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2. Trauma MCQs

Practice Set 580 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 11581

Topic: 2. Trauma
A 40-year-old farmer sustains a severe open tibia fracture (Gustilo-Anderson Type IIIA) highly contaminated with soil. According to current guidelines, what is the most appropriate initial intravenous antibiotic regimen?
. Cefazolin alone
. Cefazolin and an aminoglycoside
. Cefazolin, an aminoglycoside, and high-dose penicillin
. Vancomycin and piperacillin-tazobactam
. Ceftriaxone and clindamycin

Correct Answer & Explanation

. Cefazolin, an aminoglycoside, and high-dose penicillin

Explanation

For a Gustilo Type III open fracture with severe soil contamination (farm injury), guidelines recommend a first-generation cephalosporin, an aminoglycoside for Gram-negative coverage, and high-dose penicillin to cover Clostridium species.

Question 11582

Topic: 2. Trauma

A 30-year-old male presents with a closed tibial shaft fracture. The orthopedic surgeon suspects acute compartment syndrome. Which of the following measurements is generally accepted as an absolute indication for emergency fasciotomy?

. Absolute compartment pressure > 20 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Mean arterial pressure minus compartment pressure > 40 mmHg
. Absolute compartment pressure > 15 mmHg
. Systolic blood pressure minus compartment pressure < 20 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The delta P (diastolic blood pressure minus the compartment pressure) is the most reliable indicator for compartment syndrome. A delta P of less than 30 mmHg is an established indication for emergent four-compartment fasciotomy.

Question 11583

Topic: 2. Trauma

An 82-year-old male with severe COPD and heart failure sustains a Type II odontoid fracture after a ground-level fall. The fracture is displaced 2 mm. What is the most appropriate management, and what is the primary rationale against using a halo vest in this specific patient population?

. Surgical stabilization; halo vest increases risk of pin site infection
. Soft cervical collar; halo vest increases risk of abducens nerve palsy
. Rigid cervical collar; halo vest increases the risk of severe dysphagia
. Rigid cervical collar; halo vest is associated with respiratory failure and high mortality
. Halo vest is the treatment of choice; it avoids surgical risks

Correct Answer & Explanation

. Rigid cervical collar; halo vest is associated with respiratory failure and high mortality

Explanation

In the elderly (particularly >80 years old with comorbidities), Type II odontoid fractures have a high nonunion rate. However, a fibrous nonunion is often clinically well-tolerated. Operative intervention carries significant morbidity. A halo vest is heavily contraindicated in the elderly due to severe complications, including respiratory failure, difficulty swallowing, and a mortality rate that can approach 40%. A rigid cervical collar is the safest management for elderly patients who are poor surgical candidates.

Question 11584

Topic: 2. Trauma

A 25-year-old male falls from a 30-foot height. Imaging reveals a U-shaped sacral fracture with a transverse fracture line through the S1-S2 disc space and bilateral vertical transforaminal fractures. He has saddle anesthesia and sphincter dysfunction. What is the most appropriate surgical treatment for this fracture pattern?

. Bilateral percutaneous iliosacral screws at S1 and S2
. Anterior pelvic plating via a Pfannenstiel approach
. Sacral laminectomy without instrumentation
. Lumbopelvic fixation (spinopelvic dissociation stabilization)
. Conservative management with 6 weeks of bed rest

Correct Answer & Explanation

. Lumbopelvic fixation (spinopelvic dissociation stabilization)

Explanation

A U-type sacral fracture represents a spinopelvic dissociation where the axial skeleton is separated from the pelvic ring. Due to the high degree of instability and the translation/kyphosis of the upper sacrum, standard iliosacral screws are insufficient to resist the sheer forces. Lumbopelvic fixation (typically extending from L4/L5 to the ilium) is required to restore mechanical stability and allow mobilization. Decompression is also indicated given the neurologic deficit.

Question 11585

Topic: 2. Trauma

An 82-year-old female sustains a Type II odontoid fracture after a fall down the stairs. The fracture demonstrates 6 mm of posterior displacement. She is neurologically intact. Which of the following factors is most strongly associated with an increased risk of nonunion if managed non-operatively?

. Initial fracture displacement > 5 mm
. Anterior rather than posterior displacement
. Initial fracture gap < 1 mm
. Female sex
. Associated C1 ring fracture

Correct Answer & Explanation

. Initial fracture displacement > 5 mm

Explanation

Risk factors for nonunion in Type II odontoid fractures include age > 50 years, initial displacement > 5 mm, angulation > 10 degrees, and a delay in treatment. Posterior displacement is a risk factor for nonunion compared to anterior displacement, but displacement magnitude (> 5 mm) is the most classically tested and highly predictive variable. Operative fixation is generally favored in patients who can tolerate surgery if these risk factors are present.

Question 11586

Topic: Pelvic & Acetabular Trauma

A 68-year-old male with type 2 diabetes presents with neck stiffness. Radiographs show flowing ossification along the anterolateral aspect of five contiguous cervical and thoracic vertebrae. Disc heights are preserved, and there is no evidence of sacroiliac joint ankylosis. Which of the following is true regarding this patient's condition?

. The patient will almost certainly test positive for HLA-B27
. The condition is primarily mediated by autoimmune inflammation of the entheses
. It is defined by Resnick criteria, which includes flowing ossification of at least 4 contiguous vertebrae
. Treatment requires aggressive immunosuppression to halt progression
. The disease typically destroys the intervertebral discs leading to spontaneous fusions

Correct Answer & Explanation

. It is defined by Resnick criteria, which includes flowing ossification of at least 4 contiguous vertebrae

Explanation

The clinical picture describes Diffuse Idiopathic Skeletal Hyperostosis (DISH). The classic Resnick and Niwayama criteria for DISH include: 1. Flowing ossification along the anterolateral aspect of at least 4 contiguous vertebrae. 2. Preservation of intervertebral disc height. 3. Absence of apophyseal joint bony ankylosis or sacroiliac joint erosion/sclerosis. Unlike Ankylosing Spondylitis, DISH is not associated with HLA-B27, lacks SI joint involvement, does not erode discs, and does not respond to immunosuppressants.

Question 11587

Topic: 2. Trauma

A 20-year-old female is involved in a high-speed motor vehicle collision while wearing a lap belt. Radiographs reveal a transverse fracture through the L2 vertebral body, pedicles, and spinous process. Which of the following associated injuries must be most highly suspected?

. Aortic transection
. Bowel or mesenteric injury
. Pulmonary contusion
. Pelvic ring disruption
. Renal artery thrombosis

Correct Answer & Explanation

. Bowel or mesenteric injury

Explanation

A Chance fracture is a flexion-distraction injury strongly associated with lap belt use. Approximately 50% of these patients will have a concurrent intra-abdominal injury, most commonly involving the bowel or mesentery.

Question 11588

Topic: 2. Trauma
A 25-year-old male is placed in a halo vest for a C2 fracture. One week later, he complains of double vision. On examination, he is unable to abduct his left eye. Which cranial nerve is most likely injured, and what is the presumed mechanism?
. CN IV (Trochlear) via direct pin injury
. CN VI (Abducens) via longitudinal traction
. CN III (Oculomotor) via pin tract infection
. CN VII (Facial) via direct pin injury
. CN II (Optic) via elevated intracranial pressure

Correct Answer & Explanation

. CN VI (Abducens) via longitudinal traction

Explanation

Cranial nerve VI (abducens) palsy is a known complication of halo vest application, typically caused by excessive longitudinal traction stretching the nerve. It presents with an inability to abduct the affected eye, leading to diplopia.

Question 11589

Topic: 2. Trauma

An 8-year-old boy sustains a minor fall and presents with arm pain. X-rays show a pathologic fracture through a centrally located lytic lesion in the proximal humerus metaphysis. A "fallen leaf" sign is present. What is the most appropriate initial management of the fracture?

. Immediate curettage and bone grafting
. Aspiration and steroid injection
. Sling immobilization and observation for healing
. Wide resection and fibular strut graft
. Neoadjuvant chemotherapy

Correct Answer & Explanation

. Sling immobilization and observation for healing

Explanation

A "fallen leaf" or "fallen fragment" sign is pathognomonic for a simple (unicameral) bone cyst. Pathologic fractures through a proximal humerus UBC are initially treated non-operatively with immobilization, which occasionally results in spontaneous healing of the cyst.

Question 11590

Topic: 2. Trauma

An 8-year-old boy falls and sustains a proximal humerus fracture. Radiographs show a centrally located radiolucent lesion in the metaphysis extending to the physis, with a small piece of cortex lying at the bottom of the cyst. What is the preferred first-line treatment for this underlying lesion after the fracture heals?

. Curettage and bone grafting
. Corticosteroid injection
. Wide surgical resection
. Radiation therapy
. Amputation

Correct Answer & Explanation

. Corticosteroid injection

Explanation

The "fallen leaf" sign is pathognomonic for a unicameral (simple) bone cyst. After allowing the pathologic fracture to heal, the first-line treatment for active, symptomatic cysts is typically an aspiration followed by a corticosteroid or bone marrow aspirate injection.

Question 11591

Topic: 2. Trauma

Which of the following best describes the vascular supply to the scaphoid and its clinical implication?

. Blood supply enters distally via branches of the radial artery and flows proximally, increasing the risk of avascular necrosis in proximal pole fractures.
. Blood supply enters distally and flows proximally, increasing the risk of avascular necrosis predominantly in distal pole fractures.
. Blood supply enters proximally via the ulnar artery, making waist fractures susceptible to nonunion.
. Blood supply enters predominantly through the volar carpal branches, shielding the proximal pole from ischemia.
. The scaphoid relies entirely on intraosseous anastomoses, making any displaced fracture a strict indication for vascularized bone grafting.

Correct Answer & Explanation

. Blood supply enters distally via branches of the radial artery and flows proximally, increasing the risk of avascular necrosis in proximal pole fractures.

Explanation

The scaphoid receives its primary blood supply from branches of the radial artery that enter at the distal pole and flow retrogradely to the proximal pole. Because of this retrograde perfusion, proximal pole fractures have a high risk of avascular necrosis and nonunion.

Question 11592

Topic: 2. Trauma

According to Hertel's radiographic criteria, which of the following fracture characteristics is the most accurate predictor of humeral head ischemia in proximal humerus fractures?

. A posteromedial metaphyseal head extension (calcar length) of less than 8 mm
. Integrity of the medial hinge
. Displacement of the greater tuberosity by > 5 mm
. A medial hinge disruption of > 2 mm with a calcar length of < 8 mm
. Varus angulation greater than 20 degrees

Correct Answer & Explanation

. A medial hinge disruption of > 2 mm with a calcar length of < 8 mm

Explanation

Hertel et al. described predictors of ischemia in proximal humerus fractures. The combination of a disrupted medial hinge (>2 mm) and a short calcar segment (<8 mm attached to the articular segment) has the highest positive predictive value (97%) for subsequent humeral head ischemia.

Question 11593

Topic: 2. Trauma

Which of the following muscles is typically the most severely affected by ischemia in volar compartment syndrome of the forearm due to its deeper location and vascular anatomy?

. Flexor carpi radialis
. Palmaris longus
. Flexor digitorum superficialis
. Flexor digitorum profundus
. Pronator teres

Correct Answer & Explanation

. Flexor digitorum profundus

Explanation

The flexor digitorum profundus (FDP) and flexor pollicis longus (FPL) are located in the deep volar compartment of the forearm. Due to their deep position immediately adjacent to the radius and ulna, and their epimysial blood supply, they are typically the most severely affected muscles in forearm compartment syndrome (leading to Volkmann's ischemic contracture).

Question 11594

Topic: 2. Trauma
According to the Bado classification, a Monteggia fracture-dislocation characterized by a fracture of the ulnar diaphysis with posterior angulation and a posterior dislocation of the radial head is classified as:
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type III

Explanation

In the Bado classification for Monteggia lesions: Type I is an anterior dislocation of the radial head with anterior apex ulnar fracture; Type II is a posterior dislocation of the radial head with posterior apex ulnar fracture; Type III is lateral dislocation of the radial head with an ulnar metaphyseal fracture; Type IV is anterior dislocation with fractures of both the radius and ulna shafts.

Question 11595

Topic: 2. Trauma

A 65-year-old female presents with sudden inability to extend her thumb interphalangeal joint 6 weeks after non-operative management of a non-displaced distal radius fracture. What is the most widely accepted etiology of this complication?

. Iatrogenic division of the tendon during casting
. Ischemia and mechanical attrition of the tendon at Lister's tubercle
. Entrapment of the tendon within the fracture site
. Secondary displacement of the fracture causing direct laceration
. Unrecognized baseline rheumatoid arthritis

Correct Answer & Explanation

. Ischemia and mechanical attrition of the tendon at Lister's tubercle

Explanation

Extensor pollicis longus (EPL) rupture is a classic complication following minimally displaced or non-displaced distal radius fractures. The primary etiology is a combination of mechanical attrition over the fracture callus/Lister's tubercle and ischemia due to increased pressure within the tight, intact third extensor compartment.

Question 11596

Topic: 2. Trauma

In a 25-year-old active male with a closed midshaft clavicle fracture, which of the following radiographic characteristics is the strongest independent predictor of nonunion if treated non-operatively?

. 1 cm of longitudinal shortening
. Inferior displacement of the lateral fragment by 50%
. Complete displacement with greater than 2 cm of shortening
. Presence of a nondisplaced butterfly fragment
. Associated nondisplaced scapular body fracture

Correct Answer & Explanation

. Complete displacement with greater than 2 cm of shortening

Explanation

Complete fracture displacement with greater than 2 cm of shortening is a strong independent predictor of nonunion and poor functional outcomes in midshaft clavicle fractures. This finding strongly supports the indication for surgical fixation.

Question 11597

Topic: 2. Trauma

A 6-year-old boy sustains a Bado Type I Monteggia fracture-dislocation. Following closed reduction and casting of the ulnar shaft fracture, radiographs reveal persistent anterior subluxation of the radial head. What is the most likely anatomic block to radial head reduction?

. Interposed annular ligament
. Biceps tendon subluxation
. Brachialis muscle interposition
. Triceps tendon avulsion
. Median nerve entrapment

Correct Answer & Explanation

. Interposed annular ligament

Explanation

In pediatric Bado Type I Monteggia injuries, failure to achieve or maintain radial head reduction after anatomic ulnar realignment is most commonly due to the interposition of the torn annular ligament or joint capsule. Open reduction of the radiocapitellar joint is required to extract the interposed tissue.

Question 11598

Topic: 2. Trauma

A 55-year-old female presents with a highly comminuted, intra-articular distal radius fracture with significant volar displacement of the carpus alongside the volar fracture fragment. Which of the following is the most appropriate biomechanical principle for plate fixation of this injury pattern?

. Dorsal bridge plating
. Volar buttress plating
. Fragment-specific radial styloid pinning
. External fixation with distraction ligamentotaxis
. Tension band wiring

Correct Answer & Explanation

. Volar buttress plating

Explanation

A volar shear fracture (Barton's fracture) represents an unstable pattern where the carpus subluxates with the volar articular fragment. A volar plate acts as a buttress to counteract the shear forces, preventing volar subluxation of the carpus.

Question 11599

Topic: 2. Trauma

A 24-year-old cyclist falls and sustains a completely displaced midshaft clavicle fracture. Which of the following radiographic parameters is the strongest absolute indication for open reduction and internal fixation (ORIF) to prevent symptomatic malunion?

. Displacement of 50% of the shaft diameter
. Shortening greater than 2 cm
. Inferior displacement of the medial fragment
. Comminution with a single butterfly fragment
. Presence of a small nondisplaced segmental fracture

Correct Answer & Explanation

. Shortening greater than 2 cm

Explanation

In midshaft clavicle fractures, shortening greater than 2 cm is highly associated with symptomatic malunion, persistent pain, and shoulder weakness. ORIF is indicated to restore resting length and optimize shoulder mechanics.

Question 11600

Topic: 2. Trauma

A 25-year-old cyclist falls directly onto his shoulder. Radiographs reveal a completely displaced midshaft clavicle fracture with 2.5 cm of shortening and no cortical contact. Which of the following is the most established biomechanical and clinical advantage of open reduction internal fixation (ORIF) compared to non-operative management in this patient?

. Decreased rate of adhesive capsulitis
. Decreased risk of nonunion and symptomatic malunion
. Lower incidence of pneumothorax
. Reduced risk of suprascapular nerve injury
. Elimination of hardware-related complications

Correct Answer & Explanation

. Decreased risk of nonunion and symptomatic malunion

Explanation

Displaced midshaft clavicle fractures with shortening greater than 2 cm have a high rate of nonunion and symptomatic malunion if treated non-operatively. ORIF significantly decreases the nonunion rate and improves early functional outcomes in this specific patient population.

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