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2. Trauma MCQs

Practice Set 427 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 8521

Topic: 2. Trauma
A 6-year-old boy sustains an extension-type Gartland type III supracondylar humerus fracture. Upon initial evaluation, he has an absent radial pulse, but the hand is pink, warm, and has a brisk capillary refill. Following closed reduction and percutaneous pinning, the radial pulse remains absent, but the hand's perfusion status is unchanged (pink and warm). What is the next most appropriate step in management?
. Immediate exploration of the brachial artery.
. Observation and admission for 24-48 hours of serial neurovascular checks.
. Removal of pins and open reduction.
. Angiography of the upper extremity.
. Prophylactic volar fasciotomy of the forearm.

Correct Answer & Explanation

. Observation and admission for 24-48 hours of serial neurovascular checks.

Explanation

In a pediatric supracondylar humerus fracture with a 'pink, pulseless hand' after acceptable closed reduction and pinning, the standard of care is close observation. The collateral circulation in children is generally sufficient to maintain hand viability even if the brachial artery is in spasm or occluded. Immediate vascular exploration is indicated if the hand is ischemic ('white, pulseless hand') that does not improve after fracture reduction. Serial neurovascular checks are crucial to monitor for compartment syndrome or secondary loss of perfusion.

Question 8522

Topic: 2. Trauma

A 24-year-old male presents with a displaced fracture involving the proximal pole of the scaphoid. Regarding the surgical management and relevant vascular anatomy, which of the following statements is true?

. The major blood supply to the proximal pole is antegrade via the superficial palmar arch, favoring a volar approach for fixation.
. The major blood supply to the proximal pole is retrograde via branches of the radial artery, favoring a dorsal approach for percutaneous or open fixation.
. The major blood supply to the proximal pole is retrograde via branches of the radial artery, favoring a volar approach for fixation.
. The proximal pole relies on intraosseous anastomoses from the lunate, favoring a volar approach.
. The major blood supply to the proximal pole is antegrade via the deep palmar arch, favoring a dorsal approach.

Correct Answer & Explanation

. The major blood supply to the proximal pole is retrograde via branches of the radial artery, favoring a dorsal approach for percutaneous or open fixation.

Explanation

The scaphoid receives its primary blood supply from dorsal branches of the radial artery that enter the distal ridge and flow retrograde to the proximal pole. This tenuous retrograde blood supply puts proximal pole fractures at exceedingly high risk for avascular necrosis and nonunion. For proximal pole fractures, a dorsal surgical approach is heavily favored as it provides direct visualization, easier anatomic reduction, and a more biomechanically sound central axis for screw placement without disrupting the volar ligaments or the remaining critical dorsal blood supply.

Question 8523

Topic: 2. Trauma
While managing a 28-year-old cyclist who sustained a midshaft clavicle fracture, the orthopedic surgeon reviews the indications for operative intervention. Which of the following is considered an ABSOLUTE indication for open reduction and internal fixation of an acute clavicle fracture?
. Displacement greater than 100% of the shaft width
. Shortening greater than 1.5 cm
. Severe skin tenting without overlying skin blanching
. Open fracture
. Concomitant non-displaced rib fractures

Correct Answer & Explanation

. Open fracture

Explanation

Absolute indications for the operative fixation of an acute clavicle fracture include open fractures, fractures with associated progressive neurovascular compromise, and arguably the true 'floating shoulder' (ipsilateral displaced clavicle and scapular neck fractures, though some debate exists, open fracture remains universally absolute). Relative indications include shortening greater than 2 cm, >100% displacement, severe skin tenting (specifically with impending skin compromise/blanching), polytrauma, and symptomatic nonunions. Skin tenting without blanching or ischemia is considered a relative, not absolute, indication.

Question 8524

Topic: 2. Trauma

A 72-year-old woman sustains a 3-part proximal humerus fracture after a fall from standing height. Which of the following physical examination findings is the most reliable acute indicator of injury to the nerve most commonly affected by this fracture pattern?

. Loss of sensation over the lateral aspect of the deltoid
. Weakness in external rotation with the arm resting at the side
. Inability to actively abduct the arm past 90 degrees
. Weakness in elbow flexion against resistance
. Loss of sensation over the posterior forearm

Correct Answer & Explanation

. Loss of sensation over the lateral aspect of the deltoid

Explanation

The axillary nerve is the most commonly injured nerve in proximal humerus fractures. It provides motor innervation to the deltoid and teres minor, and sensory innervation to the lateral shoulder via the superior lateral cutaneous nerve of the arm. Testing for loss of sensation over the lateral deltoid is the most reliable acute assessment, as pain often precludes accurate motor testing of the shoulder.

Question 8525

Topic: 2. Trauma

Which of the following scenarios is considered an absolute indication for operative fixation of an acute midshaft clavicle fracture?

. 2.5 cm of shortening in a healthy 25-year-old
. Z-type displacement with significant comminution
. Open fracture
. The patient is an elite overhead throwing athlete
. Concomitant non-displaced fracture of the scapular body

Correct Answer & Explanation

. Open fracture

Explanation

Absolute indications for operative fixation of a clavicle fracture include open fractures, neurovascular compromise, and impending skin breakdown (severe skin tenting that does not resolve with reduction). Shortening, comminution, and athletic status are considered relative indications.

Question 8526

Topic: 2. Trauma

A 35-year-old man sustains a closed transverse fracture of the middle third of the humerus. On initial evaluation in the emergency department, he has an isolated, complete radial nerve palsy. Radiographs show acceptable fracture alignment. What is the most appropriate initial management?

. Immediate exploration of the radial nerve and plate fixation
. Functional bracing and clinical observation of the radial nerve
. Immediate electromyography (EMG) and nerve conduction studies
. External fixation and primary nerve grafting
. Open reduction without nerve exploration

Correct Answer & Explanation

. Functional bracing and clinical observation of the radial nerve

Explanation

Radial nerve palsy occurs in up to 18% of closed humeral shaft fractures. The vast majority of these injuries are neuropraxias that will spontaneously recover. The gold standard for initial management of a closed humeral shaft fracture with an associated primary radial nerve palsy is functional bracing and observation. Immediate exploration is indicated for open fractures, penetrating trauma, associated vascular injuries requiring repair, or in some cases if the palsy occurs secondarily after a closed reduction maneuver. EMG is not useful in the acute setting because Wallerian degeneration takes approximately 3 weeks to demonstrate signs of denervation.

Question 8527

Topic: 2. Trauma

A 65-year-old woman falls and sustains a complex proximal humerus fracture. According to the criteria established by Hertel et al., which combination of radiographic findings is the most reliable predictor of humeral head ischemia?

. Posteromedial hinge disruption and metaphyseal extension less than 8 mm
. Integrity of the medial calcar and intact periosteum
. Greater tuberosity displacement greater than 10 mm combined with a head-split
. Angular deformity of the humeral head greater than 45 degrees in the coronal plane
. Fracture of the anatomic neck with medial hinge disruption and a short calcar segment (<8 mm)

Correct Answer & Explanation

. Fracture of the anatomic neck with medial hinge disruption and a short calcar segment (<8 mm)

Explanation

Hertel et al. evaluated the predictors of humeral head ischemia following proximal humerus fractures. The most significant individual predictors include a short posteromedial metaphyseal head extension (calcar segment attached to the articular surface <8 mm), disruption of the medial hinge, and a true anatomic neck fracture. When all three factors are present, the positive predictive value for ischemia is 97%.

Question 8528

Topic: 2. Trauma

A 65-year-old woman sustains an intra-articular distal humerus fracture (AO type 13-C3). Open reduction and internal fixation is performed with dual plating. Which of the following statements regarding the biomechanical stability of plating configurations is most accurate?

. Parallel plating provides significantly superior biomechanical stability compared to orthogonal plating in all loading conditions.
. Orthogonal plating provides significantly superior biomechanical stability compared to parallel plating in all loading conditions.
. Both parallel and orthogonal plating offer comparable biomechanical stability when appropriately applied.
. A single locking plate provides equivalent stability to dual plating constructs.
. Parallel plating requires structural bone grafting to achieve stability comparable to orthogonal plating.

Correct Answer & Explanation

. Both parallel and orthogonal plating offer comparable biomechanical stability when appropriately applied.

Explanation

According to extensive biomechanical studies (such as those by O'Driscoll and others), both parallel plating (medial and lateral plates) and orthogonal plating (medial and posterolateral plates) provide sufficient and comparable biomechanical stability for the fixation of intra-articular distal humerus fractures. The choice between the two constructs largely depends on the specific fracture pattern and surgeon preference, provided that basic principles of fracture fixation and interdigitation of screws are strictly followed.

Question 8529

Topic: 2. Trauma

A 45-year-old woman falls on an outstretched hand and sustains an acute 'terrible triad' injury of the elbow.

During surgical reconstruction, after fixation of the coronoid and radial head fractures and repair of the lateral collateral ligament (LCL) complex, the elbow remains persistently unstable in extension. What is the next most appropriate step in surgical management?

. Application of a hinged external fixator
. Repair of the medial collateral ligament (MCL)
. Excision of the radial head
. Primary closure and casting in 90 degrees of flexion
. Anterior transposition of the ulnar nerve

Correct Answer & Explanation

. Repair of the medial collateral ligament (MCL)

Explanation

The standard sequence of treating terrible triad injuries includes repairing the coronoid, restoring the radial head, and repairing the LCL complex. If the elbow remains unstable in extension after these steps, the MCL should be repaired. Hinged external fixation is reserved for residual instability after all primary capsuloligamentous structures have been addressed.

Question 8530

Topic: 2. Trauma

A 35-year-old man sustains a closed spiral fracture of the distal third of the humeral shaft following an arm-wrestling match. On initial presentation in the emergency department, he is unable to actively extend his wrist or fingers, and he has decreased sensation over the dorsal first web space. Radiographs confirm a Holstein-Lewis fracture. What is the most appropriate initial management?

. Immediate surgical exploration and nerve repair
. Placement in a coaptation splint and observation
. Electromyography (EMG) and nerve conduction studies
. Open reduction and internal fixation with nerve exploration
. Application of a functional fracture brace

Correct Answer & Explanation

. Placement in a coaptation splint and observation

Explanation

Radial nerve palsy associated with a closed humeral shaft fracture (including Holstein-Lewis fractures) is typically a neuropraxia or axonotmesis. The most appropriate initial management is nonoperative treatment of the fracture (e.g., coaptation splint followed by a functional brace) and observation of the nerve palsy. Spontaneous recovery occurs in the vast majority of cases. Surgical exploration is indicated if the fracture is open, if there is an associated vascular injury, or if a nerve palsy develops AFTER a closed reduction attempt.

Question 8531

Topic: 2. Trauma

A 65-year-old right-hand-dominant woman presents after a fall onto an outstretched hand. Radiographs demonstrate a displaced intra-articular distal radius fracture with a volar marginal shear fragment.

Which of the following approaches and fixation constructs is most appropriate to prevent carpal subluxation?

. Dorsal approach with a spanning bridge plate
. Volar approach with a buttress plate
. Closed reduction and percutaneous pinning
. External fixation with supplementary K-wires
. Dorsal approach with a fragment-specific pin plate

Correct Answer & Explanation

. Volar approach with a buttress plate

Explanation

Volar Barton fractures (volar marginal shear fractures of the distal radius) represent a fracture-dislocation of the radiocarpal joint. The radiocarpal ligaments remain attached to the volar fragment, causing the carpus to subluxate volarly. Nonoperative management or isolated external fixation often fails to maintain reduction due to shear forces. The most appropriate management is open reduction via a volar approach and application of a volar buttress plate.

Question 8532

Topic: 2. Trauma

A 72-year-old woman sustains a shoulder injury after a mechanical fall.

Assuming this is a severely comminuted 4-part proximal humerus fracture with varus impaction and severe osteoporosis, which of the following is the strongest predictor of postoperative complications if treated with open reduction and internal fixation (ORIF) utilizing a locked plate?

. Initial degree of fragment displacement
. Lack of medial calcar support
. Tuberosity comminution severity
. Tear of the long head of the biceps
. Presence of an intact posteromedial hinge

Correct Answer & Explanation

. Lack of medial calcar support

Explanation

In the surgical treatment of proximal humerus fractures using locking plates, restoration or presence of medial calcar support is critical to prevent varus collapse and secondary screw cutout. Loss of medial support leads to significantly higher failure rates. Other risk factors for failure include initial severe varus angulation, poor bone quality, and inadequate superior screw placement into the humeral head.

Question 8533

Topic: 2. Trauma
A 29-year-old male cyclist falls directly onto his left shoulder. He presents with severe pain and a prominent distal clavicle. Radiographs demonstrate a 150% superior displacement of the distal clavicle relative to the acromion, with the clavicle visibly protruding and tenting the trapezius fascia on clinical exam. What is the diagnosis and recommended treatment?
. Type III AC joint separation; trial of conservative management with a sling
. Type V AC joint separation; operative reconstruction of the coracoclavicular ligaments
. Type IV AC joint separation; operative reduction and internal fixation
. Type II AC joint separation; focused physical therapy
. Distal clavicle fracture; open reduction and internal fixation

Correct Answer & Explanation

. Type V AC joint separation; operative reconstruction of the coracoclavicular ligaments

Explanation

The scenario describes a Type V acromioclavicular (AC) joint injury, characterized by 100-300% superior displacement of the clavicle, severe disruption of the coracoclavicular (CC) ligaments, and stripping of the deltotrapezial fascia. Type IV injuries involve posterior displacement into the trapezius muscle. Due to the profound biomechanical dysfunction and marked clinical deformity with soft-tissue compromise, Type V injuries generally require surgical intervention for CC ligament reconstruction and joint reduction.

Question 8534

Topic: 2. Trauma

A 6-year-old boy falls from the monkey bars and presents with a swollen, painful forearm.

Radiographs reveal a plastic deformation and fracture of the proximal ulnar shaft accompanied by an anterior dislocation of the radial head. Which of the following nerves is at greatest risk of injury with this specific fracture pattern?

. Anterior interosseous nerve (AIN)
. Posterior interosseous nerve (PIN)
. Ulnar nerve
. Superficial radial nerve
. Median nerve

Correct Answer & Explanation

. Posterior interosseous nerve (PIN)

Explanation

The patient has sustained a Bado Type I Monteggia fracture-dislocation (anterior dislocation of the radial head with an anteriorly angulated fracture or plastic deformation of the ulnar diaphysis). The posterior interosseous nerve (PIN), a deep motor branch of the radial nerve, wraps around the radial neck and is tethered by the arcade of Frohse. It is uniquely susceptible to stretch, compression, or contusion injuries from the anteriorly displaced radial head in this specific fracture configuration.

Question 8535

Topic: 2. Trauma

A 24-year-old man sustains a scaphoid waist fracture. The vascular supply to the proximal pole of the scaphoid relies primarily on retrograde flow from vessels entering which aspect of the bone?

. Volar proximal
. Dorsal proximal
. Volar distal
. Dorsal ridge
. Scapholunate interosseous ligament

Correct Answer & Explanation

. Dorsal ridge

Explanation

The scaphoid receives its primary blood supply from branches of the radial artery. The major blood supply enters via the dorsal ridge (accounting for 70-80% of the intraosseous vascularity) and supplies the proximal pole in a retrograde fashion. A secondary volar supply enters the distal tubercle. Because of this retrograde blood supply, proximal pole fractures have a notoriously high rate of avascular necrosis and nonunion.

Question 8536

Topic: 2. Trauma

A 78-year-old woman with severe rheumatoid arthritis presents with a comminuted, intra-articular distal humerus fracture. Due to the severe osteopenia and joint destruction, she undergoes a total elbow arthroplasty (TEA). Which of the following is a recognized absolute contraindication for TEA in the setting of trauma?

. Age over 65
. Patient noncompliance with a 5-pound lifetime lifting restriction
. Pre-existing ulnar neuropathy
. Active local soft tissue infection
. Non-reconstructable medial and lateral columns

Correct Answer & Explanation

. Active local soft tissue infection

Explanation

Active local or systemic infection is an absolute contraindication to total joint arthroplasty, including total elbow arthroplasty (TEA). A lifetime lifting restriction (usually 5-10 lbs) is a relative contraindication if the patient is expected to be non-compliant. Severe RA and older age are standard indications for TEA in complex distal humerus fractures, particularly when the columns are non-reconstructable.

Question 8537

Topic: 2. Trauma

A 45-year-old man sustains a closed, spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture) following a fall. On initial examination in the emergency department, he exhibits a dense radial nerve palsy. According to current orthopaedic literature, what is the most appropriate initial management for this injury?

. Immediate open reduction and internal fixation with radial nerve exploration
. Closed reduction, coaptation splinting, and clinical observation of the nerve
. Immediate electromyography (EMG) to determine the extent of nerve injury
. Application of an external fixator and delayed nerve grafting
. Ultrasound-guided nerve block to prevent reflex sympathetic dystrophy

Correct Answer & Explanation

. Closed reduction, coaptation splinting, and clinical observation of the nerve

Explanation

A primary radial nerve palsy associated with a closed humeral shaft fracture (including Holstein-Lewis types) is predominantly a neurapraxia or axonotmesis. The overall rate of spontaneous recovery is high (greater than 85%). Therefore, the standard of care is initial nonoperative management of the fracture with a coaptation splint or functional brace, and clinical observation. Surgical exploration of the nerve is indicated if the palsy occursaftera closed reduction attempt (secondary palsy), in open fractures, or if there is no clinical or electromyographic evidence of recovery by 3 to 4 months.

Question 8538

Topic: 2. Trauma

A 24-year-old man falls on an outstretched hand and sustains a fracture of the proximal pole of the scaphoid. He delays seeking treatment for 3 months. What is the primary anatomical reason for the high risk of nonunion and avascular necrosis in this specific fracture pattern?

. The scaphoid receives its primary blood supply from the volar carpal branch of the radial artery, which enters distally and flows retrograde.
. The scaphoid is enveloped by articular cartilage, preventing callus formation and relying entirely on endosteal healing.
. The proximal pole relies entirely on the dorsal carpal branch of the ulnar artery, which is commonly injured in hyperextension trauma.
. The dorsal carpal branch of the radial artery enters the scaphoid primarily at the distal pole and waist, providing a retrograde blood supply to the proximal pole.
. Ligamentous attachments to the proximal pole act as a deforming force, preventing adequate fracture approximation.

Correct Answer & Explanation

. The dorsal carpal branch of the radial artery enters the scaphoid primarily at the distal pole and waist, providing a retrograde blood supply to the proximal pole.

Explanation

The major blood supply to the scaphoid arises from branches of the radial artery (specifically the dorsal carpal branch), which enter the scaphoid at the distal pole and waist. From there, the blood flows in a retrograde fashion to supply the proximal pole. Because of this tenuous retrograde blood supply, fractures at the proximal pole carry a particularly high risk of disrupting the vascularity to the proximal fragment, strongly predisposing the patient to nonunion and avascular necrosis.

Question 8539

Topic: 2. Trauma

A 24-year-old man falls onto an outstretched hand and sustains a fracture of the scaphoid proximal pole. He is at high risk for avascular necrosis (AVN) and nonunion. Which of the following best describes the predominant arterial supply to the scaphoid that makes this fracture pattern vulnerable?

. Palmar branches of the radial artery entering proximally
. Dorsal branches of the ulnar artery entering distally
. Dorsal carpal branch of the radial artery entering the dorsal ridge distally
. Interosseous arterial branches entering the volar waist
. Deep palmar arch branches entering the proximal pole directly

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery entering the dorsal ridge distally

Explanation

The scaphoid receives 70-80% of its blood supply from the dorsal carpal branch of the radial artery, which enters along the dorsal ridge in the distal half of the bone. This retrograde blood supply puts proximal pole fractures at a disproportionately high risk for AVN, as the fracture disrupts the blood flow from distal to proximal.

Question 8540

Topic: 2. Trauma

A 28-year-old man sustains a spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture) following a fall. On presentation to the emergency department, he is unable to extend his wrist or fingers, but triceps function is intact. The fracture is closed. Which of the following scenarios is considered an absolute indication for early surgical exploration of the radial nerve?

. The presence of a radial nerve palsy immediately after the injury
. A complete radial nerve palsy rather than a partial palsy
. A radial nerve palsy in a patient who requires a Sarmiento brace
. A secondary radial nerve palsy that develops after a closed reduction attempt
. A transverse fracture pattern on radiographs rather than spiral

Correct Answer & Explanation

. A secondary radial nerve palsy that develops after a closed reduction attempt

Explanation

Primary radial nerve palsies associated with closed humeral shaft fractures (including Holstein-Lewis fractures) are generally observed, as up to 90% resolve spontaneously (representing a neurapraxia or axonotmesis). However, a secondary radial nerve palsy that occursaftera closed reduction attempt is an absolute indication for surgical exploration, because the nerve may have been drawn into the fracture site and entrapped during the reduction maneuver.

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