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2. Trauma MCQs

Practice Set 71 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 1401

Topic: 2. Trauma

During surgical exploration for a Holstein–Lewis fracture with complete radial nerve palsy, the surgeon identifies the radial nerve as depicted in the image below, carefully dissecting it from surrounding tissues.

. A. As it exits the axilla, proximal to the spiral groove.
. B. Within the spiral groove, in direct contact with the mid-shaft humerus.
. C. Where it pierces the lateral intermuscular septum to move from posterior to anterior.
. D. Distal to the lateral epicondyle, branching into superficial and deep radial nerves.
. E. Anterior to the medial epicondyle, adjacent to the brachial artery.

Correct Answer & Explanation

. C. Where it pierces the lateral intermuscular septum to move from posterior to anterior.

Explanation

Correct Answer: CThe case study emphasizes that in Holstein–Lewis fractures, the radial nerve is particularly vulnerable at the point where it pierces the lateral intermuscular septum and more distally, where it runs intimately with the periosteum of the distal humerus. This transition point, typically 10-14 cm proximal to the lateral epicondyle, is where the nerve moves from the posterior compartment to the anterior compartment of the arm, making it susceptible to entrapment or injury by the sharp, often medially displaced, proximal fracture fragment.Option A describes a more proximal location, not specific to Holstein–Lewis vulnerability. Option B describes the vulnerability in mid-shaft fractures, not the unique vulnerability in Holstein–Lewis fractures which are more distal. Option D describes the nerve's course after it has already passed the critical zone of injury for Holstein–Lewis fractures. Option E describes the ulnar nerve's general vicinity, not the radial nerve.

Question 1402

Topic: 2. Trauma

During ORIF of a Holstein–Lewis fracture, the surgeon encounters an oblique fracture pattern in the distal one-third of the humerus.

Which of the following fixation principles is most strongly supported by current literature for achieving optimal biomechanical stability in this type of fracture?

. A. Single plate fixation with a dynamic compression plate (DCP) on the anterior aspect.
. B. Intramedullary nailing, as it provides superior rotational stability.
. C. Dual plating (e.g., orthogonal or parallel constructs) combined with lag screws across the fracture line.
. D. External fixation, due to the high risk of infection in distal humeral fractures.
. E. Tension band wiring for interfragmentary compression.

Correct Answer & Explanation

. C. Dual plating (e.g., orthogonal or parallel constructs) combined with lag screws across the fracture line.

Explanation

Correct Answer: CThe 'Summary of Key Literature / Guidelines' section explicitly states that 'Contemporary literature strongly supports the use of dual plating (e.g., orthogonal or parallel plate constructs) for displaced distal humeral shaft fractures, including Holstein–Lewis patterns. This provides superior biomechanical stability compared to single plating, especially against torsional and bending forces, which are critical for the oblique/spiral nature of these fractures.' It also recommends 'The use of lag screws across the oblique or spiral fracture line, prior to plate application, is highly recommended to achieve interfragmentary compression and increase construct stiffness.'Option A (Single plate fixation) is less stable than dual plating for these fractures. Option B (Intramedullary nailing) is generally not preferred for distal humeral shaft fractures due to concerns about elbow impingement and less stable fixation in the metaphyseal region compared to plating. Option D (External fixation) is typically reserved for severe open fractures or temporary stabilization in polytrauma, not definitive fixation of closed Holstein–Lewis fractures. Option E (Tension band wiring) is more commonly used for avulsion fractures or olecranon fractures, not for diaphyseal/metaphyseal humerus fractures.

Question 1403

Topic: 2. Trauma

A 60-year-old patient, 9 months after ORIF of a Holstein–Lewis fracture, presents with persistent pain, instability, and radiographic evidence of non-union. The initial fixation involved a single plate.

What is the most appropriate salvage strategy for this patient's non-union?

. A. Continue observation and non-steroidal anti-inflammatory drugs (NSAIDs) for another 3 months.
. B. Initiate a course of systemic antibiotics, assuming a low-grade infection.
. C. Revision ORIF with robust fixation (e.g., dual plating), debridement of fibrous tissue, and bone grafting.
. D. Removal of hardware and conversion to external fixation.
. E. Tendon transfers to compensate for persistent pain and instability.

Correct Answer & Explanation

. C. Revision ORIF with robust fixation (e.g., dual plating), debridement of fibrous tissue, and bone grafting.

Explanation

Correct Answer: CThe 'Complications & Management' section, under 'Non-Union,' states that management involves 'Revision ORIF with robust fixation (dual plating), debridement of fibrous tissue, interposition bone grafting (autograft or allograft), potentially electrical stimulation.' Given the persistent pain, instability, and radiographic non-union at 9 months, a surgical revision is indicated. The initial single plate fixation may have been inadequate, making dual plating a more robust option for revision.Option A (observation and NSAIDs) is inappropriate for an established non-union. Option B (systemic antibiotics) is incorrect without evidence of infection (e.g., elevated inflammatory markers, wound drainage, positive cultures). Option D (external fixation) is generally not the definitive treatment for a non-union of the humerus unless there are severe soft tissue issues or active infection. Option E (tendon transfers) is a salvage procedure for chronic nerve palsy, not for fracture non-union.

Question 1404

Topic: 2. Trauma

A 28-year-old male presents with a Holstein–Lewis fracture after a wrestling match where his arm was twisted.

The typical mechanism of injury for a Holstein–Lewis fracture involves which of the following forces, and how does this relate to the fracture pattern's inherent instability?

. A. High-energy direct axial compression, leading to a comminuted transverse fracture stable to rotational loads.
. B. Low-energy torsional force, resulting in a spiral or oblique fracture inherently unstable to rotational loads.
. C. Direct impact to the olecranon, causing an intra-articular fracture with high bending stability.
. D. Hyperextension injury of the elbow, leading to a transverse supracondylar fracture with minimal displacement.
. E. Avulsion injury of the deltoid insertion, resulting in a proximal diaphyseal fracture.

Correct Answer & Explanation

. B. Low-energy torsional force, resulting in a spiral or oblique fracture inherently unstable to rotational loads.

Explanation

Correct Answer: BThe 'Introduction & Epidemiology' section states that the 'typical mechanism of injury involves direct trauma or a low-energy torsional force to the arm.' The 'Surgical Anatomy & Biomechanics' section further clarifies that 'The biomechanics of Holstein–Lewis fractures often involve a combination of bending and torsional forces. The oblique or spiral nature of the fracture makes it inherently unstable to rotational loads, and the smooth, often comminuted, fracture surfaces can make stable reduction challenging.'Option A describes a different mechanism and fracture pattern. Option C describes an olecranon fracture, not a Holstein–Lewis. Option D describes a supracondylar fracture, which is distinct from a Holstein–Lewis. Option E describes a proximal humeral fracture, not a distal one-third diaphyseal fracture.

Question 1405

Topic: 2. Trauma

A 45-year-old male sustains a closed, midshaft humerus fracture and is managed non-operatively with a Sarmiento functional brace. For this treatment modality to be deemed successful and to avoid malunion, which of the following represents the widely accepted maximum limits of acceptable alignment?

. <30 degrees of varus/valgus angulation
. <40 degrees of anterior bowing
. <5 cm of shortening
. <25 degrees of internal rotation
. <30 degrees of anterior bowing

Correct Answer & Explanation

. <30 degrees of varus/valgus angulation

Explanation

Acceptable alignment criteria for functional bracing of humeral shaft fractures include <20 degrees of anterior bowing, <30 degrees of varus/valgus angulation, <15 degrees of malrotation, and <3 cm of shortening.

Question 1406

Topic: Upper Extremity Trauma

During open reduction and internal fixation of a chronic acromioclavicular (AC) joint injury, the surgeon must address both vertical and horizontal instability. Which of the following native structures acts as the primary restraint to anteroposterior (horizontal) translation of the distal clavicle?

. Conoid ligament
. Trapezoid ligament
. Superior acromioclavicular ligament
. Inferior acromioclavicular ligament
. Coracoacromial ligament

Correct Answer & Explanation

. Superior acromioclavicular ligament

Explanation

The superior acromioclavicular ligament is the thickest and most robust portion of the AC capsule, serving as the primary restraint to anteroposterior translation of the distal clavicle.

Question 1407

Topic: 2. Trauma

When evaluating the literature regarding the operative management of humeral shaft fractures, randomized controlled trials comparing open reduction internal fixation (ORIF) with plates versus intramedullary (IM) nailing demonstrate which of the following significant differences in complications?

. IM nailing results in significantly lower union rates.
. IM nailing is associated with a higher incidence of postoperative shoulder pain.
. Plating is associated with a significantly higher risk of permanent radial nerve palsy.
. Plating is associated with more frequent hardware failure.
. There is no significant difference in functional outcomes or complications between the two techniques.

Correct Answer & Explanation

. IM nailing is associated with a higher incidence of postoperative shoulder pain.

Explanation

Multiple studies demonstrate that while union rates and functional outcomes are similar, intramedullary nailing of the humerus is associated with a significantly higher incidence of postoperative shoulder pain compared to plating.

Question 1408

Topic: 2. Trauma

A 25-year-old elite collegiate volleyball player sustains an isolated, displaced greater tuberosity fracture of the dominant shoulder. Radiographs show superior displacement of the fragment. What is the generally accepted threshold for surgical fixation in this specific patient demographic?

. Observation is standard of care for displacement up to 10 mm in athletes.
. Immediate operative fixation is indicated for >3 mm of displacement to prevent subacromial impingement.
. Closed reduction and percutaneous pinning is the preferred treatment for any displacement.
. Arthroscopic excision of the fracture fragment is indicated.
. Observation with a sling for 6 weeks, regardless of displacement, followed by aggressive physical therapy.

Correct Answer & Explanation

. Immediate operative fixation is indicated for >3 mm of displacement to prevent subacromial impingement.

Explanation

In overhead athletes and high-demand laborers, the threshold for surgical fixation of a greater tuberosity fracture is >3 mm of superior displacement to mitigate the high risk of subacromial impingement and loss of elevation.

Question 1409

Topic: 2. Trauma

A 35-year-old male presents with a distal-third spiral fracture of the humerus (Holstein-Lewis fracture) following an arm-wrestling incident. He has an absent brachioradialis reflex and inability to extend his wrist. At what specific anatomic location is the radial nerve most susceptible to tethering or entrapment in this fracture pattern?

. Between the brachialis and brachioradialis.
. Within the spiral groove of the posterior humerus.
. As it pierces the lateral intermuscular septum.
. As it passes anterior to the lateral epicondyle.
. At the arcade of Frohse.

Correct Answer & Explanation

. As it pierces the lateral intermuscular septum.

Explanation

In a Holstein-Lewis fracture, the radial nerve is highly susceptible to entrapment or injury as it is relatively fixed where it pierces the lateral intermuscular septum to pass from the posterior to the anterior compartment.

Question 1410

Topic: Upper Extremity Trauma
A 42-year-old male falls directly onto his shoulder. Clinical examination reveals a prominent acromion, but the distal clavicle is non-palpable and appears displaced posteriorly. Radiographs confirm posterior displacement of the clavicle through the trapezius muscle. What is the correct Rockwood classification for this injury?
. Rockwood Type II
. Rockwood Type III
. Rockwood Type IV
. Rockwood Type V
. Rockwood Type VI

Correct Answer & Explanation

. Rockwood Type IV

Explanation

A Rockwood Type IV acromioclavicular injury involves posterior displacement of the distal clavicle into or completely through the deltotrapezial fascia, typically requiring surgical intervention.

Question 1411

Topic: 2. Trauma

When managing a humeral shaft fracture non-operatively with a functional brace, which of the following fracture characteristics is most strongly associated with an increased risk of nonunion?

. Distal third spiral fracture
. Midshaft oblique fracture
. Proximal third transverse fracture
. Comminuted midshaft fracture
. Distal third transverse fracture

Correct Answer & Explanation

. Proximal third transverse fracture

Explanation

Transverse fracture patterns and proximal third locations have the highest rates of nonunion when treated non-operatively with a functional brace, largely due to distraction forces and poor soft tissue compression.

Question 1412

Topic: 2. Trauma

A 25-year-old male sustains a closed distal third spiral fracture of the humeral shaft (Holstein-Lewis) after an arm-wrestling match. On initial examination, he has weak wrist extension and numbness in the first dorsal web space. Closed reduction is performed, and post-reduction examination shows no change in his neurologic status. What is the most appropriate management of the radial nerve injury?

. Immediate surgical exploration of the radial nerve
. Observation and functional bracing, with EMG at 3 months if no recovery
. Immediate tendon transfers
. Surgical exploration within 1 week if no spontaneous recovery
. Immediate MRI of the brachial plexus

Correct Answer & Explanation

. Observation and functional bracing, with EMG at 3 months if no recovery

Explanation

Primary radial nerve palsy in the setting of a closed humeral shaft fracture is managed non-operatively, as >70% spontaneously recover. Surgical exploration is indicated for open fractures, penetrating injuries, or secondary palsies that develop after closed reduction.

Question 1413

Topic: 2. Trauma

A 45-year-old avid tennis player sustains an isolated greater tuberosity fracture of the proximal humerus. Radiographs and CT imaging show superior displacement of the tuberosity fragment. At what threshold of superior displacement is open reduction and internal fixation generally indicated to prevent subacromial impingement in this active patient?

. 2 mm
. 5 mm
. 10 mm
. 15 mm
. 20 mm

Correct Answer & Explanation

. 5 mm

Explanation

In active patients, superior displacement of the greater tuberosity of 5 mm or more is an indication for surgical fixation. Displacement greater than this predictably leads to subacromial impingement and altered rotator cuff biomechanics.

Question 1414

Topic: Upper Extremity Trauma

In evaluating the stability of the acromioclavicular (AC) joint, a surgeon considers the primary anatomical restraints. Which of the following accurately describes the primary ligamentous restraint to superior translation of the distal clavicle?

. The superior and inferior AC capsular ligaments
. The coracoacromial (CA) ligament
. The conoid and trapezoid ligaments
. The dynamic stabilization of the deltotrapezial fascia
. The articular disc of the AC joint

Correct Answer & Explanation

. The conoid and trapezoid ligaments

Explanation

The coracoclavicular (CC) ligaments, comprising the conoid and trapezoid, are the primary restraints to superior and inferior translation of the clavicle. The AC capsular ligaments primarily resist anterior-posterior (horizontal) translation.

Question 1415

Topic: 2. Trauma

A 35-year-old male presents with a closed midshaft humerus fracture and is treated with a Sarmiento functional brace. Which of the following coronal and sagittal plane angular deformities are considered the maximum acceptable limits for non-operative management of a humeral shaft fracture?

. 10 degrees varus, 10 degrees anterior bowing
. 20 degrees varus, 20 degrees anterior bowing
. 30 degrees varus, 20 degrees anterior bowing
. 40 degrees varus, 30 degrees anterior bowing
. 30 degrees varus, 40 degrees anterior bowing

Correct Answer & Explanation

. 30 degrees varus, 20 degrees anterior bowing

Explanation

Acceptable alignment for humeral shaft fractures managed non-operatively includes up to 30 degrees of varus/valgus angulation, 20 degrees of anterior/posterior bowing, and 3 cm of shortening. Deformities within these parameters are generally well compensated by shoulder and elbow motion.

Question 1416

Topic: 2. Trauma

A meta-analysis comparing compression plating versus intramedullary nailing for the treatment of humeral shaft fractures demonstrates differences in complication profiles. Which of the following complications is significantly more common with intramedullary nailing compared to plating?

. Radial nerve palsy
. Nonunion
. Shoulder impingement and pain
. Infection
. Hardware failure

Correct Answer & Explanation

. Shoulder impingement and pain

Explanation

Intramedullary nailing of humeral shaft fractures is associated with a significantly higher rate of shoulder pain, impingement, and subsequent hardware removal compared to plate fixation. Plating carries a slightly higher risk of iatrogenic radial nerve palsy.

Question 1417

Topic: 2. Trauma
A 28-year-old cyclist sustains an injury to his shoulder. Radiographs reveal a distal clavicle fracture with severe displacement. On the axillary lateral view, the distal clavicle is displaced posteriorly into the trapezius muscle fibers. The AC joint itself appears intact. Which classification best describes the equivalent AC joint injury pattern, and what is the recommended treatment?
. Rockwood Type IV; surgical reduction and fixation
. Rockwood Type III; non-operative management
. Rockwood Type V; non-operative management
. Rockwood Type VI; surgical reduction and fixation
. Rockwood Type II; physical therapy

Correct Answer & Explanation

. Rockwood Type IV; surgical reduction and fixation

Explanation

Posterior displacement of the distal clavicle into the trapezius defines a Rockwood Type IV injury. This is a high-energy injury that requires surgical reduction and stabilization due to extreme discomfort and the inability to reduce the clavicle closed.

Question 1418

Topic: 2. Trauma

When performing surgical fixation of a comminuted, osteoporotic greater tuberosity fracture, biomechanical studies favor which of the following constructs to provide the strongest fixation and minimize construct failure?

. Isolated partially threaded cancellous screws
. Isolated fully threaded cortical screws
. Suture-based tension band construct incorporating the rotator cuff
. Hook plate fixation
. Smooth Kirschner wires

Correct Answer & Explanation

. Suture-based tension band construct incorporating the rotator cuff

Explanation

In comminuted or osteoporotic greater tuberosity fractures, suture fixation incorporating the rotator cuff tendon (tension band principle) provides superior biomechanical stability. Isolated screws often fail via toggling and pullout in poor-quality cancellous bone.

Question 1419

Topic: 2. Trauma

A 40-year-old male sustains a proximal third transverse humeral shaft fracture. He is placed in a functional fracture brace. Which of the following fracture characteristics places him at the highest risk for developing a nonunion?

. Distal third location and spiral pattern
. Midshaft location and oblique pattern
. Proximal third location and transverse pattern
. Midshaft location and butterfly fragment
. Distal third location and transverse pattern

Correct Answer & Explanation

. Proximal third location and transverse pattern

Explanation

Transverse fracture patterns and proximal third locations have the highest risk of nonunion when treated with functional bracing. Functional bracing relies on soft tissue envelope compression, which is less effective for transverse patterns and proximal lesions.

Question 1420

Topic: 2. Trauma

A 32-year-old male presents with a severe midshaft humeral fracture between the insertions of the pectoralis major and the deltoid. Based on the muscular attachments, what are the predictable deforming forces on the proximal and distal fracture fragments?

. Proximal fragment is abducted; distal fragment is adducted.
. Proximal fragment is adducted; distal fragment is abducted.
. Proximal fragment is extended; distal fragment is flexed.
. Proximal fragment is flexed; distal fragment is extended.
. Proximal fragment is externally rotated; distal fragment is internally rotated.

Correct Answer & Explanation

. Proximal fragment is adducted; distal fragment is abducted.

Explanation

For fractures between the pectoralis major and deltoid insertions, the proximal fragment is adducted (by the pec major, latissimus, and teres major). The distal fragment is abducted and translated proximally by the deltoid.

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