsened by passive stretch of the hallux. His blood pressure is 110/70 mm Hg. Intracompartmental pressure monitoring is performed. Which of the following pressure readings most strongly dictates the need for an emergent four-compartment fasciotomy?

. Absolute anterior compartment pressure of 25 mm Hg
. Absolute deep posterior compartment pressure of 28 mm Hg
. Delta pressure (Diastolic BP - compartment pressure) of 25 mm Hg
. Delta pressure (Mean Arterial BP - compartment pressure) of 45 mm Hg
. Delta pressure (Systolic BP - compartment pressure) of 40 mm Hg

Correct Answer & Explanation

. Delta pressure (Diastolic BP - compartment pressure) of 25 mm Hg

Explanation

The decision to perform a fasciotomy for acute compartment syndrome is largely based on clinical signs, but when measuring pressures, the 'delta pressure' is the most reliable indicator. A delta pressure (Diastolic Blood Pressure minus Intracompartmental Pressure) of 30 mm Hg or less is the widely accepted threshold for diagnosing compartment syndrome and indicating the need for emergent fasciotomy.

Question 6225

Topic: 2. Trauma

A 30-year-old man presents with a gunshot wound to the distal thigh. He has an expanding hematoma, absent popliteal and pedal pulses, and a comminuted fracture of the distal femoral diaphysis. In the operating room, what is the most appropriate sequence of management?

. Definitive internal fixation followed by vascular repair
. Vascular repair followed by definitive internal fixation
. Temporary vascular shunting, followed by external fixation, then definitive vascular repair
. Fasciotomies, definitive internal fixation, followed by vascular shunting
. Primary amputation

Correct Answer & Explanation

. Temporary vascular shunting, followed by external fixation, then definitive vascular repair

Explanation

In the setting of a combined skeletal and arterial injury with hard signs of ischemia, minimizing ischemic time is paramount. The recommended sequence is the placement of a temporary intravascular shunt to rapidly restore perfusion, followed by quick skeletal stabilization (often with external fixation), and finally definitive vascular repair. This sequence limits total warm ischemia time and prevents disruption of the vascular repair during orthopedic manipulation.

Question 6226

Topic: 2. Trauma
A 40-year-old pedestrian is struck by a car and sustains a Gustilo-Anderson Type IIIB open fracture of the distal third of the tibia. Following serial thorough debridement and skeletal stabilization with an external fixator, the wound requires soft tissue coverage. Which of the following is the most appropriate flap option for a large defect over the distal third of the tibia?
. Gastrocnemius rotational flap
. Soleus rotational flap
. Free tissue transfer (e.g., anterolateral thigh or latissimus dorsi flap)
. Sural artery fasciocutaneous flap
. Split-thickness skin graft directly over bare bone

Correct Answer & Explanation

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

Explanation

Soft tissue coverage of the tibia is dictated by the anatomical location of the defect. The proximal third is typically covered by a gastrocnemius rotational flap. The middle third is covered by a soleus rotational flap. The distal third of the tibia lacks adequate local muscle bulk for rotational flaps and usually requires a free tissue transfer (free flap) such as an anterolateral thigh (ALT) or latissimus dorsi flap.

Question 6227

Topic: 2. Trauma

A 25-year-old man falls from a height and sustains a displaced fracture of the talar neck. He undergoes open reduction and internal fixation. At the 8-week postoperative visit, an anteroposterior radiograph of the ankle reveals subchondral radiolucency in the dome of the talus. What does this radiographic finding indicate?

. Avascular necrosis of the talar body
. Hyperemic bone resorption indicating viability of the talar body
. Nonunion of the talar neck
. Early post-traumatic osteoarthritis
. Osteomyelitis of the talus

Correct Answer & Explanation

. Hyperemic bone resorption indicating viability of the talar body

Explanation

The presence of a subchondral radiolucent line in the dome of the talus at 6 to 8 weeks post-injury is known as the Hawkins sign. It represents subchondral osteopenia secondary to hyperemia and disuse. The presence of a positive Hawkins sign is a highly reliable indicator that the talar body has maintained its vascular supply and is unlikely to develop avascular necrosis.

Question 6228

Topic: Pelvic & Acetabular Trauma
A 42-year-old construction worker is crushed by a heavy machine. On arrival, his blood pressure is 70/40 mmHg. A FAST examination is positive for intra-abdominal fluid, and a portable pelvic radiograph shows a widened pubic symphysis with disruption of the posterior sacroiliac complex (APC III injury). A commercial pelvic binder is ordered. To optimally reduce the pelvic volume and stabilize the fracture, the binder should be centered over which of the following anatomic landmarks?
. The anterior superior iliac spines
. The iliac crests
. The greater trochanters
. The pubic symphysis directly
. The mid-lumbar spine

Correct Answer & Explanation

. The greater trochanters

Explanation

For emergent stabilization of an unstable pelvic ring injury, pelvic binders or sheets should be centered strictly over the greater trochanters. Placement higher over the iliac crests or anterior superior iliac spines is less effective at reducing pelvic volume, can paradoxically open the true pelvis further in some fracture patterns, and may restrict abdominal access for exploratory laparotomy.

Question 6229

Topic: 2. Trauma

A 28-year-old male is admitted to the intensive care unit with a closed midshaft tibia fracture and a severe closed head injury. He is intubated and obtunded. His current blood pressure is 110/70 mmHg. Due to a tense leg on examination, intracompartmental pressure monitoring is initiated. Which of the following thresholds is the most widely accepted absolute indication for a four-compartment fasciotomy in this patient?

. An absolute compartment pressure of 25 mmHg
. An absolute compartment pressure of 30 mmHg
. A delta pressure (Diastolic BP minus compartment pressure) of less than 30 mmHg
. A delta pressure (Mean Arterial Pressure minus compartment pressure) of less than 40 mmHg
. A delta pressure (Systolic BP minus compartment pressure) of less than 30 mmHg

Correct Answer & Explanation

. A delta pressure (Diastolic BP minus compartment pressure) of less than 30 mmHg

Explanation

In an obtunded or uncooperative patient, compartment pressure monitoring is indicated if clinical suspicion is high. The absolute pressure is less reliable than the delta pressure (perfusion pressure). McQueen et al. demonstrated that a delta pressure (calculated as Diastolic Blood Pressure minus the intracompartmental pressure) of less than 30 mmHg is the most reliable threshold to indicate the need for fasciotomy, minimizing missed cases and unnecessary surgeries.

Question 6230

Topic: 2. Trauma

A 22-year-old motorcyclist is thrown from his bike at highway speeds. A chest radiograph in the trauma bay reveals lateral displacement of the right scapula and a widely displaced midshaft clavicle fracture. Examination of the right upper extremity shows absent pulses, pallor, and a complete lack of motor and sensory function throughout the limb. Which of the following is the most likely neurologic injury associated with this clinical picture?

. Isolated axillary nerve transection
. Complete brachial plexus avulsion
. Isolated musculocutaneous nerve palsy
. Phrenic nerve avulsion
. Spinal accessory nerve transection

Correct Answer & Explanation

. Complete brachial plexus avulsion

Explanation

This clinical picture describes scapulothoracic dissociation, a severe, high-energy traction injury characterized by lateral displacement of the scapula with intact skin. It is frequently accompanied by a fractured clavicle or AC/SC joint disruptions. It carries a dismal prognosis for the upper extremity due to the extremely high rate of complete brachial plexus avulsions and concomitant subclavian or axillary vascular injuries. An isolated nerve injury is incorrect given the complete loss of sensory and motor function.

Question 6231

Topic: 2. Trauma
A 38-year-old man sustains a Gustilo-Anderson type IIIB open fracture of the proximal third of the tibia after a severe crush injury. Following aggressive surgical debridement, there is a 6 cm by 5 cm anterior soft-tissue defect exposing bare bone devoid of periosteum. Which of the following is the most appropriate soft-tissue coverage option for this specific anatomic location?
. Soleus rotational muscle flap
. Gastrocnemius rotational muscle flap
. Anterolateral thigh free flap
. Sural artery fasciocutaneous flap
. Reverse flow sural nerve flap

Correct Answer & Explanation

. Gastrocnemius rotational muscle flap

Explanation

For soft-tissue coverage of the lower extremity, local rotational flaps are often selected based on the level of the defect. The classic algorithm utilizes the medial or lateral gastrocnemius rotational flap for defects of the proximal third of the tibia. For the middle third, the soleus flap is preferred. For the distal third, there is insufficient local muscle bulk, usually necessitating a free tissue transfer (e.g., ALT or latissimus dorsi) or a reverse sural fasciocutaneous flap.

Question 6232

Topic: 2. Trauma

A 42-year-old man sustains a high-energy distal femur fracture. A computed tomography (CT) scan is obtained, revealing a distinct coronal plane fracture of the lateral femoral condyle that was difficult to visualize on plain radiographs. What is the standard eponym for this specific fracture pattern, and how should interfragmentary lag screws generally be oriented for optimal fixation?

. Pipkin fracture; screws placed from anterior to posterior
. Tillaux fracture; screws placed from lateral to medial
. Hoffa fracture; screws placed in an anteroposterior or posteroanterior direction
. Hoffa fracture; screws placed exclusively from medial to lateral
. Chopart fracture; screws placed from distal to proximal

Correct Answer & Explanation

. Hoffa fracture; screws placed in an anteroposterior or posteroanterior direction

Explanation

A coronal shear fracture of the femoral condyle is known as a Hoffa fracture (most commonly involving the lateral condyle). Because the fracture plane is coronal, lag screws must be placed orthogonally to the fracture line to achieve compression. This requires placement in an anteroposterior (AP) or posteroanterior (PA) direction. Placing screws from medial to lateral would be parallel to the fracture plane and would fail to provide interfragmentary compression.

Question 6233

Topic: 2. Trauma

A 45-year-old man sustains a severe closed pilon fracture (OTA 43-C3) after a fall from a ladder. Examination in the emergency department reveals massive soft tissue swelling, fracture blisters, and a shortened extremity. What is the most appropriate initial surgical management?

. Primary open reduction and internal fixation with dual plating
. Application of a spanning joint external fixator and delayed open reduction and internal fixation
. Immediate intramedullary nailing of the tibia
. Circular frame external fixation as definitive management
. Primary ankle arthrodesis

Correct Answer & Explanation

. Application of a spanning joint external fixator and delayed open reduction and internal fixation

Explanation

Pilon fractures with significant soft-tissue swelling and fracture blisters are best treated with staged management. This involves temporary spanning external fixation to allow for soft-tissue resuscitation and resolution of swelling, followed by delayed definitive open reduction and internal fixation. Primary ORIF in this setting is associated with unacceptably high rates of wound breakdown and deep infection.

Question 6234

Topic: 2. Trauma
A 35-year-old farmer is brought to the trauma bay after his leg was caught in a tractor power take-off. He sustains a grade IIIb open diaphyseal tibia fracture with gross soil and organic matter contamination. In addition to surgical debridement, which of the following is the most appropriate empiric intravenous antibiotic regimen?
. Cefazolin alone
. Cefazolin and gentamicin
. Cefazolin, gentamicin, and high-dose penicillin
. Vancomycin and piperacillin-tazobactam
. Ciprofloxacin alone

Correct Answer & Explanation

. Cefazolin, gentamicin, and high-dose penicillin

Explanation

For open fractures with gross soil or agricultural contamination (farm injuries), there is a significant risk of Clostridium infection. The standard of care recommended by orthopedic trauma guidelines includes a first-generation cephalosporin (for gram-positive coverage), an aminoglycoside (for gram-negative coverage), and high-dose penicillin (for anaerobic coverage, specifically Clostridium species).

Question 6235

Topic: 2. Trauma
A 28-year-old man sustains a vertically oriented, displaced femoral neck fracture (Pauwels type III) following a high-energy motor vehicle collision. Which of the following internal fixation constructs provides the greatest biomechanical stability for this specific fracture pattern?
. Three parallel cancellous screws placed in an inverted triangle
. Three parallel cancellous screws placed in a standard triangle
. Sliding hip screw with a derotational cancellous screw
. Cephalomedullary nail
. Two parallel fully threaded cortical screws

Correct Answer & Explanation

. Sliding hip screw with a derotational cancellous screw

Explanation

Pauwels type III fractures are highly vertically oriented (angle > 50 degrees from the horizontal) and experience significant shear forces, increasing the risk of varus collapse and nonunion. Biomechanical studies have demonstrated that a fixed-angle construct, such as a sliding hip screw (SHS) with an additional derotational cancellous screw, provides superior biomechanical stability and increased resistance to shear forces compared to three parallel cancellous screws.

Question 6236

Topic: 2. Trauma

A 30-year-old man who is intubated and sedated in the intensive care unit is noted to have a tense, significantly swollen left lower extremity 24 hours after sustaining a closed, comminuted tibial shaft fracture. Pedal pulses are palpable. What is the most appropriate next step in management?

. Elevate the leg and perform serial clinical examinations every 4 hours
. Measure absolute intracompartmental pressures alone
. Measure intracompartmental pressures and calculate the delta pressure (diastolic blood pressure minus compartment pressure)
. Obtain a lower extremity venous duplex ultrasound
. Perform an immediate four-compartment fasciotomy based on swelling alone

Correct Answer & Explanation

. Measure intracompartmental pressures and calculate the delta pressure (diastolic blood pressure minus compartment pressure)

Explanation

In an obtunded, intubated, or otherwise unexaminable patient, clinical signs of compartment syndrome (such as pain out of proportion or pain with passive stretch) cannot be reliably assessed. The most appropriate next step is to measure the intracompartmental pressures and calculate the delta pressure (diastolic blood pressure minus compartment pressure). A delta pressure of 30 mm Hg or less is generally considered an absolute indication for a four-compartment fasciotomy. Relying on absolute pressure alone is less accurate than delta pressure.

Question 6237

Topic: 2. Trauma

A 40-year-old construction worker falls 20 feet from scaffolding, landing on his feet. He sustains bilateral displaced, intra-articular calcaneus fractures. Which of the following is the most common associated skeletal injury in this clinical scenario?

. Pelvic ring injury
. Thoracolumbar burst fracture
. Cervical spine facet dislocation
. Tibial plateau fracture
. Distal radius fracture

Correct Answer & Explanation

. Thoracolumbar burst fracture

Explanation

Patients who sustain calcaneus fractures from an axial load mechanism, such as a fall from a height, have a high incidence of associated injuries due to the transmission of force up the axial skeleton. Approximately 10% of patients with calcaneus fractures also have an associated thoracolumbar spine fracture, most commonly a burst or compression fracture. A thorough evaluation of the spine is mandatory in these patients.

Question 6238

Topic: Pelvic & Acetabular Trauma

A 35-year-old man is brought to the emergency department after a motorcycle collision. He is hemodynamically unstable, and a pelvic binder is ordered. Which of the following landmarks is the most appropriate location to center the pelvic binder?

. Iliac crests
. Pubic symphysis
. Greater trochanters
. Anterior superior iliac spines
. Lumbar spine

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder should be centered over the greater trochanters to effectively reduce the pelvic volume and stabilize the pelvic ring, particularly in the setting of an anteroposterior compression (open-book) injury. Placement over the iliac crests is a common clinical error and can paradoxically widen the pelvic inlet, exacerbating the deformity and bleeding.

Question 6239

Topic: 2. Trauma

A 28-year-old man sustains a closed spiral fracture of the tibial shaft. On examination, he is extremely anxious and requires increasing doses of opioid analgesia. Which of the following is the most sensitive early clinical finding of acute compartment syndrome?

. Loss of peripheral pulses
. Paresthesias in the first web space
. Pain with passive stretch of the involved muscles
. Pallor of the extremity
. Paralysis of the anterior compartment musculature

Correct Answer & Explanation

. Pain with passive stretch of the involved muscles

Explanation

Pain with passive stretch of the muscles in the involved compartment and pain out of proportion to the apparent injury are considered the earliest and most sensitive clinical signs of acute compartment syndrome. Pulselessness, pallor, and paralysis are late signs, often indicating irreversible tissue necrosis. Paresthesias can be an early sign of nerve ischemia but pain with passive stretch remains the most reliable early clinical indicator.

Question 6240

Topic: 2. Trauma
A 30-year-old man sustains a displaced, Pauwels type III (highly vertical) femoral neck fracture after a fall from a height. What is the most appropriate surgical strategy to optimize biomechanical stability for this specific fracture pattern?
. Cephalomedullary nail
. Hemiarthroplasty
. Three parallel cancellous screws placed in a standard triangle
. Three parallel cancellous screws placed in an inverted triangle
. Sliding hip screw with a derotational screw

Correct Answer & Explanation

. Sliding hip screw with a derotational screw

Explanation

Pauwels type III femoral neck fractures have a vertical orientation and are subjected to high shear forces. In young adults, head-preserving surgery is indicated. Biomechanical studies have demonstrated that a sliding hip screw (often supplemented with an anti-rotation screw) provides superior resistance to shear forces and vertical displacement for this fracture pattern compared to multiple cancellous screws.

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