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2. Trauma MCQs

Practice Set 575 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 11481

Topic: 2. Trauma

Following a closed proximal humerus fracture, a patient exhibits a complete radial nerve palsy. Electromyography at 4 weeks shows fibrillation potentials in the brachioradialis but preserved nerve sheath integrity on imaging. What is the Sunderland classification of this injury?

. First-degree
. Second-degree
. Third-degree
. Fourth-degree
. Fifth-degree

Correct Answer & Explanation

. First-degree

Explanation

A second-degree nerve injury (Sunderland) corresponds to Seddon's axonotmesis, characterized by axonal disruption with preservation of the endoneurium, perineurium, and epineurium. Fibrillation potentials indicate axonal denervation.

Question 11482

Topic: 2. Trauma

A 32-year-old male presents with severe pain out of proportion to exam after a tibial shaft fracture. When using continuous intracompartmental pressure monitoring, an acute compartment syndrome is diagnosed when the Delta P (diastolic blood pressure minus compartment pressure) falls below what threshold?

. 10 mmHg
. 20 mmHg
. 30 mmHg
. 45 mmHg
. 60 mmHg

Correct Answer & Explanation

. 10 mmHg

Explanation

A Delta P (diastolic blood pressure minus intracompartmental pressure) of less than 30 mmHg is considered the diagnostic threshold for acute compartment syndrome, necessitating emergent fasciotomies.

Question 11483

Topic: 2. Trauma

A 35-year-old cyclist falls onto his shoulder and sustains a closed, displaced midshaft clavicle fracture. Which of the following represents an absolute indication for immediate operative fixation?

. Shortening of 1.5 cm
. Displacement of > 100% of the shaft width
. Comminution with a Z-deformity
. Impending skin necrosis or tenting with skin blanching
. Presence of a small inferior butterfly fragment

Correct Answer & Explanation

. Shortening of 1.5 cm

Explanation

Absolute indications for operative fixation of clavicle fractures include open fractures, impending skin necrosis (severe tenting with ischemia), associated vascular injury, and symptomatic nonunion. Shortening > 2 cm, severe comminution, and 100% displacement are strong but relative indications.

Question 11484

Topic: 2. Trauma

In the evaluation of a displaced proximal humerus fracture, which of the following radiographic factors is most predictive of subsequent humeral head ischemia (avascular necrosis)?

. Greater tuberosity displacement > 5 mm
. Lesser tuberosity displacement
. Metaphyseal head extension (calcar length) < 8 mm
. Intact medial hinge
. Valgus impaction of the head

Correct Answer & Explanation

. Greater tuberosity displacement > 5 mm

Explanation

According to Hertel's criteria, the best predictors of humeral head ischemia are a short metaphyseal head extension (calcar length attached to the articular surface) of < 8 mm, a disrupted medial hinge, and an anatomic basicervical fracture line.

Question 11485

Topic: 2. Trauma
A 6-year-old boy falls off monkey bars and sustains a Bado Type I Monteggia fracture equivalent. What is the defining radiographic feature of a classical Bado Type I lesion?
. Fracture of the ulnar shaft with posterior dislocation of the radial head
. Fracture of the ulnar shaft with anterior dislocation of the radial head
. Fracture of the ulnar metaphysis with lateral dislocation of the radial head
. Fracture of the proximal radius with anterior dislocation of the ulna
. Fracture of both forearm bones with distal radioulnar joint dislocation

Correct Answer & Explanation

. Fracture of the ulnar shaft with anterior dislocation of the radial head

Explanation

The Bado classification describes Monteggia fracture-dislocations (ulnar shaft fracture with radial head dislocation). Type I, the most common type, is characterized by an anterior dislocation of the radial head and anterior angulation of the ulnar shaft fracture. Type II is posterior, Type III is lateral, and Type IV involves fractures of both the radius and ulna with an associated radial head dislocation.

Question 11486

Topic: 2. Trauma

A 35-year-old male sustains a closed, spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). On initial evaluation in the ER, he is noted to have a dense radial nerve palsy. He is placed in a coaptation splint. At his 2-week follow-up, the radial nerve palsy persists, and radiographs show acceptable fracture alignment. What is the most appropriate management regarding the nerve palsy?

. Immediate surgical exploration
. Obtain an electromyogram (EMG) immediately
. Observation and physical therapy
. Prescribe systemic corticosteroids
. Perform nerve grafting

Correct Answer & Explanation

. Immediate surgical exploration

Explanation

Primary radial nerve palsy in the setting of a closed humeral shaft fracture (including Holstein-Lewis) is initially managed with observation. Spontaneous recovery occurs in over 90% of cases. Immediate exploration is generally not indicated for closed fractures unless the palsy occurs secondary to a closed reduction maneuver. EMG/NCS is typically delayed until 6-12 weeks if no clinical improvement is seen.

Question 11487

Topic: 2. Trauma

A 19-year-old male is brought to the trauma bay after a motorcycle accident. He has massive swelling over the shoulder girdle and a pulseless, flail upper extremity. Radiographs show lateral displacement of the scapula with a widened acromioclavicular joint and a displaced clavicle fracture. What is the most reliable early predictor of mortality or need for forequarter amputation in this specific condition?

. Severity of the brachial plexus avulsion
. Presence of an associated head injury
. Complete disruption of the subclavian or axillary artery
. Fracture of the scapular spine
. Degree of lateral scapular displacement on AP radiograph

Correct Answer & Explanation

. Severity of the brachial plexus avulsion

Explanation

Scapulothoracic dissociation involves a complete disruption of the scapulothoracic articulation. The mortality and morbidity (including amputation risk) are primarily driven by catastrophic hemorrhage from a completely ruptured subclavian or axillary artery. Emergent vascular control is life-saving, and combined severe vascular and complete neural injuries often ultimately lead to amputation.

Question 11488

Topic: 2. Trauma
A 6-year-old child presents after falling off the monkey bars. Radiographs demonstrate a fracture of the proximal third of the ulna with an anterior dislocation of the radial head. According to the Bado classification, what type of Monteggia lesion is this, and what is the typical initial treatment in this age group?
. Bado Type I, treated with open reduction and internal fixation of the ulna
. Bado Type I, treated with closed reduction and casting
. Bado Type II, treated with closed reduction and casting
. Bado Type III, treated with elastic stable intramedullary nailing
. Bado Type IV, treated with plate osteosynthesis

Correct Answer & Explanation

. Bado Type I, treated with closed reduction and casting

Explanation

A fracture of the proximal ulna with anterior dislocation of the radial head is a Bado Type I Monteggia fracture-dislocation (the most common type). In pediatric patients, unlike adults, these are almost universally treated successfully with closed reduction of the ulnar fracture and radial head (typically by supinating the forearm and flexing the elbow) followed by cast immobilization.

Question 11489

Topic: 2. Trauma
A 60-year-old female sustains a closed fracture of the mid-diaphysis of the humerus. Which of the following is an absolute indication for immediate open reduction and internal fixation rather than conservative management with a functional brace?
. Associated radial nerve palsy present upon emergency department arrival
. Transverse fracture pattern
. Shortening of 2 cm
. Poly-trauma with bilateral humeral shaft fractures
. Obesity (BMI > 35)

Correct Answer & Explanation

. Poly-trauma with bilateral humeral shaft fractures

Explanation

Absolute indications for ORIF of a humeral shaft fracture include: open fracture, associated vascular injury requiring repair, compartment syndrome, floating elbow, massive brachial plexus injury, and bilateral humeral shaft fractures (to allow the patient to assist with transfers and self-care). Primary radial nerve palsy with a closed fracture, up to 3cm shortening, and a transverse pattern can often be managed non-operatively.

Question 11490

Topic: 2. Trauma

A 24-year-old male sustains a closed, spiral fracture of the distal third of the humerus (Holstein-Lewis fracture). Upon initial examination in the emergency department, he is noted to have a complete radial nerve palsy. What is the most appropriate initial management of the radial nerve injury?

. Immediate surgical exploration and nerve repair
. Application of a coaptation splint and observation of nerve function
. EMG and nerve conduction studies prior to applying a splint
. Open reduction internal fixation of the humerus with immediate nerve exploration
. Immediate median-to-radial nerve transfer

Correct Answer & Explanation

. Immediate surgical exploration and nerve repair

Explanation

The vast majority of radial nerve palsies associated with closed humeral shaft fractures (even Holstein-Lewis types) are neuropraxias that will spontaneously recover. The standard of care is conservative management of the fracture (e.g., functional brace or coaptation splint) and observation of the nerve. Indications for immediate exploration include open fractures, vascular injury, or a nerve palsy that develops after a closed reduction.

Question 11491

Topic: 2. Trauma

A 7-year-old boy sustains a fall on an outstretched hand resulting in an isolated proximal ulna fracture with anterior bowing. Which associated injury MUST be carefully evaluated and ruled out on the initial radiographs?

. Distal radioulnar joint (DRUJ) dislocation
. Radial head subluxation or dislocation
. Medial epicondyle avulsion
. Scaphoid fracture
. Galeazzi equivalent physeal injury

Correct Answer & Explanation

. Distal radioulnar joint (DRUJ) dislocation

Explanation

The injury described is a Monteggia fracture-dislocation (proximal/diaphyseal ulna fracture associated with a radial head dislocation). Bado classified these based on the direction of radial head dislocation, with anterior (Type I) being the most common. Any fracture of the ulna must prompt a careful evaluation of the radiocapitellar line on all views to ensure the radial head is concentrically reduced.

Question 11492

Topic: 2. Trauma

When surgically addressing a chronic Type V acromioclavicular (AC) joint separation, what is the primary biomechanical advantage of an anatomic coracoclavicular (CC) ligament reconstruction over the traditional modified Weaver-Dunn procedure?

. Superior anterior-posterior and superior-inferior stability
. Decreased risk of secondary clavicle fractures
. Lower risk of graft site morbidity
. Slower healing time allowing for better capsular stretch
. Prevention of dynamic scapular winging

Correct Answer & Explanation

. Superior anterior-posterior and superior-inferior stability

Explanation

Anatomic reconstruction utilizes free tendon grafts to recreate both the conoid and trapezoid ligaments. This restores superior anterior-posterior and superior-inferior stability significantly better than the Weaver-Dunn, which only transfers the coracoacromial (CA) ligament.

Question 11493

Topic: 2. Trauma

A 35-year-old male sustains a closed, distal third spiral fracture of the humerus (Holstein-Lewis fracture). Neurological examination in the emergency department is normal. A closed reduction and splinting are performed. Post-reduction examination reveals a new-onset complete radial nerve palsy. What is the most appropriate next step in management?

. Obtain an EMG in 3 weeks
. Immediate surgical exploration and fracture fixation
. Observation for spontaneous recovery for 3 months
. Ultrasound of the radial nerve
. Conversion to a functional fracture brace

Correct Answer & Explanation

. Obtain an EMG in 3 weeks

Explanation

A new-onset secondary radial nerve palsy occurring immediately after closed reduction of a humeral shaft fracture is a strong indication for surgical exploration, as the nerve may be entrapped within the fracture fragments.

Question 11494

Topic: 2. Trauma
A 7-year-old boy falls from the monkey bars and sustains a diaphyseal fracture of the ulna with posterior angulation. Radiographs also demonstrate 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 for Monteggia fractures categorizes injuries by the direction of radial head dislocation. Type II involves posterior dislocation of the radial head with posterior angulation of the ulnar fracture.

Question 11495

Topic: 2. Trauma

Recent quantitative anatomical studies evaluating the vascularity of the proximal humerus have shifted the traditional paradigm regarding its blood supply. Which artery is now recognized as providing the dominant blood supply to the humeral head, placing it at significant risk in displaced 4-part fractures?

. Anterior circumflex humeral artery
. Posterior circumflex humeral artery
. Thoracoacromial artery
. Profunda brachii artery
. Suprascapular artery

Correct Answer & Explanation

. Anterior circumflex humeral artery

Explanation

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

Question 11496

Topic: 2. Trauma

A 28-year-old male sustains a closed spiral fracture of the distal third of the humeral shaft (Holstein-Lewis). He has a concomitant inability to extend his wrist and fingers upon presentation in the emergency department. What is the most appropriate initial management?

. Immediate open reduction and internal fixation with nerve exploration
. Closed reduction and functional bracing with observation of the nerve palsy
. External fixation and immediate nerve grafting
. Skeletal traction via an olecranon pin
. Immediate tendon transfers

Correct Answer & Explanation

. Immediate open reduction and internal fixation with nerve exploration

Explanation

A closed Holstein-Lewis fracture with a primary radial nerve palsy is generally treated non-operatively initially with functional bracing. The nerve recovers spontaneously in over 70% of cases, making early exploration unnecessary unless reduction cannot be maintained.

Question 11497

Topic: 2. Trauma

A 7-year-old boy falls and sustains a Bado Type I Monteggia fracture-dislocation. Which of the following describes this specific injury pattern?

. Ulnar shaft fracture with anterior dislocation of the radial head
. Ulnar shaft fracture with posterior dislocation of the radial head
. Ulnar shaft fracture with lateral dislocation of the radial head
. Radial shaft fracture with distal radioulnar joint (DRUJ) dislocation
. Proximal radius fracture with ulnohumeral dislocation

Correct Answer & Explanation

. Ulnar shaft fracture with anterior dislocation of the radial head

Explanation

A Bado Type I Monteggia fracture involves a fracture of the ulnar diaphysis with an anterior dislocation of the radial head. This is the most common Bado classification type seen in pediatric patients.

Question 11498

Topic: Upper Extremity Trauma

A 21-year-old collegiate baseball pitcher undergoes ulnar collateral ligament (UCL) reconstruction using a palmaris longus autograft. To restore the primary restraint to valgus stress of the elbow between 30 and 120 degrees of flexion, the graft must appropriately reconstruct the anterior bundle. What is the anatomic ulnar insertion of the anterior bundle of the UCL?

. The supinator crest
. The olecranon tip
. The sublime tubercle
. The coronoid tip
. The radial tuberosity

Correct Answer & Explanation

. The supinator crest

Explanation

The anterior bundle of the UCL is the primary restraint to valgus stress at the elbow between 30 and 120 degrees of flexion. It originates on the anterior undersurface of the medial epicondyle and inserts on the sublime tubercle, which is located on the anteromedial aspect of the coronoid process.

Question 11499

Topic: 2. Trauma
A 30-year-old male suffers a high-energy multiligamentous knee injury (Schenck KD-III). Upon arrival at the emergency department, his knee is grossly reduced but severely swollen. His Ankle-Brachial Index (ABI) is 0.85, and his distal pulses are palpable but asymmetric. What is the most appropriate next step in management?
. Immediate spanning external fixation
. Observation and repeat ABI in 4 hours
. CT angiography or formal arteriogram
. Immediate surgical exploration of the popliteal fossa
. Compartment pressure measurements

Correct Answer & Explanation

. CT angiography or formal arteriogram

Explanation

In the setting of a knee dislocation or suspected multiligament knee injury, an ABI < 0.9 is highly indicative of an arterial injury (usually popliteal intimal tear), even if distal pulses are palpable. This mandates further vascular imaging, most commonly a CT angiogram, or immediate vascular surgery consultation if hard signs of ischemia are present. Observation is inappropriate.

Question 11500

Topic: Upper Extremity Trauma
A 30-year-old male sustains a direct blow to the point of his shoulder. Radiographs reveal an acromioclavicular (AC) joint injury. The clavicle is significantly displaced posteriorly into or through the trapezius fascia. According to the Rockwood classification, what type of AC injury is this?
. Type II
. Type III
. Type IV
. Type V
. Type VI

Correct Answer & Explanation

. Type IV

Explanation

In the Rockwood classification of AC joint injuries, a Type IV injury is characterized by posterior displacement of the distal clavicle into or through the trapezius muscle/fascia. Type III is 25-100% superior displacement; Type V is >100% superior displacement; Type VI is inferior displacement (subcoracoid).

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