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2. Trauma MCQs

Practice Set 297 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 5921

Topic: 2. Trauma
According to the Gustilo-Anderson classification, a diaphyseal tibia fracture with a 6 cm laceration, extensive soft tissue damage, periosteal stripping, and massive contamination, but with adequate soft tissue coverage requiring no flap, is classified as:
. Type II
. Type IIIA
. Type IIIB
. Type IIIC
. Type IV

Correct Answer & Explanation

. Type IIIA

Explanation

Gustilo-Anderson Type III fractures are high-energy injuries with extensive soft tissue damage (often >10 cm, or defined by severe contamination/crush). Type IIIA indicates extensive soft tissue damage, but with adequate soft tissue coverage of the fractured bone despite the extensive laceration. Type IIIB requires a local or free flap for coverage due to inadequate soft tissue. Type IIIC involves an arterial injury requiring repair.

Question 5922

Topic: Pelvic & Acetabular Trauma
A 30-year-old male is involved in a severe motorcycle collision and sustains an anteroposterior compression type III (APC-III) pelvic ring injury. After the application of a pelvic binder and initial fluid resuscitation, he remains hemodynamically unstable. An emergent angiogram is performed. Which of the following vessels is most likely to be the source of arterial bleeding in this specific injury pattern?
. Superior gluteal artery
. Internal pudendal artery
. Lumbar artery
. Inferior epigastric artery
. Iliolumbar artery

Correct Answer & Explanation

. Internal pudendal artery

Explanation

Anteroposterior compression (APC) pelvic injuries cause symphyseal diastasis and disruption of the anterior pelvic structures. Hemorrhage in APC injuries is most commonly venous, but when arterial bleeding occurs, the anterior branches of the internal iliac artery—most notably the internal pudendal and obturator arteries—are most frequently injured. The superior gluteal artery is more commonly injured in posterior ring disruptions and lateral compression (LC) injuries.

Question 5923

Topic: 2. Trauma

A 35-year-old male with a severely comminuted, closed tibial shaft fracture complains of agonizing leg pain out of proportion to the injury. The clinical suspicion for acute compartment syndrome is high, and intracompartmental pressures are measured. Which of the following pressure criteria is the most reliable and widely accepted indication for emergent four-compartment 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 delta pressure (Diastolic Blood Pressure - Compartment Pressure) is the most reliable objective indicator for acute compartment syndrome. A delta pressure of less than 30 mmHg signifies that the tissue perfusion pressure is inadequate, making it a universally accepted indication for emergent fasciotomy. Absolute pressure thresholds (e.g., >30 mmHg) are less accurate because they do not account for systemic perfusion pressure.

Question 5924

Topic: Lower Extremity Trauma

A 60-year-old patient with long-standing, poorly controlled diabetes presents with a unilaterally swollen, warm, and erythematous foot. Radiographs demonstrate dramatic tarsometatarsal joint subluxation, extensive bony fragmentation, and periarticular debris. Which classification system is strictly used to stage the radiographic progression of this specific neuroarthropathic condition?

. Brodsky classification
. Eichenholtz classification
. Hawkins classification
. Wagner classification
. Sanders classification

Correct Answer & Explanation

. Eichenholtz classification

Explanation

The Eichenholtz classification describes the natural history and radiographic staging of Charcot neuroarthropathy. Stage 0 is clinical inflammation with normal x-rays. Stage 1 is the developmental/fragmentation phase (debris, dislocation). Stage 2 is the coalescence phase (absorption of debris, early fusion). Stage 3 is the consolidation/reconstruction phase. Brodsky classifies the anatomic location of Charcot joints, while Wagner is used for diabetic foot ulcers.

Question 5925

Topic: 2. Trauma

A 30-year-old male presents to the emergency department after sustaining a closed diaphyseal fracture of the humerus. In the context of humeral shaft fractures, which of the following is considered an absolute indication for operative fixation?

. Primary radial nerve palsy
. Transverse fracture pattern
. Open fracture
. Associated brachial plexus injury
. Holstein-Lewis fracture

Correct Answer & Explanation

. Primary radial nerve palsy

Explanation

Absolute indications for operative management of a humeral shaft fracture include open fractures, fractures associated with a vascular injury requiring repair, compartment syndrome, and floating elbow injuries (ipsilateral humerus and forearm fractures). Primary radial nerve palsy, even in the setting of a Holstein-Lewis fracture (distal third spiral fracture), is generally considered a relative indication, as up to 90% of primary radial nerve palsies recover spontaneously with non-operative management.

Question 5926

Topic: 2. Trauma

When applying a dynamic compression plate (DCP) to stabilize a transverse diaphyseal fracture, the surgeon deliberately uses eccentric drilling for the screw holes nearest the fracture site. What is the primary biomechanical objective of this specific technique?

. To prevent stripping of the screw threads in osteopenic cortical bone
. To induce dynamic longitudinal interfragmentary compression across the fracture site
. To angle the screws away from intramedullary implants
. To minimize the stress-shielding effect on the underlying cortex
. To increase the axial pull-out strength of the cortical screws

Correct Answer & Explanation

. To induce dynamic longitudinal interfragmentary compression across the fracture site

Explanation

Eccentric drilling in a dynamic compression plate (DCP) involves placing the drill hole on the side of the oval plate hole furthest from the fracture line. As the spherical head of the screw engages the sloped contour of the plate hole during tightening, it slides down the ramp, forcing the bone fragment to translate axially toward the fracture site. This generates dynamic longitudinal interfragmentary compression, optimizing the conditions for primary bone healing.

Question 5927

Topic: 2. Trauma

The primary blood supply to the proximal pole of the scaphoid enters the bone at which specific anatomical location?

. Volar distal pole
. Dorsal ridge
. Volar proximal pole
. Scaphoid tubercle
. Scapholunate ligament insertion

Correct Answer & Explanation

. Dorsal ridge

Explanation

The major blood supply to the scaphoid is derived from the dorsal carpal branch of the radial artery, which enters the scaphoid at the dorsal ridge (distal to the waist) and flows in a retrograde fashion (distal to proximal). This retrograde blood supply explains why proximal pole fractures have a high rate of avascular necrosis and nonunion.

Question 5928

Topic: 2. Trauma

Which of the following fracture fixation constructs relies primarily on intramembranous ossification (primary bone healing) rather than endochondral ossification for fracture healing?

. Intramedullary nailing of a diaphyseal femoral shaft fracture
. Cast immobilization of a minimally displaced distal radius fracture
. Minimally invasive bridge plating of a comminuted tibial shaft fracture
. Absolute stability via lag screw and neutralization plate of a radial shaft fracture
. Circular external fixation of a pilon fracture

Correct Answer & Explanation

. Absolute stability via lag screw and neutralization plate of a radial shaft fracture

Explanation

Absolute stability constructs (lag screws, compression plates) eliminate interfragmentary motion, allowing for primary bone healing. Primary bone healing occurs via cutting cones and Haversian remodeling (intramembranous ossification) without intermediate cartilage or visible fracture callus. Intramedullary nails, casting, bridge plating, and external fixators permit relative stability, leading to secondary bone healing via endochondral ossification (callus formation).

Question 5929

Topic: 2. Trauma

A 40-year-old male sustains a Schatzker IV tibial plateau fracture with a predominant posteromedial coronal split fragment. To adequately buttress this fragment, which surgical approach is most appropriate?

. Anterolateral approach with submeniscal arthrotomy
. Midline transpatellar approach
. Posteromedial approach
. Direct posterolateral approach with fibular osteotomy
. Standard direct lateral approach

Correct Answer & Explanation

. Posteromedial approach

Explanation

A Schatzker IV fracture often involves a medial plateau fracture, frequently with a posteromedial shear fragment. Because screws/plates must be applied to the apex of the deformity to achieve an anti-glide (buttress) effect, a posteromedial approach is required to place a plate on the posterior aspect of the medial tibial condyle.

Question 5930

Topic: 2. Trauma

A 25-year-old male sustains a closed comminuted tibia fracture. Six hours later, he develops severe leg pain out of proportion to the apparent injury. Which of the following is considered the most sensitive and earliest clinical sign of acute compartment syndrome?

. Loss of distal arterial pulses (e.g., dorsalis pedis)
. Pallor and poikilothermia of the extremity
. Severe pain with passive stretch of the involved compartment muscles
. Decreased two-point discrimination in the first webspace
. Motor paralysis of the involved muscular compartment

Correct Answer & Explanation

. Severe pain with passive stretch of the involved compartment muscles

Explanation

Pain out of proportion and pain with passive stretch of the muscles within the affected compartment are the earliest and most sensitive clinical signs of acute compartment syndrome. Pulselessness, pallor, and paralysis are very late signs, at which point irreversible ischemic muscle and nerve damage has often already occurred.

Question 5931

Topic: Pelvic & Acetabular Trauma
A 30-year-old male is brought to the trauma bay after a motorcycle accident with an anteroposterior compression type III (APC-III) pelvic ring injury. He is hemodynamically unstable. In this type of injury, what is the most common anatomic source of massive venous hemorrhage?
. Superior gluteal vein
. Internal pudendal vein
. Presacral venous plexus
. External iliac vein
. Obturator vein

Correct Answer & Explanation

. Presacral venous plexus

Explanation

In pelvic ring injuries with posterior disruption (such as APC-III and vertical shear injuries), the presacral venous plexus and the prevesical venous plexus are the most common sources of major venous bleeding. Venous bleeding accounts for 80-90% of pelvic hemorrhage.

Question 5932

Topic: 2. Trauma

A 65-year-old female sustains a lateral compression type 1 (LC-1) pelvic ring injury following a ground-level fall. Her pain is well-controlled, and she is hemodynamically stable. What is the most appropriate initial management?

. Immediate surgical fixation with anterior symphyseal plating
. Placement of a pelvic binder and transfer to ICU
. Skeletal traction via distal femur pin
. Mobilization with weight-bearing as tolerated
. Closed reduction and percutaneous iliosacral screw fixation

Correct Answer & Explanation

. Mobilization with weight-bearing as tolerated

Explanation

LC-1 pelvic ring injuries (Denis zone 1 or 2 sacral fracture with ipsilateral rami fractures) are typically mechanically stable. The initial management is nonoperative with pain control and mobilization, allowing weight-bearing as tolerated.

Question 5933

Topic: 2. Trauma

A 40-year-old male sustains a high-energy Schatzker VI tibial plateau fracture. He presents with massive soft tissue swelling and fracture blisters over the proximal tibia. Compartment pressures are normal. What is the most appropriate initial management?

. Immediate single-incision plating
. Immediate dual-incision (medial and lateral) plating
. Spanning external fixation across the knee joint
. Closed reduction and cast application
. Intramedullary nailing of the tibia

Correct Answer & Explanation

. Spanning external fixation across the knee joint

Explanation

In high-energy Schatzker VI fractures with significant soft tissue compromise (swelling, fracture blisters), the standard of care is temporary spanning external fixation (damage control orthopedics) to allow soft tissues to recover before definitive open reduction and internal fixation.

Question 5934

Topic: 2. Trauma
A 25-year-old man sustains a closed diaphyseal tibia fracture. He reports out-of-proportion leg pain. His blood pressure is 110/70 mmHg. Compartment pressures are measured. What is the generally accepted threshold (delta p) for diagnosing acute compartment syndrome and indicating fasciotomy?
. Absolute pressure > 30 mmHg
. Diastolic pressure minus compartment pressure < 30 mmHg
. Mean arterial pressure minus compartment pressure < 40 mmHg
. Systolic pressure minus compartment pressure < 30 mmHg
. Absolute pressure > 45 mmHg

Correct Answer & Explanation

. Diastolic pressure minus compartment pressure < 30 mmHg

Explanation

The delta p (Δp) threshold for fasciotomy in acute compartment syndrome is defined as the diastolic blood pressure minus the intra-compartmental pressure. A Δp < 30 mmHg is highly indicative of compartment syndrome and requires emergent fasciotomy.

Question 5935

Topic: Pelvic & Acetabular Trauma

Which of the following arterial structures is most commonly injured and causes significant hemorrhage in a patient with a lateral compression (LC) pelvic ring injury with a displaced sacral fracture?

. Superior gluteal artery
. Internal pudendal artery
. Obturator artery
. Inferior epigastric artery
. Corona mortis

Correct Answer & Explanation

. Superior gluteal artery

Explanation

The superior gluteal artery exits the pelvis through the greater sciatic foramen in close proximity to the posterior sacroiliac complex and sacrum. It is the most commonly injured artery in posterior pelvic ring disruptions, particularly lateral compression injuries with displaced sacral fractures.

Question 5936

Topic: 2. Trauma

A 40-year-old male sustains a Schatzker IV tibial plateau fracture. Imaging reveals a displaced posteromedial shear fragment. What is the most appropriate surgical approach to reduce and buttress this specific fragment?

. Anterolateral approach
. Direct medial approach
. Posteromedial approach
. Posterior approach via a Carlsson incision
. Anteromedial approach

Correct Answer & Explanation

. Posteromedial approach

Explanation

Schatzker IV fractures often involve a high-energy medially based shear fragment, frequently with a posteromedial component. An anteromedial approach is insufficient for posterior fragments. A posteromedial approach (interval between the medial head of the gastrocnemius and the pes anserinus) allows direct visualization, anatomical reduction, and placement of a posteromedial anti-glide/buttress plate to counteract the deforming shear forces.

Question 5937

Topic: 2. Trauma

A 25-year-old male develops acute compartment syndrome in the right lower leg following a tibial shaft fracture. If the deep posterior compartment is left unreleased during fasciotomy, which of the following deficits is most likely to persist?

. Loss of active ankle dorsiflexion
. Loss of sensation in the first web space
. Loss of active toe flexion and sensation on the plantar aspect of the foot
. Loss of active foot eversion
. Loss of sensation over the lateral aspect of the foot

Correct Answer & Explanation

. Loss of active toe flexion and sensation on the plantar aspect of the foot

Explanation

The deep posterior compartment of the leg contains the flexor digitorum longus, flexor hallucis longus, tibialis posterior, and the tibial nerve. Failure to decompress this compartment will lead to ischemic necrosis of these muscles (loss of active toe flexion and ankle inversion) and ischemic injury to the tibial nerve (loss of sensation on the plantar surface of the foot).

Question 5938

Topic: Lower Extremity Trauma
A 7-year-old boy presents with torticollis following an upper respiratory tract infection. Radiographs and CT show anterior displacement of the atlas on the axis of 4 mm, with one lateral mass acting as the pivot point. According to the Fielding and Hawkins classification, what type of atlantoaxial rotatory subluxation is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

Fielding and Hawkins Type II AARS involves anterior displacement of the atlas by 3-5 mm, with one lateral mass acting as the pivot point, indicating a deficiency of the transverse ligament. Type I has no anterior displacement (pivot on the dens). Type III has >5mm anterior displacement (deficiency of transverse and alar ligaments). Type IV involves posterior displacement.

Question 5939

Topic: 2. Trauma

A 28-year-old motorcyclist sustains a distal femur fracture. CT imaging reveals a coronal plane fracture of the lateral femoral condyle. What is the standard classification and typical mechanism for this specific fracture pattern?

. AO 33-A; severe valgus stress
. Hoffa fracture; direct anteroposterior force to a flexed knee
. Segond fracture; internal rotation and varus stress
. Barton fracture; axial load
. Chauffeur's fracture; direct lateral impact

Correct Answer & Explanation

. Hoffa fracture; direct anteroposterior force to a flexed knee

Explanation

A coronal plane fracture of the femoral condyle is known as a Hoffa fracture (AO/OTA 33-B3). It most commonly involves the lateral condyle. The typical mechanism of injury is a direct anterior-to-posterior force applied to the knee while in a flexed position, such as striking a dashboard during a motor vehicle collision.

Question 5940

Topic: 2. Trauma

A 40-year-old male is brought to the trauma bay after a severe crush injury. He has a hemodynamically unstable 'open book' pelvic fracture. A commercial pelvic binder is applied. To maximize mechanical advantage and safely reduce pelvic volume, over which anatomical landmarks should the binder be centered?

. Iliac crests
. Anterior superior iliac spines (ASIS)
. Greater trochanters
. Symphysis pubis
. Sacral promontory

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder or circumferential sheet must be centered directly over the greater trochanters. This alignment effectively creates an internal rotation moment around the posterior pelvis, closing the open book (APC) injury and effectively reducing pelvic volume. Placing the binder too high (e.g., over the iliac crests) is less effective and can paradoxically widen the symphysis.

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