Menu

2. Trauma MCQs

Practice Set 559 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 11161

Topic: 2. Trauma

A 35-year-old male presents with a closed tibia fracture following an MVC.

Several hours after admission, he develops severe leg pain out of proportion to the injury, exacerbated by passive stretch of the toes. His diastolic blood pressure is 80 mmHg. Intracompartmental pressure in the anterior compartment is measured at 55 mmHg. What is the Delta P, and what is the most appropriate next step in management?

. Delta P is 25 mmHg, perform an urgent four-compartment fasciotomy
. Delta P is 55 mmHg, continue close clinical observation
. Delta P is 30 mmHg, perform an urgent four-compartment fasciotomy
. Delta P is 25 mmHg, elevate the leg and re-measure in 2 hours
. Delta P is 80 mmHg, continue close clinical observation

Correct Answer & Explanation

. Delta P is 25 mmHg, perform an urgent four-compartment fasciotomy

Explanation

The Delta P is calculated as the Diastolic Blood Pressure minus the Intracompartmental Pressure. In this case, 80 mmHg - 55 mmHg = 25 mmHg. A Delta P of 30 mmHg or less is widely accepted as an absolute indication for urgent decompressive fasciotomies in cases of suspected acute compartment syndrome, as it indicates critically compromised microvascular perfusion.

Question 11162

Topic: 2. Trauma
Which of the following bone morphogenetic proteins (BMPs) is currently FDA-approved as an alternative to autogenous bone graft for acute, open tibial shaft fractures treated with an intramedullary nail?
. rhBMP-2
. rhBMP-3
. rhBMP-4
. rhBMP-7
. rhBMP-9

Correct Answer & Explanation

. rhBMP-2

Explanation

Recombinant human bone morphogenetic protein-2 (rhBMP-2, also known as INFUSE) is FDA-approved for acute open tibial shaft fractures stabilized with intramedullary nail fixation, as well as for anterior lumbar interbody fusion (ALIF). rhBMP-7 (OP-1) was previously approved under a Humanitarian Device Exemption for recalcitrant tibial nonunions but is not the correct answer here.

Question 11163

Topic: 2. Trauma

A trauma patient sustains an isolated, high-energy intra-articular fracture of the distal femur. The operative report describes the fixation of a 'Hoffa fracture'. Which of the following accurately describes a Hoffa fracture?

. A transverse fracture of the supracondylar region
. A coronal plane fracture of the femoral condyle
. A sagittal plane fracture of the femoral condyle
. A highly comminuted fracture involving the metaphyseal-diaphyseal junction
. An avulsion fracture of the medial epicondyle by the MCL

Correct Answer & Explanation

. A transverse fracture of the supracondylar region

Explanation

A Hoffa fracture is a distinct, intra-articular coronal plane fracture of the distal femoral condyle. It most commonly involves the lateral femoral condyle. Because it lies in the coronal plane, it is often poorly visualized on standard AP radiographs and best appreciated on a lateral view or CT scan.

Question 11164

Topic: Pelvic & Acetabular Trauma
Review the clinical scenario. A patient involved in an MVC sustains a pelvic ring injury. AP Pelvis radiograph reveals widening of the pubic symphysis of 3.0 cm, alongside widening of the anterior sacroiliac joints bilaterally. CT scan confirms that the posterior sacroiliac ligaments remain intact. According to the Young-Burgess classification system, what specific type of injury is this?
. Anteroposterior Compression I (APC I)
. Anteroposterior Compression II (APC II)
. Anteroposterior Compression III (APC III)
. Lateral Compression I (LC I)
. Lateral Compression II (LC II)

Correct Answer & Explanation

. Anteroposterior Compression II (APC II)

Explanation

An Anteroposterior Compression Type II (APC II) injury is an 'open book' pelvis characterized by disruption of the pubic symphysis (>2.5 cm) and tearing of the anterior SI ligaments, sacrotuberous, and sacrospinous ligaments. The critical feature distinguishing it from an APC III is that the posterior SI ligaments remain intact, rendering the pelvis rotationally unstable but vertically stable.

Question 11165

Topic: Pelvic & Acetabular Trauma



A 28-year-old male is brought to the trauma bay following a high-speed motor vehicle collision. He is hypotensive and tachycardic. An AP pelvic radiograph demonstrates a symphyseal diastasis of 3.5 cm with anterior sacroiliac joint widening. Which of the following is the most common anatomical source of massive hemorrhage in this type of injury?

. Superior gluteal artery
. Obturator artery
. Presacral venous plexus
. Internal pudendal artery
. Medial circumflex femoral artery

Correct Answer & Explanation

. Superior gluteal artery

Explanation

The presacral venous plexus and bleeding from fractured cancellous bone account for approximately 80% of hemorrhage in pelvic ring injuries. While arterial bleeding (e.g., internal pudendal or superior gluteal) can occur and is often more rapidly fatal, venous bleeding remains the most common overall source.

Question 11166

Topic: 2. Trauma

A 25-year-old male sustains a closed comminuted tibial shaft fracture. Two hours later, he complains of severe pain out of proportion to the injury. His blood pressure is 110/65 mmHg. Direct compartment pressure measurement yields an absolute pressure of 40 mmHg in the anterior compartment. What is his delta P, and what is the recommendation?

. Delta P is 25 mmHg; emergent fasciotomy is indicated
. Delta P is 25 mmHg; continue close clinical observation
. Delta P is 70 mmHg; emergent fasciotomy is indicated
. Delta P is 45 mmHg; continue close clinical observation
. Delta P is 40 mmHg; emergent fasciotomy is indicated

Correct Answer & Explanation

. Delta P is 25 mmHg; emergent fasciotomy is indicated

Explanation

Delta P is calculated as Diastolic Blood Pressure minus Compartment Pressure (65 - 40 = 25 mmHg). A Delta P of less than 30 mmHg is an objective indication for emergent fasciotomy to prevent irreversible muscle and nerve ischemia.

Question 11167

Topic: 2. Trauma



A 35-year-old male presents with a displaced fracture of the middle third of the clavicle. Radiographs show superior displacement of the medial fragment. Which muscle is primarily responsible for this deforming force?

. Pectoralis major
. Sternocleidomastoid
. Trapezius
. Deltoid
. Subclavius

Correct Answer & Explanation

. Pectoralis major

Explanation

The sternocleidomastoid muscle inserts on the superior medial aspect of the clavicle and pulls the proximal fracture fragment superiorly and posteriorly. The weight of the arm and the pectoralis major pull the distal fragment inferiorly and medially.

Question 11168

Topic: 2. Trauma

According to the Denis classification for sacral fractures, which zone is associated with the highest incidence of neurologic injury, including bowel and bladder dysfunction?

. Zone 1
. Zone 2
. Zone 3
. Zone 4
. Zone 5

Correct Answer & Explanation

. Zone 1

Explanation

Denis Zone 3 involves fractures medial to the neural foramina, crossing the central sacral canal. These fractures have the highest rate of neurologic injury (up to 57%), commonly affecting the sacral nerve roots responsible for bowel, bladder, and sexual function.

Question 11169

Topic: 2. Trauma
A 45-year-old farmer sustains an open tibia fracture highly contaminated with soil and farm debris. According to classical guidelines for open fracture management, which of the following prophylactic antibiotic regimens is most appropriate?
. Ceftriaxone and vancomycin
. Cefazolin and clindamycin
. Cefazolin and gentamicin
. Cefazolin, gentamicin, and high-dose penicillin
. Piperacillin-tazobactam

Correct Answer & Explanation

. Cefazolin, gentamicin, and high-dose penicillin

Explanation

Farm injuries are associated with a high risk of anaerobic contamination, particularly Clostridium species. The classic prophylactic regimen for Type III farm-related open fractures includes a first-generation cephalosporin, an aminoglycoside, and high-dose penicillin.

Question 11170

Topic: 2. Trauma

A 30-year-old man is admitted with a comminuted tibial shaft fracture and complains of pain out of proportion to the injury. Which of the following absolute compartment pressure thresholds, relative to the patient's diastolic blood pressure (Delta P), is the most accepted indication for emergency fasciotomy?

. Delta P < 10 mmHg
. Delta P < 20 mmHg
. Delta P < 30 mmHg
. Delta P < 40 mmHg
. Delta P < 50 mmHg

Correct Answer & Explanation

. Delta P < 10 mmHg

Explanation

A Delta P (diastolic blood pressure minus intracompartmental pressure) of less than 30 mmHg indicates inadequate tissue perfusion. This is the standard threshold necessitating urgent four-compartment fasciotomy.

Question 11171

Topic: 2. Trauma

According to Perren's strain theory of fracture healing, what level of interfragmentary tissue strain is required for primary bone healing (direct osteonal remodeling) to occur without the formation of intermediate tissue such as cartilage or fibrous tissue?

. < 2%
. 2% to 10%
. 10% to 30%
. 30% to 50%
. > 50%

Correct Answer & Explanation

. < 2%

Explanation

Perren's strain theory states that the type of tissue that forms in a fracture gap is dictated by the amount of strain. Primary bone healing (direct osteonal remodeling) requires absolute stability with interfragmentary strain less than 2%. Strains between 2% and 10% result in secondary bone healing via endochondral ossification (callus formation), while higher strains lead to fibrous tissue or nonunion.

Question 11172

Topic: 2. Trauma

A 25-year-old male sustains a high-energy tibial plateau fracture and develops an acute compartment syndrome. If fasciotomies are not performed, irreversible muscle necrosis typically begins to occur after what duration of continuous continuous total ischemia?

. 1 to 2 hours
. 3 to 4 hours
. 6 to 8 hours
. 10 to 12 hours
. 14 to 16 hours

Correct Answer & Explanation

. 1 to 2 hours

Explanation

Striated muscle in the extremities can typically tolerate ischemia for up to 4 hours with reversible damage. However, continuous absolute ischemia exceeding 6 to 8 hours will result in irreversible muscle necrosis. Peripheral nerves begin to sustain irreversible damage somewhat earlier, around 4 to 6 hours.

Question 11173

Topic: 2. Trauma

Fat Embolism Syndrome (FES) is a life-threatening systemic complication following long bone fractures. According to Gurd's diagnostic criteria, which of the following is considered a major criterion?

. Tachycardia > 120 bpm
. Retinal changes (cotton wool spots)
. Jaundice
. Petechial rash
. Fever > 39°C

Correct Answer & Explanation

. Tachycardia > 120 bpm

Explanation

Gurd's major criteria for Fat Embolism Syndrome (FES) include: 1) Respiratory insufficiency (hypoxemia), 2) Cerebral involvement (neurologic signs), and 3) Petechial rash (typically on the axilla, conjunctiva, or upper chest). Tachycardia, fever, retinal changes, and jaundice are considered minor criteria.

Question 11174

Topic: 2. Trauma

Which of the following fracture fixation constructs relies primarily on cutting cones to achieve bone healing?

. Bridge plating of a comminuted femur fracture
. Intramedullary nailing of a midshaft tibia fracture
. External fixation of a distal radius fracture
. Compression plating of a transverse radius fracture
. Casting of a non-displaced humerus fracture

Correct Answer & Explanation

. Bridge plating of a comminuted femur fracture

Explanation

Primary (direct) bone healing occurs via Haversian remodeling (cutting cones) without callus formation. This requires absolute stability and direct bone apposition, which is best achieved clinically with compression plating. The other options provide relative stability and heal via secondary bone healing (callus formation).

Question 11175

Topic: 2. Trauma

Which of the following is the earliest and most reliable clinical indicator of acute compartment syndrome in an alert, communicative patient following a tibial plateau fracture?

. Loss of peripheral pulses (dorsalis pedis and posterior tibial)
. Pallor of the distal extremity
. Pain out of proportion to the injury or with passive stretch
. Paralysis of the anterior compartment muscles
. Paresthesia in the first web space

Correct Answer & Explanation

. Loss of peripheral pulses (dorsalis pedis and posterior tibial)

Explanation

Pain out of proportion to the injury, especially pain exacerbated by passive stretching of the muscles within the affected compartment, is the earliest and most sensitive clinical sign of acute compartment syndrome. Pulselessness and paralysis are late, ominous signs of irreversible ischemic damage.

Question 11176

Topic: 2. Trauma
According to Advanced Trauma Life Support (ATLS) guidelines, a patient presenting with acute hemorrhagic shock transitions to Class III hemorrhage (30% to 40% blood volume loss). This class is classically differentiated from Class II by the onset of which of the following?
. Tachycardia with a normal blood pressure
. Tachycardia with a measurable drop in systolic blood pressure
. Normal heart rate with an increased respiratory rate
. Bradycardia with absent urine output
. Tachycardia with an isolated widened pulse pressure

Correct Answer & Explanation

. Tachycardia with a measurable drop in systolic blood pressure

Explanation

According to traditional ATLS classifications, Class I and Class II hemorrhage typically present with a normal systolic blood pressure (though pulse pressure may narrow in Class II). The defining hallmark of a Class III hemorrhage (30-40% blood loss) is a drop in systolic blood pressure, accompanied by marked tachycardia and decreased urine output.

Question 11177

Topic: 2. Trauma

When using continuous compartmental pressure monitoring in an obtunded trauma patient with a tibial shaft fracture, what pressure threshold is generally considered the absolute indication for fasciotomy?

. Absolute compartment pressure greater than 15 mmHg
. Absolute compartment pressure greater than 20 mmHg
. Delta P (Diastolic blood pressure minus compartment pressure) less than 30 mmHg
. Delta P (Mean arterial pressure minus compartment pressure) less than 45 mmHg
. Absolute compartment pressure equal to systolic blood pressure

Correct Answer & Explanation

. Absolute compartment pressure greater than 15 mmHg

Explanation

A 'Delta P' of less than 30 mmHg is considered the standard threshold indicating acute compartment syndrome. It is calculated by subtracting the intracompartmental pressure from the patient's diastolic blood pressure.

Question 11178

Topic: Pelvic & Acetabular Trauma

A 22-year-old hockey player presents with anterior groin pain with flexion and internal rotation. Radiographs demonstrate an alpha angle of 65 degrees on the Dunn lateral view. Which of the following pathomechanical processes is most likely occurring in this patient?

. Impingement of the femoral neck on the labrum due to acetabular retroversion
. Shear forces on the anterosuperior articular cartilage leading to delamination
. Contrecoup lesion in the posteroinferior acetabulum
. Pincer impingement causing primarily posterior labral tearing
. Increased femoral anteversion leading to anterior subluxation

Correct Answer & Explanation

. Impingement of the femoral neck on the labrum due to acetabular retroversion

Explanation

An alpha angle > 55 degrees indicates a Cam deformity. Cam impingement typically causes outside-in shear forces as the non-spherical femoral head enters the acetabulum during flexion and internal rotation. This leads to delamination of the anterosuperior acetabular cartilage from the subchondral bone, often leaving the labrum relatively intact in the early stages.

Question 11179

Topic: 2. Trauma

A 24-year-old marathon runner presents with bilateral exercise-induced anterior leg pain. Which of the following intracompartmental pressure measurements (using the Pedowitz criteria) is diagnostic for Chronic Exertional Compartment Syndrome (CECS)?

. Pre-exercise pressure > 10 mmHg
. 1 minute post-exercise pressure > 20 mmHg
. 5 minutes post-exercise pressure > 20 mmHg
. 15 minutes post-exercise pressure > 15 mmHg
. 5 minutes post-exercise pressure > 30 mmHg

Correct Answer & Explanation

. Pre-exercise pressure > 10 mmHg

Explanation

The modified Pedowitz criteria for diagnosing Chronic Exertional Compartment Syndrome (CECS) require one or more of the following: pre-exercise resting pressure > 15 mmHg, 1 minute post-exercise pressure > 30 mmHg, or 5 minutes post-exercise pressure > 20 mmHg.

Question 11180

Topic: Lower Extremity Trauma

A 21-year-old football player sustains a syndesmotic ankle injury. Which of the following radiographic measurements is the most reliable indicator of a syndesmotic injury on a standard AP and mortise radiograph?

. Tibiofibular clear space > 5 mm on AP view
. Tibiofibular overlap > 1 mm on mortise view
. Tibiofibular clear space > 5 mm on both AP and mortise views
. Medial clear space > 4 mm on AP view
. Talar tilt angle > 10 degrees

Correct Answer & Explanation

. Tibiofibular clear space > 5 mm on AP view

Explanation

The tibiofibular clear space is measured 1 cm proximal to the plafond. A distance > 5 mm on BOTH the AP and Mortise views is the most reliable indicator of syndesmotic widening, as it is relatively unaffected by rotational variations during image acquisition, unlike tibiofibular overlap.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page