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2. Trauma MCQs

Practice Set 574 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 11461

Topic: 2. Trauma

Six weeks following open reduction and internal fixation of a Hawkins type II talar neck fracture, an anteroposterior radiograph of the ankle demonstrates a distinct subchondral radiolucent band in the talar dome. This radiographic finding most accurately indicates:

. Imminent structural collapse of the talar dome
. Development of severe, progressive avascular necrosis
. Intact vascularity and an excellent prognosis against total avascular necrosis
. Early postoperative joint infection and osteomyelitis
. Nonunion at the talar neck fracture site

Correct Answer & Explanation

. Imminent structural collapse of the talar dome

Explanation

The Hawkins sign is a subchondral radiolucent band seen in the talar dome typically 6 to 8 weeks post-injury. It represents localized subchondral osteopenia secondary to active bone resorption, a process that physiologically requires an intact, functioning blood supply. Therefore, the presence of the Hawkins sign is a reliable indicator that vascularity to the talar body is preserved, effectively ruling out total avascular necrosis.

Question 11462

Topic: 2. Trauma

A patient develops a severe compartment syndrome of the foot following a heavy crush injury. Surgical fasciotomy is planned using a standard dual dorsal incision technique. Based on anatomic consensus, how many distinct osseofascial compartments are recognized in the human foot?

. 4
. 5
. 7
. 9
. 11

Correct Answer & Explanation

. 4

Explanation

The foot contains 9 classically recognized osseofascial compartments: 4 interosseous, 3 central (superficial, shallow, deep), 1 medial, and 1 lateral compartment. Fasciotomy is typically achieved via two dorsal longitudinal incisions (one placed medial to the 2nd metatarsal, one lateral to the 4th metatarsal), with an optional medial incision utilized to ensure complete release of the deep central structures if necessary.

Question 11463

Topic: 2. Trauma

A 24-year-old elite basketball player sustains an acute Zone 2 fracture of the proximal fifth metatarsal. Which of the following describes the most appropriate management to minimize the risk of nonunion and allow early return to play?

. Hard-soled shoe with weight-bearing as tolerated
. Short leg cast, non-weight-bearing for 6 weeks
. Intramedullary screw fixation
. Plating of the fifth metatarsal base
. Primary excision of the proximal fragment

Correct Answer & Explanation

. Hard-soled shoe with weight-bearing as tolerated

Explanation

Zone 2 fractures (Jones fractures) have a higher risk of nonunion due to a vascular watershed area. Intramedullary screw fixation is recommended for high-level athletes to decrease nonunion risk and expedite return to sport.

Question 11464

Topic: 2. Trauma

A 19-year-old track athlete experiences vague dorsal midfoot pain. A CT scan reveals an incomplete, non-displaced stress fracture of the tarsal navicular. What is the recommended initial treatment?

. Pneumatic walking boot, weight-bearing as tolerated for 4 weeks
. Non-weight-bearing cast for 6 to 8 weeks
. Immediate percutaneous screw fixation
. Open reduction and internal fixation with bone grafting
. Corticosteroid injection and activity modification

Correct Answer & Explanation

. Pneumatic walking boot, weight-bearing as tolerated for 4 weeks

Explanation

Non-displaced navicular stress fractures should initially be treated with strict non-weight-bearing in a cast for 6 to 8 weeks. Weight-bearing modalities have an unacceptably high rate of delayed union or frank nonunion.

Question 11465

Topic: 2. Trauma

Six weeks following open reduction and internal fixation of a Hawkins Type II talar neck fracture, an AP radiograph of the ankle reveals a subchondral radiolucent line in the talar dome. What is the clinical significance of this finding?

. It indicates early talar collapse and avascular necrosis
. It represents a deep infection in the talar body
. It is the Hawkins sign, indicating intact vascularity and ruling out avascular necrosis
. It represents hardware loosening
. It indicates an impending nonunion of the fracture site

Correct Answer & Explanation

. It indicates early talar collapse and avascular necrosis

Explanation

The Hawkins sign is a subchondral radiolucency observed in the talar dome 6-8 weeks post-injury, representing subchondral bone resorption secondary to an intact blood supply. It is a highly reliable indicator that avascular necrosis is unlikely to occur.

Question 11466

Topic: 2. Trauma

During an ankle fracture ORIF, the surgeon performs an intraoperative Cotton test and notes widening of the medial clear space and tibiofibular clear space. Which of the following is the most appropriate management?

. Cast immobilization for 6 weeks
. Repair of the deltoid ligament only
. Placement of syndesmotic screws or a suture-button device
. Primary arthrodesis of the tibiofibular joint
. No further action if the fibula is anatomically reduced

Correct Answer & Explanation

. Cast immobilization for 6 weeks

Explanation

A positive Cotton test indicates syndesmotic instability after fibular fixation. This requires stabilization using either syndesmotic screws or a dynamic suture-button construct to restore the tibiofibular relationship.

Question 11467

Topic: 2. Trauma

A 22-year-old collegiate basketball player sustains a fracture of the proximal fifth metatarsal. Radiographs show a fracture line at the metaphyseal-diaphyseal junction extending into the fourth-fifth intermetatarsal articulation. To minimize the risk of nonunion and allow early return to play, which of the following is the most appropriate surgical treatment?

. Open reduction and internal fixation with a tension band construct
. Percutaneous placement of a solid intramedullary screw
. Closed reduction and percutaneous pinning
. Excision of the proximal fragment and peroneus brevis advancement
. Primary arthrodesis of the fifth tarsometatarsal joint

Correct Answer & Explanation

. Open reduction and internal fixation with a tension band construct

Explanation

This is a Zone 2 (Jones) fracture, which is prone to nonunion due to watershed vascularity. In high-level athletes, intramedullary screw fixation is recommended for faster return to play and higher union rates compared to nonoperative management.

Question 11468

Topic: 2. Trauma

A patient sustains a talar neck fracture. Routine follow-up radiographs at 8 weeks demonstrate a subchondral radiolucent band in the dome of the talus. This radiographic finding indicates which of the following?

. Impending collapse of the talar dome
. Failure of internal fixation
. Intact vascularity to the talar body
. Avascular necrosis of the talar body
. Development of an osteochondral lesion

Correct Answer & Explanation

. Impending collapse of the talar dome

Explanation

This describes the Hawkins sign, which is subchondral radiolucency secondary to localized disuse osteopenia. Its presence indicates intact vascular supply to the talar body, effectively ruling out avascular necrosis.

Question 11469

Topic: 2. Trauma

A 21-year-old track athlete is diagnosed with a navicular stress fracture. Which area of the navicular is most susceptible to this injury due to its watershed blood supply?

. Medial tuberosity
. Plantar-medial pole
. Central one-third
. Dorsal articulation with the cuneiforms
. Lateral articular facet

Correct Answer & Explanation

. Medial tuberosity

Explanation

Navicular stress fractures typically occur in the central one-third of the bone. This area is relatively avascular (a watershed zone) between the medial and lateral vascular supplies, predisposing it to delayed healing and nonunion.

Question 11470

Topic: 2. Trauma
A 45-year-old male sustains a high-energy closed tibial pilon fracture with severe soft tissue compromise (Tscherne Grade III). What is the standard staged protocol for managing this injury?
. Immediate spanning external fixation, followed by definitive ORIF when soft tissues permit
. Immediate definitive ORIF using dual plating through dual approaches
. Immediate intramedullary nailing with percutaneous lag screws
. Primary below-knee amputation
. Spanning external fixation combined with immediate open bone grafting

Correct Answer & Explanation

. Immediate spanning external fixation, followed by definitive ORIF when soft tissues permit

Explanation

High-energy pilon fractures with severe soft-tissue injury are managed with a staged approach: immediate spanning external fixation to restore length and alignment, allowing the soft tissue envelope to recover (often 10-21 days) before definitive ORIF.

Question 11471

Topic: 2. Trauma

A 32-year-old male arrives in the emergency department with a highly displaced midshaft tibia fracture. He is complaining of severe pain out of proportion to his injury. His diastolic blood pressure is 75 mmHg. Compartment pressure measurements are obtained using a solid-state transducer. According to widely accepted clinical guidelines, at what absolute compartment pressure measurement would the delta pressure strongly indicate the need for a four-compartment fasciotomy?

. 25 mmHg
. 35 mmHg
. 46 mmHg
. 56 mmHg
. 66 mmHg

Correct Answer & Explanation

. 25 mmHg

Explanation

Compartment syndrome is a clinical diagnosis, but pressure measurements are helpful when the diagnosis is ambiguous. The 'delta pressure' is calculated as Diastolic Blood Pressure minus Compartment Pressure. A delta pressure of less than 30 mmHg (some sources say <20-30 mmHg) is an indication for fasciotomy. With a diastolic BP of 75 mmHg, an absolute compartment pressure of 46 mmHg yields a delta pressure of 29 mmHg, which is <30 mmHg and therefore indicates fasciotomy.

Question 11472

Topic: 2. Trauma
Fat embolism syndrome (FES) is a potentially life-threatening complication in orthopedic trauma. Among the following scenarios, which carries the highest pathophysiological risk for the release of embolic marrow fat into the venous circulation?
. Closed pelvic ring disruption treated with external fixation
. Open grade IIIb tibia fracture treated with immediate intramedullary nailing
. Reamed intramedullary nailing of a closed diaphyseal femur fracture
. Total knee arthroplasty utilizing an extramedullary alignment guide
. Multiple rib fractures and flail chest treated with plating

Correct Answer & Explanation

. Reamed intramedullary nailing of a closed diaphyseal femur fracture

Explanation

Fat embolism syndrome is most commonly associated with fractures of long bones, particularly the femur. Reaming the intramedullary canal dramatically increases intramedullary pressures (often >500 mmHg), which forces marrow contents, including fat and pro-coagulant tissue factors, directly into the venous sinuses and systemic circulation. While unreamed nailing or other procedures carry risk, reamed femoral nailing has historically posed the highest discrete risk for embolic showers.

Question 11473

Topic: Pelvic & Acetabular Trauma
A 24-year-old male is brought to the trauma bay following a motorcycle collision. He is hypotensive with a systolic blood pressure of 75 mmHg. Pelvic radiograph shows an APC-III pelvic ring injury. A pelvic binder is applied, and he receives 2 units of packed red blood cells, but his hemodynamics do not improve. FAST scan is negative. What is the most appropriate next step in management?
. Application of an external fixator
. Exploratory laparotomy
. Preperitoneal pelvic packing or angiography
. Administration of tranexamic acid and wait 1 hour
. Transfer for definitive open reduction and internal fixation

Correct Answer & Explanation

. Preperitoneal pelvic packing or angiography

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST scan, the source of bleeding is presumed to be the pelvis. The next appropriate step is preperitoneal pelvic packing or pelvic angiography for embolization.

Question 11474

Topic: 2. Trauma

A 40-year-old male sustains a high-energy varus and axial load injury to his knee, resulting in a Schatzker IV tibial plateau fracture (medial plateau). Due to the mechanism and displacement, which associated vascular structure is at the highest risk for injury?

. Anterior tibial artery
. Posterior tibial artery
. Popliteal artery
. Peroneal artery
. Femoral artery

Correct Answer & Explanation

. Anterior tibial artery

Explanation

Schatzker IV fractures (medial plateau) are often the result of high-energy trauma (varus/axial load) and can be associated with knee subluxation or dislocation, placing the tethered popliteal artery at high risk of injury.

Question 11475

Topic: 2. Trauma

When choosing an intramedullary nail for a femur fracture, a surgeon decides to use a 12 mm solid nail instead of a 10 mm solid nail of the same material. According to biomechanical principles, the bending rigidity of the nail increases by a factor proportional to the radius raised to what power?

. Second power (r^2)
. Third power (r^3)
. Fourth power (r^4)
. Fifth power (r^5)
. It scales linearly with the radius

Correct Answer & Explanation

. Second power (r^2)

Explanation

The bending rigidity of a solid cylindrical orthopedic implant is determined by the area moment of inertia, which is proportional to the radius to the fourth power (r^4). Thus, a small increase in nail diameter yields a massive increase in bending stiffness.

Question 11476

Topic: 2. Trauma
A 30-year-old farm worker sustains a severe open tibial shaft fracture (Gustilo-Anderson Grade IIIB) highly contaminated with soil. In addition to prompt surgical debridement and standard cephalosporin coverage, which antibiotic should be added to specifically cover likely soil-based pathogens like Clostridium?
. Vancomycin
. Penicillin
. Gentamicin
. Clindamycin
. Doxycycline

Correct Answer & Explanation

. Penicillin

Explanation

Farm injuries or severe open fractures highly contaminated with soil carry a high risk of clostridial infection. The standard antibiotic protocol involves a first-generation cephalosporin, an aminoglycoside (for gram-negatives), and high-dose Penicillin to cover anaerobes like Clostridium.

Question 11477

Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the emergency department after a high-speed motor vehicle collision. He is hemodynamically unstable with a suspected anterior-posterior compression (APC) type III pelvic ring injury. When applying a non-invasive pelvic circumferential compression device (pelvic binder), at what anatomical level should it be centered for maximum efficacy?
. Iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Symphysis pubis directly
. Sacral promontory

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder must be centered over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement higher over the iliac crests is less effective and may paradoxically open the true pelvis in certain fracture patterns.

Question 11478

Topic: 2. Trauma
A 25-year-old male sustains a closed tibial shaft fracture. Two hours later, he develops severe pain out of proportion to the injury. Which of the following objective measurement criteria is the most reliable threshold for diagnosing acute compartment syndrome and indicating the need for fasciotomy?
. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 25 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Mean arterial pressure minus compartment pressure < 40 mmHg
. Systolic blood pressure minus compartment pressure < 30 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The most reliable parameter for diagnosing acute compartment syndrome is the delta pressure (ΔP), defined as the diastolic blood pressure minus the compartment pressure. A ΔP of less than 30 mmHg strongly indicates inadequate tissue perfusion and is a threshold for performing a fasciotomy.

Question 11479

Topic: 2. Trauma

A 28-year-old male is evaluated for compartment syndrome of the leg following a severe crush injury. Tissue perfusion in the compartment ceases when the compartment tissue pressure approaches which of the following parameters?

. Systolic blood pressure
. Mean arterial pressure
. Diastolic blood pressure
. Central venous pressure
. Capillary closing pressure

Correct Answer & Explanation

. Systolic blood pressure

Explanation

Tissue perfusion in a compartment is driven by the arteriovenous gradient. When the interstitial compartment pressure rises to within 10-30 mmHg of the diastolic blood pressure, capillary flow is obstructed, leading to ischemia.

Question 11480

Topic: 2. Trauma

A 24-year-old male sustains a closed comminuted femoral shaft fracture. Forty-eight hours post-injury, he develops confusion, tachypnea, and a petechial rash over his axillae. According to Gurd's criteria, which of the following is considered a major criterion for his likely diagnosis?

. Tachycardia greater than 120 bpm
. Fever greater than 39.5 degrees Celsius
. Petechial rash
. Jaundice
. Retinal changes

Correct Answer & Explanation

. Tachycardia greater than 120 bpm

Explanation

Fat embolism syndrome is diagnosed using Gurd's criteria. The major criteria include petechial rash (typically on the axillae, chest, and conjunctiva), respiratory insufficiency, and cerebral involvement (confusion).

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