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2. Trauma MCQs

Practice Set 548 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 10941

Topic: 2. Trauma

Recent quantitative anatomical studies (e.g., Hettrich et al.) have redefined the primary arterial blood supply to the humeral head. Which vessel provides the majority of the blood supply to the humeral head, putting it at risk for avascular necrosis in 4-part proximal humerus fractures?

. Anterior humeral circumflex artery
. Posterior humeral circumflex artery
. Circumflex scapular artery
. Thoracoacromial artery
. Deep brachial artery

Correct Answer & Explanation

. Anterior humeral circumflex artery

Explanation

Historically, the anterior humeral circumflex artery (via the arcuate branch) was thought to be the primary supply. However, recent studies demonstrate that the posterior humeral circumflex artery provides approximately 64% of the blood supply to the humeral head.

Question 10942

Topic: 2. Trauma

A 30-year-old male sustains a closed, spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). On initial presentation in the emergency department, his radial nerve function is intact. Following a closed reduction and application of a coaptation splint, he develops a complete wrist drop and inability to extend his fingers. What is the most appropriate next step in management?

. Observation and scheduled follow-up in 2 weeks
. Application of a functional Sarmiento brace
. Immediate surgical exploration and nerve release
. Electromyography (EMG) and nerve conduction studies
. Local corticosteroid injection into the spiral groove

Correct Answer & Explanation

. Observation and scheduled follow-up in 2 weeks

Explanation

A radial nerve palsy that develops AFTER a closed reduction of a humeral shaft fracture is an absolute indication for surgical exploration. This secondary palsy suggests the nerve may have become entrapped in the fracture site during manipulation.

Question 10943

Topic: 2. Trauma

A 40-year-old male involved in a high-speed motor vehicle collision sustains an isolated intra-articular distal femur fracture. CT imaging demonstrates a coronal plane fracture of the lateral femoral condyle (Hoffa fracture). Which fixation strategy offers the highest biomechanical stability for this specific fragment?

. Medial-to-lateral directed lag screws
. A lateral locking plate without independent lag screws
. Anterior-to-posterior (AP) directed lag screws
. Posterior-to-anterior (PA) directed lag screws
. Distal-to-proximal directed headless compression screws

Correct Answer & Explanation

. Medial-to-lateral directed lag screws

Explanation

A Hoffa fracture is a coronal shear fracture of the femoral condyle. Posterior-to-anterior (PA) directed lag screws are biomechanically superior to AP screws because they are directed perpendicular to the fracture line and engage the dense anterior cortical bone.

Question 10944

Topic: 2. Trauma

A 25-year-old polytrauma patient (ISS 45) presents with bilateral closed femoral shaft fractures, severe bilateral pulmonary contusions, and a pelvic ring injury. His initial serum lactate is 4.5 mmol/L, base deficit is 8 mEq/L, and temperature is 34.5°C. What is the most appropriate initial management of his femoral fractures?

. Bilateral reamed intramedullary nailing (Early Total Care)
. Unilateral intramedullary nailing and unilateral external fixation
. Bilateral external fixation of the femurs (Damage Control Orthopedics)
. Bilateral distal femoral skeletal traction
. Open reduction and internal fixation with plates bilaterally

Correct Answer & Explanation

. Bilateral reamed intramedullary nailing (Early Total Care)

Explanation

This patient is physiologically unstable (acidosis, hypothermia, high ISS, and pulmonary contusions), meeting the criteria for Damage Control Orthopedics (DCO). Immediate reamed intramedullary nailing in this setting risks a "second hit" phenomenon, exacerbating ARDS and systemic inflammation; therefore, temporary external fixation is indicated.

Question 10945

Topic: Pelvic & Acetabular Trauma

A 45-year-old male sustains a pelvic injury after being struck by a vehicle from the side. Pelvic radiographs and CT demonstrate an internal rotation deformity of the hemipelvis with a fracture extending from the sacroiliac joint through the posterior iliac wing. How is this injury classified according to the Young-Burgess system?

. Anteroposterior Compression I (APC-I)
. Anteroposterior Compression II (APC-II)
. Lateral Compression I (LC-I)
. Lateral Compression II (LC-II)
. Vertical Shear (VS)

Correct Answer & Explanation

. Anteroposterior Compression I (APC-I)

Explanation

A fracture extending from the sacroiliac joint through the posterior iliac wing is known as a "crescent fracture." In the Young-Burgess classification, this defines a Lateral Compression Type II (LC-II) injury.

Question 10946

Topic: 2. Trauma

An 8-week follow-up radiograph of a 25-year-old patient who sustained a talar neck fracture shows a distinct subchondral radiolucent band running across the talar dome. What does this radiographic finding signify?

. Impending complete avascular necrosis of the talar body
. Intact vascularity to the talar body, ruling out widespread avascular necrosis
. Development of rapidly progressive post-traumatic subtalar arthritis
. Nonunion of the talar neck fracture requiring bone grafting
. Chronic osteomyelitis of the talar dome

Correct Answer & Explanation

. Impending complete avascular necrosis of the talar body

Explanation

This finding is known as the Hawkins sign. The radiolucent line represents subchondral osteopenia secondary to active bone resorption, which can only occur if the vascular supply to the talar body is intact.

Question 10947

Topic: 2. Trauma

A 45-year-old female falls onto an outstretched hand with her wrist in palmar flexion. Radiographs demonstrate a fracture of the volar margin of the distal radius with associated volar subluxation of the carpus. What is the eponymous name for this fracture pattern?

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

Correct Answer & Explanation

. Colles fracture

Explanation

A volar Barton fracture is a fracture-dislocation or subluxation in which the volar rim of the distal radius fractures and displaces volarly along with the carpus. It is a shear injury best treated with a volar buttress plate.

Question 10948

Topic: 2. Trauma

Why is a fracture through the proximal pole of the scaphoid at a significantly higher risk for nonunion and avascular necrosis compared to a distal pole fracture?

. The blood supply enters the distal pole and flows in a retrograde fashion to the proximal pole
. The blood supply enters the proximal pole and flows distally, which is easily disrupted
. The proximal pole lacks any intraosseous blood supply
. The proximal pole is entirely dependent on the deep palmar arch, which tears during FOOSH
. The radiocarpal ligaments forcibly distract the proximal pole fragment

Correct Answer & Explanation

. The blood supply enters the distal pole and flows in a retrograde fashion to the proximal pole

Explanation

The major blood supply to the scaphoid comes from branches of the radial artery that enter the dorsal ridge near the waist and distal pole, flowing proximally in a retrograde manner. Fractures at the proximal pole isolate it from this blood supply, predisposing it to AVN.

Question 10949

Topic: 2. Trauma

A 60-year-old male sustains a basicervical femoral neck fracture. From a biomechanical and treatment perspective, how should this specific fracture pattern be managed?

. It behaves like an intertrochanteric fracture and should be treated with a cephalomedullary nail or sliding hip screw
. It behaves like a subcapital fracture and should be treated with parallel cannulated screws
. It is exceptionally stable and should be managed conservatively
. It routinely causes avascular necrosis and must be treated with hemiarthroplasty
. It requires a primary proximal femoral replacement regardless of age

Correct Answer & Explanation

. It behaves like an intertrochanteric fracture and should be treated with a cephalomedullary nail or sliding hip screw

Explanation

Basicervical femoral neck fractures are extracapsular and biomechanically unstable. They behave much like intertrochanteric fractures and are best treated with fixed-angle devices like a cephalomedullary nail or a sliding hip screw with a derotation screw, rather than multiple cancellous screws.

Question 10950

Topic: 2. Trauma

A 30-year-old male sustains a low-velocity gunshot wound to the thigh resulting in a comminuted midshaft femur fracture. The bullet passed cleanly through the thigh, and the patient has no vascular deficits. What is the most appropriate management of the fracture?

. Immediate aggressive debridement of the entire bullet tract and external fixation
. Local wound care, tetanus prophylaxis, and standard intramedullary nailing
. Primary above-knee amputation due to massive soft tissue injury
. Plate osteosynthesis with acute cancellous bone grafting
. Excision of the bullet tract followed by delayed intramedullary nailing at 2 weeks

Correct Answer & Explanation

. Immediate aggressive debridement of the entire bullet tract and external fixation

Explanation

Low-velocity gunshot wounds resulting in femur fractures without gross contamination or vascular injury are effectively treated as closed fractures. Standard management includes local wound care at the entry/exit sites and early intramedullary nailing without aggressive tract debridement.

Question 10951

Topic: 2. Trauma
A 28-year-old male is admitted with a comminuted tibial shaft fracture. He complains of excruciating leg pain unresponsive to intravenous opioids. His current blood pressure is 110/60 mmHg. Intracompartmental pressure testing of the anterior compartment yields a measurement of 45 mmHg. What is the Delta P (ΔP), and what is the indicated treatment?
. ΔP = 65 mmHg; Elevation and observation
. ΔP = 25 mmHg; Immediate application of a bivalved cast
. ΔP = 15 mmHg; Emergent 4-compartment fasciotomy
. ΔP = 25 mmHg; Emergent 4-compartment fasciotomy
. ΔP = 65 mmHg; Administration of intravenous mannitol

Correct Answer & Explanation

. ΔP = 15 mmHg; Emergent 4-compartment fasciotomy

Explanation

Delta P is calculated as Diastolic Blood Pressure minus Compartment Pressure (60 - 45 = 15). A Delta P of less than 30 mmHg is highly specific for acute compartment syndrome and is an absolute indication for emergent 4-compartment fasciotomies.

Question 10952

Topic: 2. Trauma

A 40-year-old male sustains a high-energy OTA/AO 43-C3 pilon fracture. On presentation, the soft tissues about the ankle are severely swollen with multiple fracture blisters. What is the most appropriate initial management?

. Immediate open reduction and internal fixation with dual plating
. Joint-spanning external fixation and limb elevation
. Primary tibiotalar arthrodesis
. Application of a circular fine-wire frame for definitive fixation immediately
. Closed reduction and application of a long leg cast

Correct Answer & Explanation

. Immediate open reduction and internal fixation with dual plating

Explanation

High-energy pilon fractures are notorious for severe soft tissue compromise. The standard of care is a staged approach: initial joint-spanning external fixation to restore length and alignment while allowing the soft tissues to heal, followed by definitive internal fixation 10-21 days later.

Question 10953

Topic: 2. Trauma
A 25-year-old male sustains a midshaft clavicle fracture following a motorcycle accident. According to current AAOS guidelines, which of the following is considered an absolute indication for open reduction and internal fixation?
. 1.5 cm of shortening
. Floating shoulder
. Open fracture
. Z-type comminution
. Brachial plexus neuropraxia

Correct Answer & Explanation

. Open fracture

Explanation

Absolute indications for operative fixation of clavicle fractures include open fractures, skin tenting that threatens skin integrity, and progressive neurologic deficit. Shortening >2cm, severe comminution (Z-type), and floating shoulder are considered relative indications.

Question 10954

Topic: 2. Trauma

A 30-year-old male falls and sustains a closed humeral shaft fracture at the distal third (Holstein-Lewis type). He is unable to extend his wrist or digits at presentation. He is placed in a coaptation splint. At 12 weeks of follow-up, radiographs show bridging callus, but there is no clinical sign of nerve recovery. What is the next best step in management?

. Immediate surgical exploration
. EMG and nerve conduction studies
. Tendon transfers
. Observation for another 3 months
. High-resolution ultrasound of the nerve

Correct Answer & Explanation

. Immediate surgical exploration

Explanation

Initial management for closed humeral shaft fractures with primary radial nerve palsy is observation. If there is no clinical evidence of recovery by 12 weeks (3 months), an EMG/NCS should be ordered to evaluate for subclinical reinnervation or severe denervation, which would dictate the need for surgical exploration.

Question 10955

Topic: 2. Trauma

A 28-year-old male presents with a scaphoid waist fracture nonunion.

MRI demonstrates avascular necrosis (AVN) of the proximal pole with a structural humpback deformity. Which of the following is the most appropriate graft option to achieve union and correct the deformity?

. Non-vascularized iliac crest bone graft
. 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) vascularized graft
. Free vascularized medial femoral condyle (MFC) bone graft
. Free non-vascularized fibula graft
. Distal radius cancellous autograft

Correct Answer & Explanation

. Non-vascularized iliac crest bone graft

Explanation

A free vascularized medial femoral condyle (MFC) bone graft is highly effective for scaphoid nonunions complicated by proximal pole AVN and structural collapse (humpback deformity), as it provides both robust vascularity and a strong corticocancellous strut. The 1,2 ICSRA graft provides less reliable vascularity in advanced AVN and less structural support.

Question 10956

Topic: Upper Extremity Trauma
A patient sustains a Type III acromioclavicular (AC) joint separation. The coracoclavicular (CC) ligaments are ruptured. Which CC ligament originates from the base of the coracoid and inserts onto the conoid tubercle of the clavicle?
. Trapezoid ligament
. Conoid ligament
. Coracoacromial ligament
. Superior AC ligament
. Acromioclavicular ligament

Correct Answer & Explanation

. Conoid ligament

Explanation

The coracoclavicular (CC) ligament complex consists of the conoid and trapezoid ligaments. The conoid ligament is the more medial and posterior of the two, originating at the base of the coracoid and inserting on the conoid tubercle. The trapezoid ligament is more lateral and anterior.

Question 10957

Topic: 2. Trauma

A 55-year-old male sustains a displaced transverse olecranon fracture after a ground-level fall. The surgeon decides to fix the fracture using tension band wiring. Biomechanically, the primary purpose of tension band fixation in this scenario is to convert which type of force at the dorsal cortex into what type of force at the articular surface?

. Shear into compression
. Torsion into tension
. Tension into compression
. Compression into tension
. Bending into shear

Correct Answer & Explanation

. Shear into compression

Explanation

The biomechanical principle of a tension band is to counteract distractive (tensile) forces on the convex (tension) side of a bone and convert them into compressive forces on the concave (articular) side during joint movement. In an olecranon fracture, the pull of the triceps creates tensile forces on the dorsal cortex. The figure-of-eight wire placed on the dorsal surface absorbs these tensile forces, compressing the articular surface of the greater sigmoid notch together during elbow flexion.

Question 10958

Topic: 2. Trauma

A 19-year-old male presents with a scaphoid waist fracture. Which of the following best describes the predominant vascular supply to the scaphoid that dictates its risk of nonunion?

. The volar carpal branch of the radial artery entering the distal pole
. The dorsal carpal branch of the radial artery entering via the dorsal ridge and supplying the proximal 80% in a retrograde fashion
. The anterior interosseous artery entering the proximal pole
. The deep palmar arch supplying the proximal pole directly
. The ulnar artery entering via the scapholunate ligament

Correct Answer & Explanation

. The volar carpal branch of the radial artery entering the distal pole

Explanation

The major blood supply to the scaphoid comes from the dorsal carpal branch of the radial artery, which enters the bone at the dorsal ridge (distal to the waist) and provides retrograde blood flow to the proximal 70-80% of the scaphoid. This retrograde supply is the primary reason proximal pole fractures are at a high risk for avascular necrosis and nonunion.

Question 10959

Topic: 2. Trauma

A 28-year-old male sustains a closed spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). On initial presentation in the emergency department, his radial nerve function is intact. Following closed reduction and splinting, he completely loses active wrist and digit extension. What is the most appropriate management regarding the nerve injury?

. Observation and electromyography (EMG) at 6 weeks
. Immediate surgical exploration of the radial nerve
. Ultrasound-guided steroid injection into the radial tunnel
. Removal of the splint and re-manipulation into varus
. Wait 3 months for spontaneous recovery, then perform tendon transfers if no improvement

Correct Answer & Explanation

. Observation and electromyography (EMG) at 6 weeks

Explanation

A secondary radial nerve palsy (loss of radial nerve function AFTER a closed reduction maneuver) in a humeral shaft fracture is an absolute indication for surgical exploration. The nerve may be entrapped between the fracture fragments. Primary palsies (present on initial exam) can often be observed, but secondary palsies require exploration.

Question 10960

Topic: 2. Trauma

A 35-year-old male develops acute compartment syndrome of the volar forearm after a crush injury. If left untreated, Volkmann's ischemic contracture will develop. Which muscles are most severely and earliest affected in the deep volar compartment?

. Flexor carpi radialis (FCR) and Pronator teres (PT)
. Flexor digitorum superficialis (FDS) and Flexor carpi ulnaris (FCU)
. Flexor digitorum profundus (FDP) and Flexor pollicis longus (FPL)
. Brachioradialis and Extensor carpi radialis longus (ECRL)
. Pronator quadratus and Palmaris longus

Correct Answer & Explanation

. Flexor carpi radialis (FCR) and Pronator teres (PT)

Explanation

The deep volar compartment of the forearm contains the Flexor Digitorum Profundus (FDP) and Flexor Pollicis Longus (FPL). Because they lie deep against the bone and their blood supply is most vulnerable to increased compartment pressures, they are the most severely and earliest affected muscles in Volkmann's ischemic contracture.

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