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2. Trauma MCQs

Practice Set 605 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 12081

Topic: 2. Trauma
A 30-year-old male sustains a talar neck fracture with subluxation of both the subtalar and tibiotalar joints following a motor vehicle accident. What is his estimated risk of developing avascular necrosis (AVN) of the talar body?
. Less than 10%
. 15-25%
. 30-50%
. 70-100%
. AVN does not occur with this fracture pattern

Correct Answer & Explanation

. 70-100%

Explanation

This describes a Hawkins Type III talar neck fracture (fracture with dislocation of the subtalar and tibiotalar joints). The risk of AVN in Hawkins Type III fractures is historically reported to be between 70-100% due to the disruption of the tenuous retrograde blood supply.

Question 12082

Topic: 2. Trauma

A 22-year-old collegiate basketball player complains of lateral foot pain after an awkward landing. Radiographs reveal a transverse fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal. Which of the following is the most appropriate management to optimize his return to sport?

. Non-weight-bearing cast for 6 weeks
. Weight-bearing in a hard-soled shoe
. Intramedullary screw fixation
. Excision of the proximal pole
. Plate and screw fixation

Correct Answer & Explanation

. Intramedullary screw fixation

Explanation

Fractures at the metaphyseal-diaphyseal junction of the fifth metatarsal (Zone 2/Jones fracture) are at a high risk of nonunion due to a watershed blood supply. Intramedullary screw fixation is the standard of care for elite athletes to minimize nonunion and expedite return to sport.

Question 12083

Topic: 2. Trauma

A 35-year-old male sustains a high-energy closed tibial pilon fracture. The soft tissues are severely swollen with fracture blisters present. Which of the following defines the optimal timing for definitive open reduction and internal fixation?

. Within the first 6 hours before further swelling occurs
. After 48 hours to allow initial hematoma consolidation
. Once the skin wrinkles and fracture blisters have re-epithelialized
. Immediately after applying a negative pressure wound therapy dressing
. Only when definitive callous formation is seen on radiographs

Correct Answer & Explanation

. Once the skin wrinkles and fracture blisters have re-epithelialized

Explanation

High-energy pilon fractures are typically managed with a two-staged approach (span, scan, and plan). Definitive fixation is delayed until the soft tissue envelope improves, indicated by the "wrinkle sign" and healing of fracture blisters, typically 10-21 days post-injury.

Question 12084

Topic: 2. Trauma

A 29-year-old male suffers a severe crush injury to his foot. Compartment syndrome is suspected. How many distinct fascial compartments are generally recognized in the foot for the purpose of surgical decompression?

. 3
. 5
. 7
. 9
. 11

Correct Answer & Explanation

. 9

Explanation

There are 9 distinct fascial compartments in the foot: 4 interosseous, 3 central (superficial, deep, and adductor), 1 medial, and 1 lateral. Complete decompression requires dual dorsal incisions or an extensive medial approach.

Question 12085

Topic: 2. Trauma
A 30-year-old male sustains a Hawkins Type III talar neck fracture. Six weeks post-operatively, an AP radiograph of the ankle reveals a subchondral radiolucent band in the talar dome. What does this finding indicate?
. Impending avascular necrosis
. Intact vascularity of the talar body
. Osteomyelitis
. Nonunion of the fracture
. Post-traumatic osteoarthritis

Correct Answer & Explanation

. Intact vascularity of the talar body

Explanation

The presence of a subchondral radiolucent band at 6 to 8 weeks is known as the Hawkins sign. It represents subchondral osteopenia secondary to hyperemia, indicating intact vascularity and ruling out avascular necrosis.

Question 12086

Topic: 2. Trauma

A 20-year-old cross-country runner reports 2 months of vague dorsal midfoot pain. Plain radiographs are normal, but an MRI demonstrates a stress fracture in the central third of the navicular without displacement. What is the recommended initial management?

. Weight-bearing in a CAM boot for 4 weeks
. Non-weight-bearing in a short leg cast for 6 to 8 weeks
. Immediate percutaneous screw fixation
. Open reduction and internal fixation with bone grafting
. Custom orthotics with a medial arch support

Correct Answer & Explanation

. Non-weight-bearing in a short leg cast for 6 to 8 weeks

Explanation

The central third of the navicular is a vascular watershed area prone to delayed healing and nonunion. The standard initial management for a nondisplaced navicular stress fracture is strict non-weight-bearing in a cast for 6 to 8 weeks.

Question 12087

Topic: 2. Trauma

A 72-year-old female presents with 6 weeks of severe back pain following a mechanical fall. Radiographs show an L1 vertebral compression fracture with 30% height loss. Neurological exam is intact. She has been treated with bracing, NSAIDs, and physical therapy but reports no improvement in her pain. Which of the following is the most appropriate next step?

. Anterior spinal fusion
. Posterior spinal fusion with instrumentation
. Balloon kyphoplasty or vertebroplasty
. Continuation of conservative management for 6 more months
. Laminectomy at L1

Correct Answer & Explanation

. Balloon kyphoplasty or vertebroplasty

Explanation

In patients with osteoporotic vertebral compression fractures who have failed conservative management (typically 4-6 weeks) and continue to have severe, localized pain without neurological deficits, cement augmentation (kyphoplasty or vertebroplasty) is indicated to stabilize the fracture and relieve pain.

Question 12088

Topic: Upper Extremity Trauma
A 28-year-old manual laborer sustains a high-energy fall onto the point of his shoulder. Radiographs demonstrate a >100% superior displacement of the clavicle relative to the acromion. Regarding the key stabilizing structures of this joint, which of the following best describes the anatomy and function of the coracoclavicular (CC) ligaments?
. The conoid ligament is medial and resists mainly superior displacement, while the trapezoid ligament is lateral and resists axial compression.
. The conoid ligament is lateral and resists mainly superior displacement, while the trapezoid ligament is medial and resists axial compression.
. The conoid ligament is medial and resists primarily anteroposterior translation.
. Both the conoid and trapezoid ligaments attach to the base of the coracoid and resist exclusively inferior clavicular displacement.
. The trapezoid ligament is the primary restraint to superior translation of the clavicle.

Correct Answer & Explanation

. The conoid ligament is medial and resists mainly superior displacement, while the trapezoid ligament is lateral and resists axial compression.

Explanation

The coracoclavicular (CC) ligaments provide critical superior-inferior stability to the acromioclavicular joint. The conoid ligament is located more medially and posteriorly; it is the primary restraint to superior translation of the clavicle. The trapezoid ligament is located more laterally and anteriorly; it primarily resists axial compression to the shoulder.

Question 12089

Topic: 2. Trauma

During the treatment of a midshaft femur fracture with a solid intramedullary nail, the surgeon selects a larger diameter implant. If the working length remains constant, increasing the radius of a solid intramedullary nail by a factor of 2 will increase its torsional rigidity by a factor of:

. 2
. 4
. 8
. 16
. 32

Correct Answer & Explanation

. 16

Explanation

The torsional rigidity of a solid cylinder is directly proportional to its polar moment of inertia, which scales with the radius raised to the fourth power (r^4). Therefore, doubling the radius (2^4) increases the torsional rigidity by a factor of 16.

Question 12090

Topic: 2. Trauma
A 25-year-old male sustains an open tibia fracture following a motorcycle accident. The wound is 12 cm long with extensive periosteal stripping, requiring a rotational flap for soft tissue coverage. According to standard guidelines for a Gustilo-Anderson Type IIIB fracture without farm/soil contamination, what is the most appropriate initial intravenous antibiotic regimen in the emergency department?
. First-generation cephalosporin only
. First-generation cephalosporin and an aminoglycoside
. Fluoroquinolone alone
. Third-generation cephalosporin only
. Vancomycin and Piperacillin-Tazobactam

Correct Answer & Explanation

. First-generation cephalosporin and an aminoglycoside

Explanation

This is a Gustilo-Anderson Type IIIB open fracture (extensive soft tissue injury requiring a flap). Historically and widely tested on boards, the standard of care for Type III open fractures includes a first-generation cephalosporin (for Gram-positive coverage) plus an aminoglycoside (for Gram-negative coverage). If soil or farm contamination is present, high-dose penicillin is added for Clostridium coverage.

Question 12091

Topic: Pelvic & Acetabular Trauma
In the Young-Burgess classification of pelvic ring injuries, an Anterior Posterior Compression Type II (APC II) injury is defined by the widening of the symphysis pubis and the disruption of which of the following posterior pelvic structures?
. Sacrospinous, sacrotuberous, and posterior sacroiliac ligaments
. Sacrospinous, sacrotuberous, and anterior sacroiliac ligaments
. Complete disruption of both anterior and posterior sacroiliac ligaments
. Fracture of the iliac wing with intact sacroiliac ligaments
. Sacral fracture with intact sacroiliac ligaments

Correct Answer & Explanation

. Sacrospinous, sacrotuberous, and anterior sacroiliac ligaments

Explanation

An APC II pelvic ring injury (an 'open book' pelvis) is rotationally unstable but vertically stable. It involves disruption of the symphysis pubis anteriorly, along with tearing of the sacrospinous, sacrotuberous, and the anterior sacroiliac ligaments. The strong posterior sacroiliac ligaments remain intact, which preserves the vertical stability of the hemipelvis. If the posterior SI ligaments fail, the injury becomes an APC III.

Question 12092

Topic: 2. Trauma

The Sanders classification system for intra-articular calcaneus fractures dictates prognosis and guides surgical management. This classification is primarily based on the fracture line pattern assessed using which of the following specific imaging views?

. Lateral radiograph
. Harris axial radiograph
. Sagittal CT reconstruction of the subtalar joint
. Coronal CT image of the widest portion of the posterior facet
. Axial CT image of the calcaneocuboid joint

Correct Answer & Explanation

. Coronal CT image of the widest portion of the posterior facet

Explanation

The Sanders classification is based on coronal CT images taken through the widest point of the posterior facet of the calcaneus. It categorizes fractures based on the number and location of primary fracture lines extending through the posterior facet articular surface.

Question 12093

Topic: 2. Trauma

Which of the following internal fixation constructs provides absolute stability, thereby predominantly resulting in primary (direct) bone healing without the formation of a visible cartilaginous fracture callus?

. Intramedullary nailing of a diaphyseal femur fracture
. Bridge plating of a severely comminuted humeral shaft fracture
. Interfragmentary lag screw and neutralization plating of a lateral malleolus fracture
. Circular external fixation of a tibial pilon fracture
. Locked plating utilizing exclusively locking screws in a bridge fashion

Correct Answer & Explanation

. Interfragmentary lag screw and neutralization plating of a lateral malleolus fracture

Explanation

Primary (direct) bone healing occurs under conditions of absolute stability and anatomic reduction, such as with compression plating (an interfragmentary lag screw plus a neutralization plate). It relies on direct osteonal remodeling (cutting cones) without an intermediate cartilaginous callus phase. The other options provide relative stability, resulting in secondary (indirect) healing via callus formation.

Question 12094

Topic: 2. Trauma
A surgeon utilizes a locked plating construct to bridge a highly comminuted diaphyseal fracture of the tibia. During preoperative planning, the surgeon decides to leave three empty screw holes directly over the fracture site instead of one. How does increasing the working length of this locked plate construct affect its biomechanical properties?
. Increases torsional rigidity and increases fracture strain
. Increases bending stiffness and decreases fracture strain
. Decreases construct stiffness and decreases fracture strain
. Decreases construct stiffness and increases fracture strain
. Has no effect on construct stiffness but decreases fracture strain

Correct Answer & Explanation

. Decreases construct stiffness and decreases fracture strain

Explanation

The working length of a plate is the distance between the closest screws on either side of the fracture. Increasing the working length makes the construct less stiff (more flexible), which allows for more interfragmentary motion. However, because strain is defined as the change in length divided by the original gap length (∆L/L), distributing the motion over a longer 'original gap length' (due to a longer working length) actually decreases the overall strain at the fracture site, promoting secondary bone healing.

Question 12095

Topic: 2. Trauma

When applying a bridging locking plate for a comminuted diaphyseal fracture, increasing the 'working length' (leaving more empty screw holes over the fracture site) will have which of the following biomechanical effects on the construct?

. Increases the overall torsional stiffness
. Increases the bending stiffness
. Decreases construct stiffness and increases interfragmentary strain tolerance
. Decreases the risk of screw pullout by shifting load distally
. Has no effect on construct flexibility

Correct Answer & Explanation

. Decreases construct stiffness and increases interfragmentary strain tolerance

Explanation

Increasing the working length of a plate (the distance between the two innermost screws) decreases the construct's longitudinal stiffness. This allows for more relative motion (strain) at the fracture site, promoting secondary bone healing through callus formation.

Question 12096

Topic: 2. Trauma

A high-velocity gunshot wound to the thigh causes massive soft tissue destruction and a comminuted femur fracture. According to the principles of ballistics, which factor is most responsible for the kinetic energy transferred to the patient's tissues?

. Mass of the bullet
. Caliber of the bullet
. Velocity of the bullet
. Distance from the muzzle
. Type of gunpowder used

Correct Answer & Explanation

. Velocity of the bullet

Explanation

The kinetic energy of a projectile is calculated as KE = 1/2 * mass * velocity^2. Because velocity is squared in the equation, it is the most critical determinant of the energy transferred and the resulting tissue damage.

Question 12097

Topic: 2. Trauma

To minimize personal scatter radiation exposure when using a C-arm fluoroscope in the lateral position during fracture fixation, where is the optimal location for the surgeon to stand?

. Directly adjacent to the x-ray tube emitter
. On the side of the x-ray tube emitter
. On the side of the image intensifier (receiver)
. At the head of the operating table directly in line with the beam
. Directly behind the x-ray tube emitter

Correct Answer & Explanation

. On the side of the image intensifier (receiver)

Explanation

Scatter radiation is highest near the x-ray source (tube). Standing on the side of the image intensifier significantly reduces radiation exposure to the surgical team.

Question 12098

Topic: 2. Trauma
An orthopedic surgeon is deciding between two plates of the same width but different thicknesses for a fracture fixation. If the thickness of the plate is doubled while the width remains constant, its bending rigidity increases by a factor of:
. 2
. 4
. 8
. 16
. 32

Correct Answer & Explanation

. 8

Explanation

The bending rigidity of a rectangular plate is proportional to the width and the cube of the thickness (base × height^3 / 12). Therefore, doubling the thickness increases the bending rigidity by a factor of 8, making it a highly effective way to stiffen a construct.

Question 12099

Topic: 2. Trauma

A surgeon is utilizing a locking compression plate (LCP) for a highly comminuted distal femur fracture, planning for secondary bone healing. Which of the following modifications to the construct will most effectively decrease construct stiffness and promote beneficial callus formation?

. Using bicortical locking screws instead of unicortical screws
. Decreasing the working length of the plate
. Placing locking screws in the holes immediately adjacent to the fracture site
. Increasing the distance between the plate and the bone
. Using a titanium plate and omitting screws in the holes closest to the fracture gap

Correct Answer & Explanation

. Using a titanium plate and omitting screws in the holes closest to the fracture gap

Explanation

Omitting screws immediately adjacent to the fracture gap increases the 'working length' of the plate, which effectively decreases the construct's bending stiffness and permits controlled interfragmentary micromotion. Titanium has a lower modulus of elasticity than stainless steel, which also helps decrease construct rigidity and promotes secondary bone healing.

Question 12100

Topic: 2. Trauma

A 10-year-old boy sustains a minor twisting injury to his proximal humerus. Radiographs show a centrally located, expansile, purely lytic lesion in the metadiaphysis with a 'fallen leaf' sign.

Which of the following describes the most appropriate initial management for this lesion after the fracture heals?

. En bloc resection and allograft reconstruction
. Aspiration and injection of methylprednisolone or bone marrow aspirate
. Wide local excision with margins
. Radiation therapy
. Denosumab therapy

Correct Answer & Explanation

. Aspiration and injection of methylprednisolone or bone marrow aspirate

Explanation

The scenario and 'fallen leaf' sign describe a simple (unicameral) bone cyst (UBC), classic for a proximal humerus lesion. After the pathologic fracture heals, initial management typically involves cyst aspiration (yielding serous fluid) followed by an injection of corticosteroids (methylprednisolone) or bone marrow aspirate to stimulate healing.

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