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2. Trauma MCQs

Practice Set 598 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 11941

Topic: 2. Trauma

A 68-year-old female is evaluated for severe right elbow pain. Radiographs show advanced post-traumatic arthritis with severe metaphyseal bone loss in both the distal humerus and proximal ulna, as well as gross ligamentous instability. Unlinked (resurfacing) total elbow arthroplasty (TEA) is considered. Which of the following is an absolute contraindication to an unlinked TEA in this patient?

. Patient age over 65
. Severe ligamentous insufficiency and bone loss
. History of distal humerus fracture
. Concomitant rheumatoid arthritis
. Intact triceps mechanism

Correct Answer & Explanation

. Severe ligamentous insufficiency and bone loss

Explanation

Total elbow arthroplasties are generally classified as linked (semi-constrained) or unlinked (resurfacing). Unlinked implants rely completely on the integrity of the collateral ligaments and the surrounding bony architecture for stability. Therefore, profound ligamentous insufficiency and severe metaphyseal bone loss are absolute contraindications to unlinked TEA. In such cases, a linked (semi-constrained) prosthesis is required to prevent dislocation.

Question 11942

Topic: 2. Trauma
A 45-year-old female sustains an elbow injury. Radiographs reveal a coronal shear fracture of the distal humerus involving the capitellum and extending medially into the lateral trochlear ridge. Which classification best describes this fracture, and what is the preferred treatment?
. Hahn-Steinthal; nonoperative management
. Kocher-Lorenz; fragment excision
. Bryan-Morrey Type IV; open reduction and internal fixation
. Bryan-Morrey Type III; closed reduction and pinning
. Broberg-Morrey; hinged external fixation

Correct Answer & Explanation

. Bryan-Morrey Type IV; open reduction and internal fixation

Explanation

A coronal shear fracture involving the capitellum and lateral trochlear ridge is classified as a Bryan-Morrey Type IV (McKee modification). The involvement of the lateral trochlear ridge compromises elbow stability, making open reduction and internal fixation (typically with headless compression screws) the standard of care to restore articular congruity and stability.

Question 11943

Topic: 2. Trauma

Recent anatomical studies, notably by Gerber et al., have redefined the primary arterial blood supply to the humeral head. Which vessel provides the dominant blood supply and is most at risk of disruption in a severe 4-part proximal humerus fracture?

. Posterior humeral circumflex artery
. Anterior humeral circumflex artery (arcuate branch)
. Profunda brachii artery
. Suprascapular artery
. Thoracoacromial artery

Correct Answer & Explanation

. Posterior humeral circumflex artery

Explanation

While older literature suggested the anterior humeral circumflex artery (arcuate branch) was the main blood supply to the humeral head, newer quantitative studies (e.g., Gerber et al., JBJS 1990) established that the posterior humeral circumflex artery provides the dominant intraosseous vascularity to the humeral head.

Question 11944

Topic: Upper Extremity Trauma

A 25-year-old cyclist falls directly onto his shoulder. Radiographs demonstrate the distal clavicle is displaced superiorly by 200% compared to the uninjured side. Which structures are disrupted in this specific grade of acromioclavicular (AC) joint injury?

. AC ligaments are ruptured; CC ligaments are intact
. AC ligaments and CC ligaments are ruptured; deltotrapezial fascia is intact
. AC ligaments, CC ligaments, and the deltotrapezial fascia are completely ruptured
. AC ligaments are intact; CC ligaments are ruptured
. Only the conoid ligament is ruptured

Correct Answer & Explanation

. AC ligaments, CC ligaments, and the deltotrapezial fascia are completely ruptured

Explanation

This describes a Rockwood Type V AC joint separation, characterized by >100% (up to 300%) superior displacement of the distal clavicle. Pathologically, it involves rupture of the AC ligaments, the coracoclavicular (CC) ligaments, and extensive detachment/tearing of the deltotrapezial fascia, allowing the clavicle to severely elevate subcutaneously.

Question 11945

Topic: 2. Trauma

A 45-year-old male on chronic hemodialysis falls directly onto his elbow. He presents with an inability to actively extend his elbow against gravity. A lateral radiograph demonstrates a small cortical avulsion fracture (fleck sign) 1 cm superior to the olecranon tip. What is the most likely diagnosis?

. Type I Olecranon fracture
. Triceps tendon rupture
. Biceps tendon rupture
. Coronoid fracture
. Gouty tophus rupture

Correct Answer & Explanation

. Triceps tendon rupture

Explanation

Chronic renal failure is a significant risk factor for tendon ruptures. The inability to extend the elbow against gravity, combined with a 'fleck sign' (small avulsion off the olecranon tip) on a lateral radiograph, is pathognomonic for a complete triceps tendon rupture, which requires operative repair.

Question 11946

Topic: 2. Trauma

A 25-year-old male sustains a closed, distal-third spiral fracture of the humerus (Holstein-Lewis fracture). On initial presentation in the emergency department, he is unable to extend his wrist or fingers. He undergoes closed reduction and splinting. Post-reduction examination shows his radial nerve deficit is unchanged. What is the next best step in management?

. Immediate surgical exploration of the radial nerve
. Immediate surgical exploration with nerve grafting
. Observation of nerve function for 3-4 months
. Early prophylactic tendon transfers
. Magnetic resonance imaging (MRI) of the arm

Correct Answer & Explanation

. Observation of nerve function for 3-4 months

Explanation

This patient has a primary radial nerve palsy associated with a closed humeral shaft fracture. The vast majority of these are neuropraxias that will recover spontaneously. The standard of care is observation for 3-4 months. Immediate surgical exploration is indicated for open fractures, associated vascular injuries, or a secondary palsy (palsy that occurs newlyafterclosed reduction).

Question 11947

Topic: 2. Trauma

According to the Hertel criteria, which of the following radiographic features is the most reliable predictor of subsequent avascular necrosis (AVN) following a proximal humerus fracture?

. Metaphyseal head extension less than 8 mm
. Displacement of the greater tuberosity greater than 5 mm
. Varus angulation of the head greater than 20 degrees
. Medial hinge disruption greater than 2 mm
. Head splitting fracture pattern without calcar involvement

Correct Answer & Explanation

. Medial hinge disruption greater than 2 mm

Explanation

Hertel identified three major risk factors for AVN in proximal humerus fractures: metaphyseal extension less than 8 mm, disruption of the medial hinge, and an anatomical neck fracture pattern.

Question 11948

Topic: 2. Trauma

According to Hertel's criteria, which combination of radiographic findings in an acute proximal humerus fracture yields the highest positive predictive value for the development of avascular necrosis (AVN) of the humeral head?

. Greater tuberosity displacement >5 mm and a surgical neck fracture.
. Short calcar segment (<8 mm), disrupted medial hinge, and anatomic neck fracture.
. Long calcar segment (>8 mm), intact medial hinge, and a surgical neck fracture.
. Lesser tuberosity displacement, head-shaft angle <100 degrees, and metaphyseal comminution.
. Valgus impacted head segment with a disrupted lateral hinge.

Correct Answer & Explanation

. Short calcar segment (<8 mm), disrupted medial hinge, and anatomic neck fracture.

Explanation

Hertel et al. described reliable predictors for humeral head ischemia. The highest positive predictive value for AVN occurs when there is an anatomic neck fracture (disrupting intraosseous blood supply), a short metaphyseal head extension (calcar segment <8 mm), and disruption of the medial hinge (>2 mm displacement), which compromises the ascending branch of the anterior humeral circumflex artery.

Question 11949

Topic: 2. Trauma
A 26-year-old cyclist falls directly onto his shoulder and sustains a distal clavicle fracture. Radiographs show a fracture line situated between the coracoclavicular ligaments. The proximal fragment is displaced superiorly. Surgical exploration reveals the conoid ligament is torn from the proximal fragment, but the trapezoid ligament remains intact and attached to the distal fragment. How is this fracture classified according to the Neer classification?
. Type I
. Type IIA
. Type IIB
. Type III
. Type IV

Correct Answer & Explanation

. Type IIB

Explanation

Neer Type II distal clavicle fractures are unstable due to loss of the coracoclavicular (CC) ligamentous restraint to the proximal fragment. Type IIA fractures occur medial to the CC ligaments (ligaments remain attached to the distal fragment). Type IIB fractures occur between the CC ligaments; the conoid ligament is ruptured, allowing the proximal fragment to displace superiorly, while the trapezoid remains intact on the distal fragment.

Question 11950

Topic: 2. Trauma

When planning a total elbow arthroplasty (TEA) for a patient with advanced rheumatoid arthritis, the surgeon considers whether to use a linked (semi-constrained) or unlinked implant. What is an absolute prerequisite for using an unlinked TEA design?

. A completely deficient triceps mechanism.
. Competent medial and lateral collateral ligaments and anterior capsule.
. Severe distal humeral bone loss > 5 cm.
. Prior radial head excision.
. A nonunion of the distal humerus.

Correct Answer & Explanation

. Competent medial and lateral collateral ligaments and anterior capsule.

Explanation

Unlinked (unconstrained) total elbow arthroplasty relies heavily on the patient's native soft tissues for stability. Therefore, competent medial and lateral collateral ligaments, as well as an intact anterior capsule, are an absolute prerequisite to prevent dislocation. Linked (semi-constrained) implants are used when ligaments are incompetent, or in cases of severe bone loss and trauma.

Question 11951

Topic: 2. Trauma

A surgeon plans to perform tension band wiring for a displaced, transverse olecranon fracture. Biomechanically, for the tension band principle to function successfully and convert tensile distraction forces into articular compression during active elbow flexion, which of the following prerequisites MUST be met?

. The anterior cortex (articular surface) must be intact or anatomically reconstructable to provide a buttress.
. The fracture must be highly comminuted to allow for dynamic shortening.
. The hardware must be placed on the anterior tension surface of the ulna.
. The triceps insertion must be partially detached and repaired over the wire.
. The K-wires must penetrate the anterior cortex of the ulna at a 90-degree angle.

Correct Answer & Explanation

. The anterior cortex (articular surface) must be intact or anatomically reconstructable to provide a buttress.

Explanation

The tension band principle relies on placing a device (like a wire loop) on the tension side of a bone (the posterior cortex of the olecranon). As the elbow flexes, the triceps pulls on the proximal fragment, and the tension band converts this distracting tensile force into compressive forces at the opposite (articular) side. This biomechanical conversion absolutely requires an intact or anatomically reduced opposing cortex (the anterior articular surface) to act as a solid buttress for compression. If the anterior cortex is comminuted or absent, tension band wiring will fail and the fracture will collapse.

Question 11952

Topic: Upper Extremity Trauma

A 40-year-old male develops severe elbow stiffness secondary to heterotopic ossification (HO) following a terrible triad injury. When planning surgical excision of the HO to restore motion, what is the most reliable clinical and radiographic indicator that the ectopic bone is mature enough for safe resection?

. Exactly 6 months of elapsed time from the injury
. Normalization of serum alkaline phosphatase levels
. Cold uptake on a technetium-99m bone scan
. Sharp, distinct trabecular margins seen on plain radiographs with cessation of ROM changes
. Resolution of all soft tissue swelling

Correct Answer & Explanation

. Sharp, distinct trabecular margins seen on plain radiographs with cessation of ROM changes

Explanation

Historically, alkaline phosphatase and bone scans were used to determine HO maturity, but these have been shown to be unreliable. The current gold standard for timing surgical excision is clinical (cessation of progressive stiffness) and radiographic (appearance of sharp, distinct trabecular margins indicating mature bone on plain radiographs).

Question 11953

Topic: 2. Trauma

A 28-year-old male sustains a direct blow to the anterior shoulder and is diagnosed with an Ogawa Type I coracoid process fracture. According to this classification, an Ogawa Type I fracture involves a fracture line located:

. Distal to the coracoclavicular (CC) ligaments
. Through the tip of the coracoid involving only the conjoined tendon origin
. Proximal to the coracoclavicular (CC) ligaments
. Through the base extending into the suprascapular notch without CC involvement
. Isolated to the medial border of the coracoid

Correct Answer & Explanation

. Proximal to the coracoclavicular (CC) ligaments

Explanation

The Ogawa classification divides coracoid fractures based on their relationship to the coracoclavicular (CC) ligaments. Type I fractures occur proximal to the CC ligaments (meaning the CC ligaments remain attached to the distal fragment). Type II fractures occur distal to the CC ligaments.

Question 11954

Topic: Upper Extremity Trauma

A 32-year-old bodybuilder ruptures his pectoralis major tendon at its insertion during a heavy bench press. Which of the following accurately describes the anatomical orientation of the normal pectoralis major tendon at its insertion on the proximal humerus?

. The clavicular head inserts deep and proximal to the sternal head
. The sternal head twists 180 degrees so its lowest fibers insert highest (proximal) and deep to the clavicular head
. Both heads blend completely, making it impossible to distinguish layers at the footprint
. The clavicular head inserts deep and distal to the sternal head
. The sternal head inserts superficial and distal to the clavicular head

Correct Answer & Explanation

. The sternal head twists 180 degrees so its lowest fibers insert highest (proximal) and deep to the clavicular head

Explanation

The pectoralis major tendon consists of two main heads: clavicular and sternocostal. As the tendon courses laterally to insert on the lateral lip of the bicipital groove, it twists 180 degrees. The clavicular head inserts proximally and superficially, while the sternocostal head twists such that its most inferior fibers insert the most superiorly (proximally) and deep to the clavicular head.

Question 11955

Topic: 2. Trauma

When evaluating a displaced proximal humerus fracture for the risk of avascular necrosis (AVN) of the humeral head, which of the following criteria described by Hertel is considered a strong predictor of ischemia?

. Metaphyseal head extension (calcar length) less than 8 mm
. Greater tuberosity displacement greater than 5 mm
. Integrity of the medial hinge with less than 2 mm displacement
. Angulation of the surgical neck greater than 30 degrees
. Subcapital fracture line above the equator of the head

Correct Answer & Explanation

. Integrity of the medial hinge with less than 2 mm displacement

Explanation

Hertel described several criteria predicting ischemia (and thus AVN) of the humeral head after proximal humerus fractures. The strongest predictors include a metaphyseal head extension (calcar length) of less than 8 mm, disruption of the medial hinge (> 2 mm displacement), and an anatomic neck fracture line.

Question 11956

Topic: Upper Extremity Trauma
A 28-year-old cyclist falls directly onto his shoulder. Radiographs demonstrate a displaced acromioclavicular (AC) joint injury. The clavicle is displaced superiorly by 150% of the normal joint space relative to the acromion. The deltotrapezial fascia is clinically disrupted. Which Rockwood classification type best describes this injury?
. Type II
. Type III
. Type IV
. Type V
. Type VI

Correct Answer & Explanation

. Type V

Explanation

Rockwood Type V AC joint separations are characterized by complete tearing of the AC and CC ligaments, severe disruption of the deltotrapezial fascia, and severe superior displacement of the distal clavicle by >100% (often up to 300%) compared to the normal contralateral side.

Question 11957

Topic: 2. Trauma

A 30-year-old male developed severe heterotopic ossification (HO) restricting elbow motion following a complex distal humerus fracture treated with ORIF. When timing the surgical excision of the HO, what is currently considered the most reliable clinical indicator that the HO is 'mature' and safe to resect with a minimized risk of recurrence?

. Normalization of serum alkaline phosphatase levels
. Decreased radiotracer uptake on a three-phase technetium bone scan
. Radiographic appearance showing distinct trabecular markings and sharp, well-defined cortical margins
. A minimum of 18 months elapsed since the initial trauma
. Resolution of clinical pain at rest

Correct Answer & Explanation

. Radiographic appearance showing distinct trabecular markings and sharp, well-defined cortical margins

Explanation

Historically, serum alkaline phosphatase and bone scans were used to determine HO maturity, but these have proven unreliable. Currently, the most reliable indicator for mature HO safe for resection is the plain radiographic appearance, characterized by distinct trabecular patterns and sharp, well-defined cortical margins. Excision is typically performed when this maturity is evident, often around 6 months post-injury.

Question 11958

Topic: Upper Extremity Trauma

A surgeon performs an anatomic coracoclavicular (CC) ligament reconstruction for a chronic Type V acromioclavicular joint separation. To accurately reproduce the native biomechanics, drill holes are placed in the clavicle corresponding to the native footprints of the conoid and trapezoid ligaments. What are the approximate distances of these insertions from the distal aspect of the clavicle?

. Conoid at 15 mm, Trapezoid at 30 mm
. Conoid at 25 mm, Trapezoid at 15 mm
. Conoid at 45 mm, Trapezoid at 25 mm
. Conoid at 25 mm, Trapezoid at 45 mm
. Both tunnels placed symmetrically at exactly 30 mm

Correct Answer & Explanation

. Conoid at 45 mm, Trapezoid at 25 mm

Explanation

The native footprints of the CC ligaments are critical for anatomic reconstruction. The conoid ligament is positioned more medial and slightly posterior, inserting approximately 45 mm from the distal clavicle. The trapezoid ligament is more lateral and anterior, inserting approximately 25 to 30 mm from the distal clavicle.

Question 11959

Topic: 2. Trauma

A 21-year-old rugby player presents to the trauma bay after a pile-up. He complains of severe medial chest pain and difficulty swallowing. Exam reveals a palpable depression over the medial left clavicle. He is hemodynamically stable. What is the most appropriate next step in management?

. Immediate closed reduction in the emergency department using anterior traction
. Observation and application of a figure-of-eight brace
. Open or closed reduction in the operating room with cardiothoracic surgery on standby
. Resection of the medial third of the clavicle
. Application of an arm sling and outpatient orthopedic follow-up

Correct Answer & Explanation

. Open or closed reduction in the operating room with cardiothoracic surgery on standby

Explanation

The patient has a posterior sternoclavicular (SC) joint dislocation, evidenced by the palpable depression and dysphagia (compression of the esophagus/mediastinal structures). Because of the proximity of the brachiocephalic vessels, reduction (whether closed or open) carries a high risk of catastrophic hemorrhage. Therefore, reduction must be performed in the OR with cardiothoracic surgery readily available.

Question 11960

Topic: 2. Trauma
A 24-year-old gymnast sustains a fall onto an outstretched hand and presents with elbow pain. Radiographs reveal a fracture of the capitellum. Intraoperative findings demonstrate a large fracture fragment consisting of articular cartilage and a substantial portion of the underlying subchondral bone. According to the Bryan and Morrey classification, what type of capitellar fracture is this?
. Type I (Hahn-Steinthal)
. Type II (Kocher-Lorenz)
. Type III (Broberg-Morrey)
. Type IV (McKee)
. Type V

Correct Answer & Explanation

. Type I (Hahn-Steinthal)

Explanation

The Bryan and Morrey classification describes capitellum fractures. Type I (Hahn-Steinthal) is a shear fracture in the coronal plane involving a large piece of osseous subchondral bone and articular cartilage. Type II (Kocher-Lorenz) involves an articular cartilage sleeve with minimal subchondral bone. Type III (Broberg-Morrey) is a highly comminuted fracture. Type IV, added by McKee, involves a shear fracture that extends medially to include the lateral trochlear ridge.

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