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2. Trauma MCQs

Practice Set 524 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 10461

Topic: 2. Trauma

A 72-year-old female presents with a 4-part proximal humerus fracture after a fall.

Which of the following factors most significantly increases the risk of avascular necrosis (AVN) of the humeral head in this setting?

. Medial calcar hinge length of 15 mm
. Disruption of the anterior humeral circumflex artery
. Anatomic neck fracture with short calcar segment (<8 mm)
. Varus angulation of 10 degrees
. Greater tuberosity displacement of 5 mm

Correct Answer & Explanation

. Medial calcar hinge length of 15 mm

Explanation

Hertel described radiographic predictors of ischemia (and potential AVN) in proximal humerus fractures. The most significant predictors include an anatomic neck fracture pattern, a short medial calcar segment (< 8 mm) attached to the articular segment, and disruption of the medial hinge. While historically the anterior humeral circumflex artery was thought to be the main supply, recent studies show the posterior humeral circumflex artery is the primary blood supply; regardless, Hertel's radiographic criteria remain standard for predicting AVN.

Question 10462

Topic: 2. Trauma
A 30-year-old male sustains a femoral neck fracture in a high-speed MVC. The fracture is oriented nearly vertically (Pauwels Type III, 70 degrees). Which of the following biomechanical forces predominates at the fracture site, making internal fixation challenging?
. Compressive forces
. Tensile forces
. Shear forces
. Rotational forces
. Torsional forces

Correct Answer & Explanation

. Shear forces

Explanation

The Pauwels classification of femoral neck fractures is based on the angle of the fracture line relative to the horizontal. Type I is < 30 degrees, Type II is 30-50 degrees, and Type III is > 50 degrees. As the angle increases (more vertical fracture line), the biomechanical forces at the fracture site shift from predominantly compressive (which are favorable for healing) to primarily shear forces, which promote displacement, varus collapse, and nonunion, making stable internal fixation challenging.

Question 10463

Topic: 2. Trauma

A 55-year-old female presents with a wrist injury after a fall. Radiographs show a fracture of the distal radius with a displaced volar articular lip and volar subluxation of the carpus. Which of the following is the most accurate diagnosis and recommended treatment?

. Colles fracture; closed reduction and short arm cast
. Smith fracture; closed reduction and long arm cast
. Volar Barton fracture; open reduction and internal fixation with a volar buttress plate
. Chauffeur's fracture; percutaneous pinning
. Die-punch fracture; external fixation

Correct Answer & Explanation

. Colles fracture; closed reduction and short arm cast

Explanation

A volar Barton fracture is a shear-type intra-articular fracture of the distal radius with displacement of the volar articular margin and concomitant volar subluxation of the carpus. Because it is highly unstable and involves the articular surface, the standard of care is open reduction and internal fixation, typically utilizing a volar buttress plate to counteract the shear forces.

Question 10464

Topic: 2. Trauma

A 24-year-old male cyclist falls and sustains a midshaft clavicle fracture. Which of the following is an absolute indication for immediate operative management (ORIF) of this fracture?

. 1.5 cm of shortening
. Completely displaced fracture with no cortical contact
. Open fracture
. Z-type comminution
. Age over 20 years

Correct Answer & Explanation

. 1.5 cm of shortening

Explanation

Absolute indications for surgical fixation of a clavicle fracture include an open fracture, an associated neurovascular injury, skin tenting that threatens to progress to an open fracture (impending open), and a floating shoulder (clavicle fracture combined with an unstable scapular neck fracture). While displacement and shortening > 2 cm are strong relative indications in active adults to prevent nonunion and shoulder dysfunction, an open fracture represents a surgical emergency and is an absolute indication.

Question 10465

Topic: 2. Trauma

The Lower Extremity Assessment Project (LEAP) evaluated outcomes following severe lower extremity trauma resulting in a mangled limb. Which of the following statements most accurately reflects the findings of this multicenter study?

. The Mangled Extremity Severity Score (MESS) is a highly specific predictor for successful limb salvage.
. Early amputation results in lower long-term cumulative healthcare costs compared to limb salvage.
. Functional outcomes and quality of life at 2 years are comparable between limb salvage and early amputation.
. Patients undergoing limb salvage have a significantly higher rate of return to work at 2 years.
. Limb salvage patients exhibit significantly lower rates of delayed complications and rehospitalizations.

Correct Answer & Explanation

. The Mangled Extremity Severity Score (MESS) is a highly specific predictor for successful limb salvage.

Explanation

The LEAP study demonstrated that at 2 years, there was no significant difference in functional outcomes between limb salvage and early amputation. It also found that the MESS score does not accurately predict successful limb salvage.

Question 10466

Topic: 2. Trauma
A 28-year-old male sustains a Hawkins Type III fracture of the talar neck. At 8 weeks post-operative follow-up, an AP radiograph of the ankle reveals a subchondral radiolucent band across the talar dome (Hawkins sign). What does this radiographic finding indicate?
. Impending avascular necrosis of the talar body.
. Intact vascularity and active revascularization of the talar body.
. Atrophic nonunion of the talar neck.
. Deep bone infection of the talar dome.
. Early post-traumatic tibiotalar arthritis.

Correct Answer & Explanation

. Intact vascularity and active revascularization of the talar body.

Explanation

The Hawkins sign represents subchondral osteopenia, which requires an intact blood supply to resorb bone. Its presence indicates intact vascularity and heavily rules out avascular necrosis.

Question 10467

Topic: 2. Trauma

In a polytraumatized patient presenting with a closed femoral shaft fracture, which of the following is considered an absolute indication for Damage Control Orthopedics (DCO) using external fixation rather than Early Total Care (ETC) with intramedullary nailing?

. Glasgow Coma Scale (GCS) score of 12.
. Bilateral femoral shaft fractures in an otherwise stable patient.
. Arterial lactate level of 1.5 mmol/L.
. Pulmonary contusion with a PaO2/FiO2 ratio < 200 mmHg.
. Closed head injury with normal intracranial pressure (ICP).

Correct Answer & Explanation

. Glasgow Coma Scale (GCS) score of 12.

Explanation

A PaO2/FiO2 ratio < 200 mmHg defines acute respiratory distress syndrome (ARDS) and profound physiologic instability. In such borderline or unstable patients, DCO minimizes the second hit of systemic inflammation associated with reaming and nailing.

Question 10468

Topic: 2. Trauma

During an extensile lateral approach for the fixation of a displaced intra-articular calcaneus fracture, the surgeon elevates a full-thickness subperiosteal flap.

To prevent wound edge necrosis, this flap relies primarily on blood supply from which of the following vessels?

. Lateral calcaneal artery.
. Medial calcaneal artery.
. Dorsalis pedis artery.
. Sural artery.
. Anterior tibial artery.

Correct Answer & Explanation

. Lateral calcaneal artery.

Explanation

The lateral calcaneal artery, a branch of the peroneal artery, provides the primary vascular supply to the lateral soft tissues of the heel. A full-thickness subperiosteal "no-touch" flap preserves this critical angiosome.

Question 10469

Topic: 2. Trauma

A 22-year-old male presents with a comminuted midshaft tibia fracture and pain out of proportion to the injury. His blood pressure is 110/70 mmHg. Intracompartmental pressure measurements of the lower leg are obtained. What pressure threshold indicates the need for emergent four-compartment fasciotomies?

. Delta pressure (Diastolic BP - Compartment Pressure) < 30 mmHg.
. Absolute compartment pressure > 20 mmHg.
. Delta pressure (Diastolic BP - Compartment Pressure) > 45 mmHg.
. Absolute compartment pressure > 15 mmHg.
. Delta pressure (Mean Arterial Pressure - Compartment Pressure) < 10 mmHg.

Correct Answer & Explanation

. Delta pressure (Diastolic BP - Compartment Pressure) < 30 mmHg.

Explanation

A delta pressure (diastolic blood pressure minus intracompartmental pressure) of less than 30 mmHg is the accepted threshold for diagnosing acute compartment syndrome and mandates emergent fasciotomy.

Question 10470

Topic: 2. Trauma

A 45-year-old male sustains an acetabular fracture after a motor vehicle collision. AP and Judet views show disruption of the iliopectineal line with an intact ilioischial line. Which of the following best describes this fracture pattern?

. Posterior column
. Anterior column
. Transverse
. T-type
. Both column

Correct Answer & Explanation

. Posterior column

Explanation

Disruption of the iliopectineal line indicates an anterior column or anterior wall fracture. The ilioischial line represents the posterior column, which is intact in this isolated anterior injury.

Question 10471

Topic: 2. Trauma

A 25-year-old polytrauma patient with bilateral femoral shaft fractures and a severe pulmonary contusion is evaluated for definitive fracture fixation versus damage control orthopedics (DCO). Which of the following physiological parameters is the most reliable indicator of adequate resuscitation for safe early total care?

. Serum lactate clearance to < 2.5 mmol/L
. Hemoglobin > 8 g/dL
. Urine output > 0.5 mL/kg/hr
. Systolic blood pressure consistently > 90 mmHg
. Platelet count > 100,000/microL

Correct Answer & Explanation

. Serum lactate clearance to < 2.5 mmol/L

Explanation

Serum lactate clearance (< 2.5 mmol/L) and correction of base deficit are the most sensitive and reliable markers of adequate tissue perfusion and resuscitation. Early total care in under-resuscitated polytrauma patients drastically increases the risk of ARDS.

Question 10472

Topic: 2. Trauma

A 22-year-old male presents with a closed distal-third spiral humeral shaft fracture (Holstein-Lewis) following an arm-wrestling match. On examination, he has an absent brachioradialis reflex and inability to extend his wrist. What is the most appropriate initial management?

. Immediate surgical exploration and primary nerve repair
. Coaptation splinting and observation for 3 to 4 months
. Open reduction internal fixation with prophylactic radial nerve transposition
. Spanning external fixation to maintain length until nerve recovery
. Acute tendon transfers for wrist extension

Correct Answer & Explanation

. Immediate surgical exploration and primary nerve repair

Explanation

Primary radial nerve palsy in the setting of a closed humeral shaft fracture is managed non-operatively with a coaptation splint and observation. Spontaneous nerve recovery occurs in up to 90% of cases within 3 to 4 months.

Question 10473

Topic: 2. Trauma
A 40-year-old farmer sustains an open tibial shaft fracture with massive soft tissue stripping and gross soil contamination after his leg is caught in a tractor. According to the updated guidelines for severe agricultural open fractures, which empiric antibiotic regimen should be initiated immediately?
. First-generation cephalosporin alone
. First-generation cephalosporin and an aminoglycoside
. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin
. A third-generation fluoroquinolone alone
. Vancomycin and Piperacillin/Tazobactam only

Correct Answer & Explanation

. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin

Explanation

For severe agricultural injuries with gross soil contamination (Gustilo IIIB/C), high-dose penicillin is added to a standard regimen (first-generation cephalosporin and an aminoglycoside). This provides specific coverage against Clostridium species to prevent gas gangrene.

Question 10474

Topic: 2. Trauma

A 28-year-old male with a closed tibial shaft fracture reports severe, unrelenting leg pain out of proportion to his injury. His blood pressure is 110/70 mmHg. Which of the following intracompartmental pressure readings is an absolute indication for emergency four-compartment fasciotomy?

. Absolute anterior compartment pressure of 25 mmHg
. Absolute deep posterior compartment pressure of 20 mmHg
. Delta pressure (Diastolic BP minus Compartment Pressure) of 45 mmHg
. Delta pressure (Diastolic BP minus Compartment Pressure) of 20 mmHg
. Delta pressure (Mean Arterial BP minus Compartment Pressure) of 50 mmHg

Correct Answer & Explanation

. Absolute anterior compartment pressure of 25 mmHg

Explanation

A delta pressure (diastolic blood pressure minus intracompartmental pressure) of less than 30 mmHg is the most reliable threshold for diagnosing acute compartment syndrome. A delta pressure of 20 mmHg indicates profound ischemia mandating emergent fasciotomy.

Question 10475

Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable 35-year-old male with an APC-III pelvic ring injury remains hypotensive (BP 70/40 mmHg) despite pelvic binder application, activation of a massive transfusion protocol, and a negative FAST exam. What is the most appropriate next step in acute management?
. CT angiography to localize specific arterial bleeding
. Emergent exploratory laparotomy
. Preperitoneal pelvic packing or pelvic angiography with embolization
. Application of an external fixator to replace the pelvic binder
. Diagnostic peritoneal lavage (DPL)

Correct Answer & Explanation

. Preperitoneal pelvic packing or pelvic angiography with embolization

Explanation

In a hemodynamically unstable pelvic fracture with a negative FAST (ruling out major intra-abdominal hemorrhage), the bleeding is presumed pelvic. Immediate preperitoneal packing or angiography with embolization is indicated to control retroperitoneal hemorrhage.

Question 10476

Topic: Upper Extremity Trauma
A 28-year-old cyclist falls directly onto his shoulder. X-rays show a Rockwood Type III acromioclavicular (AC) joint separation. What defines a Type III injury?
. AC ligaments torn, CC ligaments intact, clavicle minimally displaced.
. AC ligaments torn, CC ligaments torn, clavicle displaced superiorly 25-100% of the normal CC distance.
. AC ligaments torn, CC ligaments torn, clavicle displaced posteriorly into the trapezius.
. AC ligaments torn, CC ligaments torn, clavicle displaced superiorly >100% of the normal CC distance.
. AC ligaments torn, CC ligaments intact, clavicle displaced inferiorly.

Correct Answer & Explanation

. AC ligaments torn, CC ligaments torn, clavicle displaced superiorly 25-100% of the normal CC distance.

Explanation

A Rockwood Type III AC joint separation involves tearing of both the acromioclavicular (AC) and coracoclavicular (CC) ligaments, with the distal clavicle displaced superiorly between 25% and 100% of the normal CC distance compared to the contralateral side.

Question 10477

Topic: Lower Extremity Trauma

A football player sustains a syndesmotic ankle sprain. Which ligament is typically the first to tear in a syndesmotic injury?

. Posterior inferior tibiofibular ligament (PITFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Interosseous membrane
. Deltoid ligament
. Calcaneofibular ligament

Correct Answer & Explanation

. Posterior inferior tibiofibular ligament (PITFL)

Explanation

In a syndesmotic injury (high ankle sprain), the progression of tearing typically begins anteriorly with the anterior inferior tibiofibular ligament (AITFL), followed by the interosseous ligament/membrane, and finally the posterior inferior tibiofibular ligament (PITFL).

Question 10478

Topic: 2. Trauma

A 19-year-old basketball player sustains a zone 2 fracture (Jones fracture) of the fifth metatarsal. Intramedullary screw fixation is recommended over non-operative management primarily due to the high risk of nonunion. What anatomical factor most directly contributes to this nonunion risk?

. Overpull of the peroneus brevis tendon
. A vascular watershed area at the metaphyseal-diaphyseal junction
. High density of cortical bone lacking cancellous marrow
. Lack of periosteal coverage in zone 2
. Overpull of the lateral band of the plantar fascia

Correct Answer & Explanation

. Overpull of the peroneus brevis tendon

Explanation

Zone 2 of the fifth metatarsal represents a vascular watershed area between the metaphyseal and diaphyseal blood supplies. This tenuous blood supply is the primary reason for the high rates of delayed union and nonunion in athletes.

Question 10479

Topic: Upper Extremity Trauma
A 26-year-old cyclist falls directly onto his shoulder. Radiographs reveal a Type V acromioclavicular (AC) joint injury. Which of the following strict criteria distinguishes a Type V injury from a Type III injury?
. Complete rupture of the AC ligaments with intact CC ligaments
. Posterior displacement of the clavicle into the trapezius
. Inferior displacement of the clavicle under the coracoid process
. Greater than 100% superior displacement of the clavicle with detachment of the deltotrapezial fascia
. 25-100% superior displacement of the clavicle with an intact deltotrapezial fascia

Correct Answer & Explanation

. Greater than 100% superior displacement of the clavicle with detachment of the deltotrapezial fascia

Explanation

A Type V AC joint injury is characterized by severe superior displacement (>100% to 300% compared to the contralateral side). This massive displacement occurs because the deltotrapezial fascia is extensively stripped from the distal clavicle.

Question 10480

Topic: Lower Extremity Trauma

The anterolateral ligament (ALL) of the knee is an important secondary stabilizer against anterolateral rotatory instability. Where does the ALL typically insert on the tibia?

. Midway between Gerdy's tubercle and the fibular head
. Directly on Gerdy's tubercle
. At the tip of the fibular head
. Posterior to the fibular head
. The medial tibial plateau

Correct Answer & Explanation

. Midway between Gerdy's tubercle and the fibular head

Explanation

The ALL originates near the lateral epicondyle and inserts on the anterolateral tibia, approximately midway between Gerdy's tubercle and the fibular head. It acts as a secondary restraint to internal tibial rotation.

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