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2. Trauma MCQs

Practice Set 114 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 2261

Topic: 2. Trauma
A 'floating shoulder' classically involves ipsilateral fractures of the clavicle and which other anatomical structure?
. Coracoid process
. Acromion
. Scapular neck
. Glenoid fossa
. Proximal humerus

Correct Answer & Explanation

. Scapular neck

Explanation

A floating shoulder is defined as an ipsilateral fracture of the clavicle and the scapular neck. This disrupts the superior shoulder suspensory complex (SSSC) in two places, often requiring surgical stabilization.

Question 2262

Topic: 2. Trauma

During open reduction and internal fixation of a midshaft clavicle fracture, a superiorly placed reconstruction plate is biomechanically superior to an anteroinferiorly placed plate in resisting which type of force?

. Axial compression
. Torsional stress
. Bending forces (tension band effect)
. Shear forces
. Distraction forces

Correct Answer & Explanation

. Bending forces (tension band effect)

Explanation

The superior surface of the clavicle is the tension side of the bone. A superiorly applied plate acts as a tension band, making it biomechanically superior in resisting bending forces compared to an anteroinferior plate.

Question 2263

Topic: 2. Trauma

Review the clinical image provided.

In a 65-year-old patient presenting with a proximal humerus fracture, what is the primary determinant of avascular necrosis (AVN) risk of the humeral head?

. Length of the medial calcar segment attached to the articular surface
. Presence of a greater tuberosity fracture
. Degree of inferior subluxation of the humeral head
. Age of the patient
. Choice of surgical approach (deltopectoral vs anterolateral)

Correct Answer & Explanation

. Length of the medial calcar segment attached to the articular surface

Explanation

Hertel's radiographic predictors for ischemia of the humeral head include a metaphyseal calcar length of less than 8 mm, disruption of the medial hinge, and a basicervical fracture pattern.

Question 2264

Topic: 2. Trauma

A 45-year-old smoker presents with a symptomatic atrophic nonunion of a midshaft humerus fracture 8 months after nonoperative management in a Sarmiento brace. What is the most appropriate surgical treatment?

. Exchange casting with a new functional brace
. Open reduction and internal fixation (ORIF) with compression plating and bone grafting
. Intramedullary nailing without bone grafting
. External fixation
. Pulsed electromagnetic field therapy

Correct Answer & Explanation

. Open reduction and internal fixation (ORIF) with compression plating and bone grafting

Explanation

Symptomatic atrophic nonunions of the humeral shaft are best treated with rigid stabilization and biological augmentation. ORIF with compression plating and autologous bone grafting is the gold standard.

Question 2265

Topic: 2. Trauma

During fixation of a complex proximal humerus fracture, the long head of the biceps (LHB) tendon is found to be severely contused and subluxated. The surgeon decides to perform a biceps tenodesis. Where is the optimal location for tenodesis to prevent postoperative anterior shoulder pain?

. Above the bicipital groove
. At the level of the transverse humeral ligament
. Subpectoral (distal to the bicipital groove)
. To the conjoined tendon
. To the coracoacromial ligament

Correct Answer & Explanation

. Subpectoral (distal to the bicipital groove)

Explanation

Subpectoral tenodesis removes the LHB tendon completely from the bicipital groove. This eliminates the groove as a source of persistent anterior shoulder pain and tenosynovitis.

Question 2266

Topic: 2. Trauma

According to Hertel's criteria, which of the following is the most reliable predictor of humeral head ischemia following a proximal humerus fracture?

. Metaphyseal head extension greater than 8 mm
. Intact medial calcar hinge
. Disruption of the medial hinge greater than 2 mm
. Greater tuberosity displacement of 5 mm
. Fracture of the surgical neck only

Correct Answer & Explanation

. Disruption of the medial hinge greater than 2 mm

Explanation

Hertel identified several risk factors for avascular necrosis (AVN) in proximal humerus fractures. The strongest predictors of ischemia include a medial calcar hinge disruption >2 mm, metaphyseal extension <8 mm, and an anatomic neck fracture. An intact medial hinge provides a vital conduit for intraosseous blood supply.

Question 2267

Topic: 2. Trauma

A 35-year-old male sustains a completely displaced, shortened midshaft clavicle fracture. Which of the following factors most significantly increases his risk of developing a nonunion if treated nonoperatively?

. Male gender
. Shortening of less than 1 cm
. Lack of comminution
. Advanced age
. Distal third location

Correct Answer & Explanation

. Advanced age

Explanation

Risk factors for clavicle fracture nonunion include advanced age, female sex, complete displacement, shortening greater than 2 cm, and severe comminution. While displacement and shortening are key biomechanical factors, advancing age is a predominant biological risk factor for nonunion.

Question 2268

Topic: 2. Trauma

During open reduction and internal fixation of a midshaft clavicle fracture, a surgeon notes a sensory nerve crossing directly over the surgical field. Iatrogenic injury to this nerve will most likely result in numbness over which area?

. Lateral arm
. Anterior-medial forearm
. Anterior chest wall just inferior to the clavicle
. Posterior shoulder
. Dorsal web space of the hand

Correct Answer & Explanation

. Anterior chest wall just inferior to the clavicle

Explanation

The supraclavicular nerves predictably cross over the midshaft of the clavicle. Iatrogenic injury during clavicle plating leads to a characteristic patch of numbness over the anterior chest wall just inferior to the surgical incision.

Question 2269

Topic: 2. Trauma

A 55-year-old patient sustains the injury seen in the provided radiograph.

Based on modern anatomic studies, which vessel provides the predominant blood supply to the articular segment in this specific fracture pattern?

. Anterior circumflex humeral artery
. Posterior circumflex humeral artery
. Thoracoacromial artery
. Suprascapular artery
. Circumflex scapular artery

Correct Answer & Explanation

. Posterior circumflex humeral artery

Explanation

Recent anatomic injection studies (e.g., Brooks et al.) have demonstrated that the posterior circumflex humeral artery provides the predominant blood supply to the humeral head. The arcuate artery (a branch of the anterior circumflex) was historically thought to be the primary supply but is now considered secondary.

Question 2270

Topic: Upper Extremity Trauma

A 25-year-old cyclist falls directly onto his shoulder and sustains a Type V acromioclavicular (AC) joint separation. During surgical reconstruction, the surgeon aims to reconstruct the primary restraint to superior translation of the distal clavicle. Which ligament serves this function?

. Acromioclavicular ligament
. Trapezoid ligament
. Conoid ligament
. Coracoacromial ligament
. Transverse humeral ligament

Correct Answer & Explanation

. Conoid ligament

Explanation

The coracoclavicular (CC) ligaments consist of the conoid and trapezoid. The conoid ligament is located posteromedially and serves as the primary restraint to superior translation of the clavicle.

Question 2271

Topic: 2. Trauma

A 65-year-old female sustains a proximal humerus fracture after a ground-level fall. Radiographs demonstrate a 4-part fracture pattern. According to Hertel's criteria, which of the following radiographic findings is the MOST reliable predictor for the development of avascular necrosis (AVN) of the humeral head?

. Metaphyseal head extension (calcar length) greater than 8 mm
. Disruption of the medial hinge by greater than 2 mm
. Isolated fracture of the greater tuberosity with 5 mm of displacement
. An intact posteromedial periosteal sleeve
. Valgus impaction of the humeral head

Correct Answer & Explanation

. Disruption of the medial hinge by greater than 2 mm

Explanation

According to Hertel, disruption of the medial hinge (>2 mm) and a short metaphyseal calcar segment (<8 mm attached to the articular segment) are the strongest predictors of humeral head ischemia and subsequent AVN. Valgus impaction and an intact medial hinge are relatively protective.

Question 2272

Topic: 2. Trauma

A 42-year-old male presents as a polytrauma following a motorcycle accident. Radiographs and CT imaging reveal an isolated scapula fracture. Which of the following findings is an absolute indication for operative fixation of this injury?

. A 2 mm intra-articular step-off of the glenoid fossa
. An extra-articular scapular body fracture with 50% displacement
. A glenoid neck fracture with 5 mm of medial translation
. An intra-articular fracture involving 30% of the anterior glenoid with anterior humeral subluxation
. A scapular spine fracture with 2 mm of displacement

Correct Answer & Explanation

. An intra-articular fracture involving 30% of the anterior glenoid with anterior humeral subluxation

Explanation

Operative indications for scapula fractures include intra-articular glenoid fractures with >5 mm step-off or involving >25% of the anterior glenoid associated with humeral head subluxation. Extra-articular body fractures are typically managed non-operatively unless severely displaced (e.g., >20 mm medial translation).

Question 2273

Topic: 2. Trauma

A 35-year-old male sustains a midshaft clavicle fracture. He opts for non-operative management. Which of the following initial injury characteristics MOST significantly increases his risk of developing a nonunion?

. Initial fracture shortening of 5 mm
. A non-displaced transverse fracture pattern
. Comminution with 100% initial fracture displacement
. Distal third clavicle fracture (Neer Type I)
. A butterfly fragment with less than 1 cm of overall shortening

Correct Answer & Explanation

. Comminution with 100% initial fracture displacement

Explanation

Risk factors for clavicle fracture nonunion with non-operative management include 100% initial displacement, severe comminution, and shortening greater than 2 cm. Advanced age and smoking also independently increase nonunion risk.

Question 2274

Topic: 2. Trauma

A 72-year-old female with osteoporosis was treated 6 months ago with open reduction and internal fixation (locking plate) for a 3-part proximal humerus fracture. She now presents with severe, mechanically limiting shoulder pain and restricted active elevation. Based on the likely complication shown in the provided imaging context, what is the most common etiology for her current presentation?

. Primary avascular necrosis of the humeral head
. Axillary nerve neuropraxia secondary to retractor placement
. Intra-articular screw penetration secondary to fracture settling
. Nonunion of the greater tuberosity
. Post-operative adhesive capsulitis

Correct Answer & Explanation

. Intra-articular screw penetration secondary to fracture settling

Explanation

The most common complication following locked plating of proximal humerus fractures is intra-articular screw penetration. This typically occurs as the fracture settles and collapses over time, driving the fixed-angle screws through the osteoporotic articular surface.

Question 2275

Topic: 2. Trauma

A 30-year-old male sustains a severely displaced midshaft clavicle fracture. On the AP radiograph, the medial fragment is displaced superiorly and posteriorly, while the lateral fragment is translated inferiorly. Which specific muscle forces are primarily responsible for the characteristic displacement of these two fragments, respectively?

. Sternocleidomastoid; Pectoralis major and the weight of the arm
. Trapezius; Deltoid and the short head of the biceps
. Subclavius; Pectoralis minor and the latissimus dorsi
. Deltoid; Sternocleidomastoid and the weight of the arm
. Pectoralis major; Latissimus dorsi and the trapezius

Correct Answer & Explanation

. Sternocleidomastoid; Pectoralis major and the weight of the arm

Explanation

In midshaft clavicle fractures, the sternocleidomastoid muscle pulls the medial fragment superiorly and posteriorly. The lateral fragment is pulled inferiorly by the weight of the arm and medially by the pectoralis major and latissimus dorsi muscles.

Question 2276

Topic: Upper Extremity Trauma

A surgeon is performing a coracoclavicular ligament reconstruction for a chronic Type V acromioclavicular (AC) joint separation. To anatomically restore the ligaments, the surgeon must understand their native footprints. Which of the following accurately describes the anatomy of the coracoclavicular ligaments?

. The conoid ligament inserts anterolateral to the trapezoid ligament on the clavicle
. The conoid ligament inserts posteromedial to the trapezoid ligament on the clavicle
. Both ligaments insert on the superior aspect of the coracoid process identically
. The trapezoid ligament is the primary restraint to superior translation
. The conoid ligament originates from the base of the coracoid and inserts laterally on the acromion

Correct Answer & Explanation

. The conoid ligament inserts posteromedial to the trapezoid ligament on the clavicle

Explanation

The coracoclavicular complex consists of the conoid and trapezoid ligaments. The conoid ligament inserts posteromedial to the trapezoid on the clavicle and acts as the primary restraint to superior translation.

Question 2277

Topic: Lower Extremity Trauma

A 45-year-old male marathon runner complains of isolated medial knee pain. Radiographs demonstrate medial compartment osteoarthritis with a mechanical axis passing through the medial compartment. He is scheduled for a medial opening-wedge high tibial osteotomy (HTO). What is the optimal target for the postoperative mechanical axis?

. Exactly through the center of the knee joint (50% of the tibial plateau)
. Through the center of the medial compartment (25% of the tibial plateau)
. At the Fujisawa point (62% of the tibial plateau from medial to lateral)
. At the extreme lateral articular margin (100% of the tibial plateau)
. Anterior to the center of rotation to decrease patellofemoral pressure

Correct Answer & Explanation

. At the Fujisawa point (62% of the tibial plateau from medial to lateral)

Explanation

The goal of an HTO for medial compartment OA is to slightly overcorrect the mechanical axis into valgus to offload the medial side. The classic target is the Fujisawa point, located at 62-62.5% of the tibial plateau width from the medial edge.

Question 2278

Topic: Upper Extremity Trauma
A 24-year-old manual laborer sustains a Grade III acromioclavicular (AC) joint separation. Biomechanical studies indicate that the primary restraint to superior translation of the distal clavicle is provided by which of the following structures?
. Superior AC ligament
. Inferior AC ligament
. Trapezoid ligament
. Conoid ligament
. Coracoacromial ligament

Correct Answer & Explanation

. Conoid ligament

Explanation

The conoid ligament is the primary restraint to superior translation of the distal clavicle. The trapezoid ligament provides the primary restraint to axial compression, while the AC ligaments provide horizontal stability.

Question 2279

Topic: 2. Trauma

A 28-year-old construction worker sustains a direct blow to his left forearm with obvious deformity and severe pain. On examination, there is a small puncture wound over the ulnar shaft. What is the most critical immediate next step in management after initial ATLS primary survey and limb exposure?

. Obtain AP and lateral forearm radiographs.
. Administer IV antibiotics and tetanus prophylaxis.
. Assess neurovascular status distal to the injury.
. Immobilize the limb with a splint.
. Measure compartment pressures in the forearm.

Correct Answer & Explanation

. Assess neurovascular status distal to the injury.

Explanation

Correct Answer: CWhile all options are important, immediate assessment of neurovascular status distal to the injury (Option C) is paramount. Any compromise (e.g., absent pulses, severe paresthesias, motor weakness) warrants urgent intervention to prevent limb ischemia and permanent neurological damage. This assessment dictates the immediate urgency of further steps. Identifying the puncture wound implies an open fracture, for which IV antibiotics and tetanus prophylaxis (Option B) are crucial to prevent infection, but limb viability takes precedence. Radiographs (Option A) are necessary to characterize the fracture but follow neurovascular assessment. Immobilization (Option D) provides comfort and prevents further injury but is not the most critical immediate step for limb salvage. Measuring compartment pressures (Option E) is indicated if acute compartment syndrome is suspected, which is a secondary assessment after initial neurovascular evaluation and often triggered by the findings of that initial assessment.

Question 2280

Topic: 2. Trauma

A 45-year-old male with a mid-diaphyseal both bones forearm fracture undergoes open reduction and internal fixation (ORIF) with 3.5mm dynamic compression plates. What is the generally accepted minimum number of cortices that should be engaged by screws proximally and distally to achieve adequate stability for these fractures?

. 4 cortices (2 screws)
. 6 cortices (3 screws)
. 8 cortices (4 screws)
. 10 cortices (5 screws)
. 12 cortices (6 screws)

Correct Answer & Explanation

. 8 cortices (4 screws)

Explanation

Correct Answer: CFor adequate stability in plating diaphyseal forearm fractures, the general consensus and biomechanical studies recommend achieving at least 8 cortices (4 screws) proximally and 8 cortices (4 screws) distally. This provides sufficient screw-bone purchase to resist bending, rotational, and axial forces, which are critical for primary bone healing and preventing fixation failure, non-union, or malunion. Fewer than 8 cortices on either side of the fracture can lead to higher rates of fixation failure, screw pullout, and non-union, especially given the high torsional and bending stresses the forearm experiences during daily activities.

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