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2. Trauma MCQs

Practice Set 520 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 10381

Topic: 2. Trauma

A 29-year-old male sustains a closed comminuted tibial shaft fracture. On the morning following intramedullary nailing, he complains of severe leg pain out of proportion to the injury. His blood pressure is 110/60 mmHg. Intracompartmental pressure measurements are obtained. Which of the following intracompartmental pressures is an absolute indication for emergent four-compartment fasciotomy?

. 15 mmHg
. 20 mmHg
. 25 mmHg
. 35 mmHg
. Intracompartmental pressure > 45 mmHg is the only valid indication

Correct Answer & Explanation

. 15 mmHg

Explanation

The diagnosis of acute compartment syndrome is supported by calculating the Delta P (Diastolic Blood Pressure minus Intracompartmental Pressure). A Delta P of less than or equal to 30 mmHg is a strong indication for emergent fasciotomy to prevent irreversible muscle and nerve necrosis. With a diastolic BP of 60 mmHg, a compartment pressure of 35 mmHg yields a Delta P of 25 mmHg (60 - 35 = 25), which dictates emergent release. Absolute pressure thresholds (e.g., >30 or >40 mmHg) are less reliable than the Delta P in modern trauma care.

Question 10382

Topic: 2. Trauma
A 40-year-old male sustains a Gustilo-Anderson IIIB open midshaft tibia fracture. Following initial debridement and external fixation, a free tissue transfer is required for soft tissue coverage. Current literature suggests that to minimize the risk of deep infection and flap failure, soft tissue coverage should ideally be performed within what time frame from the time of injury?
. Less than 24 hours
. Within 5 to 7 days
. Between 10 to 14 days
. Between 3 to 4 weeks
. Only after definitive intramedullary nailing is completed

Correct Answer & Explanation

. Within 5 to 7 days

Explanation

Historically, Godina recommended flap coverage within 72 hours for open tibia fractures. More recent literature and modern trauma protocols indicate that coverage within 5 to 7 days provides optimal outcomes, minimizing rates of deep infection, osteomyelitis, and flap failure. Delaying coverage beyond 7 days significantly increases complication rates. Often, definitive bone stabilization and flap coverage are coordinated during this period.

Question 10383

Topic: 2. Trauma

A 45-year-old male presents with a high-energy closed severe pilon fracture. There is significant soft tissue swelling, fracture blisters, and ecchymosis around the ankle. What is the most appropriate management plan regarding the timing and method of definitive internal fixation?

. Immediate single-stage open reduction internal fixation to restore articular congruity
. Immediate application of a circular frame external fixator as definitive treatment
. Application of a spanning external fixator, delaying definitive ORIF for 10-21 days until soft tissue swelling subsides
. Casting the lower extremity and delaying surgery until fracture blisters resolve
. Immediate percutaneous pinning and rigid boot immobilization

Correct Answer & Explanation

. Immediate single-stage open reduction internal fixation to restore articular congruity

Explanation

High-energy pilon fractures are associated with profound soft tissue compromise. Immediate open reduction and internal fixation (ORIF) carries an unacceptably high rate of wound necrosis and deep infection. The standard of care is a staged protocol: initial application of a joint-spanning external fixator (with or without limited fibular fixation) to restore length and alignment, followed by delayed definitive ORIF of the tibial articular surface 10 to 21 days later, once the soft tissue envelope has recovered (evidenced by the return of skin wrinkles and re-epithelialization of blisters).

Question 10384

Topic: 2. Trauma

A 31-year-old male sustains a Hawkins type II talar neck fracture following an MVA. He undergoes open reduction and internal fixation. At the 8-week follow-up, an AP radiograph of the ankle demonstrates a subchondral radiolucent band in the talar dome. What does this finding indicate?

. Impending avascular necrosis of the talar body
. Normal hyperemic response indicating an intact vascular supply to the talar body
. Failure of fixation and impending nonunion
. Post-traumatic osteoarthritis
. Subchondral collapse

Correct Answer & Explanation

. Impending avascular necrosis of the talar body

Explanation

The Hawkins sign is a subchondral radiolucent band seen in the talar dome on the AP or mortise radiograph, typically appearing 6 to 8 weeks after a talar neck fracture. It represents subchondral osteopenia secondary to disuse and hyperemia. This requires an intact vascular supply to the talar body. Thus, a positive Hawkins sign is a highly reliable indicator that the talar body has not undergone avascular necrosis (AVN).

Question 10385

Topic: 2. Trauma

A 50-year-old male undergoes ORIF of a displaced intra-articular calcaneus fracture using an extensile lateral approach. He is a 1-pack-per-day smoker. Which of the following is the most common postoperative complication associated with this specific surgical approach?

. Sural nerve transection
. Subtalar arthritis requiring late arthrodesis
. Wound edge necrosis and dehiscence at the apex of the incision
. Nonunion of the calcaneal tuberosity
. Peroneal tendon subluxation

Correct Answer & Explanation

. Sural nerve transection

Explanation

The extensile lateral approach for calcaneus fractures relies on an L-shaped flap that is supplied by the lateral calcaneal artery. Wound edge necrosis and dehiscence at the apex (corner) of the flap is the most common complication, with rates historically ranging from 10% to 25%, significantly higher in patients who smoke, have diabetes, or when surgery is performed before swelling has adequately subsided.

Question 10386

Topic: 2. Trauma

A 65-year-old female sustains a 4-part proximal humerus fracture. Recent anatomical studies by Hertel et al. have redefined the understanding of the blood supply to the proximal humerus. According to these studies, preservation of which of the following is the most critical predictor of humeral head viability?

. The arcuate artery
. The anterior circumflex humeral artery
. The ascending branch of the anterior circumflex humeral artery
. The posterior circumflex humeral artery and the posteromedial hinge
. The suprascapular artery

Correct Answer & Explanation

. The arcuate artery

Explanation

Historically, the anterior circumflex humeral artery (and its anterolateral ascending branch) was thought to be the primary blood supply to the humeral head. However, landmark anatomical studies by Hertel et al. established that the posterior circumflex humeral artery provides the dominant blood supply to the humeral head. A calcar length of less than 8 mm, disruption of the posteromedial hinge, and basicervical fracture patterns are highly predictive of ischemia and subsequent avascular necrosis.

Question 10387

Topic: 2. Trauma

A 44-year-old female undergoes open reduction and internal fixation of an intercondylar distal humerus fracture (13-C2) using an olecranon osteotomy approach. Regarding the management of the ulnar nerve during this procedure, current evidence suggests:

. Routine anterior subcutaneous transposition reduces the incidence of postoperative neuropathy compared to in situ release
. Routine anterior submuscular transposition is the standard of care for all distal humerus fractures
. In situ decompression without transposition is associated with a lower rate of ulnar neuritis compared to routine transposition
. The ulnar nerve should not be exposed or visualized to avoid devascularization
. Subcutaneous transposition is required only if parallel plating is used instead of orthogonal plating

Correct Answer & Explanation

. Routine anterior subcutaneous transposition reduces the incidence of postoperative neuropathy compared to in situ release

Explanation

Current evidence and randomized trials (e.g., Chen et al.) suggest that routine anterior transposition of the ulnar nerve during ORIF of distal humerus fractures is associated with a higher rate of postoperative ulnar neuritis compared to in situ release (decompression) alone. The nerve should be identified, protected, and decompressed, but transposition is not routinely indicated unless the hardware physically impinges on the nerve in its bed or there is a specific indication (e.g., subluxating nerve).

Question 10388

Topic: 2. Trauma

A 25-year-old male sustains a low-velocity, civilian handgun wound to the mid-thigh. Radiographs show a midshaft femur fracture with a non-comminuted, short oblique pattern. The bullet has exited the limb. The patient is neurovascularly intact. What is the most appropriate infection prophylaxis protocol for this injury?

. Intravenous penicillin and gentamicin for 7 days
. Immediate formal surgical debridement of the wound track and 5 days of broad-spectrum IV antibiotics
. Superficial wound care, a short course (24-48 hours) of an IV first-generation cephalosporin, followed by intramedullary nailing
. Application of an external fixator and immediate flap coverage
. No antibiotics are necessary for low-velocity wounds; proceed straight to nailing

Correct Answer & Explanation

. Intravenous penicillin and gentamicin for 7 days

Explanation

Low-velocity civilian gunshot wounds with resulting fractures are generally treated as low-grade open fractures (similar to Gustilo type I or II). The standard protocol involves superficial wound care (cleaning the entry/exit sites) without the need for formal tracking or extensive surgical debridement (unless there is gross contamination or joint involvement). Infection prophylaxis requires a short course (24-48 hours) of a first-generation cephalosporin (e.g., cefazolin), followed by standard definitive fixation such as intramedullary nailing.

Question 10389

Topic: 2. Trauma

A 33-year-old male motorcyclist is struck by a truck and suffers an open pelvic ring injury with a massive perineal laceration extending to the rectum. He is hemodynamically unstable but responds transiently to blood products. Upon arrival to the OR, after initial pelvic stabilization with an external fixator and preperitoneal packing, what is the mandatory next step regarding the perineal wound?

. Primary closure of the perineal wound with retention sutures
. Fecal diversion with a diverting colostomy
. Application of a vacuum-assisted closure (VAC) device and delayed primary closure
. Observation and daily wet-to-dry dressings
. Immediate split-thickness skin grafting

Correct Answer & Explanation

. Primary closure of the perineal wound with retention sutures

Explanation

Open pelvic fractures with perineal or rectal involvement carry an extremely high mortality rate, primarily driven by early hemorrhagic shock and late pelvic sepsis. The contamination of the massive pelvic hematoma and open fracture site by fecal matter is a critical issue. Therefore, mandatory fecal diversion (diverting colostomy) is the standard of care for open pelvic fractures with rectal tears or massive perineal wounds in proximity to the anus, to prevent devastating pelvic sepsis.

Question 10390

Topic: 2. Trauma

A 42-year-old male sustains a high-energy OTA/AO 41-C3 bicondylar tibial plateau fracture. CT scanning reveals a significant posteromedial shear fragment that is displaced distally. What is the optimal surgical approach and positioning to address this specific fracture component?

. Supine position, standard anterolateral approach with lag screws directed medial to lateral
. Supine position, standard medial approach
. Prone or lateral position, direct posteromedial approach
. Supine position, midline longitudinal incision with a tibial tubercle osteotomy
. Application of an isolated spanning external fixator indefinitely

Correct Answer & Explanation

. Supine position, standard anterolateral approach with lag screws directed medial to lateral

Explanation

A displaced posteromedial shear fragment in a bicondylar tibial plateau fracture is poorly visualized and nearly impossible to reduce and buttress adequately through standard anterior or anteromedial approaches. The optimal strategy requires direct visualization and buttress plating of the posteromedial apex. This is best achieved using a direct posteromedial approach with the patient in the prone or lateral decubitus position, allowing placement of an anti-glide or buttress plate to resist the apical displacement.

Question 10391

Topic: 2. Trauma

When performing a posteromedial approach to the tibial plateau for a coronal shear fracture (Moore Type I), the standard surgical interval to expose the posterior aspect of the medial condyle is between the:

. Medial head of the gastrocnemius and pes anserinus
. Medial head of the gastrocnemius and soleus
. Semitendinosus and semimembranosus
. Sartorius and gracilis
. Tibialis posterior and flexor digitorum longus

Correct Answer & Explanation

. Medial head of the gastrocnemius and pes anserinus

Explanation

The posteromedial approach to the tibial plateau is indicated for posteromedial shear fractures. The surgical interval is developed between the pes anserinus (anteriorly) and the medial head of the gastrocnemius (posteriorly). Retracting the medial head of the gastrocnemius posteriorly and laterally protects the popliteal neurovascular bundle.

Question 10392

Topic: 2. Trauma

A 42-year-old male presents with a high-energy closed pilon fracture. Initial management included a spanning external fixator. Definitive internal fixation is planned. What is the most reliable clinical indicator that the soft tissues are ready for definitive surgical management?

. Resolution of hemorrhagic fracture blisters
. Return of palpable pedal pulses
. Appearance of skin wrinkles on the anterior ankle
. Normalization of C-reactive protein (CRP)
. Decrease in swelling to less than 1 cm compared to the contralateral side

Correct Answer & Explanation

. Resolution of hemorrhagic fracture blisters

Explanation

The timing of definitive internal fixation for high-energy pilon fractures is dictated by the soft tissue envelope. The 'wrinkle sign' (the appearance of skin lines when the ankle is dorsiflexed or naturally as edema subsides) is the most reliable clinical indicator that the swelling has resolved sufficiently to allow for safe surgical incisions and skin closure, typically occurring 10 to 21 days post-injury.

Question 10393

Topic: 2. Trauma

A 28-year-old snowboarder sustains a Hawkins Type II talar neck fracture. At 8 weeks postoperatively, a plain AP radiograph of the ankle demonstrates a subchondral radiolucent band in the dome of the talus. What does this finding indicate?

. Onset of avascular necrosis (AVN)
. Intact vascularity to the talar body
. Nonunion of the talar neck
. Post-traumatic arthritis of the tibiotalar joint
. Osteomyelitis of the talus

Correct Answer & Explanation

. Onset of avascular necrosis (AVN)

Explanation

The 'Hawkins sign' is a subchondral radiolucent band seen in the talar dome on an AP or mortise radiograph 6 to 8 weeks after a talar neck fracture. It represents subchondral osteopenia secondary to hyperemia, which is a definitive sign that the talar body has an intact vascular supply, thereby effectively ruling out avascular necrosis (AVN).

Question 10394

Topic: 2. Trauma

A 40-year-old male is involved in a high-speed motor vehicle collision. Radiographs of the pelvis demonstrate an acetabular fracture. Which of the following radiographic findings on an obturator oblique view is pathognomonic for a both-column fracture?

. Gull sign
. Spur sign
. Teardrop disruption
. Ischial spine avulsion
. Iliopectineal line disruption without ilioischial line involvement

Correct Answer & Explanation

. Gull sign

Explanation

The 'spur sign' on an obturator oblique radiograph is pathognomonic for a both-column fracture of the acetabulum. It represents the lowest intact portion of the ilium that remains attached to the axial skeleton, projecting posteriorly as a 'spur' relative to the medially displaced articular segments.

Question 10395

Topic: 2. Trauma
A 25-year-old female sustains a vertically oriented, displaced femoral neck fracture (Pauwels Type III) after a fall from a horse. Which of the following fixation constructs offers the highest biomechanical stability against shear forces for this fracture pattern?
. Three parallel cannulated cancellous screws
. Two parallel cannulated cancellous screws
. Fixed-angle sliding hip screw with an anti-rotation screw
. Flexible intramedullary nails
. Hemiarthroplasty

Correct Answer & Explanation

. Fixed-angle sliding hip screw with an anti-rotation screw

Explanation

Pauwels Type III femoral neck fractures have a vertical fracture line (angle >50 degrees), which subjects them to extremely high shear forces. Standard parallel cannulated screws have a high failure rate in this pattern. A fixed-angle device, such as a sliding hip screw (with a derotational screw) or a proximal femoral locking plate, provides superior biomechanical stability against vertical shear.

Question 10396

Topic: 2. Trauma

In the treatment of intertrochanteric femur fractures, the integrity of the lateral trochanteric wall is a critical determinant of construct stability. According to orthopedic literature, a lateral wall thickness less than what threshold is considered an absolute indication for a cephalomedullary nail rather than a sliding hip screw?

. 10.5 mm
. 20.5 mm
. 30.5 mm
. 40.5 mm
. 50.5 mm

Correct Answer & Explanation

. 10.5 mm

Explanation

Hsu et al. demonstrated that a lateral trochanteric wall thickness of less than 20.5 mm is highly predictive of postoperative lateral wall fracture when fixed with a sliding hip screw. This converts a stable pattern into an unstable one, leading to massive collapse. Therefore, lateral wall thickness <20.5 mm is an indication for cephalomedullary nailing.

Question 10397

Topic: 2. Trauma
A 30-year-old polytrauma patient presents with bilateral femoral shaft fractures, a pulmonary contusion, and a grade III spleen laceration. Which of the following physiological parameters is an absolute indication for temporary external fixation (Damage Control Orthopedics) rather than early total care with intramedullary nailing?
. Base deficit of 2.0 mmol/L
. Arterial Lactate of 1.5 mmol/L
. Arterial pH of 7.20
. Core temperature of 36.5°C
. Platelet count of 120,000/μL

Correct Answer & Explanation

. Arterial pH of 7.20

Explanation

Damage Control Orthopedics (DCO) is indicated in unstable polytrauma patients to avoid the 'second hit' phenomenon from early total care (ETC). Absolute clinical indicators of physiologic instability demanding DCO include: pH < 7.24, Core Temperature < 33°C, Lactate > 2.5 mmol/L, Base Deficit > 5 mmol/L, and coagulopathy (Platelets < 90,000 or INR > 1.5).

Question 10398

Topic: 2. Trauma

A 34-year-old motorcyclist sustains a coronal shear fracture of the lateral femoral condyle. What is the standard eponym for this fracture, and what is the standard direction of screw fixation to secure the fragment?

. Segond fracture; medial approach, posterior-to-anterior lag screws
. Hoffa fracture; lateral approach, anterior-to-posterior lag screws
. Barton fracture; posterior approach, plate fixation
. Tillaux fracture; anterior approach, tension band wiring
. Cotton fracture; medial approach, anterior-to-posterior lag screws

Correct Answer & Explanation

. Segond fracture; medial approach, posterior-to-anterior lag screws

Explanation

A coronal shear fracture of the femoral condyle is known as a Hoffa fracture. It most commonly affects the lateral condyle. Standard fixation involves open reduction (often via a lateral or parapatellar approach) and lag screw fixation placed from anterior-to-posterior. Although posterior-to-anterior screws are biomechanically stronger, AP screws are technically easier and avoid the risk of neurovascular injury in the popliteal fossa.

Question 10399

Topic: 2. Trauma
A 22-year-old male is admitted with a closed midshaft tibia fracture. Twelve hours later, he complains of severe leg pain out of proportion to the injury, unrelieved by opioids. His blood pressure is 120/70 mmHg. Intracompartmental pressure in the anterior compartment is 45 mmHg. What is the patient's delta pressure, and is fasciotomy indicated?
. Delta pressure is 25 mmHg; fasciotomy is indicated
. Delta pressure is 25 mmHg; fasciotomy is not indicated
. Delta pressure is 75 mmHg; fasciotomy is indicated
. Delta pressure is 75 mmHg; fasciotomy is not indicated
. Delta pressure is 50 mmHg; fasciotomy is not indicated

Correct Answer & Explanation

. Delta pressure is 25 mmHg; fasciotomy is indicated

Explanation

Delta pressure (ΔP) is calculated as Diastolic Blood Pressure minus Compartment Pressure. Here, ΔP = 70 mmHg - 45 mmHg = 25 mmHg. A delta pressure of less than 30 mmHg is highly specific for acute compartment syndrome and is an absolute indication for emergency four-compartment fasciotomy.

Question 10400

Topic: 2. Trauma
A 45-year-old male farm worker caught his leg in an auger, sustaining a highly contaminated open diaphyseal tibia fracture. There is a 12 cm soft tissue laceration with extensive periosteal stripping. On examination, the foot is pulseless, and vascular surgery determines that an arterial repair is required to salvage the limb. What is the Gustilo-Anderson classification?
. Type II
. Type IIIA
. Type IIIB
. Type IIIC
. Type IV

Correct Answer & Explanation

. Type IIIC

Explanation

The Gustilo-Anderson classification for open fractures categorizes any open fracture that is associated with an arterial injury requiring repair to restore distal perfusion as a Type IIIC, regardless of the size of the soft tissue wound or the degree of bone comminution.

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