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2. Trauma MCQs

Practice Set 615 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 12281

Topic: Pelvic & Acetabular Trauma
According to the Young-Burgess classification, an Anteroposterior Compression Type III (APC III) pelvic ring injury represents complete disruption of the symphysis pubis and which of the following posterior ligamentous complexes?
. Anterior sacroiliac (SI) ligaments only
. Anterior SI, sacrotuberous, and sacrospinous ligaments
. Posterior SI ligaments only
. Anterior SI, posterior SI, sacrotuberous, and sacrospinous ligaments
. Sacrospinous and sacrotuberous ligaments only

Correct Answer & Explanation

. Anterior SI, posterior SI, sacrotuberous, and sacrospinous ligaments

Explanation

An APC III injury implies a complete anterior and posterior disruption of the hemipelvis. This includes the symphysis pubis anteriorly, and the anterior SI, posterior SI, sacrotuberous, and sacrospinous ligaments posteriorly, resulting in a completely unstable hemipelvis.

Question 12282

Topic: 2. Trauma

A 32-year-old man sustains a closed tibial shaft fracture. His blood pressure is 140/80 mmHg. What is the highest absolute intracompartmental pressure at which surgical fasciotomy is NOT yet strictly indicated based on the delta P concept?

. 25 mmHg
. 35 mmHg
. 45 mmHg
. 55 mmHg
. 65 mmHg

Correct Answer & Explanation

. 45 mmHg

Explanation

The delta P is defined as the diastolic blood pressure minus the compartment pressure. A delta P of less than or equal to 30 mmHg is the classic indication for fasciotomy. With a diastolic BP of 80 mmHg, a compartment pressure of 50 mmHg would give a delta P of 30 mmHg. Therefore, 45 mmHg (Delta P = 35 mmHg) is the highest pressure listed where fasciotomy is not yet strictly indicated by the delta P rule.

Question 12283

Topic: Pelvic & Acetabular Trauma
In a hemodynamically unstable patient with an anteroposterior compression (APC) type III pelvic ring injury, at which precise anatomical landmark should a pelvic binder be applied to optimally reduce pelvic volume?
. Iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Pubic symphysis
. Subtrochanteric femur

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic circumferential compression device (binder or sheet) must be placed at the level of the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests is incorrect and can act as a fulcrum to worsen pelvic displacement.

Question 12284

Topic: 2. Trauma

The pathophysiology of acute compartment syndrome involves an initial cascade leading to tissue ischemia. Which of the following best describes the critical initiating hemodynamic event?

. Arterial occlusion causing direct ischemia
. Venous hypertension decreasing the local arteriovenous gradient
. Lymphatic obstruction leading to interstitial fibrosis
. Reperfusion injury causing oxygen free radical damage
. Direct nerve compression causing reflex vasospasm

Correct Answer & Explanation

. Venous hypertension decreasing the local arteriovenous gradient

Explanation

Acute compartment syndrome begins with an increase in tissue pressure that eventually exceeds venous pressure, leading to venous outflow obstruction (venous hypertension). This decreases the local arteriovenous (AV) gradient, leading to diminished capillary perfusion and subsequent cellular ischemia.

Question 12285

Topic: 2. Trauma

During bone healing, various bone morphogenetic proteins (BMPs) play crucial roles in osteoinduction. Which of the following recombinant human BMPs is currently FDA-approved for use in 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

rhBMP-2 is FDA-approved for acute, open tibial shaft fractures and anterior lumbar interbody fusion (ALIF). While rhBMP-7 (OP-1) was previously used for long bone nonunions, rhBMP-2 is the correct indication for acute open tibias.

Question 12286

Topic: Pelvic & Acetabular Trauma
A 28-year-old male is brought to the trauma bay in hemorrhagic shock following a motorcycle crash. Pelvic radiographs reveal a wide pubic symphysis diastasis (>2.5 cm) and disruption of the anterior sacroiliac ligaments. Where is the most mechanically effective location to place a pelvic circumferential compression device (binder)?
. Over the iliac crests
. At the level of the greater trochanters
. Over the lower abdomen, superior to the ASIS
. Around the proximal thighs
. Directly over the pubic symphysis only

Correct Answer & Explanation

. At the level of the greater trochanters

Explanation

Pelvic binders are most effective at reducing pelvic volume and controlling hemorrhage when placed accurately at the level of the greater trochanters. Placement higher over the iliac crests can paradoxically worsen the deformity.

Question 12287

Topic: 2. Trauma

A 30-year-old male sustains an isolated midshaft femur fracture and is treated with a retrograde intramedullary nail. Postoperatively, what is the most commonly reported complication unique to the retrograde approach compared to antegrade nailing?

. Heterotopic ossification of the abductors
. Iatrogenic fracture of the femoral neck
. Anterior knee pain
. Pudendal nerve palsy
. Avascular necrosis of the femoral head

Correct Answer & Explanation

. Anterior knee pain

Explanation

Anterior knee pain is the most frequent complication specific to retrograde femoral nailing, often due to the intra-articular starting point or hardware prominence. Antegrade nailing is more commonly associated with hip pain or heterotopic ossification of the abductors.

Question 12288

Topic: 2. Trauma

During an acute knee injury, an avulsion fracture of the anterolateral proximal tibia is visible on an AP radiograph (Segond fracture). This pathognomonic sign represents an avulsion of which structure?

. Iliotibial band
. Biceps femoris tendon
. Anterolateral ligament (ALL)
. Fibular collateral ligament (FCL)
. Popliteus tendon

Correct Answer & Explanation

. Anterolateral ligament (ALL)

Explanation

A Segond fracture is a bony avulsion of the anterolateral ligament (ALL) and the meniscotibial attachment of the lateral capsule. It is considered pathognomonic for an anterior cruciate ligament (ACL) tear.

Question 12289

Topic: 2. Trauma

A 28-year-old male sustains a closed tibial shaft fracture. Two hours post-admission, he develops severe pain out of proportion to the injury. Which intracompartmental pressure measurement strategy dictates an absolute indication for emergency fasciotomy?

. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 25 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Systolic blood pressure minus compartment pressure < 40 mmHg
. Mean arterial pressure minus compartment pressure < 50 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

A Delta P (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the most reliable threshold for diagnosing acute compartment syndrome. Absolute pressure thresholds are less reliable due to variations in patient perfusion pressures.

Question 12290

Topic: 2. Trauma
A 45-year-old male arrives in the trauma bay in hemorrhagic shock following a severe crush injury to the pelvis. Radiographs show an Anteroposterior Compression (APC) Type III pelvic ring injury. What is the most common anatomical source of massive hemorrhage in this specific injury pattern?
. Superior gluteal artery
. Internal pudendal artery
. Obturator artery
. Presacral venous plexus
. External iliac vein

Correct Answer & Explanation

. Presacral venous plexus

Explanation

In the majority of pelvic ring injuries (approximately 80%), massive hemorrhage is venous in origin, primarily from the presacral venous plexus or fractured cancellous bone surfaces. While arterial bleeding (e.g., superior gluteal artery) can occur, the presacral venous plexus is the most common source overall.

Question 12291

Topic: 2. Trauma
According to current guidelines, what is the most appropriate initial prophylactic antibiotic regimen for a 25-year-old male with a Gustilo-Anderson Type IIIb open tibia fracture occurring in a highly contaminated agricultural setting?
. First-generation cephalosporin only
. First-generation cephalosporin and an aminoglycoside
. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin
. Fluoroquinolone alone
. Vancomycin and piperacillin-tazobactam

Correct Answer & Explanation

. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin

Explanation

For a Gustilo Type III open fracture, standard prophylaxis includes a first-generation cephalosporin and an aminoglycoside. The addition of high-dose penicillin is specifically indicated for farm/agricultural injuries to cover Clostridium species.

Question 12292

Topic: Pelvic & Acetabular Trauma
In the Young-Burgess classification of pelvic ring injuries, what is the primary anatomic discriminator that differentiates an Anteroposterior Compression Type II (APC-II) injury from an Anteroposterior Compression Type III (APC-III) injury?
. Disruption of the anterior sacroiliac ligaments
. Disruption of the symphysis pubis
. Disruption of the posterior sacroiliac ligaments
. Disruption of the sacrotuberous ligament
. Disruption of the sacrospinous ligament

Correct Answer & Explanation

. Disruption of the symphysis pubis

Explanation

An APC-II injury is characterized by a widened symphysis pubis and disruption of the anterior sacroiliac (SI), sacrotuberous, and sacrospinous ligaments, but the critical posterior SI ligaments remain intact, providing rotational instability but vertical stability. An APC-III injury involves the complete disruption of both the anterior and posterior SI ligaments, resulting in both rotational and vertical instability.

Question 12293

Topic: 2. Trauma

In a polytrauma patient with a comminuted tibial shaft fracture, the diagnosis of acute compartment syndrome is suspected. Intracompartmental pressure monitoring is performed. Which of the following absolute or differential pressure measurements is the most widely accepted indication for immediate four-compartment fasciotomy?

. Absolute compartment pressure greater than 15 mmHg
. Absolute compartment pressure greater than 20 mmHg
. The difference between mean arterial pressure and compartment pressure (Delta P) less than 40 mmHg
. The difference between diastolic blood pressure and compartment pressure (Delta P) less than 30 mmHg
. The difference between systolic blood pressure and compartment pressure (Delta P) less than 50 mmHg

Correct Answer & Explanation

. The difference between diastolic blood pressure and compartment pressure (Delta P) less than 30 mmHg

Explanation

The most widely accepted parameter for diagnosing acute compartment syndrome is a 'Delta P' of less than 30 mmHg. Delta P is calculated as the Diastolic Blood Pressure minus the Absolute Compartment Pressure (Delta P = DBP - Compartment Pressure). This takes into account the patient's systemic perfusion pressure, making it much more accurate than an absolute pressure threshold.

Question 12294

Topic: 2. Trauma

According to Perren's strain theory, what is the maximum tissue strain allowable at a fracture site for primary (direct) bone healing to occur?

. < 2%
. 2 - 10%
. 10 - 30%
. 30 - 100%
. > 100%

Correct Answer & Explanation

. < 2%

Explanation

Primary (direct) bone healing requires absolute stability with tissue strain of less than 2%, allowing osteonal cutting cones to cross the fracture site without callus formation. Secondary bone healing (endochondral ossification) occurs with strain between 2% and 10%, allowing for callus formation. If strain exceeds 10%, granulation tissue persists and nonunion occurs.

Question 12295

Topic: 2. Trauma

A patient with suspected acute compartment syndrome of the lower leg undergoes intra-compartmental pressure monitoring. According to current orthopedic principles, which of the following thresholds is the most widely accepted absolute indication for fasciotomy?

. Absolute compartment pressure > 20 mm Hg
. Absolute compartment pressure > 30 mm Hg
. Delta pressure (Diastolic blood pressure minus compartment pressure) < 30 mm Hg
. Delta pressure (Mean arterial pressure minus compartment pressure) < 40 mm Hg
. Delta pressure (Systolic blood pressure minus compartment pressure) < 30 mm Hg

Correct Answer & Explanation

. Delta pressure (Diastolic blood pressure minus compartment pressure) < 30 mm Hg

Explanation

A delta pressure (Diastolic blood pressure - intra-compartmental pressure) of less than 30 mm Hg is the most reliable threshold for diagnosing acute compartment syndrome and is a widely accepted absolute indication for four-compartment fasciotomy. Relying on an absolute pressure of 30 mm Hg can lead to unnecessary fasciotomies in normotensive or hypertensive patients.

Question 12296

Topic: 2. Trauma
A 25-year-old male sustains a vertically oriented femoral neck fracture (Pauwels Type III) after a high-energy fall. Which of the following internal fixation constructs provides the most biomechanically stable fixation to resist vertical shear forces in this patient?
. Three parallel fully threaded cannulated screws
. Two parallel partially threaded cannulated screws
. Sliding hip screw with a derotation screw
. Cemented unipolar hemiarthroplasty
. Total hip arthroplasty

Correct Answer & Explanation

. Sliding hip screw with a derotation screw

Explanation

Pauwels III femoral neck fractures are vertically oriented (angle >50 degrees from the horizontal) and experience exceptionally high shear forces. Biomechanical studies have consistently demonstrated that a fixed-angle device, such as a sliding hip screw (often supplemented with a derotation screw), provides superior resistance to vertical shear and varus collapse compared to multiple parallel cannulated screws.

Question 12297

Topic: 2. Trauma
A 40-year-old pedestrian is struck by a car and sustains a Schatzker IV tibial plateau fracture. Because of the specific injury mechanism and anatomy, this specific fracture pattern has a uniquely high association with which of the following injuries compared to Schatzker I-III fractures?
. Medial meniscus root tear
. Common peroneal nerve neuropraxia
. Popliteal artery injury
. Patellar tendon rupture
. Lateral collateral ligament tear

Correct Answer & Explanation

. Popliteal artery injury

Explanation

A Schatzker IV fracture involves the medial tibial plateau and is often the result of a high-energy varus or axial loading mechanism. Because it effectively represents a subluxation or fracture-dislocation event of the knee, it has a uniquely high association with catastrophic injury to the popliteal artery and requires emergent vascular evaluation (often with an ABI or CT angiogram).

Question 12298

Topic: 2. Trauma

Which of the following pressure measurements is most universally accepted as the threshold indicating the need for a fasciotomy in a patient with suspected acute compartment syndrome of the leg?

. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 30 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Mean arterial pressure minus compartment pressure < 40 mmHg
. Systolic blood pressure minus compartment pressure < 50 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

A Delta P (diastolic blood pressure minus absolute compartment pressure) of less than 30 mmHg is the most reliable physiological indicator for fasciotomy. Absolute pressure alone is less accurate due to individual variations in systemic blood perfusion pressures.

Question 12299

Topic: 2. Trauma
A 45-year-old male presents following a high-speed motor vehicle collision with an open book pelvic fracture (APC-III) and is hemodynamically unstable despite initial fluid resuscitation. He has an associated right femur shaft fracture. Which of the following is the most appropriate initial orthopedic intervention?
. Immediate definitive open reduction and internal fixation of the pelvic fracture
. Application of an external fixator to the pelvis and femur
. Resuscitative endovascular balloon occlusion of the aorta (REBOA) followed by pelvic external fixation
. Diagnostic peritoneal lavage to rule out intra-abdominal hemorrhage
. Anterior plating of the symphysis pubis to stabilize the pelvis

Correct Answer & Explanation

. Resuscitative endovascular balloon occlusion of the aorta (REBOA) followed by pelvic external fixation

Explanation

Hemodynamic instability in severe pelvic trauma is often due to venous plexus bleeding or arterial injury. Initial management prioritizes hemorrhage control. REBOA is a critical temporizing measure in patients with non-compressible torso hemorrhage and hemodynamic instability, allowing time for definitive hemorrhage control (e.g., angioembolization or surgical packing) and initial pelvic stabilization (e.g., external fixator or pelvic binder). Definitive fixation of the pelvis and femur is part of damage control orthopedics but typically follows hemodynamic stabilization. DPL is less sensitive for retroperitoneal bleeding common in pelvic fractures and is superseded by imaging like CT with contrast in stable patients or focused assessment with sonography for trauma (FAST) in unstable patients for intraperitoneal blood. Anterior plating is a definitive fixation method, not an initial damage control measure for an unstable patient.

Question 12300

Topic: 2. Trauma

A 65-year-old female on long-term alendronate for osteoporosis presents with a prodromal dull, aching pain in her mid-thigh for several months, followed by an acute, low-energy fall resulting in a transverse fracture of the subtrochanteric femur. Radiographs show cortical thickening and a 'beaking' appearance at the fracture site. What is the most appropriate management strategy?

. Discontinue alendronate, stabilize the fracture with a long intramedullary nail, and monitor the contralateral femur for stress reaction
. Continue alendronate, stabilize the fracture with a plate and screws, and encourage early weight-bearing
. Initiate teriparatide immediately after surgery
. Treat non-operatively with a cast brace and physical therapy
. Perform prophylactic intramedullary nailing of the contralateral femur immediately

Correct Answer & Explanation

. Discontinue alendronate, stabilize the fracture with a long intramedullary nail, and monitor the contralateral femur for stress reaction

Explanation

The clinical presentation (long-term bisphosphonate use, prodromal thigh pain, low-energy transverse subtrochanteric fracture with cortical thickening and 'beaking') is highly characteristic of an atypical femur fracture (AFF). The management of an AFF includes surgical stabilization, typically with a long intramedullary nail (IMN), due to the high risk of displacement and nonunion with conservative management. It is also crucial to discontinue bisphosphonates and consider alternative anti-osteoporosis agents. Furthermore, the contralateral femur has a high risk (up to 50%) of developing an AFF, so monitoring with radiographs or MRI and potentially prophylactic nailing if a stress reaction or incomplete fracture is identified is recommended. Continuing alendronate or plating (which has higher failure rates than IMN for AFFs) is inappropriate. Immediate teriparatide can be considered after an AFF but is not themost appropriateinitial strategy. Non-operative management is contraindicated. Prophylactic nailing of the contralateral side is generally reserved for symptomatic stress reactions or incomplete fractures, not immediate upon diagnosis of the ipsilateral fracture.

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