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2. Trauma MCQs

Practice Set 228 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 4541

Topic: Pelvic & Acetabular Trauma
A trauma patient presents with a pelvic ring injury after a motor vehicle collision. Radiographs and CT demonstrate a vertically oriented fracture through the sacrum and rami fractures on the same side. According to the Young-Burgess classification, which of the following injury mechanisms is most strongly associated with the highest volume of retroperitoneal hemorrhage requiring angioembolization?
. Lateral Compression Type I (LC-1)
. Lateral Compression Type II (LC-2)
. Anteroposterior Compression Type I (APC-1)
. Anteroposterior Compression Type III (APC-3)
. Isolated pubic rami fractures

Correct Answer & Explanation

. Anteroposterior Compression Type III (APC-3)

Explanation

Anteroposterior compression (APC) injuries, specifically APC-II and APC-III (open book pelvis), are associated with a significant increase in pelvic volume and major disruption of the posterior venous plexus and branches of the internal iliac artery. APC-III injuries, which involve complete disruption of the anterior and posterior sacroiliac ligaments (complete spinopelvic dissociation), historically carry the highest risk for massive, life-threatening retroperitoneal hemorrhage.

Question 4542

Topic: 2. Trauma

A 60-year-old osteoporotic female sustains a highly comminuted, intra-articular distal humerus fracture.

You are planning open reduction and internal fixation (ORIF) with dual plating. Based on biomechanical studies comparing parallel versus orthogonal plate configurations for distal humerus fractures, which of the following statements is most accurate?

. Orthogonal plating offers superior resistance to axial compression.
. Parallel plating constructs offer significantly higher resistance to torsional and axial loading.
. Orthogonal plating has a lower rate of iatrogenic ulnar neuropathy.
. Parallel plating has been shown to have significantly higher clinical union rates.
. Orthogonal plating is biomechanically superior when treating fractures with metaphyseal comminution.

Correct Answer & Explanation

. Orthogonal plating offers superior resistance to axial compression.

Explanation

Biomechanical studies have demonstrated that parallel plating constructs for distal humerus fractures are significantly stiffer and provide greater resistance to both axial and torsional loading compared to orthogonal (90-90) plating, especially in the setting of metaphyseal comminution or osteoporotic bone. However, clinical studies have not shown a statistically significant difference in union rates or functional outcomes between the two techniques.

Question 4543

Topic: 2. Trauma

A 32-year-old male sustains a closed, oblique fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). Upon examination in the emergency department, he is unable to extend his wrist or fingers, though his triceps function is intact. There is no open wound. What is the most appropriate initial management?

. Immediate surgical exploration and ORIF
. Application of a functional fracture brace and clinical observation for nerve recovery
. Immediate external fixation and nerve grafting
. Electromyography (EMG) and Nerve Conduction Studies (NCS) prior to any treatment
. Closed reduction under general anesthesia and casting

Correct Answer & Explanation

. Immediate surgical exploration and ORIF

Explanation

A primary radial nerve palsy in the setting of a closed humeral shaft fracture (including Holstein-Lewis distal third oblique fractures) is best managed with a functional brace and observation. More than 70-85% of these primary palsies are neuropraxias and will recover spontaneously. Surgical exploration is indicated for an open fracture, a secondary palsy that occurs after closed reduction, a vascular injury, or if there is no clinical or EMG evidence of nerve recovery by 3 to 4 months.

Question 4544

Topic: 2. Trauma

A 68-year-old female sustains a complex proximal humerus fracture.

According to Hertel's radiographic criteria, which combination of findings is the most reliable predictor of subsequent avascular necrosis (AVN) of the humeral head?

. Surgical neck fracture, valgus impaction, and an intact medial hinge
. Anatomic neck fracture, metaphyseal extension (calcar length) less than 8 mm, and a disrupted medial hinge
. Greater tuberosity displacement greater than 10 mm and a bicipital groove fracture
. Three-part fracture with posterior medial comminution
. Head-splitting fracture with intact lesser tuberosity

Correct Answer & Explanation

. Surgical neck fracture, valgus impaction, and an intact medial hinge

Explanation

Hertel identified specific radiographic predictors for ischemia of the humeral head following proximal humerus fractures. The most predictive combination for the development of avascular necrosis includes: 1) an anatomic neck fracture, 2) a short calcar segment (metaphyseal extension < 8 mm attached to the articular segment), and 3) disruption of the medial capsular hinge (> 2 mm displacement of the shaft relative to the head).

Question 4545

Topic: Upper Extremity Trauma

A 25-year-old mountain biker falls directly onto the point of his shoulder, sustaining an acute high-grade (Type V) acromioclavicular (AC) joint separation.

Surgical reconstruction of the coracoclavicular (CC) ligaments is planned. Biomechanically, which native structure acts as the primary restraint to superior translation of the distal clavicle?

. Acromioclavicular (AC) capsular ligaments
. Trapezoid ligament
. Conoid ligament
. Coracoacromial (CA) ligament
. Superior transverse scapular ligament

Correct Answer & Explanation

. Acromioclavicular (AC) capsular ligaments

Explanation

The coracoclavicular (CC) ligaments provide primary vertical stability to the AC joint. The conoid ligament is the more medial of the two CC ligaments and is the primary restraint to superior translation of the clavicle. The trapezoid ligament is more lateral and provides the primary restraint against axial compression. The AC capsular ligaments primarily provide anteroposterior (horizontal) stability.

Question 4546

Topic: Upper Extremity Trauma

A 35-year-old mechanic sustains an Essex-Lopresti injury after falling from a ladder. This injury pattern is characterized by a radial head fracture, disruption of the distal radioulnar joint (DRUJ), and tearing of the interosseous membrane (IOM). If the radial head is completely excised without replacement in this patient, what is the expected biomechanical consequence?

. Proximal migration of the radius, resulting in ulnocarpal impaction and wrist pain
. Distal migration of the radius, resulting in radiocarpal subluxation
. Varus instability of the elbow joint without wrist involvement
. Posterior subluxation of the ulnar head at the DRUJ only
. Anterior subluxation of the radial head remnant

Correct Answer & Explanation

. Proximal migration of the radius, resulting in ulnocarpal impaction and wrist pain

Explanation

An Essex-Lopresti injury involves a longitudinal radioulnar dissociation. The radial head and the interosseous membrane are the primary restraints to proximal migration of the radius. If the radial head is resected in the setting of an IOM tear (Essex-Lopresti lesion), the radius will migrate proximally. This causes positive ulnar variance, leading to severe ulnocarpal impaction, wrist pain, and restricted forearm rotation. Therefore, the radial head must be fixed or replaced with an arthroplasty to restore the longitudinal stability of the forearm.

Question 4547

Topic: 2. Trauma

A 45-year-old male sustains a transverse fracture of the olecranon. The surgeon plans to use a tension band wiring technique. To maximize the biomechanical strength of the construct and minimize wire pullout, where should the K-wires be directed and seated?

. Down the intramedullary canal of the ulna without engaging the anterior cortex
. Through the posterior cortex of the proximal ulna only
. Bicortically, engaging the anterior ulnar cortex distal to the coronoid process
. Into the radial head to provide rotational stability
. Transversely across the olecranon fossa

Correct Answer & Explanation

. Bicortically, engaging the anterior ulnar cortex distal to the coronoid process

Explanation

In tension band wiring of olecranon fractures, engaging the K-wires into the anterior ulnar cortex distal to the coronoid process (bicortical fixation) provides significantly greater resistance to wire back-out and loss of fixation compared to placing the wires straight down the intramedullary canal. Intramedullary placement relies solely on friction, which is biomechanically inferior to bicortical purchase.

Question 4548

Topic: 2. Trauma

A 50-year-old male is involved in a high-speed motor vehicle accident and sustains a closed fracture of the scapular neck.

According to the criteria described by Goss and Ada, what threshold of medial displacement (medialization) of the glenoid fragment relative to the lateral border of the scapula is widely considered an absolute indication for operative fixation?

. Greater than 5 mm
. Greater than 10 mm
. Greater than 20 mm
. Greater than 30 mm
. Greater than 45 mm

Correct Answer & Explanation

. Greater than 20 mm

Explanation

Most extra-articular scapular neck fractures are managed non-operatively. However, significant displacement alters shoulder biomechanics (rotator cuff tension, impingement). The classic indications for operative management (ORIF) of scapula fractures based on Goss and Ada criteria include: medial/lateral displacement (medialization) greater than 20 mm, angular displacement greater than 40 degrees, or a combination of >10 mm displacement with >40 degrees of angulation. Intra-articular step-off >4-5 mm is also an indication for fixation.

Question 4549

Topic: 2. Trauma
A 38-year-old female falls onto an extended arm and presents with severe elbow pain. Radiographs and CT scan reveal a coronal shear fracture of the distal humerus. The fracture fragment includes the capitellum and the lateral half of the trochlea. According to the Bryan and Morrey classification with McKee's modification, what type of fracture is this?
. Type I (Hahn-Steinthal lesion)
. Type II (Kocher-Lorenz lesion)
. Type III (Broberg-Morrey lesion)
. Type IV
. Type V

Correct Answer & Explanation

. Type IV

Explanation

In the Bryan and Morrey classification of capitellar fractures: Type I (Hahn-Steinthal) is a large osseous piece of the capitellum. Type II (Kocher-Lorenz) is a sleeve fracture of articular cartilage with minimal subchondral bone. Type III is a comminuted capitellar fracture. McKee modified the classification by adding Type IV, which is a coronal shear fracture that involves the capitellum and extends medially to include a large portion of the trochlea. It is a critical distinction because Type IV fractures require more extensile exposures (often an extended lateral or olecranon osteotomy) for adequate fixation of the trochlear component.

Question 4550

Topic: 2. Trauma

A 65-year-old male with chronic kidney disease presents with posterior elbow pain and an inability to actively extend his elbow against gravity following a sudden eccentric load. Radiographs show a small "Fleck sign" avulsed from the proximal ulna. You diagnose a complete triceps tendon rupture and plan for surgical repair. What is the anatomic characteristic of the triceps insertion on the olecranon?

. It inserts precisely on the tip of the olecranon via a narrow 5 mm band.
. The medial head inserts superficially, while the lateral head inserts deep on the olecranon.
. It inserts over a broad, dome-shaped footprint, with the muscular insertion extending an average of 1 to 2 cm distal to the tip of the olecranon.
. It shares a conjoint insertion with the anconeus on the lateral supracondylar ridge.
. It inserts directly onto the sublime tubercle.

Correct Answer & Explanation

. It inserts over a broad, dome-shaped footprint, with the muscular insertion extending an average of 1 to 2 cm distal to the tip of the olecranon.

Explanation

The triceps tendon inserts onto the proximal ulna over a broad, dome-shaped footprint. Studies on the anatomic footprint of the triceps reveal it inserts slightly distal to the tip of the olecranon (often 1-2 cm wide). The medial head of the triceps has a deep, fleshy insertion, while the lateral and long heads form a superficial tendinous insertion. Repair techniques aim to restore this broad footprint to maximize biomechanical strength and tendon-to-bone healing.

Question 4551

Topic: 2. Trauma
Which of the following variables is considered the strongest independent predictor for the development of nonunion in a midshaft clavicle fracture treated non-operatively?
. Male gender
. Fracture shortening greater than 2 cm
. Distal third fracture location
. Presence of a butterfly fragment (comminution)
. Z-type fracture pattern

Correct Answer & Explanation

. Fracture shortening greater than 2 cm

Explanation

In non-operatively treated midshaft clavicle fractures, fracture shortening (displacement) greater than 2 cm is the strongest predictor of nonunion, with some studies citing a nonunion rate of up to 15-20% in these highly displaced fractures compared to <5% for non-displaced fractures. While comminution, older age, and female gender are also known risk factors, displacement without bone contact (100% displacement / >2 cm shortening) remains the most significant indication to consider operative fixation to prevent nonunion and symptomatic malunion.

Question 4552

Topic: 2. Trauma
A 42-year-old male is brought to the trauma bay following a motorcycle crash. He is diagnosed with a "floating shoulder," defined as a double disruption of the superior shoulder suspensory complex (SSSC). According to Goss, the SSSC is a bone-and-soft-tissue ring. Which of the following components is NOT considered part of the SSSC?
. Coracoid process
. Acromion process
. Glenoid process
. Proximal third of the clavicle
. Coracoclavicular (CC) ligaments

Correct Answer & Explanation

. Proximal third of the clavicle

Explanation

The Superior Shoulder Suspensory Complex (SSSC), as described by Goss, is a continuous structural ring consisting of bone and soft tissue that maintains the relationship between the upper extremity and the axial skeleton. The SSSC ring is composed of the glenoid process, the coracoid process, the coracoclavicular (CC) ligaments, the distal clavicle, the acromioclavicular (AC) joint, and the acromion process. The proximal clavicle is not considered part of this specific suspensory ring (the struts are the middle clavicle and the lateral scapular body). A "floating shoulder" implies disruptions in two places of this complex (e.g., a surgical neck fracture of the glenoid combined with a clavicle fracture or CC ligament tear).

Question 4553

Topic: 2. Trauma

What is the strongest predictor of nonunion in nonoperatively managed midshaft clavicle fractures?

. Lack of cortical contact (100% displacement)
. Shortening greater than 1 cm
. Z-type fracture pattern
. Inferior displacement of the lateral fragment
. Associated rib fractures

Correct Answer & Explanation

. Lack of cortical contact (100% displacement)

Explanation

The lack of cortical contact (i.e., 100% displacement) is widely recognized as the strongest predictive factor for nonunion in diaphyseal clavicle fractures treated conservatively. Other significant risk factors include advanced age, smoking, severe comminution, and shortening > 2 cm.

Question 4554

Topic: 2. Trauma
A 6-year-old boy presents with an elbow injury after falling from monkey bars. Radiographs demonstrate a fracture of the proximal third of the ulna with apex posterior angulation and a posterior dislocation of the radial head. According to the Bado classification, what type of Monteggia lesion is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

The Bado classification of Monteggia fractures depends on the direction of the radial head dislocation. Type I: Anterior dislocation with anterior angulation of the ulnar fracture. Type II: Posterior dislocation with posterior angulation of the ulnar fracture. Type III: Lateral or anterolateral dislocation (most common in children). Type IV: Anterior dislocation with fractures of the radius and ulna at the same level. Therefore, apex posterior angulation with posterior dislocation is Bado Type II.

Question 4555

Topic: 2. Trauma

A 28-year-old man sustains a closed, displaced transverse fracture of the middle third of the humeral shaft. On initial evaluation, he is unable to extend his wrist or fingers, and has numbness in the first dorsal web space. What is the most appropriate management regarding the nerve palsy?

. Immediate surgical exploration of the radial nerve and ORIF of the humerus
. Closed reduction and functional bracing, with nerve exploration if no recovery in 3-4 months
. Immediate EMG/NCS to confirm the diagnosis
. Closed reduction and splinting, with nerve exploration if no recovery in 3 weeks
. MRI of the arm to evaluate nerve continuity

Correct Answer & Explanation

. Closed reduction and functional bracing, with nerve exploration if no recovery in 3-4 months

Explanation

Primary radial nerve palsy associated with a closed humeral shaft fracture is typically a neurapraxia or axonotmesis. The initial management is conservative (e.g., coaptation splint followed by functional bracing), as >85% will recover spontaneously. Operative exploration is indicated if there is an open fracture, vascular injury requiring repair, or if there is no clinical or EMG evidence of nerve recovery after 3 to 4 months of observation.

Question 4556

Topic: Upper Extremity Trauma

A 25-year-old cyclist falls directly onto his right shoulder. He complains of severe pain at the top of the shoulder. Radiographs show a 200% superior displacement of the distal clavicle relative to the acromion.

Which ligaments are disrupted in this Rockwood Type V injury?

. Acromioclavicular ligaments only
. Coracoclavicular ligaments only
. Acromioclavicular and coracoacromial ligaments
. Acromioclavicular and coracoclavicular ligaments, and detachment of the deltotrapezial fascia
. Coracoclavicular and coracoacromial ligaments

Correct Answer & Explanation

. Acromioclavicular and coracoclavicular ligaments, and detachment of the deltotrapezial fascia

Explanation

In a Rockwood Type V acromioclavicular (AC) joint injury, there is complete disruption of both the AC ligaments and the coracoclavicular (CC) ligaments, along with gross disruption of the deltotrapezial fascia. This extensive soft tissue stripping allows severe superior displacement of the clavicle (100-300% compared to the contralateral side).

Question 4557

Topic: 2. Trauma

When performing a shoulder hemiarthroplasty for a severe 4-part proximal humerus fracture, what is the most critical factor for a successful functional outcome?

. Achieving precise retroversion of the prosthesis at 40 degrees
. Using a cemented instead of a press-fit stem
. Anatomic reduction and healing of the tuberosities to the shaft and prosthesis
. Resection of the long head of the biceps
. Overstuffing the joint to maintain deltoid tension

Correct Answer & Explanation

. Anatomic reduction and healing of the tuberosities to the shaft and prosthesis

Explanation

In hemiarthroplasty for proximal humerus fractures, functional outcome is directly related to the anatomic reduction and reliable healing of the greater and lesser tuberosities. Malposition or nonunion of the tuberosities leads to profound weakness, loss of active motion, and poor function. While appropriate version and height are important for tuberosity healing, the actual healing of the tuberosities is the single most critical determinant of clinical success.

Question 4558

Topic: 2. Trauma
A 'floating shoulder' typically involves ipsilateral fractures of the clavicular shaft and which other structure?
. Scapular body
. Scapular neck
. Coracoid process
. Proximal humerus
. Acromion

Correct Answer & Explanation

. Scapular neck

Explanation

A 'floating shoulder' refers to a double disruption of the superior shoulder suspensory complex (SSSC). The classic description is an ipsilateral fracture of the midshaft clavicle and the scapular neck. This inherently unstable injury can lead to inferior and medial displacement of the glenoid. Operative fixation of at least one of the lesions (most commonly the clavicle) is often indicated to restore the SSSC.

Question 4559

Topic: Upper Extremity Trauma

A 35-year-old man undergoes surgical release for post-traumatic elbow stiffness following a terrible triad injury 1 year ago. To prevent recurrence due to heterotopic ossification (HO), which of the following is the most standard prophylactic regimen?

. Indomethacin 75 mg SR daily for 3-6 weeks
. High-dose oral corticosteroids for 2 weeks
. Single-fraction radiation therapy (700-800 cGy)
. Methotrexate weekly for 4 weeks
. Celecoxib 200 mg daily for 5 days

Correct Answer & Explanation

. Indomethacin 75 mg SR daily for 3-6 weeks

Explanation

Prophylaxis for heterotopic ossification (HO) around the elbow typically involves either nonsteroidal anti-inflammatory drugs (NSAIDs) such as Indomethacin (e.g., 75 mg sustained release daily or 25 mg TID for 3-6 weeks) or a single fraction of low-dose radiation therapy (700-800 cGy) administered within 24 to 48 hours before or after surgery. Corticosteroids and methotrexate are not standard HO prophylaxis.

Question 4560

Topic: 2. Trauma

Which combination of radiographic findings in a proximal humerus fracture is most highly predictive of humeral head ischemia according to Hertel's criteria?

. Calcar length < 8 mm, disrupted medial hinge, and an anatomical neck fracture
. Calcar length > 8 mm, intact medial hinge, and a surgical neck fracture
. Head-split fracture, greater tuberosity displacement > 1 cm, and calcar length > 8 mm
. Varus angulation > 45 degrees, lesser tuberosity fracture, and an intact medial hinge
. Valgus impaction, intact medial hinge, and diaphyseal extension

Correct Answer & Explanation

. Calcar length < 8 mm, disrupted medial hinge, and an anatomical neck fracture

Explanation

Hertel identified that a calcar segment less than 8 mm, disruption of the medial hinge, and an anatomical neck fracture pattern are the most reliable predictors of humeral head ischemia. Combined, these factors indicate severe disruption of the critical vascular supply via the anterior and posterior humeral circumflex arteries.

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