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2. Trauma MCQs

Practice Set 326 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 6501

Topic: 2. Trauma

Which of the following radiographic features is the most reliable predictor of ischemia and subsequent avascular necrosis of the humeral head following a proximal humerus fracture?

. Greater tuberosity displacement > 1 cm
. Metaphyseal head extension < 8 mm
. Disruption of the lateral periosteal hinge
. Displaced surgical neck fracture
. Angulation > 45 degrees

Correct Answer & Explanation

. Metaphyseal head extension < 8 mm

Explanation

Hertel identified specific predictors of humeral head ischemia, most notably a short calcar segment (metaphyseal head extension < 8 mm) and disruption of the medial periosteal hinge. These morphological features reflect critical damage to the anterior humeral circumflex artery supply.

Question 6502

Topic: 2. Trauma

A 22-year-old man presents with chronic wrist pain and is diagnosed with a scaphoid waist nonunion demonstrating a humpback deformity and no evidence of avascular necrosis. What is the most appropriate surgical treatment?

. Dorsal approach with headless compression screw
. Volar approach with non-vascularized structural wedge bone graft
. Vascularized bone graft from the dorsal radius
. Proximal row carpectomy
. Four-corner fusion

Correct Answer & Explanation

. Volar approach with non-vascularized structural wedge bone graft

Explanation

A humpback deformity represents volar structural bone loss and abnormal flexion of the scaphoid. It is best corrected through a volar approach utilizing a non-vascularized structural wedge bone graft (such as iliac crest) to restore proper length and sagittal alignment.

Question 6503

Topic: 2. Trauma

A 28-year-old man sustains a closed spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). On initial evaluation, he has a complete radial nerve palsy. What is the most appropriate initial management?

. Immediate surgical exploration and nerve repair
. Open reduction internal fixation of the fracture and nerve exploration
. Closed reduction and functional bracing with observation
. Electromyography and nerve conduction studies
. External fixation of the humerus

Correct Answer & Explanation

. Closed reduction and functional bracing with observation

Explanation

Primary radial nerve palsy associated with a closed humeral shaft fracture is typically a neuropraxia with a high rate of spontaneous recovery. Observation and functional bracing remain the initial standard of care, reserving nerve exploration for cases that fail to recover clinically or electrodiagnostically by 3 to 4 months.

Question 6504

Topic: 2. Trauma

According to Hertel's criteria, which combination of radiographic findings is the most highly predictive of humeral head ischemia following a proximal humerus fracture?

. Metaphyseal head extension < 8 mm and disrupted medial hinge
. Metaphyseal head extension > 8 mm and intact medial hinge
. Greater tuberosity displacement > 10 mm and surgical neck fracture
. Four-part fracture with any degree of valgus impaction
. Displaced lesser tuberosity with bicipital groove involvement

Correct Answer & Explanation

. Metaphyseal head extension < 8 mm and disrupted medial hinge

Explanation

Hertel identified that a metaphyseal head extension (calcar segment) of less than 8 mm combined with a disrupted medial hinge has a 97% positive predictive value for humeral head ischemia.

Question 6505

Topic: 2. Trauma

A 25-year-old man falls on an outstretched hand and sustains a fracture of the scaphoid proximal pole. What is the primary anatomical reason this specific fracture pattern is at a high risk for avascular necrosis?

. The dominant blood supply enters palmarly and flows proximally
. The dominant blood supply enters dorsally at the distal pole and flows retrograde
. The proximal pole is entirely covered by articular cartilage with no vascular foramina
. The radiocarpal ligaments tear and disrupt the volar blood supply
. The deep palmar arch branches are exclusively extraosseous

Correct Answer & Explanation

. The dominant blood supply enters dorsally at the distal pole and flows retrograde

Explanation

The scaphoid receives its primary blood supply from branches of the radial artery entering the dorsal ridge near the distal pole, which then flow in a retrograde direction to the proximal pole.

Question 6506

Topic: 2. Trauma

A 30-year-old woman falls on an outstretched hand and sustains a coronal shear fracture of the capitellum that extends into the lateral trochlear ridge (McKee modification of Bryan and Morrey Type IV). Which surgical approach provides the most optimal visualization for fixation of this specific injury?

. Extensile lateral approach
. Medial approach
. Posterior olecranon osteotomy
. Posterior triceps-splitting approach
. Anterior approach

Correct Answer & Explanation

. Extensile lateral approach

Explanation

The extensile lateral approach (often utilizing a Kocher or Kaplan interval extended proximally) provides the best anterior exposure for complex capitellar fractures involving the trochlea. An olecranon osteotomy provides excellent posterior visualization but poor access to the anterior articular surface.

Question 6507

Topic: 2. Trauma

A 70-year-old woman sustains a highly displaced 4-part proximal humerus fracture.

According to Hertel's radiographic criteria, which of the following findings is the most reliable predictor of humeral head ischemia?

. Greater tuberosity displacement > 1 cm
. Shaft translation > 5 mm
. Head angulation > 45 degrees
. Metaphyseal head extension < 8 mm
. Lesser tuberosity split

Correct Answer & Explanation

. Metaphyseal head extension < 8 mm

Explanation

Hertel described specific criteria predictive of humeral head ischemia after proximal humerus fractures. The most reliable predictors are a metaphyseal head extension (calcar length) of less than 8 mm and a disrupted medial hinge of greater than 2 mm.

Question 6508

Topic: 2. Trauma

Which of the following is the most reliable radiographic predictor of humeral head ischemia following a proximal humerus fracture?

. Metaphyseal head extension (calcar length) less than 8 mm
. Displacement of the greater tuberosity greater than 5 mm
. Varus angulation greater than 20 degrees
. Valgus angulation greater than 45 degrees
. Intra-articular comminution

Correct Answer & Explanation

. Metaphyseal head extension (calcar length) less than 8 mm

Explanation

According to Hertel's criteria, a metaphyseal head extension (calcar length) of less than 8 mm, medial hinge disruption greater than 2 mm, and an anatomic neck fracture pattern are the most reliable predictors of humeral head ischemia. Loss of the medial periosteal hinge significantly compromises the ascending branches of the anterior circumflex humeral artery.

Question 6509

Topic: Upper Extremity Trauma

Recent quantitative anatomic studies have redefined the primary arterial supply to the articular segment of the proximal humerus. Which vessel provides the majority of the blood supply to the humeral head?

. Anterior humeral circumflex artery
. Posterior humeral circumflex artery
. Thoracoacromial artery
. Subscapular artery
. Suprascapular artery

Correct Answer & Explanation

. Posterior humeral circumflex artery

Explanation

While older literature emphasized the anterior humeral circumflex artery (arcuate branch), recent studies (e.g., Hettrich et al.) demonstrate that the posterior humeral circumflex artery provides approximately 64% of the blood supply to the humeral head.

Question 6510

Topic: 2. Trauma

In a Galeazzi fracture-dislocation, which of the following radiographic or anatomic findings is the strongest predictor of distal radioulnar joint (DRUJ) instability following anatomic fixation of the radius?

. Volar displacement of the radius
. Fracture location less than 7.5 cm from the articular surface
. Radial shortening less than 5 mm
. Concomitant ulnar styloid tip fracture
. Transverse fracture pattern

Correct Answer & Explanation

. Fracture location less than 7.5 cm from the articular surface

Explanation

Radius fractures located within 7.5 cm of the articular surface are associated with a high rate of DRUJ instability. Fractures proximal to this 7.5 cm threshold uncommonly result in DRUJ disruption.

Question 6511

Topic: 2. Trauma

A 6-year-old child presents with a Bado Type I Monteggia fracture-dislocation. What is the direction of the radial head dislocation in this injury pattern?

. Anterior
. Posterior
. Lateral
. Medial
. Divergent

Correct Answer & Explanation

. Anterior

Explanation

A Bado Type I Monteggia lesion involves a fracture of the proximal or middle third of the ulna with an anterior dislocation of the radial head. It is the most common type of Monteggia fracture in children.

Question 6512

Topic: 2. Trauma

Which of the following is the most significant clinical or radiographic risk factor for nonunion of a midshaft clavicle fracture treated nonoperatively?

. Fracture shortening greater than 2 cm
. Inferior displacement of the medial fragment
. Female gender
. Age over 65
. Distal third fracture location

Correct Answer & Explanation

. Fracture shortening greater than 2 cm

Explanation

Fracture shortening greater than 2 cm and 100% displacement are the most significant risk factors for nonunion and symptomatic malunion in completely displaced midshaft clavicle fractures.

Question 6513

Topic: 2. Trauma

An 80-year-old female sustains a highly comminuted, osteoporotic intercondylar distal humerus fracture (AO/OTA 13-C3). What is the primary advantage of total elbow arthroplasty (TEA) over ORIF in this demographic?

. Improved long-term lifting capacity
. No permanent weight-bearing restrictions
. Decreased risk of ulnar neuropathy
. More predictable functional outcome with earlier mobilization
. Lower lifetime risk of periprosthetic infection compared to ORIF

Correct Answer & Explanation

. More predictable functional outcome with earlier mobilization

Explanation

TEA provides a more predictable functional outcome and permits immediate post-operative mobilization in elderly patients with poor bone stock, bypassing the high failure rates of ORIF in comminuted osteoporotic fractures. However, TEA requires lifelong lifting restrictions.

Question 6514

Topic: 2. Trauma

A spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture) is most commonly associated with a primary injury to which of the following nerves?

. Median nerve
. Ulnar nerve
. Radial nerve
. Axillary nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Radial nerve

Explanation

A Holstein-Lewis fracture is a spiral fracture of the distal third of the humeral shaft. It is associated with a high incidence of radial nerve palsy as the nerve becomes tethered as it passes through the lateral intermuscular septum.

Question 6515

Topic: 2. Trauma

Review the clinical scenario provided. A 68-year-old female sustains a 4-part proximal humerus fracture.

Which of the following is the most reliable radiographic predictor of humeral head ischemia in this setting?

. Greater than 45 degrees of head angulation
. Less than 8 mm of posteromedial metaphyseal extension (calcar)
. Disruption of the greater tuberosity
. Displacement of the bicipital groove
. Oblique fracture line at the surgical neck

Correct Answer & Explanation

. Less than 8 mm of posteromedial metaphyseal extension (calcar)

Explanation

Hertel et al. identified specific predictors of humeral head ischemia. A posteromedial metaphyseal head extension (calcar length) of less than 8 mm and disruption of the medial hinge are the most reliable predictors of AVN.

Question 6516

Topic: 2. Trauma

A 19-year-old male falls on his shoulder and sustains a midshaft clavicle fracture. Which of the following findings is an absolute indication for operative management?

. 1.5 cm of shortening
. Z-deformity on the AP radiograph
. Impending skin ulceration (skin tenting)
. Middle third location of the fracture
. Concomitant non-displaced rib fracture

Correct Answer & Explanation

. Impending skin ulceration (skin tenting)

Explanation

Absolute indications for clavicle fracture fixation include open fractures, neurovascular compromise, and severe skin tenting that implies impending skin breakdown. Shortening and displacement are considered relative indications.

Question 6517

Topic: 2. Trauma

A 60-year-old male undergoes tension band wiring for a transverse olecranon fracture. Which of the following is the most frequent complication associated with this specific surgical technique?

. Nonunion of the fracture
. Deep surgical site infection
. Ulnar nerve palsy
. Symptomatic hardware requiring removal
. Elbow extension deficit greater than 30 degrees

Correct Answer & Explanation

. Symptomatic hardware requiring removal

Explanation

The most common complication of tension band wiring for olecranon fractures is prominent and symptomatic hardware, which necessitates hardware removal in up to 40-80% of patients once the fracture has healed.

Question 6518

Topic: 2. Trauma

A 7-year-old child presents with a Bado Type I Monteggia fracture-dislocation. Based on this specific fracture pattern, what associated neurological deficit is most likely to be observed on physical examination?

. Inability to make an 'OK' sign (AIN palsy)
. Numbness in the median nerve distribution
. Weakness in finger adduction (Ulnar nerve palsy)
. Inability to actively extend the thumb and fingers (PIN palsy)
. Numbness over the dorsal first web space without motor loss

Correct Answer & Explanation

. Inability to actively extend the thumb and fingers (PIN palsy)

Explanation

Bado Type I Monteggia fractures (anterior dislocation of the radial head with anterior angulation of the ulna) are most commonly associated with posterior interosseous nerve (PIN) neuropraxia due to the anterior displacement of the radial head.

Question 6519

Topic: Upper Extremity Trauma

Which of the following describes the typical mechanism of injury for a 'terrible triad' of the elbow?

. Axial load, valgus stress, and forearm supination
. Axial load, varus stress, and forearm pronation
. Direct blow to the posterior olecranon with the elbow flexed
. Hyperextension with sudden varus stress
. Traction injury with the elbow in extension

Correct Answer & Explanation

. Axial load, valgus stress, and forearm supination

Explanation

A terrible triad injury of the elbow (elbow dislocation, radial head fracture, coronoid fracture) typically occurs from a fall on an outstretched hand resulting in an axial load, valgus stress, and forearm supination. This causes sequential failure of structures from lateral to medial.

Question 6520

Topic: 2. Trauma

Which of the following is considered an absolute indication for open reduction and internal fixation of an acute midshaft clavicle fracture?

. Greater than 2 cm of shortening
. 100% displacement without bony contact
. Z-deformity on the AP radiograph
. Skin tenting with evolving skin necrosis
. Patient preference for a faster return to collision sports

Correct Answer & Explanation

. Skin tenting with evolving skin necrosis

Explanation

Skin tenting with impending necrosis is an absolute indication for operative fixation of a clavicle fracture to prevent progression to an open fracture. Shortening and severe displacement are relative indications.

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