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2. Trauma MCQs

Practice Set 104 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 2061

Topic: 2. Trauma
A 28-year-old male presents with a displaced fracture of the talar neck with associated subluxation of the subtalar and tibiotalar joints. According to the Hawkins classification, what is the approximate rate of avascular necrosis (AVN) for this specific injury pattern?
. 0-10%
. 15-20%
. 20-50%
. 50-100%
. Always 100%

Correct Answer & Explanation

. 50-100%

Explanation

A Hawkins III fracture involves a talar neck fracture with dislocation of both the subtalar and tibiotalar joints. The rate of avascular necrosis in these injuries is exceedingly high, historically cited between 50% and 100%.

Question 2062

Topic: 2. Trauma
A 30-year-old male sustains a vertically oriented femoral neck fracture (Pauwels type III) after a fall from a height. Which of the following biomechanical constructs provides the most stable fixation for this specific fracture pattern?
. Three parallel cancellous screws placed in an inverted triangle
. A dynamic hip screw (DHS) alone
. A dynamic hip screw (DHS) with an anti-rotation screw
. Two parallel cancellous screws
. A cephalomedullary nail

Correct Answer & Explanation

. A dynamic hip screw (DHS) with an anti-rotation screw

Explanation

Pauwels type III fractures are highly vertically oriented, experiencing significant shear forces. A dynamic hip screw with an anti-rotation screw has been shown to offer superior biomechanical stability against vertical shear compared to multiple cancellous screws.

Question 2063

Topic: Pelvic & Acetabular Trauma
A 45-year-old male arrives in the trauma bay with a pelvic binder in place after an anteroposterior compression (APC-III) injury. He remains hypotensive despite 2 liters of crystalloid and 2 units of packed RBCs. Focused assessment with sonography for trauma (FAST) is negative. What is the most appropriate next step in management?
. Perform an exploratory laparotomy
. Remove the pelvic binder to assess the skin
. Proceed to pelvic angiography for embolization or preperitoneal packing
. Apply a definitive anterior external fixator in the ER
. Administer broad-spectrum antibiotics and observe

Correct Answer & Explanation

. Proceed to pelvic angiography for embolization or preperitoneal packing

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST exam, the bleeding is likely from the retroperitoneal pelvic venous plexus or arterial branches. Emergent pelvic angiography for embolization or preperitoneal pelvic packing is indicated.

Question 2064

Topic: 2. Trauma

A 55-year-old female presents with a medial tibial plateau fracture following a varus-producing force. Radiographs show a depressed, split fragment of the medial plateau. Which of the following complications is most highly associated with this specific injury pattern compared to isolated lateral plateau fractures?

. Popliteal artery injury
. Common peroneal nerve palsy
. Anterior cruciate ligament tear
. Patellar tendon rupture
. Nonunion

Correct Answer & Explanation

. Popliteal artery injury

Explanation

Schatzker IV (medial tibial plateau) fractures often result from high-energy trauma and represent a subluxation or dislocation of the knee. They carry a high risk of vascular injury, specifically to the popliteal artery, necessitating careful vascular assessment.

Question 2065

Topic: 2. Trauma

A 25-year-old male sustains a closed comminuted tibial shaft fracture. He complains of pain out of proportion to the injury. His diastolic blood pressure is 75 mmHg. Intracompartmental pressure monitoring of the anterior compartment reveals a pressure of 48 mmHg. What is his Delta P, and what is the definitive management?

. Delta P is 27 mmHg; proceed to emergent 4-compartment fasciotomies
. Delta P is 27 mmHg; elevate the leg and re-evaluate in 2 hours
. Delta P is 48 mmHg; proceed to emergent 4-compartment fasciotomies
. Delta P is 123 mmHg; observe
. Delta P is 27 mmHg; apply a short leg cast

Correct Answer & Explanation

. Delta P is 27 mmHg; proceed to emergent 4-compartment fasciotomies

Explanation

Delta P is calculated as Diastolic Blood Pressure minus Compartment Pressure (75 - 48 = 27 mmHg). A Delta P of less than 30 mmHg is highly indicative of acute compartment syndrome and warrants emergent 4-compartment fasciotomies.

Question 2066

Topic: 2. Trauma
A 35-year-old farmer sustains a severe open tibial shaft fracture (Gustilo-Anderson Type IIIA) heavily contaminated with soil and manure. According to evidence-based guidelines, what is the most appropriate initial empiric antibiotic regimen?
. First-generation cephalosporin alone
. 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 severe open fractures (Type III) with heavy soil or agricultural contamination, standard guidelines recommend a first-generation cephalosporin, an aminoglycoside (for Gram-negative coverage), and penicillin to cover Clostridium species.

Question 2067

Topic: 2. Trauma

An 82-year-old female presents with a periprosthetic fracture of the distal femur above a posterior-stabilized total knee arthroplasty (TKA). The fracture is a comminuted spiral fracture proximal to the flange (Vancouver/Su Type II). The femoral component is radiographically well-fixed. What is the preferred surgical treatment?

. Revision to a distal femoral replacement
. Lateral locked plating or retrograde intramedullary nailing
. Non-operative management in a hinged knee brace
. Skeletal traction for 6 weeks
. Amputation

Correct Answer & Explanation

. Lateral locked plating or retrograde intramedullary nailing

Explanation

For a periprosthetic distal femur fracture with a well-fixed TKA component, surgical fixation using either lateral locked plating or a retrograde intramedullary nail is the standard of care to allow early mobilization.

Question 2068

Topic: 2. Trauma

A 34-year-old motorcyclist sustains a distal femur fracture. CT imaging reveals an intra-articular coronal plane fracture of the lateral femoral condyle. What is the eponymous name for this fracture pattern, and what is the optimal direction for screw fixation?

. Barton fracture; anterior-to-posterior screws
. Hoffa fracture; anterior-to-posterior screws
. Hoffa fracture; posterior-to-anterior screws
. Chopart fracture; anterior-to-posterior screws
. Tillaux fracture; lateral-to-medial screws

Correct Answer & Explanation

. Hoffa fracture; anterior-to-posterior screws

Explanation

A coronal plane fracture of the femoral condyle is known as a Hoffa fracture. Fixation is typically achieved with lag screws placed in an anterior-to-posterior direction to optimally compress the intra-articular fragment.

Question 2069

Topic: Pelvic & Acetabular Trauma

On an AP pelvis radiograph of a patient with an acetabular fracture, the iliopectineal line is disrupted, but the ilioischial line remains intact. Which specific component of the acetabulum is most likely fractured?

. Anterior column
. Posterior column
. Posterior wall
. Transverse
. Both columns

Correct Answer & Explanation

. Anterior column

Explanation

The iliopectineal line represents the anterior column of the acetabulum on an AP radiograph. Disruption of this line with an intact ilioischial line (which represents the posterior column) is pathognomonic for an anterior column fracture.

Question 2070

Topic: 2. Trauma

A 42-year-old construction worker falls from a height of 15 feet, sustaining a high-energy injury to his left knee. Radiographs and CT scan demonstrate a bicondylar tibial plateau fracture with complete dissociation of the metaphysis from the diaphysis. According to the Schatzker classification system, what type of fracture is this?

. Type II
. Type IV
. Type V
. Type VI
. Type VII

Correct Answer & Explanation

. Type VI

Explanation

A Schatzker Type VI fracture is defined by the separation of the metaphysis from the diaphysis, often involving both condyles. Type V is a bicondylar fracture where the metaphysis remains attached to the diaphysis.

Question 2071

Topic: Pelvic & Acetabular Trauma
A 45-year-old male is crushed by heavy machinery and arrives hemodynamically unstable with a blood pressure of 75/40 mmHg. An anteroposterior pelvic radiograph reveals an anteroposterior compression (APC) Type III pelvic ring injury. A circumferential pelvic sheet or binder should be applied at which of the following anatomic levels to best reduce the pelvic volume?
. Iliac crests
. Greater trochanters
. Anterior superior iliac spines (ASIS)
. Pubic symphysis
. L5-S1 junction

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders must be centered over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests is incorrect and can paradoxically open the pelvis further in some fracture patterns.

Question 2072

Topic: 2. Trauma

A 28-year-old male presents after an aviation accident with a talar neck fracture. Radiographs show a displaced fracture of the talar neck with subluxation of the subtalar joint, while the ankle joint remains congruous. What is the approximate rate of avascular necrosis (AVN) of the talar body associated with this Hawkins classification?

. 0-10%
. 20-50%
. 70-90%
. 100%
. AVN does not occur in this pattern

Correct Answer & Explanation

. 20-50%

Explanation

This describes a Hawkins Type II talar neck fracture, defined by subluxation or dislocation of the subtalar joint with an intact ankle joint. The risk of avascular necrosis of the talar body in Type II fractures is historically estimated at 20% to 50%.

Question 2073

Topic: 2. Trauma

A 30-year-old male sustains a subtrochanteric femur fracture. On preoperative radiographs, the proximal fracture fragment is noted to be flexed, abducted, and externally rotated. Which muscle is primarily responsible for the flexion deformity of the proximal fragment?

. Gluteus medius
. Gluteus maximus
. Iliopsoas
. Piriformis
. Adductor longus

Correct Answer & Explanation

. Iliopsoas

Explanation

In subtrochanteric femur fractures, the iliopsoas muscle pulls the lesser trochanter, causing flexion of the proximal fragment. The gluteus medius and minimus cause abduction, while the short external rotators cause external rotation.

Question 2074

Topic: 2. Trauma

To prevent the typical procurvatum (apex anterior) and valgus deformities associated with intramedullary nailing of proximal third tibial shaft fractures, where is the optimal placement for blocking (Poller) screws in the proximal segment relative to the intended nail path?

. Posterior and lateral
. Anterior and medial
. Posterior and medial
. Anterior and lateral
. Directly central to the medullary canal

Correct Answer & Explanation

. Posterior and lateral

Explanation

Proximal third tibia fractures treated with intramedullary nails frequently drift into apex anterior (procurvatum) and valgus. Blocking screws placed posterior and lateral in the proximal segment effectively narrow the canal, forcing the nail anteriorly and medially to counteract these specific deforming forces.

Question 2075

Topic: 2. Trauma

What is the primary rationale for utilizing a staged protocol (immediate spanning external fixation followed by delayed internal fixation at 10-14 days) in the management of high-energy tibial pilon fractures?

. To achieve immediate, rigid articular reduction
. To minimize the incidence of severe soft-tissue complications and deep infections
. To stimulate early primary bone healing and endochondral ossification
. To permit early full weight-bearing mobilization
. To eliminate the necessity for locking plate technology

Correct Answer & Explanation

. To minimize the incidence of severe soft-tissue complications and deep infections

Explanation

High-energy pilon fractures incur severe soft-tissue trauma. A staged protocol allows for early skeletal stabilization and restoration of length while waiting for soft-tissue swelling to subside (indicated by the 'wrinkle sign'), thereby drastically reducing the risk of catastrophic wound breakdown and deep infection.

Question 2076

Topic: 2. Trauma

A 45-year-old patient presents with a displaced coronal plane fracture of the lateral femoral condyle (Hoffa fracture). Which of the following describes the biomechanically optimal fixation strategy for this specific injury?

. Posterior-to-anterior interfragmentary lag screws
. Anterior-to-posterior interfragmentary lag screws
. Medial-to-lateral transcondylar position screws
. Lateral-to-medial transcondylar position screws
. A single isolated cerclage wire

Correct Answer & Explanation

. Anterior-to-posterior interfragmentary lag screws

Explanation

A Hoffa fracture is an intra-articular coronal shear fracture. Because the posterior aspect of the condyle fragment is covered entirely with articular cartilage, anterior-to-posterior (AP) lag screw fixation provides excellent biomechanical compression while minimizing iatrogenic articular damage.

Question 2077

Topic: 2. Trauma
A 25-year-old male sustains a displaced, highly vertical (Pauwels Type III) femoral neck fracture. To maximize biomechanical stability and prevent failure secondary to high shear forces, which of the following constructs is most appropriate?
. Three parallel cannulated screws deployed in an inverted triangle configuration
. Three parallel cannulated screws deployed in a standard triangle configuration
. A fixed-angle sliding hip screw construct supplemented with an anti-rotation screw
. Cemented unipolar hemiarthroplasty
. Uncemented total hip arthroplasty

Correct Answer & Explanation

. A fixed-angle sliding hip screw construct supplemented with an anti-rotation screw

Explanation

Pauwels Type III (vertical) femoral neck fractures are subject to massive shear forces, leading to high failure rates with standard parallel cannulated screws. Fixed-angle constructs, such as a sliding hip screw with a supplemental derotational screw, provide superior biomechanical resistance to vertical shear.

Question 2078

Topic: 2. Trauma

When stabilizing an intertrochanteric femur fracture utilizing a sliding hip screw, maintaining a Tip-Apex Distance (TAD) of less than 25 mm on combined AP and lateral radiographs primarily minimizes the risk of which complication?

. Fracture nonunion
. Varus malunion
. Avascular necrosis of the femoral head
. Lag screw cut-out
. Deep surgical site infection

Correct Answer & Explanation

. Lag screw cut-out

Explanation

Baumgaertner et al. demonstrated that a combined Tip-Apex Distance (TAD) of less than 25 mm is the single most important surgeon-controlled variable in intertrochanteric fracture fixation. Minimizing TAD significantly reduces the biomechanical risk of the lag screw cutting out of the femoral head.

Question 2079

Topic: 2. Trauma

A 40-year-old male presents with a transverse mid-shaft tibial fracture. During internal fixation, the surgeon plans to apply a bone plate. If the primary bending load on the tibia during early weight-bearing is anticipated to cause tension on the medial side, where should the plate ideally be positioned to optimize the construct's resistance to this bending force?

. Anteriorly, for ease of surgical access
. Posteriorly, to avoid neurovascular structures
. Medially, on the tension side
. Laterally, to facilitate soft tissue coverage
. Circumferentially, using multiple small plates

Correct Answer & Explanation

. Medially, on the tension side

Explanation

Correct Answer: CRationale:Bone plates are most effective when placed on the tension side of a bone relative to the anticipated primary bending load. When a bone is subjected to bending, one side experiences tensile stress (pulling apart), and the opposite side experiences compressive stress (pushing together). Plates are strong in tension and prevent the bone from failing under tensile forces. By placing the plate on the tension side, it acts as a tension band, effectively increasing the Area Moment of Inertia of the bone-plate construct and providing optimal resistance to the bending moment. In this scenario, if the medial side is under tension, placing the plate medially optimizes its function.A) Anteriorly, for ease of surgical access:While surgical access is a practical consideration, it should not override biomechanical principles for optimal stability.B) Posteriorly, to avoid neurovascular structures:This is a critical anatomical consideration, but biomechanically, if the posterior side is under compression, the plate would be less effective than on the tension side.D) Laterally, to facilitate soft tissue coverage:Similar to surgical access, soft tissue considerations are important but secondary to biomechanical stability for fracture healing.E) Circumferentially, using multiple small plates:While multiple plates can increase stability, the principle of placing a plate on the tension side still applies to each plate's contribution to resisting bending.

Question 2080

Topic: Lower Extremity Trauma

An orthopedic implant manufacturer is developing a new intramedullary nail. If they increase the nail's outer diameter by 15%, assuming identical material and inner diameter (if cannulated), by approximately what factor would its bending stiffness increase?

. 1.15
. 1.32
. 1.52
. 1.75
. 2.00

Correct Answer & Explanation

. 1.75

Explanation

Correct Answer: DRationale:The bending stiffness (EI) of an intramedullary nail is directly proportional to its Area Moment of Inertia (I). For a circular cross-section, the Area Moment of Inertia is proportional to the fourth power of its outer diameter (I ~ d4).If the diameter (d) increases by 15%, the new diameter (d') will be 1.15d.The new Area Moment of Inertia (I') will be proportional to (1.15d)4.I' ~ (1.15)4* d4I' ~ 1.74900625 * d4Therefore, the bending stiffness would increase by a factor of approximately 1.75.A) 1.15:This would be a linear increase, not considering the d4relationship.B) 1.32:This is approximately 1.152, which would be relevant for area, not MOI.C) 1.52:This is approximately 1.153.E) 2.00:This would require a larger increase in diameter.

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