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2. Trauma MCQs

Practice Set 34 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 661

Topic: 2. Trauma
In a healthy 25-year-old patient with a displaced, vertically oriented (Pauwels type III) femoral neck fracture, what is the most significant biomechanical advantage of using a sliding hip screw with a derotation screw compared to multiple cancellous screws?
. Decreased surgical time
. Superior resistance to vertical shear forces
. Lower risk of avascular necrosis
. Preservation of the lateral femoral circumflex artery
. Allows for early unrestricted weight-bearing

Correct Answer & Explanation

. Superior resistance to vertical shear forces

Explanation

Pauwels type III fractures are highly vertical and subjected to significant shear forces. A fixed-angle device like a sliding hip screw provides superior biomechanical resistance to these vertical shear forces compared to parallel cancellous screws.

Question 662

Topic: 2. Trauma
A 25-year-old male sustains a vertically oriented (Pauwels type III) femoral neck fracture. Which of the following fixation constructs provides the most biomechanically stable fixation against shear forces?
. Three parallel cancellous screws placed in an inverted triangle
. Two parallel cancellous screws
. A sliding hip screw with a derotational screw
. A cephalomedullary nail
. A dynamic condylar screw

Correct Answer & Explanation

. A sliding hip screw with a derotational screw

Explanation

Pauwels type III fractures have a high vertical shear angle, leading to increased rates of nonunion and varus collapse. A fixed-angle device, such as a sliding hip screw with a derotational screw, provides superior biomechanical stability against shear forces compared to multiple cancellous screws.

Question 663

Topic: 2. Trauma

Primary (direct) bone healing, which occurs without callus formation, relies heavily on the activity of cutting cones. This type of healing is typically achieved by which of the following fixation methods?

. Intramedullary nailing of a comminuted diaphyseal fracture
. Bridge plating of a multifragmentary femur fracture
. Absolute stability utilizing a lag screw and neutralization plate
. Casting of a closed tibial shaft fracture
. External fixation of a distal radius fracture

Correct Answer & Explanation

. Absolute stability utilizing a lag screw and neutralization plate

Explanation

Primary bone healing requires absolute stability and anatomical reduction, typically achieved with rigid internal fixation like lag screws and neutralization plates. Methods providing relative stability (e.g., IM nails, casts, bridge plates) result in secondary bone healing with visible callus formation.

Question 664

Topic: 2. Trauma

Which of the following is the most useful symptom or sign of a foot compartment syndrome:

. Numbness in the lateral plantar nerve distribution
. Weakness of toe extension (interossei muscles)
. Decreased capillary refill
. Severe pain
. Weakness of ankle plantarfexion

Correct Answer & Explanation

. Severe pain

Explanation

Pain out of proportion to injury is the most reliable indicator of a foot compartment syndrome. Foot compartment syndromes can be difficult to diagnose compared to compartment syndromes of the leg. In the leg, one can rely on motor and nerve testing while motor testing in the foot is difficult secondary to the pain from the injury. The severe pain is usually out of proportion to injury. Pain suggestive of compartment syndrome includes: Unremitting pain Pain not responsive to increasing doses of narcotics Pain that is so severe the patient cannot lie still or cooperate with the examiner

Question 665

Topic: 2. Trauma
Which of the following is the most useful sign in diagnosing a foot compartment syndrome?
. Numbness in the lateral plantar nerve distribution
. Numbness in the medial plantar nerve distribution
. Weakness with toe dorsiflexion
. Weakness when testing ankle plantarflexion
. Severe pain with passive toe flexion

Correct Answer & Explanation

. Severe pain with passive toe flexion

Explanation

Pain with passive stretch is a reliable sign in compartment syndrome of the leg, foot, and ankle. In Myerson's study, he found that pain with passive stretch was present in 86% of patients when those intrinsic muscles of the foot were stretched.

Question 666

Topic: 2. Trauma

Which of the following compartments are most commonly involved (increased tissue pressure) in compartment syndrome of the foot:

. Superficial
. Medial
. C alcaneal
. Adductor
. First interosseus

Correct Answer & Explanation

. C alcaneal

Explanation

The calcaneal compartment is most commonly involved in foot compartment syndromes. Approximately 5% to 10% of calcaneus fractures are complicated by a compartment syndrome. The cancellous bone of the calcaneus may have significant bleeding. Swelling of the hindfoot can be severe.

Question 667

Topic: 2. Trauma
A 45-year-old man has severe, unremitting pain after sustaining a displaced calcaneus fracture. He is immobilized in a bulky compression dressing with plaster splints. After removing his dressing, he is noted to have marked swelling with no resolution of his pain. The next step in management is:
. Ice and elevation
. Ice, elevation, and an increase in pain medication
. Application of a foot pump
. Epidural block for pain control
. Measurement of the calcaneal compartment tissue pressure

Correct Answer & Explanation

. Measurement of the calcaneal compartment tissue pressure

Explanation

The patient has the most reliable finding in foot compartment syndromes: unremitting pain that is out of proportion to injury. When patients have unremitting pain following removal of a compression dressing, the compartment pressures should be measured to determine if a compartment syndrome is present. If the tissue pressure is within 30 mm Hg of the diastolic pressure, the pressures are above 30 mm Hg, and a neurological deficit is present, a compartment syndrome has occurred and the patient should undergo an emergency fasciotomy.

Question 668

Topic: 2. Trauma
A 45-year-old man has severe, unremitting pain after sustaining a displaced calcaneus fracture. His hindfoot is swollen. The calcaneal compartment tissue pressure is 47 mm Hg. His diastolic pressure is 70 mm Hg. The next step in management is:
. Ice and elevation
. Ice, elevation, and an increase in pain medication
. Application of a foot pump
. Epidural block for pain control
. Emergent release of the foot compartments

Correct Answer & Explanation

. Emergent release of the foot compartments

Explanation

The patient has the most reliable finding in foot compartment syndromes: unremitting pain that is out of proportion to injury. When patients have unremitting pain following removal of a compression dressing, the compartment pressures should be measured to determine if a compartment syndrome is present. If the tissue pressure is within 30 mm Hg of the diastolic pressure, the pressures are above 30 mm Hg, and a neurological deficit is present, a compartment syndrome has occurred and the patient should undergo an emergency fasciotomy.

Question 669

Topic: 2. Trauma

Polyglycolide screws used for fixation of ankle fractures:

. Are associated with a higher rate of sterile effusion than polylactide screws
. Are associated with a lower rate of sterile effusion than polylactide screws
. Are not associated with sterile effusion
. Provide more rigid fixation than polylactide screws
. Do not resorb over time

Correct Answer & Explanation

. Are associated with a higher rate of sterile effusion than polylactide screws

Explanation

Polyglycolide screws have a high incidence of sterile effusions as a result of rapid hydrolysis; polylactide screws showed no soft tissue reactions.

Question 670

Topic: 2. Trauma

The plantar ecchymosis sign is:

. An indication of possible compartment syndrome
. An indication of possible compartment syndrome
. An indication of possible Lisfranc fracture or sprain
. Described as a sign of plantar fascia rupture
. Requires immediate fasciotomy

Correct Answer & Explanation

. An indication of possible Lisfranc fracture or sprain

Explanation

The plantar ecchymosis sign is described as an ecchymotic area on the plantar midfoot that is indicative of possible injury to the plantar tarsometatarsal ligaments.

Question 671

Topic: 2. Trauma

Delayed unions and nonunions of base of fifth metatarsal fractures have been demonstrated to heal by:

. Prolonged cast immobilization and non-weight bearing
. Pulsed electromagnetic fields
. C ontinued use of a fracture boot with protected weight- bearing
. Injection of demineralized bone matrix
. Rigid carbon fiber shoe inserts

Correct Answer & Explanation

. Pulsed electromagnetic fields

Explanation

Nine delayed unions and nonunions of the proximal fifth metatarsal were treated with pulsed electromagnetic fields. All fractures healed in a mean of 4 months (follow-up 39 months, no refractures).

Question 672

Topic: 2. Trauma
According to the Sanders computed tomography (CT) classification for calcaneus fractures, a Sanders III fracture has:
. One fracture line in the posterior facet
. Two fracture lines in the posterior facet
. Three fracture lines in the posterior facet
. Four fracture lines in the posterior facet
. Five fracture lines in the posterior facet

Correct Answer & Explanation

. Three fracture lines in the posterior facet

Explanation

The Sanders CT classification is determined on coronal CT scans of the calcaneus at the level where the posterior facet is widest. A Sanders I is a nondisplaced fracture; Sanders II consists of a single fracture line splitting the posterior facet into two main fragments; Sanders III has two fracture lines with three main posterior facet fragments; and a Sanders IV has four or more articular fragments present.

Question 673

Topic: 2. Trauma

Which of the following measurements is the most reliable threshold for diagnosing an acute compartment syndrome of the lower extremity requiring fasciotomy?

. Diastolic blood pressure minus compartment pressure is less than 30 mmHg
. Systolic blood pressure minus compartment pressure is less than 30 mmHg
. Mean arterial pressure minus compartment pressure is less than 30 mmHg
. Absolute compartment pressure is greater than 20 mmHg
. Absolute compartment pressure is greater than 25 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure is less than 30 mmHg

Explanation

Delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the most reliable indicator for diagnosing acute compartment syndrome and indicates the need for emergent fasciotomy.

Question 674

Topic: Pelvic & Acetabular Trauma

According to the Young-Burgess classification, an Anteroposterior Compression Type II (APC-II) pelvic ring injury is characterized by which of the following ligamentous disruptions?

. Symphysis disruption with intact anterior and posterior sacroiliac ligaments
. Symphysis disruption with torn anterior sacroiliac ligaments but intact posterior sacroiliac ligaments
. Symphysis disruption with completely torn anterior and posterior sacroiliac ligaments
. Complete disruption of the sacrotuberous, sacrospinous, and posterior sacroiliac ligaments only
. Vertical shear through the ilium with completely intact sacroiliac ligaments

Correct Answer & Explanation

. Symphysis disruption with torn anterior sacroiliac ligaments but intact posterior sacroiliac ligaments

Explanation

An APC-II injury is an "open book" pelvic fracture where the pubic symphysis is widened, the sacrotuberous/sacrospinous and anterior sacroiliac ligaments are disrupted, but the stout posterior sacroiliac ligaments remain intact.

Question 675

Topic: 2. Trauma

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is utilized in orthopedic surgery to promote bone healing. According to the FDA, which of the following is an approved indication for the use of rhBMP-2?

. Posterior lumbar instrumented fusion
. Anterior lumbar interbody fusion (ALIF)
. Nonunion of the scaphoid
. Acute closed tibial shaft fractures
. Avascular necrosis of the femoral head

Correct Answer & Explanation

. Anterior lumbar interbody fusion (ALIF)

Explanation

rhBMP-2 is currently FDA-approved for single-level anterior lumbar interbody fusion (ALIF) using an LT-CAGE device, as well as for acute, open tibial shaft fractures treated with an intramedullary nail.

Question 676

Topic: 2. Trauma

In the setting of a polytraumatized patient with an Injury Severity Score (ISS) of 36, severe closed head injury, and a closed femoral shaft fracture, which of the following is the most appropriate initial management for the femur?

. Immediate reamed intramedullary nailing
. Immediate unreamed intramedullary nailing
. External fixation spanning the fracture
. Open reduction and internal fixation with a plate
. Skeletal traction until head injury resolves

Correct Answer & Explanation

. External fixation spanning the fracture

Explanation

In a borderline or unstable polytrauma patient with a severe traumatic brain injury, Damage Control Orthopedics (DCO) is indicated. External fixation provides rapid stability without the physiologic "second hit" and increased intracranial pressure associated with prolonged surgery or canal reaming.

Question 677

Topic: 2. Trauma

A 25-year-old male presents with a closed, highly comminuted tibial shaft fracture following a motorcycle accident. Which of the following is the most sensitive and earliest clinical sign of developing acute compartment syndrome?

. Loss of distal pulses
. Pallor of the distal extremity
. Pain with passive stretch of the toes
. Flaccid paralysis of the foot
. Decreased capillary refill

Correct Answer & Explanation

. Pain with passive stretch of the toes

Explanation

Pain out of proportion to the injury and pain with passive muscle stretch are the earliest and most sensitive clinical indicators of acute compartment syndrome. Pulselessness, pallor, and paralysis are late, often irreversible signs.

Question 678

Topic: 2. Trauma

In a patient with an intra-articular calcaneus fracture, the Sanders classification system is most heavily based on the fracture pattern seen on which of the following imaging modalities and planes?

. Lateral plain radiograph measuring Bohler's angle
. Harris axial plain radiograph
. Sagittal computed tomography (CT) scan
. Coronal computed tomography (CT) scan
. Axial magnetic resonance imaging (MRI)

Correct Answer & Explanation

. Coronal computed tomography (CT) scan

Explanation

The Sanders classification system is based on the number and location of articular fracture lines extending through the posterior facet of the calcaneus. These fracture lines are best visualized on coronal CT images.

Question 679

Topic: 2. Trauma

A 22-year-old professional athlete sustains an acute fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal (Jones fracture). Why is this specific fracture pattern uniquely prone to delayed union and nonunion?

. Excessive avulsion force from the peroneus brevis tendon
. Interruption of the nutrient artery providing retrograde blood flow
. High concentration of type I collagen in the diaphysis
. Inadequate fixation options due to medullary canal size
. Frequent intra-articular involvement of the cuboid articulation

Correct Answer & Explanation

. Interruption of the nutrient artery providing retrograde blood flow

Explanation

A true Jones fracture occurs at the metaphyseal-diaphyseal junction, representing a vascular watershed zone. The nutrient artery supplies this diaphyseal region in a retrograde fashion, making the area highly susceptible to ischemia and nonunion.

Question 680

Topic: 2. Trauma

A 40-year-old male sustains a severe high-energy closed tibial pilon fracture. Examination reveals significant soft tissue swelling and multiple fracture blisters. What is the most widely accepted initial management strategy?

. Immediate open reduction and internal fixation (ORIF) of the tibia with dual plating
. Placement of a circular fine-wire frame for definitive fixation
. Spanning external fixation and delayed ORIF once soft tissues allow
. Closed reduction and long leg cast application
. Prophylactic fasciotomies followed immediately by plate fixation

Correct Answer & Explanation

. Spanning external fixation and delayed ORIF once soft tissues allow

Explanation

High-energy pilon fractures are associated with severe soft tissue compromise. The standard of care involves a two-stage approach: initial application of a spanning external fixator, followed by definitive ORIF at a later date once soft tissue swelling has subsided (wrinkle sign present).

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