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2. Trauma MCQs

Practice Set 296 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 5901

Topic: 2. Trauma
A 32-year-old male sustains a high-energy trauma resulting in an ipsilateral displaced clavicle shaft fracture and a displaced extra-articular scapular neck fracture. According to Goss, what constitutes a 'double disruption' of the superior shoulder suspensory complex (SSSC) in this scenario?
. Disruption of the acromioclavicular and coracoclavicular ligaments
. Disruption of the clavicular strut and the scapular neck
. Fracture of the coracoid and the acromion
. Glenohumeral dislocation with a greater tuberosity fracture
. Fracture of the sternoclavicular joint and the clavicular shaft

Correct Answer & Explanation

. Disruption of the clavicular strut and the scapular neck

Explanation

The Superior Shoulder Suspensory Complex (SSSC) is a bony and soft-tissue ring composed of the glenoid, coracoid, coracoclavicular ligaments, distal clavicle, acromioclavicular joint, and acromion. A 'floating shoulder' represents a double disruption of this complex, classically involving a fracture of the clavicular strut and a fracture of the scapular neck, which destabilizes the suspensory mechanism of the upper extremity.

Question 5902

Topic: 2. Trauma

In the evaluation of a posterior wall acetabular fracture, which of the following methods has been shown to be the most accurate in assessing true hip instability to determine the need for operative fixation?

. Standard AP pelvis and Judet radiographs alone
. CT scan calculating the posterior wall fragment as a percentage of the entire acetabular surface
. Dynamic fluoroscopic stress examination of the hip under anesthesia
. 3D CT reconstruction measuring the volume of the fracture fragment
. MRI to evaluate the integrity of the posterior capsule and labrum

Correct Answer & Explanation

. Dynamic fluoroscopic stress examination of the hip under anesthesia

Explanation

While historically a posterior wall fragment size greater than 50% on CT was an absolute indication for surgery, Moed et al. demonstrated that CT measurements can overestimate or incorrectly predict instability. Dynamic fluoroscopic stress testing under anesthesia is the most accurate dynamic assessment for identifying true occult hip instability.

Question 5903

Topic: 2. Trauma

A Hoffa fracture is a coronal shear fracture of the distal femur. Which condyle is most commonly involved, and what is the typical mechanism of injury?

. Medial condyle; direct blow to the flexed knee
. Medial condyle; hyperextension varus force
. Lateral condyle; direct blow to the flexed knee with an axial load
. Lateral condyle; hyperextension with internal rotation
. Lateral condyle; direct anterior-to-posterior impact on a fully extended knee

Correct Answer & Explanation

. Lateral condyle; direct blow to the flexed knee with an axial load

Explanation

Hoffa fractures (coronal plane fractures of the femoral condyle) predominantly involve the lateral condyle. The mechanism usually involves an axial load with an anterior-to-posterior force directed to the lateral condyle while the knee is in a flexed position (e.g., striking the dashboard in an MVA).

Question 5904

Topic: 2. Trauma

A 30-year-old male sustains a severely comminuted fracture of the tibia. In the emergency department, he complains of severe leg pain out of proportion to the injury, exacerbated by passive stretch of the toes. Which of the following parameters is the most reliable objective threshold for diagnosing acute compartment syndrome and indicating urgent fasciotomy?

. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 30 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 widely accepted and reliable objective criterion for diagnosing acute compartment syndrome is the differential pressure (Delta P). A Delta P (Diastolic Blood Pressure minus intracompartmental pressure) of 30 mmHg or less is a strong indicator for fasciotomy. Absolute compartment pressures are less reliable, especially in hypotensive patients.

Question 5905

Topic: 2. Trauma
In elderly patients (age > 65) with a Type II odontoid fracture, which of the following radiographic findings is considered the strongest predictor for nonunion when managed nonoperatively with a hard cervical collar?
. Anterior displacement of 3 mm
. Initial displacement greater than 5 mm
. Concomitant C1 posterior arch fracture
. Presence of osteoporosis on DEXA scan
. A fracture gap of 1 mm

Correct Answer & Explanation

. Initial displacement greater than 5 mm

Explanation

In Type II odontoid fractures, risk factors for nonunion with nonoperative management include initial displacement greater than 5 mm, posterior displacement, angulation > 10 degrees, age > 50 years, and delayed treatment. A displacement of > 5 mm is a highly significant predictor of failure with conservative management.

Question 5906

Topic: Pelvic & Acetabular Trauma
In the Young-Burgess classification of pelvic ring injuries, which of the following accurately describes the ligamentous disruption in an Anteroposterior Compression Type II (APC II) injury?
. Symphyseal diastasis less than 2.5 cm with intact posterior ligaments
. Symphyseal diastasis greater than 2.5 cm with disruption of both anterior and posterior sacroiliac ligaments
. Symphyseal diastasis with disruption of the anterior sacroiliac ligaments and intact posterior sacroiliac ligaments
. Vertical displacement of the hemipelvis with complete ligamentous disruption
. Internal rotation of the hemipelvis with a crush injury to the anterior sacrum

Correct Answer & Explanation

. Symphyseal diastasis with disruption of the anterior sacroiliac ligaments and intact posterior sacroiliac ligaments

Explanation

An APC II pelvic ring injury is an 'open book' injury caused by an anteroposterior force. It involves symphyseal diastasis (usually > 2.5 cm), disruption of the sacrotuberous and sacrospinous ligaments, and tearing of the anterior sacroiliac (SI) ligaments. Crucially, the strong posterior SI ligaments remain intact, providing rotational instability but vertical stability. Complete posterior disruption defines an APC III injury.

Question 5907

Topic: 2. Trauma

A 25-year-old motorcyclist is thrown from his bike, sustaining a massive traction injury to his right upper extremity. Radiographs reveal marked lateral displacement of the scapula with an intact glenohumeral joint and a displaced clavicle fracture. Examination shows a pulseless, flail right arm. Which of the following vascular injuries is most commonly associated with this specific skeletal injury pattern?

. Subclavian artery
. Axillary artery
. Brachial artery
. Suprascapular artery
. Posterior circumflex humeral artery

Correct Answer & Explanation

. Subclavian artery

Explanation

Scapulothoracic dissociation is a devastating, high-energy closed traction injury involving complete disruption of the scapulothoracic articulation. It is essentially a closed forequarter amputation. The classic triad includes massive swelling/hematoma, lateral displacement of the scapula on chest X-ray, and an acromioclavicular/sternoclavicular/clavicle injury. It is highly associated with severe neurovascular injuries. The subclavian artery or axillary artery may be injured, but the subclavian artery is anatomically tethered as it crosses the first rib and is most commonly ruptured or avulsed in this specific high-energy distraction pattern, along with brachial plexus root avulsions.

Question 5908

Topic: 2. Trauma
According to the Grauer modification of the Anderson and D'Alonzo classification for odontoid fractures, which specific fracture pattern is considered the best candidate for an anterior odontoid screw osteosynthesis, assuming the patient's anatomy and bone quality are favorable?
. Type I fracture
. Type IIA fracture
. Type IIB fracture
. Type IIC fracture
. Type III fracture

Correct Answer & Explanation

. Type IIB fracture

Explanation

The Grauer modification breaks Type II odontoid fractures into three subtypes to guide treatment. Type IIA is a transverse fracture with minimal displacement, often treated with a halo. Type IIB is an oblique fracture extending anterosuperiorly to posteroinferiorly; this trajectory is perpendicular to an anteriorly placed lag screw, making it the ideal candidate for anterior odontoid screw fixation. Type IIC is comminuted or fractures from posterosuperior to anteroinferior, mechanically unfavorable for an anterior screw and better treated with posterior C1-C2 fusion.

Question 5909

Topic: Pelvic & Acetabular Trauma
In the Young-Burgess classification, an Anterior Posterior Compression (APC) Type II pelvic ring injury is primarily characterized by the rupture of the anterior sacroiliac ligaments along with which other ligamentous structures, leading to a rotationally unstable but vertically stable pelvis?
. Posterior sacroiliac and iliolumbar ligaments
. Sacrotuberous and sacrospinous ligaments
. Iliolumbar ligaments only
. Symphyseal ligaments only
. Sacrotuberous, sacrospinous, and posterior sacroiliac ligaments

Correct Answer & Explanation

. Sacrotuberous and sacrospinous ligaments

Explanation

An APC II injury involves disruption of the symphysis pubis (or parasymphyseal fractures) combined with tearing of the anterior sacroiliac ligaments, the sacrotuberous ligaments, and the sacrospinous ligaments. This creates an 'open book' pelvis that is rotationally unstable. Crucially, the strong posterior sacroiliac ligaments remain intact, preserving the vertical stability of the hemipelvis. If the posterior SI ligaments rupture, the injury becomes an APC III (rotationally and vertically unstable).

Question 5910

Topic: Upper Extremity Trauma
Goss introduced the concept of the 'superior suspensory shoulder complex' (SSSC) as a bone-and-soft-tissue ring crucial for understanding the stability of 'floating shoulder' injuries. Which of the following structures acts as an inferior strut rather than a constituent part of the SSSC ring itself?
. Glenoid process
. Coracoid process
. Distal clavicle
. Acromial process
. Scapular spine

Correct Answer & Explanation

. Scapular spine

Explanation

The SSSC consists of a continuous ring of bone and soft tissue: the glenoid process, the coracoid process, the coracoclavicular ligaments, the distal clavicle, the acromioclavicular joint, and the acromial process. This ring is suspended by the middle clavicle (superior strut) and supported inferiorly by the lateral scapular body and the scapular spine (inferior strut). Therefore, the scapular spine is a strut supporting the ring, not part of the ring itself.

Question 5911

Topic: 2. Trauma
According to the Young-Burgess classification, a lateral compression type II (LC-II) pelvic ring injury is characterized by which of the following injury patterns?
. Sacral compression fracture with ipsilateral rami fractures
. Ipsilateral crescent fracture of the ilium with rami fractures
. Contralateral crescent fracture of the ilium with rami fractures (windswept pelvis)
. Disruption of the anterior SI ligaments with intact posterior SI ligaments
. Complete disruption of the symphysis pubis, anterior and posterior SI ligaments

Correct Answer & Explanation

. Ipsilateral crescent fracture of the ilium with rami fractures

Explanation

In the Young-Burgess classification, an LC-II injury is characterized by an anterior ring fracture (usually rami) and an ipsilateral posterior ilium fracture (crescent fracture) due to internal rotation force extending past the SI joint. LC-I is a sacral compression fracture. LC-III is a 'windswept' pelvis.

Question 5912

Topic: Lower Extremity Trauma
A 45-year-old male sustains a high-energy traumatic injury to his knee. Radiographs and CT show a bicondylar fracture of the tibial plateau with extension of the fracture line into the tibial diaphysis. This injury is best classified as which Schatzker type?
. Schatzker III
. Schatzker IV
. Schatzker V
. Schatzker VI
. Schatzker VII

Correct Answer & Explanation

. Schatzker VI

Explanation

Schatzker VI is a bicondylar tibial plateau fracture with dissociation of the metaphysis from the diaphysis. Schatzker V is a bicondylar fracture with intact metaphyseal-diaphyseal continuity.

Question 5913

Topic: Pelvic & Acetabular Trauma
A 35-year-old male arrives in the trauma bay after a motorcycle crash. His pelvis radiograph shows an anteroposterior compression type III (APC III) injury. His blood pressure is 80/40 mmHg. What is the most anatomically effective location for the application of a circumferential pelvic sheet or binder?
. Over the iliac wings
. At the level of the anterior superior iliac spines
. Centered over the greater trochanters
. Just superior to the umbilicus
. Around the proximal thighs

Correct Answer & Explanation

. Centered over the greater trochanters

Explanation

A pelvic binder must be centered over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac wings can paradoxically open the pelvic ring by acting as a fulcrum.

Question 5914

Topic: Pelvic & Acetabular Trauma

The Salter innominate osteotomy is commonly used in the treatment of developmental dysplasia of the hip (DDH). Around which anatomic structure does the distal fragment rotate to improve anterolateral coverage of the femoral head?

. The sacroiliac joint
. The pubic symphysis
. The triradiate cartilage
. The ischial spine
. The greater sciatic notch

Correct Answer & Explanation

. The greater sciatic notch

Explanation

The Salter osteotomy is a single-cut innominate osteotomy that goes from the greater sciatic notch to the anterior inferior iliac spine. The distal fragment hinges and rotates on the pubic symphysis to provide improved anterolateral coverage of the femoral head.

Question 5915

Topic: 2. Trauma

A 24-year-old male sustains a distal femur fracture. CT imaging reveals a coronal plane fracture of the femoral condyle (Hoffa fracture). Which of the following statements regarding this fracture pattern is correct?

. It most commonly involves the medial femoral condyle.
. It is classified as an extra-articular injury.
. It most commonly involves the lateral femoral condyle.
. It is best fixed with mediolateral directed lag screws.
. Conservative management is the gold standard.

Correct Answer & Explanation

. It most commonly involves the lateral femoral condyle.

Explanation

A Hoffa fracture (AO type 33-B3) is a coronal plane fracture of the distal femoral condyle. It most commonly involves the lateral condyle due to the physiologic valgus of the knee and the typical direction of axial load. It is an intra-articular fracture requiring anatomic reduction and rigid fixation, typically with anteroposterior or posteroanterior directed lag screws.

Question 5916

Topic: 2. Trauma

A 40-year-old male presents with a high-energy Schatzker VI tibial plateau fracture. On examination, the leg is tense, pale, and the patient has severe pain out of proportion to the injury with passive stretch of the toes. An invasive compartment pressure monitor reveals a delta pressure of 15 mmHg. What is the most appropriate next step in management?

. Elevation of the limb and serial clinical examinations
. Immediate internal fixation of the fracture followed by fasciotomies
. Application of a long leg cast and admission for observation
. Immediate four-compartment fasciotomies followed by spanning external fixation
. Intravenous mannitol administration and urgent MRI

Correct Answer & Explanation

. Immediate four-compartment fasciotomies followed by spanning external fixation

Explanation

The patient has classic signs of acute compartment syndrome with an absolute delta pressure < 30 mmHg (diastolic BP minus compartment pressure). This requires emergent surgical decompression via four-compartment fasciotomies. Given the high-energy nature of a Schatzker VI fracture with soft tissue compromise, a spanning external fixator is the most appropriate initial stabilization method.

Question 5917

Topic: 2. Trauma
A patient presents with a tibia fracture following a motorcycle accident. The fracture is highly comminuted. There is a 6 cm laceration over the anterior tibia. After surgical debridement, adequate soft tissue is available to close the wound primarily without the need for a flap. How is this fracture classified according to the Gustilo-Anderson system?
. Type II
. Type IIIA
. Type IIIB
. Type IIIC
. Type I

Correct Answer & Explanation

. Type IIIA

Explanation

Despite the wound being less than 10 cm, the high-energy nature of the injury (motorcycle accident) and high degree of comminution automatically classify it as a Type III open fracture. Because there is adequate soft tissue coverage remaining after debridement without requiring a flap, it is Type IIIA.

Question 5918

Topic: 2. Trauma

In the setting of acute compartment syndrome following a tibial shaft fracture, irreversible muscle necrosis is generally accepted to begin after how many hours of continuous ischemia?

. 1 to 2 hours
. 3 to 4 hours
. 6 to 8 hours
. 12 to 14 hours
. 24 hours

Correct Answer & Explanation

. 6 to 8 hours

Explanation

Irreversible muscle damage (necrosis) begins to occur after 6 to 8 hours of ischemia due to acute compartment syndrome. Nerve injury begins earlier (paresthesias within 30-120 minutes) but muscles undergo irreversible necrosis if fasciotomy is delayed beyond the 6-8 hour window.

Question 5919

Topic: 2. Trauma

A 40-year-old man sustains a closed tibial shaft fracture. He complains of disproportionate pain. Intracompartmental pressure monitoring is performed. Which of the following values is the most universally accepted threshold for performing an emergency four-compartment fasciotomy?

. Absolute compartment pressure greater than 20 mmHg
. Absolute compartment pressure greater than 30 mmHg
. Delta P (Diastolic blood pressure minus compartment pressure) less than 30 mmHg
. Delta P (Mean arterial pressure minus compartment pressure) less than 45 mmHg
. Systolic blood pressure minus compartment pressure less than 30 mmHg

Correct Answer & Explanation

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

Explanation

The Delta P (diastolic blood pressure minus the intracompartmental pressure) is the most reliable indicator for acute compartment syndrome. A Delta P of less than 30 mmHg is the universally accepted threshold indicating the need for emergent fasciotomy. Absolute pressure readings alone can be misleading, especially in hypotensive patients.

Question 5920

Topic: 2. Trauma
A 28-year-old man sustains a displaced, vertically oriented femoral neck fracture (Pauwels Type III) after a motor vehicle collision. He undergoes closed reduction and internal fixation with multiple cannulated screws. Biomechanically, this fracture pattern has the highest risk for failure due to which of the following forces?
. Compressive forces at the fracture site
. Rotational forces primarily
. High shear forces causing varus displacement
. Tension forces on the medial calcar
. Distraction forces from the abductor musculature

Correct Answer & Explanation

. High shear forces causing varus displacement

Explanation

Pauwels Type III femoral neck fractures are highly vertical (>50 degrees to the horizontal). Biomechanically, this vertical orientation converts weight-bearing and muscle forces into extremely high shear forces across the fracture site. This makes them inherently unstable and prone to varus collapse, nonunion, and fixation failure when treated with standard parallel cannulated screws alone.

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