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2. Trauma MCQs

Practice Set 321 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 6401

Topic: 2. Trauma
A 35-year-old male is brought to the trauma bay after a motorcycle collision. He is hypotensive and tachycardic. A pelvic radiograph demonstrates an anteroposterior compression (APC) III injury. The trauma team decides to apply a circumferential pelvic binder. To most effectively reduce the pelvic volume and stabilize the fracture, over which anatomic landmark should the binder be centered?
. Iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Symphysis pubis
. Sacral promontory

Correct Answer & Explanation

. Greater trochanters

Explanation

Circumferential pelvic binders are most effective at reducing pelvic volume and stabilizing the pelvic ring when centered over the greater trochanters. Placement over the iliac crests is less effective and can inadvertently increase pelvic volume in certain fracture patterns.

Question 6402

Topic: 2. Trauma
A 24-year-old male sustains an isolated Gustilo-Anderson type IIIB open tibial shaft fracture following a farming accident. According to current evidence-based guidelines, which of the following interventions is the most critical factor in reducing his risk of developing a deep-seated infection?
. Time to operative debridement within 6 hours
. Time to administration of appropriate intravenous antibiotics
. Use of high-pressure pulsatile lavage during debridement
. Primary closure of the soft tissue defect
. Addition of systemic corticosteroids to reduce inflammation

Correct Answer & Explanation

. Time to administration of appropriate intravenous antibiotics

Explanation

Early administration of appropriate intravenous antibiotics is the single most important factor in reducing infection rates in open fractures. The traditional 6-hour rule for surgical debridement has not been strongly supported by modern evidence compared to the timing of antibiotic administration.

Question 6403

Topic: 2. Trauma

A 42-year-old male presents with a severely displaced, closed midshaft tibia fracture. He is complaining of intense leg pain out of proportion to the apparent injury, and pain with passive stretch of the hallux. His blood pressure is 110/70 mmHg. Intracompartmental pressures are measured. Which of the following pressure readings definitively indicates the need for an emergent four-compartment fasciotomy?

. Absolute compartment pressure of 25 mmHg
. Absolute compartment pressure of 30 mmHg
. Compartment pressure of 35 mmHg with a diastolic blood pressure of 80 mmHg
. Compartment pressure of 45 mmHg with a diastolic blood pressure of 70 mmHg
. Compartment pressure of 20 mmHg with a mean arterial pressure of 65 mmHg

Correct Answer & Explanation

. Compartment pressure of 45 mmHg with a diastolic blood pressure of 70 mmHg

Explanation

The most reliable physiological indicator for fasciotomy is the Delta P (diastolic blood pressure minus the absolute compartment pressure) being 30 mmHg or less. A compartment pressure of 45 mmHg and a diastolic BP of 70 mmHg yields a Delta P of 25 mmHg, definitively indicating emergent fasciotomy.

Question 6404

Topic: 2. Trauma

A 78-year-old female presents with neck pain after a low-energy fall. CT reveals a Type II odontoid fracture with 2 mm of posterior displacement.

What is the most significant risk factor for nonunion if treated nonoperatively?

. Age greater than 50 years
. Displacement greater than 1 mm
. Female sex
. Mechanism of injury
. Presence of a posterior arch fracture

Correct Answer & Explanation

. Age greater than 50 years

Explanation

The most significant risk factor for nonunion in Type II odontoid fractures is age over 50 years. Other factors include displacement > 5 mm, posterior displacement, and excessive angulation.

Question 6405

Topic: 2. Trauma

A 68-year-old man presents with neck pain after a low-speed motor vehicle collision. Radiographs demonstrate a Type II odontoid fracture with 6 mm of posterior displacement. He is neurologically intact. Which of the following factors is most strongly associated with a high risk of nonunion if this injury is treated nonoperatively in a halo vest?

. Posterior displacement rather than anterior displacement
. Displacement greater than 5 mm
. Concomitant C1 arch fracture
. Male sex
. Use of a hard collar instead of a halo vest

Correct Answer & Explanation

. Displacement greater than 5 mm

Explanation

Risk factors for nonunion of Type II odontoid fractures include displacement > 5 mm, angulation > 10 degrees, and patient age > 50 years. Posterior displacement is not inherently a higher risk than anterior displacement, provided the magnitude is matched.

Question 6406

Topic: 2. Trauma

A 28-year-old man sustains a Type II odontoid fracture in a motor vehicle collision. The fracture is displaced 6 mm posteriorly with a comminuted base. Which of the following factors is most strongly associated with nonunion if treated nonoperatively in a halo vest?

. Displacement greater than 5 mm
. Age less than 30 years
. Posterior displacement
. Anterior displacement
. Associated C1 ring fracture

Correct Answer & Explanation

. Displacement greater than 5 mm

Explanation

Risk factors for nonunion of Type II odontoid fractures include initial displacement > 5 mm, angulation > 10 degrees, comminution at the fracture base, and advanced age (> 50 years).

Question 6407

Topic: 2. Trauma

A 35-year-old man involved in a high-speed motor vehicle collision as a restrained passenger sustains a flexion-distraction injury (Chance fracture) at L2. He is neurologically intact. Which of the following associated injuries must be most aggressively ruled out during his initial trauma evaluation?

. Blunt cardiac injury
. Aortic dissection
. Hollow viscus abdominal injury
. Diaphragmatic rupture
. Pelvic ring disruption

Correct Answer & Explanation

. Hollow viscus abdominal injury

Explanation

Chance fractures (flexion-distraction injuries) are frequently associated with lap-belt use and have a high correlation (up to 40-50%) with intra-abdominal organ injuries. Hollow viscus (bowel) injuries are the most common and must be urgently ruled out via advanced imaging or general surgery consultation.

Question 6408

Topic: 2. Trauma

A 22-year-old man sustains a severe fracture-dislocation at T4 with complete spinal cord injury (ASIA A). In the trauma bay, his blood pressure is 80/50 mm Hg and his heart rate is 52 bpm. His extremities are warm and pink. What is the primary etiology of his hemodynamic instability?

. Hemorrhagic shock from occult abdominal injury
. Cardiogenic shock from myocardial contusion
. Loss of sympathetic vascular tone
. Loss of parasympathetic outflow
. Adrenal insufficiency

Correct Answer & Explanation

. Loss of sympathetic vascular tone

Explanation

The patient is in neurogenic shock, characterized by hypotension and bradycardia due to the disruption of descending sympathetic pathways in the cervical or upper thoracic cord (above T6). This loss of sympathetic tone leads to unopposed vagal tone, peripheral vasodilation, and an inability to mount a tachycardic response.

Question 6409

Topic: 2. Trauma

A 75-year-old man presents with a Type II odontoid fracture following a fall. Which of the following fracture characteristics is the strongest independent predictor of nonunion with nonoperative management?

. Displacement greater than 5 mm
. Angulation greater than 5 degrees
. Anterior rather than posterior displacement
. Oblique fracture pattern
. Concomitant C1 ring fracture

Correct Answer & Explanation

. Displacement greater than 5 mm

Explanation

Displacement greater than 5 mm is a well-established and strong independent risk factor for nonunion in Type II odontoid fractures treated conservatively. Other relative risk factors include age older than 50 years and initial angulation greater than 10 degrees.

Question 6410

Topic: 2. Trauma

An 80-year-old man sustains a Type II odontoid fracture after a ground-level fall. Which of the following factors most significantly increases his risk of nonunion if treated conservatively with a rigid cervical collar?

. Age greater than 50 years
. Displacement of less than 2 mm
. Anterior angulation of 5 degrees
. Associated skull fracture
. Absence of neurological deficits

Correct Answer & Explanation

. Age greater than 50 years

Explanation

Risk factors for nonunion in Type II odontoid fractures include age >50 years, displacement >5 mm, posterior displacement, and comminution. Geriatric patients have significantly higher nonunion rates with conservative care, often warranting a discussion on surgical stabilization.

Question 6411

Topic: 2. Trauma

A 78-year-old woman falls and sustains a Type II odontoid fracture. Which of the following factors is most strongly associated with an increased risk of nonunion for this injury?

. Age less than 40 years
. Anterior displacement of 2 mm
. Initial displacement greater than 5 mm
. Associated C1 ring fracture
. Mechanism of injury

Correct Answer & Explanation

. Initial displacement greater than 5 mm

Explanation

Risk factors for nonunion of a Type II odontoid fracture include age greater than 50 years, initial displacement greater than 5 mm, posterior displacement, and significant angulation.

Question 6412

Topic: 2. Trauma

A 25-year-old woman is brought in after falling from a third-story balcony. Imaging reveals a U-shaped sacral fracture with severe focal kyphosis and bilateral S1 nerve root deficits. Which surgical technique is most appropriate to stabilize this spinopelvic dissociation?

. Anterior plate fixation of the pubic symphysis
. Percutaneous iliosacral screws alone
. Lumbopelvic fixation connecting L4/L5 to the ilium
. Sacroiliac joint fusion with triangular titanium implants
. Non-operative management with prolonged bed rest

Correct Answer & Explanation

. Lumbopelvic fixation connecting L4/L5 to the ilium

Explanation

U-shaped sacral fractures represent a severe form of spinopelvic dissociation. They are highly unstable and typically require robust lumbopelvic fixation (connecting the lower lumbar spine to the ilium) to restore alignment and permit mobilization.

Question 6413

Topic: 2. Trauma

A 22-year-old man wearing a lap seatbelt is involved in a frontal motor vehicle collision. He has severe focal back pain but is neurologically intact. CT imaging shows a fracture extending horizontally through the spinous process, pedicles, and vertebral body of L1. What is the most appropriate definitive management?

. Immediate surgical decompression and posterior fusion
. Extension orthosis (TLSO)
. Anterior column reconstruction with a cage
. Percutaneous vertebroplasty
. Bed rest for 6 weeks

Correct Answer & Explanation

. Extension orthosis (TLSO)

Explanation

This is a bony Chance fracture (flexion-distraction injury). Because it is purely bony and the patient is neurologically intact, it has a high rate of healing when treated conservatively with an extension orthosis.

Question 6414

Topic: 2. Trauma

According to the Denis classification of sacral fractures, which zone injury carries the highest risk of accompanying neurologic deficit?

. Zone 1 (alar)
. Zone 2 (foraminal)
. Zone 3 (central canal)
. Zone 4 (coccygeal)
. Zone 5 (iliac)

Correct Answer & Explanation

. Zone 3 (central canal)

Explanation

Denis Zone 3 sacral fractures involve the central sacral canal and carry the highest risk of neurologic injury (up to 57%), frequently affecting bowel, bladder, and sexual function.

Question 6415

Topic: 2. Trauma

A 45-year-old man sustains a high-energy pilon fracture with severe soft tissue swelling and fracture blisters. A spanning external fixator is applied. What is the most reliable clinical indicator that the soft tissues are ready for definitive open reduction and internal fixation (ORIF)?

. Normalization of the erythrocyte sedimentation rate (ESR)
. Resolution of fracture blisters and the return of skin wrinkles
. Radiographic evidence of early callus formation
. Post-injury day 10
. Negative wound cultures from the external fixator pin sites

Correct Answer & Explanation

. Resolution of fracture blisters and the return of skin wrinkles

Explanation

Definitive ORIF of high-energy pilon fractures must be delayed until soft tissue swelling subsides to minimize wound breakdown and infection. The return of skin wrinkles (the "wrinkle sign") is the most reliable clinical indicator.

Question 6416

Topic: 2. Trauma

A 62-year-old diabetic patient with significant peripheral neuropathy sustains a bimalleolar equivalent ankle fracture. When comparing the postoperative management of this patient to a non-diabetic patient, what modification is most strongly recommended?

. Immediate weight-bearing in a CAM boot
. Prolonged immobilization and non-weight-bearing for at least double the standard duration
. Early hardware removal at 6 weeks
. Routine use of a fibular intramedullary nail instead of a plate
. Application of a circular frame external fixator in all cases

Correct Answer & Explanation

. Prolonged immobilization and non-weight-bearing for at least double the standard duration

Explanation

Diabetic patients with neuropathy have significantly higher rates of hardware failure, nonunion, and Charcot arthropathy post-fracture. Treatment requires augmented fixation constructs and a doubled duration of non-weight-bearing immobilization (often 10-12 weeks).

Question 6417

Topic: 2. Trauma

Which of the following injury patterns represents a Lauge-Hansen Supination-Adduction (SAD) stage II ankle fracture?

. Transverse medial malleolus fracture and high fibular fracture
. Spiral fracture of the lateral malleolus and rupture of the deltoid ligament
. Transverse lateral malleolus fracture at or below the joint line and a vertical fracture of the medial malleolus
. Avulsion of the anterior inferior tibiofibular ligament and a short oblique fibula fracture
. Isolated rupture of the syndesmosis

Correct Answer & Explanation

. Transverse lateral malleolus fracture at or below the joint line and a vertical fracture of the medial malleolus

Explanation

In the Lauge-Hansen Supination-Adduction classification, Stage I is a transverse avulsion fracture of the lateral malleolus below the joint line, and Stage II includes the addition of a vertical shear fracture of the medial malleolus.

Question 6418

Topic: 2. Trauma

A 24-year-old marathon runner presents with 6 weeks of vague dorsal midfoot pain. Radiographs are normal, but a CT scan reveals a non-displaced incomplete fracture of the dorsal aspect of the navicular. What is the most appropriate initial treatment?

. Open reduction and internal fixation with headless compression screws
. Weight-bearing as tolerated in a CAM boot
. Strict non-weight-bearing cast for 6 to 8 weeks
. Immediate return to running with orthotics
. Primary talonavicular arthrodesis

Correct Answer & Explanation

. Strict non-weight-bearing cast for 6 to 8 weeks

Explanation

Non-displaced navicular stress fractures have a high risk of nonunion due to a tenuous central blood supply. The standard of care for initial management is strict non-weight-bearing in a cast for 6-8 weeks.

Question 6419

Topic: 2. Trauma

Following open reduction and internal fixation of an unstable ankle fracture with a suspected syndesmotic injury, intraoperative fluoroscopy is used to assess reduction. However, literature shows plain radiography is often inadequate. What is the most sensitive and specific imaging modality to assess syndesmotic malreduction?

. Weight-bearing AP radiograph
. Gravity stress radiograph
. Axial CT scan of both ankles
. Magnetic Resonance Imaging (MRI)
. Ultrasound of the tibiofibular clear space

Correct Answer & Explanation

. Axial CT scan of both ankles

Explanation

Bilateral axial CT scanning is the most sensitive and specific imaging modality for diagnosing subtle syndesmotic malreduction postoperatively, detecting malrotation and widening missed by plain radiographs.

Question 6420

Topic: 2. Trauma

A 35-year-old man sustains a pronation-external rotation ankle fracture. Following open reduction and internal fixation of the medial and lateral malleoli, the Cotton test is positive. What is the most appropriate next step in management?

. Deltoid ligament repair
. Syndesmotic screw or suture button fixation
. Anterior inferior tibiofibular ligament (AITFL) repair
. Cast immobilization without further fixation
. Distal fibular osteotomy

Correct Answer & Explanation

. Syndesmotic screw or suture button fixation

Explanation

A positive Cotton test indicates syndesmotic instability after malleolar fixation. It requires stabilization using syndesmotic screws or a flexible suture button construct.

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