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2. Trauma MCQs

Practice Set 238 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 4741

Topic: 2. Trauma
A 28-year-old male sustains a vertically oriented (Pauwels type III) femoral neck fracture. Which of the following internal fixation constructs provides the greatest biomechanical stability and highest failure load for this specific shear-pattern fracture?
. Three parallel cancellous screws placed in an inverted triangle
. Two parallel cancellous screws
. Sliding hip screw with an anti-rotation cancellous screw
. Cephalomedullary nail with a single head screw
. Fully threaded dynamic condylar screw

Correct Answer & Explanation

. Sliding hip screw with an anti-rotation cancellous screw

Explanation

Pauwels type III fractures are highly vertical (>50 degrees) and experience massive shear forces, leading to high rates of nonunion and fixation failure. Biomechanical studies have demonstrated that fixed-angle devices, specifically a sliding hip screw (SHS) combined with a derotational cancellous screw, provide superior biomechanical stability and withstand higher shear forces compared to multiple parallel cancellous screws, which are prone to cut-out and varus collapse in these patterns.

Question 4742

Topic: Upper Extremity Trauma
A 24-year-old cyclist falls directly onto his shoulder. Clinical examination reveals a prominent distal clavicle. An axillary radiograph demonstrates the distal clavicle is displaced posteriorly, penetrating into the trapezius fascia. According to the Rockwood classification, what is the appropriate injury type and generally accepted management?
. Type III; nonoperative management
. Type IV; surgical reconstruction
. Type V; surgical reconstruction
. Type IV; nonoperative management
. Type VI; urgent surgical reduction

Correct Answer & Explanation

. Type IV; surgical reconstruction

Explanation

The Rockwood classification of acromioclavicular (AC) joint injuries defines a Type IV injury as posterior displacement of the distal clavicle into or through the trapezius fascia. This injury is extremely painful, often irreducible closed, and fundamentally disrupts the deltotrapezial fascia. Because of the persistent disability and irreducible nature, Rockwood Type IV, V, and VI injuries are generally treated with surgical reduction and reconstruction.

Question 4743

Topic: 2. Trauma

A 32-year-old male sustains a closed comminuted tibia fracture and subsequently develops intense, unrelenting leg pain. His blood pressure is 120/70 mmHg. Intracompartmental pressure monitoring reveals an anterior compartment pressure of 45 mmHg. What is the calculated Delta P, and what is the most appropriate next step in management?

. 25 mmHg; emergent four-compartment fasciotomy
. 45 mmHg; continuous observation
. 75 mmHg; emergent four-compartment fasciotomy
. 25 mmHg; elevate the leg above the heart
. 50 mmHg; administer intravenous mannitol

Correct Answer & Explanation

. 25 mmHg; emergent four-compartment fasciotomy

Explanation

Delta P is defined as the diastolic blood pressure minus the absolute intracompartmental pressure (Delta P = DBP - ICP). In this scenario, Delta P = 70 mmHg - 45 mmHg = 25 mmHg. A Delta P of less than 30 mmHg represents inadequate capillary perfusion and is an absolute indication for emergent four-compartment fasciotomy to prevent irreversible ischemic necrosis. Elevating the leg above the heart decreases arterial inflow and would worsen the ischemia.

Question 4744

Topic: 2. Trauma

During the evaluation of a highly comminuted intra-articular distal femur fracture (OTA/AO type 33-C3), a CT scan reveals a distinct coronal plane fracture of the lateral femoral condyle. What is the eponym for this specific fracture pattern, and what is the optimal vector for its interfragmentary lag screw fixation?

. Barton fracture; anterior to posterior
. Die-punch fracture; lateral to medial
. Hoffa fracture; anterior to posterior
. Chauffeur fracture; posterior to anterior
. Hoffa fracture; distal to proximal

Correct Answer & Explanation

. Hoffa fracture; anterior to posterior

Explanation

A Hoffa fracture is a coronal plane fracture of the femoral condyle (most commonly lateral). Because it is an intra-articular shear fracture (OTA/AO type 33-B3), it demands anatomic reduction and absolute stability. The optimal fixation technique involves interfragmentary lag screws placed from anterior to posterior (A-P) perpendicular to the fracture plane. Although P-A is sometimes required based on surgical approach, A-P placement counters the primary shear forces and utilizes the denser anterior cortical bone for screw head purchase.

Question 4745

Topic: 2. Trauma

A 40-year-old male sustains a high-energy varus load to his knee, resulting in a displaced fracture of the medial tibial plateau with a large single fragment. Which of the following statements regarding this fracture pattern (Schatzker Type IV) is most accurate?

. It is a low-energy injury typically seen in osteoporotic females
. It is most effectively treated with a lateral locking plate acting as a tension band
. It carries a high risk of peroneal nerve palsy due to the varus mechanism
. It has a high association with popliteal artery injury and ligamentous disruption
. The primary fixation strategy requires an isolated interfragmentary lag screw without a plate

Correct Answer & Explanation

. It has a high association with popliteal artery injury and ligamentous disruption

Explanation

A Schatzker Type IV fracture is a high-energy medial tibial plateau fracture. Because the medial plateau is structurally much denser than the lateral plateau, fracturing it requires massive force. Consequently, this injury represents a fracture-subluxation or knee dislocation equivalent, carrying a notoriously high association with multi-ligamentous injuries, popliteal artery damage, and compartment syndrome. It must be addressed with a medial buttress plate to counteract the varus displacing forces.

Question 4746

Topic: 2. Trauma

A 35-year-old man sustains a high-energy trauma resulting in an ipsilateral displaced midshaft clavicle fracture and a displaced scapular neck fracture ('floating shoulder'). Which of the following radiographic findings serves as the strongest indication for operative fixation of the scapular neck fracture?

. Glenopolar angle of 45 degrees
. Intra-articular extension with 1 mm step-off
. Glenopolar angle of 20 degrees
. Medialization of the glenoid of 5 mm
. Scapular neck displacement of 5 mm

Correct Answer & Explanation

. Glenopolar angle of 20 degrees

Explanation

A 'floating shoulder' disrupts the superior shoulder suspensory complex. Indications for operative fixation of the scapula include a glenopolar angle (GPA) of less than 22 degrees, medial translation > 10-20 mm, or severe angulation. A GPA of 20 degrees represents significant rotational malalignment of the glenoid, leading to poor functional outcomes and rotator cuff dysfunction, thus strongly indicating the need for fixation.

Question 4747

Topic: 2. Trauma

A 28-year-old man presents to the emergency department with a closed, spiral fracture of the distal third of the humeral shaft. On initial evaluation, he has full wrist and finger extension. Following application of a coaptation splint and closed reduction, he is re-evaluated and found to have a complete loss of wrist and finger extension. What is the most appropriate next step in management?

. Observation with serial clinical examinations
. EMG and nerve conduction studies
. Operative exploration and fracture fixation
. Urgent MRI of the humerus
. Removal of splint and placement of a functional brace

Correct Answer & Explanation

. Operative exploration and fracture fixation

Explanation

The patient has a Holstein-Lewis fracture. Primary radial nerve palsy with a closed humeral shaft fracture is generally treated with observation. However, a secondary (iatrogenic) radial nerve palsy that occursafterclosed reduction or splinting indicates possible entrapment or laceration of the nerve in the fracture site. This is a strong, absolute indication for surgical exploration and operative fracture fixation.

Question 4748

Topic: 2. Trauma

A 40-year-old construction worker sustains a midshaft clavicle fracture. The treating orthopedic surgeon is discussing the pros and cons of nonoperative management versus plate fixation. Which of the following radiographic characteristics is considered the strongest risk factor for nonunion if this fracture is treated nonoperatively?

. Displacement greater than 100% with no cortical contact
. Inferior displacement of the medial fragment
. Oblique fracture pattern without comminution
. Male gender
. Age younger than 30 years

Correct Answer & Explanation

. Displacement greater than 100% with no cortical contact

Explanation

When treating midshaft clavicle fractures nonoperatively, the most significant risk factor for nonunion is displacement of >100% (lack of cortical contact). Other risk factors include advancing age, smoking, fracture comminution, and female gender.

Question 4749

Topic: 2. Trauma

An 80-year-old woman sustains a 3-part proximal humerus fracture with anterior fracture-dislocation of the humeral head. Which of the following physical examination findings would most accurately indicate a complete injury to the axillary nerve in the acute setting?

. Inability to actively abduct the arm past 90 degrees
. Loss of sensation over the lateral aspect of the shoulder
. Weakness in external rotation with the arm adducted
. Weakness with elbow extension
. Loss of sensation over the first dorsal web space

Correct Answer & Explanation

. Loss of sensation over the lateral aspect of the shoulder

Explanation

The axillary nerve provides motor innervation to the deltoid and teres minor, and sensory innervation to the lateral shoulder via the superior lateral cutaneous nerve of the arm. In the acute trauma setting, pain prevents reliable motor testing of the deltoid. Therefore, sensory testing over the lateral aspect of the shoulder (regimental badge area) is the most reliable clinical indicator of an axillary nerve injury.

Question 4750

Topic: 2. Trauma
A 32-year-old male sustains a vertically oriented basicervical femoral neck fracture (Pauwels type III) after a fall. Which of the following fixation constructs provides the most biomechanically stable construct for this specific high-shear fracture pattern?
. Three parallel partially threaded cancellous screws
. Sliding hip screw with a derotational cancellous screw
. Intramedullary piriformis-entry nail
. Two crossed partially threaded cancellous screws
. A single fully threaded 7.3mm transverse screw

Correct Answer & Explanation

. Sliding hip screw with a derotational cancellous screw

Explanation

Pauwels type III (vertical) fractures experience high shear forces leading to varus collapse and nonunion. A sliding hip screw combined with a derotational screw provides superior biomechanical stability against shear forces compared to multiple parallel cancellous screws.

Question 4751

Topic: 2. Trauma

A 45-year-old male sustains a fracture of the medial tibial plateau with extension into the intercondylar eminence (Schatzker IV). The primary fracture line exits posteromedially. Which surgical approach is most appropriate for direct visualization and buttress plating?

. Anterolateral approach
. Standard anterior midline approach
. Posteromedial approach
. Direct medial approach
. Posterolateral approach

Correct Answer & Explanation

. Posteromedial approach

Explanation

Schatzker IV fractures involving a posteromedial fragment are prone to varus collapse if not adequately supported. A posteromedial approach allows for direct visualization, reduction, and application of a posterior buttress plate to resist the displacement forces.

Question 4752

Topic: 2. Trauma

A 29-year-old male with a closed midshaft tibia fracture complains of escalating leg pain out of proportion to injury 4 hours after admission. Which compartment pressure measurement is the most reliable threshold to indicate the need for a fasciotomy?

. Absolute compartment pressure strictly greater than 20 mmHg
. Absolute compartment pressure strictly greater than 30 mmHg
. Delta pressure (diastolic blood pressure minus compartment pressure) less than 30 mmHg
. Delta pressure (mean arterial pressure minus compartment pressure) less than 40 mmHg
. Delta pressure (systolic blood pressure minus compartment pressure) less than 50 mmHg

Correct Answer & Explanation

. Delta pressure (diastolic blood pressure minus compartment pressure) less than 30 mmHg

Explanation

Delta pressure, calculated as diastolic blood pressure minus the measured intra-compartmental pressure, is the most accurate diagnostic metric for acute compartment syndrome. A delta pressure of less than 30 mmHg represents inadequate tissue perfusion and is an indication for emergent fasciotomy.

Question 4753

Topic: Upper Extremity Trauma
A 28-year-old male laborer sustains an acromioclavicular (AC) joint injury. Radiographs reveal 100% superior displacement of the clavicle relative to the acromion, with the coracoclavicular distance increased but less than 100% compared to the normal side (Rockwood Type III). What is the preferred initial management?
. Nonoperative management with a brief period of sling immobilization followed by physical therapy
. Arthroscopic coracoclavicular ligament reconstruction
. Immediate open reduction and internal fixation with a hook plate
. Primary distal clavicle excision
. Acromioclavicular joint fusion

Correct Answer & Explanation

. Immediate open reduction and internal fixation with a hook plate

Explanation

Rockwood Type III AC joint separations are initially treated nonoperatively with a brief sling and early physical therapy. Surgical intervention is generally reserved for patients who remain symptomatic after an exhausted trial of conservative management, or occasionally for high-demand overhead athletes.

Question 4754

Topic: 2. Trauma

An 18-year-old male is recovering from a Hawkins type II talar neck fracture. At his 8-week follow-up, an AP mortise radiograph shows a subchondral radiolucent band in the talar dome. What is the clinical significance of this finding?

. It indicates impending avascular necrosis of the talar body
. It signifies intact vascularity and osteoclast resorption in the talar body
. It is pathognomonic for an unrecognized osteochondral defect
. It suggests an established nonunion of the talar neck fracture
. It indicates early post-traumatic subtalar arthritis

Correct Answer & Explanation

. It signifies intact vascularity and osteoclast resorption in the talar body

Explanation

Hawkins sign is the appearance of a subchondral radiolucent band in the talar dome 6 to 8 weeks after a talar neck fracture. It indicates active subchondral osteoclastic resorption, which requires an intact blood supply, thus predicting a low likelihood of avascular necrosis.

Question 4755

Topic: 2. Trauma

A 42-year-old roofer falls from a ladder, sustaining an intra-articular calcaneus fracture with severe depression of the posterior facet. Which of the following best describes the expected radiographic changes to the angle of Gissane and Bohler's angle?

. Angle of Gissane increases, Bohler's angle increases
. Angle of Gissane decreases, Bohler's angle decreases
. Angle of Gissane increases, Bohler's angle decreases
. Angle of Gissane decreases, Bohler's angle increases
. Both angles typically remain unchanged

Correct Answer & Explanation

. Angle of Gissane increases, Bohler's angle decreases

Explanation

In a joint-depression type intra-articular calcaneus fracture, the posterior facet is driven downward into the calcaneal body. This collapse causes Bohler's angle (normally 20-40 degrees) to flatten or decrease, and the angle of Gissane (normally 105-135 degrees) to widen or increase.

Question 4756

Topic: 2. Trauma

A 35-year-old male sustains an acetabular fracture in a motor vehicle accident. Radiographs and CT imaging are obtained. According to the Letournel and Judet classification, which of the following specific radiographic or CT findings distinguishes a T-type fracture from a standard transverse fracture of the acetabulum?

. Disruption of the iliopectineal line
. Disruption of the ilioischial line
. A vertical fracture line extending through the obturator ring
. Involvement of the posterior wall
. A fracture line exiting the iliac crest

Correct Answer & Explanation

. A vertical fracture line extending through the obturator ring

Explanation

In the Letournel and Judet classification, a standard transverse fracture splits the acetabulum horizontally into a superior (iliac) and inferior (ischiopubic) segment, disrupting both the anterior and posterior columns. A T-type fracture is a transverse fracture with an added vertical split that extends inferiorly through the obturator ring, dividing the inferior segment into separate anterior and posterior pillars.

Question 4757

Topic: Pelvic & Acetabular Trauma
Which of the following specific ligamentous disruptions is the primary distinguishing feature between an Anteroposterior Compression II (APC-II) and an Anteroposterior Compression III (APC-III) pelvic ring injury in the Young-Burgess classification?
. Posterior sacroiliac ligament disruption
. Anterior sacroiliac ligament disruption
. Sacrotuberous ligament disruption
. Sacrospinous ligament disruption
. Symphysis pubis disruption

Correct Answer & Explanation

. Symphysis pubis disruption

Explanation

In the Young-Burgess classification, APC-II injuries involve a disrupted symphysis pubis (or vertical rami fractures) along with disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments, while the posterior sacroiliac ligaments remain intact (opening of the anterior SI joint). An APC-III injury involves the additional complete disruption of the posterior sacroiliac ligaments, leading to complete hemipelvic instability.

Question 4758

Topic: 2. Trauma
A 28-year-old male sustains a vertically oriented, highly displaced femoral neck fracture (Pauwels Type III). Which of the following internal fixation constructs provides the highest biomechanical stability against the high vertical shear forces inherent to this fracture pattern?
. A fixed-angle sliding hip screw (SHS) construct supplemented with a derotation screw
. Three parallel cancellous lag screws in a standard triangle configuration
. Three parallel cancellous lag screws in an inverted triangle configuration
. Fully threaded, non-cannulated 4.5 mm cortical screws
. Two partially threaded cancellous screws placed perpendicularly to the fracture line

Correct Answer & Explanation

. Three parallel cancellous lag screws in an inverted triangle configuration

Explanation

Pauwels Type III fractures (>50 degrees to the horizontal) experience immense vertical shear forces rather than compressive forces. Multiple biomechanical studies have shown that a fixed-angle construct, such as a sliding hip screw (SHS), provides superior resistance to shear and varus collapse compared to parallel cancellous screws. A supplemental derotation screw is often added to control rotational forces.

Question 4759

Topic: 2. Trauma

According to Hertel's radiographic criteria, which combination of findings in an acute proximal humerus fracture carries the highest positive predictive value (up to 97%) for subsequent humeral head ischemia?

. Surgical neck fracture, valgus impaction, and intact medial hinge
. Anatomical neck fracture, short calcar segment (<8 mm), and disrupted medial hinge
. Three-part fracture, long calcar segment (>8 mm), and disrupted lateral hinge
. Four-part valgus impacted fracture with a calcar segment of 12 mm
. Greater tuberosity fracture with 10 mm of superior displacement and intact medial hinge

Correct Answer & Explanation

. Anatomical neck fracture, short calcar segment (<8 mm), and disrupted medial hinge

Explanation

Hertel et al. established that the risk of humeral head ischemia is greatest when there is a combination of an anatomical neck fracture (disrupting intraosseous supply), a short posteromedial metaphyseal head extension (calcar segment <8 mm), and disruption of the medial hinge (>2 mm displacement), indicating severe damage to the ascending branch of the anterior circumflex humeral artery and overall soft tissue envelope.

Question 4760

Topic: 2. Trauma
A 24-year-old male is admitted after sustaining a closed tibial shaft fracture. Two hours later, he develops excruciating leg pain out of proportion to the injury and increased analgesic requirements. His blood pressure is 110/60 mmHg, and his mean arterial pressure (MAP) is 76 mmHg. Which of the following absolute intracompartmental pressure measurements, or derived calculations, is universally accepted as the most reliable threshold for diagnosing acute compartment syndrome and indicating urgent fasciotomy?
. Absolute compartment pressure > 30 mm Hg
. Absolute compartment pressure > 45 mm Hg
. Mean arterial pressure minus compartment pressure < 30 mm Hg
. Diastolic blood pressure minus compartment pressure < 30 mm Hg
. Systolic blood pressure minus compartment pressure < 40 mm Hg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mm Hg

Explanation

The delta pressure (ΔP), defined as the diastolic blood pressure minus the intracompartmental pressure, is the most reliable objective metric for diagnosing acute compartment syndrome. A ΔP of less than or equal to 30 mm Hg indicates inadequate tissue perfusion and is the standard threshold for proceeding with emergent fasciotomies. Relying solely on absolute pressure numbers can lead to overtreatment in hypotensive or normal patients.

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