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2. Trauma MCQs

Practice Set 303 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 6041

Topic: 2. Trauma
A 28-year-old male sustains a high-energy vertical shear fracture of the femoral neck (Pauwels Type III). What biomechanical characteristic of this fracture makes it at highest risk for nonunion, and how is it optimally addressed during internal fixation?
. High compressive forces; managed with a sliding hip screw.
. High varus and shear forces; managed with multiple cancellous screws in an inverted triangle.
. High shear forces; managed with a sliding hip screw and a derotation screw or a fixed-angle device.
. High rotational forces; managed with an intramedullary nail.
. High valgus impaction forces; managed with non-operative touch-down weight bearing.

Correct Answer & Explanation

. High shear forces; managed with a sliding hip screw and a derotation screw or a fixed-angle device.

Explanation

Pauwels Type III femoral neck fractures have a high fracture angle (>50 degrees), which subjects the fracture site to high vertical shear and varus forces. This increases the risk of nonunion and fixation failure. They are biomechanically best stabilized with a fixed-angle device like a sliding hip screw (often with a derotational screw) rather than multiple cancellous screws alone, which are prone to fail under shear.

Question 6042

Topic: 2. Trauma

A 32-year-old male sustains a spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). On presentation, he is found to have a complete radial nerve palsy. Closed reduction and functional bracing are selected as the initial treatment. What is the most widely accepted indication for surgical exploration of the radial nerve in this scenario?

. The nerve palsy is present immediately after the injury.
. The nerve palsy develops secondary to a closed reduction attempt.
. The fracture is a spiral pattern.
. Failure of the nerve to recover by 4 weeks post-injury.
. Presence of severe pain at the fracture site.

Correct Answer & Explanation

. The nerve palsy develops secondary to a closed reduction attempt.

Explanation

Primary radial nerve palsy in closed humeral shaft fractures is typically treated expectantly, as >85% recover spontaneously (mostly neuropraxia or axonotmesis). However, a radial nerve palsy that develops after a closed reduction attempt suggests the nerve may have become entrapped in the fracture site, which is a widely accepted absolute indication for immediate surgical exploration. Another indication is failure of spontaneous recovery by 3-6 months.

Question 6043

Topic: 2. Trauma
According to the Young-Burgess classification, a lateral compression type II (LC-II) pelvic ring injury is characterized by an anterior ring fracture combined with which of the following posterior injuries?
. Sacral compression fracture on the ipsilateral side
. Ipsilateral crescent fracture of the ilium
. Contralateral sacroiliac joint dislocation
. Bilateral sacral vertical shear fractures
. Complete disruption of the sacrotuberous and sacrospinous ligaments bilaterally

Correct Answer & Explanation

. Ipsilateral crescent fracture of the ilium

Explanation

An LC-II injury in the Young-Burgess classification is characterized by an anterior ring injury (rami fractures) and an ipsilateral posterior ilium fracture (often a 'crescent' fracture) due to internal rotation force pivoting on the strong posterior sacroiliac ligaments. LC-I involves an ipsilateral sacral compression fracture. LC-III is an LC-I or LC-II with a contralateral anteroposterior compression (APC) injury (windswept pelvis).

Question 6044

Topic: 2. Trauma

A 55-year-old woman falls on an outstretched hand and sustains a distal radius fracture. Radiographs show a fracture of the volar rim of the distal radius with volar subluxation of the carpus. The dorsal cortex remains intact. What is the correct eponymous term for this fracture pattern?

. Colles' fracture
. Smith's fracture
. Volar Barton's fracture
. Chauffeur's fracture
. Die-punch fracture

Correct Answer & Explanation

. Volar Barton's fracture

Explanation

A volar Barton's fracture is an intra-articular shear fracture of the volar rim of the distal radius with associated volar subluxation or dislocation of the radiocarpal joint. Colles' is a dorsal angulated extra-articular fracture; Smith's is a volar angulated extra-articular fracture; Chauffeur's is a radial styloid fracture; Die-punch involves a depressed lunate fossa.

Question 6045

Topic: 2. Trauma

A 28-year-old male sustains a closed tibial shaft fracture. Two hours post-admission, he complains of severe pain out of proportion to the injury, unrelieved by opioids. Compartment pressure monitoring is performed. Which of the following pressure measurements is generally accepted as the threshold indicating the need for emergent 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 delta pressure (Diastolic Blood Pressure minus Intracompartmental Pressure) is the most reliable indicator for acute compartment syndrome. A delta pressure of less than 30 mmHg (some sources say <=30 mmHg) strongly indicates the need for emergent fasciotomy, as absolute pressures can be misleading depending on the patient's systemic blood pressure.

Question 6046

Topic: 2. Trauma
The Sanders classification system for intra-articular calcaneal fractures is heavily utilized to guide surgical management. This classification is primarily based on the number and location of fracture lines through which articular surface on coronal Computed Tomography (CT) scans?
. Anterior facet of the calcaneus
. Middle facet of the calcaneus
. Posterior facet of the calcaneus
. Calcaneocuboid joint surface
. Sustentaculum tali

Correct Answer & Explanation

. Posterior facet of the calcaneus

Explanation

The Sanders classification is based on coronal CT images detailing the fracture lines through the posterior facet of the calcaneus. It dictates surgical decision-making. Type I fractures are nondisplaced regardless of the number of fracture lines. Type II are 2-part (1 fracture line in the posterior facet), Type III are 3-part (2 fracture lines), and Type IV are 4-part (highly comminuted).

Question 6047

Topic: 2. Trauma

A 25-year-old male undergoes a dual-incision fasciotomy for acute compartment syndrome of the leg following a tibial shaft fracture. When releasing the deep posterior compartment, the surgeon must be mindful of the structures running within it. Which major nerve courses through the deep posterior compartment of the leg?

. Superficial peroneal nerve
. Deep peroneal nerve
. Tibial nerve
. Sural nerve
. Saphenous nerve

Correct Answer & Explanation

. Tibial nerve

Explanation

The tibial nerve runs through the deep posterior compartment of the leg, along with the posterior tibial artery and the deep flexor muscles (tibialis posterior, flexor digitorum longus, and flexor hallucis longus). The deep peroneal nerve is in the anterior compartment, the superficial peroneal nerve is in the lateral compartment, and the sural and saphenous nerves are subcutaneous.

Question 6048

Topic: Pelvic & Acetabular Trauma
A 32-year-old male is brought to the emergency department after a motorcycle collision. He is hemodynamically unstable. Pelvic radiographs demonstrate an anteroposterior compression type III (APC III) pelvic ring injury. After application of a pelvic binder and initial fluid resuscitation, his blood pressure remains 70/40 mmHg. What is the most appropriate next step in management?
. Immediate open reduction and internal fixation of the pubic symphysis
. Pelvic angiography and embolization
. Laparotomy and bilateral internal iliac artery ligation
. Preperitoneal/retroperitoneal pelvic packing
. Placement of a supra-acetabular external fixator and transfer to the ICU

Correct Answer & Explanation

. Preperitoneal/retroperitoneal pelvic packing

Explanation

In a hemodynamically unstable patient with a mechanically unstable pelvic ring injury who does not respond to initial resuscitation and pelvic binding, preperitoneal/retroperitoneal pelvic packing is the most rapid and effective intervention to control venous bleeding, which represents the source in 80-90% of pelvic hemorrhage. Angiography is indicated if arterial bleeding is confirmed (e.g., contrast blush on CT) or if instability persists after packing.

Question 6049

Topic: 2. Trauma
According to the Sanders classification of intra-articular calcaneus fractures, which of the following best describes a Sanders Type III fracture?
. A nondisplaced fracture of the posterior facet
. A two-part fracture of the posterior facet with one fracture line
. A three-part fracture of the posterior facet with two fracture lines
. A four-part, highly comminuted fracture of the posterior facet
. An extra-articular fracture involving the anterior process

Correct Answer & Explanation

. A four-part, highly comminuted fracture of the posterior facet

Explanation

The Sanders classification is based on coronal CT images through the posterior facet of the calcaneus. Type I fractures are nondisplaced. Type II are two-part fractures (one fracture line). Type III are three-part fractures (two fracture lines). Type IV are four-part or highly comminuted fractures.

Question 6050

Topic: 2. Trauma
A 6-year-old girl falls on an outstretched hand and sustains a Bado Type III Monteggia equivalent lesion. Which of the following best describes the radiographic findings?
. Fracture of the ulnar diaphysis with anterior dislocation of the radial head
. Fracture of the ulnar diaphysis with posterior dislocation of the radial head
. Fracture of the ulnar metaphysis with lateral dislocation of the radial head
. Fracture of the proximal radius and ulna at the same level
. Plastic bowing of the ulna with anterior dislocation of the radial head

Correct Answer & Explanation

. Fracture of the ulnar metaphysis with lateral dislocation of the radial head

Explanation

The Bado classification describes Monteggia fracture-dislocations. Type I: Anterior dislocation of the radial head with anterior angulation of the ulnar fracture. Type II: Posterior dislocation with posterior angulation. Type III: Lateral or anterolateral dislocation of the radial head with a fracture of the ulnar metaphysis (most common in children). Type IV: Anterior dislocation of the radial head with fractures of both the radius and ulna shafts.

Question 6051

Topic: 2. Trauma

The blood supply to the humeral head is a critical factor in determining the risk of avascular necrosis following a proximal humerus fracture. According to Hertel's radiographic criteria, which of the following fracture patterns carries the highest risk of ischemia to the humeral head?

. A fracture with an intact medial hinge greater than 2 mm
. A posteromedial metaphyseal head extension greater than 8 mm
. An anatomic neck fracture with loss of the medial hinge
. An isolated greater tuberosity fracture with 5 mm displacement
. A surgical neck fracture with 15 degrees varus angulation

Correct Answer & Explanation

. An anatomic neck fracture with loss of the medial hinge

Explanation

Hertel identified several predictors of humeral head ischemia after proximal humerus fractures. The highest risk factors are an anatomic neck fracture pattern, a short calcar length (posteromedial metaphyseal head extension < 8 mm), and disruption of the medial hinge (> 2 mm displacement). An anatomic neck fracture intrinsically disrupts the primary blood supply (the ascending branch of the anterior circumflex humeral artery and intraosseous vessels).

Question 6052

Topic: 2. Trauma
A 6-year-old boy falls on an outstretched hand and sustains an ulnar diaphyseal fracture associated with a radial neck fracture. According to the Bado classification equivalents, what type of Monteggia lesion does this represent?
. Type I equivalent
. Type II equivalent
. Type III equivalent
. Type IV equivalent
. Type V equivalent

Correct Answer & Explanation

. Type I equivalent

Explanation

A Bado Type I equivalent involves an anterior dislocation of the radial head or a fracture of the radial neck combined with an ulnar diaphyseal fracture. Type I Bado injuries are the most common Monteggia lesions in children, traditionally characterized by anterior apex ulnar bowing or fracture combined with an anterior radial head dislocation.

Question 6053

Topic: Lower Extremity Trauma

During the surgical approach to the posteromedial aspect of the tibial plateau for internal fixation of a Schatzker IV fracture, the primary internervous/intermuscular plane is utilized. Which structures define the borders of this interval?

. Semimembranosus and the medial head of the gastrocnemius
. Pes anserinus and the medial head of the gastrocnemius
. Tibialis posterior and flexor digitorum longus
. Medial head of the gastrocnemius and the soleus
. Semitendinosus and semimembranosus

Correct Answer & Explanation

. Pes anserinus and the medial head of the gastrocnemius

Explanation

The posteromedial approach to the tibial plateau utilizes an interval between the medial head of the gastrocnemius (innervated by the tibial nerve) posteriorly, and the pes anserinus (innervated by the femoral and sciatic nerves) anteriorly. Retracting the gastrocnemius posteriorly and laterally protects the popliteal neurovascular bundle.

Question 6054

Topic: 2. Trauma
The Pauwels classification for femoral neck fractures categorizes fractures based on which of the following parameters?
. The degree of comminution of the posterior neck
. The anatomical location of the fracture line (subcapital vs transcervical)
. The angle of the fracture line relative to the horizontal plane
. The amount of displacement on the anteroposterior radiograph
. The severity of associated varus collapse

Correct Answer & Explanation

. The angle of the fracture line relative to the horizontal plane

Explanation

The Pauwels classification is based on the angle of the fracture line relative to the horizontal plane. Type I is <30 degrees, Type II is 30-50 degrees, and Type III is >50 degrees. Higher angles indicate increased shear forces across the fracture site, which correlates with higher rates of nonunion and fixation failure.

Question 6055

Topic: 2. Trauma

Primary bone healing (contact healing via osteonal reconstruction) is achieved under which of the following mechanical and biological conditions?

. Absolute stability with a gap less than 0.01 mm
. Relative stability with a gap of 2 mm
. Cast immobilization allowing micro-motion
. Intramedullary nailing of a diaphyseal fracture
. External fixation with dynamic axial loading

Correct Answer & Explanation

. Absolute stability with a gap less than 0.01 mm

Explanation

Primary bone healing requires absolute mechanical stability and precise anatomical reduction with a fracture gap of less than 0.01 mm. It occurs via direct Haversian remodeling (cutting cones advancing across the fracture site) without intermediate callus formation.

Question 6056

Topic: Pelvic & Acetabular Trauma

In the Young-Burgess classification of pelvic ring injuries, an anteroposterior compression (APC) Type II injury is characterized by the rupture of which ligaments?

. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments with an intact posterior sacroiliac ligament
. Anterior and posterior sacroiliac ligaments
. Sacrotuberous ligament only
. Posterior sacroiliac ligament only
. Iliolumbar ligament only

Correct Answer & Explanation

. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments with an intact posterior sacroiliac ligament

Explanation

An APC II injury involves symphyseal diastasis (usually >2.5 cm) with disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. The critical posterior sacroiliac ligament remains intact, making the pelvis rotationally unstable ('open book') but vertically stable.

Question 6057

Topic: 2. Trauma

A 30-year-old man with a comminuted tibial shaft fracture presents with severe pain out of proportion to the injury. Clinical suspicion for acute compartment syndrome is high. Which of the following pressure measurements strongly supports the need for an emergent fasciotomy?

. Absolute compartment pressure of 20 mmHg
. Absolute compartment pressure of 25 mmHg
. Delta pressure (Diastolic Blood Pressure minus Compartment Pressure) less than 30 mmHg
. Delta pressure (Mean Arterial Pressure minus Compartment Pressure) greater than 40 mmHg
. Compartment pressure equal to central venous pressure

Correct Answer & Explanation

. Delta pressure (Diastolic Blood Pressure minus Compartment Pressure) less than 30 mmHg

Explanation

The most reliable indicator for diagnosing acute compartment syndrome in a borderline clinical scenario is the delta pressure, calculated as Diastolic Blood Pressure (DBP) minus Intracompartmental Pressure (ICP). A delta pressure of less than 30 mmHg (indicating critically compromised tissue perfusion) is an absolute indication for emergent fasciotomy.

Question 6058

Topic: Pelvic & Acetabular Trauma
According to the Young-Burgess classification of pelvic ring injuries, which of the following ligamentous disruptions distinguishes an Anteroposterior Compression III (APC III) injury from an APC II injury?
. Symphysis pubis
. Sacrospinous ligament
. Sacrotuberous ligament
. Anterior sacroiliac ligament
. Posterior sacroiliac ligament

Correct Answer & Explanation

. Sacrospinous ligament

Explanation

In the Young-Burgess classification, an APC II injury involves disruption of the pubic symphysis, anterior sacroiliac (SI) ligaments, and the sacrotuberous/sacrospinous ligaments, but the posterior SI ligaments remain intact. An APC III injury involves complete disruption of both the anterior and posterior SI ligaments, resulting in complete spinopelvic dissociation.

Question 6059

Topic: 2. Trauma
According to the American Society for Bone and Mineral Research (ASBMR) criteria, which of the following is a required major radiographic feature for the diagnosis of an atypical femur fracture (AFF) associated with prolonged bisphosphonate use?
. Fracture line originates at the medial cortex
. Spiral fracture morphology
. Location exclusively in the femoral neck
. Transverse or short oblique configuration originating at the lateral cortex
. Extensive comminution

Correct Answer & Explanation

. Transverse or short oblique configuration originating at the lateral cortex

Explanation

ASBMR major criteria for an atypical femur fracture include: location along the femoral diaphysis from just distal to the lesser trochanter to just proximal to the supracondylar flare, a transverse or short oblique fracture line originating at the lateral cortex, noncomminuted or minimally comminuted, and often a localized periosteal reaction of the lateral cortex ('beaking').

Question 6060

Topic: 2. Trauma

A 25-year-old male is admitted after a motorcycle accident with a closed highly comminuted tibial shaft fracture. He develops severe leg pain out of proportion to the injury, pain with passive stretch of the toes, and paresthesias. To confirm the diagnosis of acute compartment syndrome using intracompartmental pressure monitoring, which of the following is considered the most reliable threshold for emergent fasciotomy?

. Absolute compartment pressure > 20 mm Hg
. Absolute compartment pressure > 30 mm Hg
. Delta pressure (Diastolic Blood Pressure - Compartment Pressure) < 30 mm Hg
. Delta pressure (Mean Arterial Pressure - Compartment Pressure) < 40 mm Hg
. Delta pressure (Systolic Blood Pressure - Compartment Pressure) < 30 mm Hg

Correct Answer & Explanation

. Delta pressure (Diastolic Blood Pressure - Compartment Pressure) < 30 mm Hg

Explanation

McQueen et al. demonstrated that the delta pressure (diastolic blood pressure minus intracompartmental pressure) is the most accurate and reliable indicator for compartment syndrome, avoiding unnecessary fasciotomies that occur when relying solely on absolute pressures. A delta pressure of < 30 mm Hg is an absolute indication for emergent fasciotomy, especially in hypotensive trauma patients.

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