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2. Trauma MCQs

Practice Set 445 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 8881

Topic: Pelvic & Acetabular Trauma
A 35-year-old male presents with a hemodynamically unstable APC-III pelvic ring injury following a motorcycle collision. What is the correct anatomical landmark to center a pelvic circumferential compression device?
. Iliac crests
. Greater trochanters
. Anterior superior iliac spines
. Pubic symphysis
. Umbilicus

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders must be centered over the greater trochanters to effectively reduce pelvic volume and stabilize the fracture, minimizing internal hemorrhage. Placement over the iliac crests can paradoxically worsen the deformity.

Question 8882

Topic: 2. Trauma

A 28-year-old cyclist falls onto his shoulder. Radiographs show a midshaft clavicle fracture. Which of the following is considered a widely accepted relative indication for operative intervention?

. Shortening of 1 cm
. Undisplaced butterfly fragment
. Z-deformity with 2.5 cm of shortening
. Age under 30
. Fracture located in the medial third

Correct Answer & Explanation

. Z-deformity with 2.5 cm of shortening

Explanation

Operative fixation of midshaft clavicle fractures is generally indicated for shortening greater than 2 cm, 100% displacement (Z-deformity), skin tenting, or open fractures. These factors are associated with higher rates of nonunion and symptomatic malunion.

Question 8883

Topic: 2. Trauma
A 40-year-old male sustains a Gustilo-Anderson Type IIIA open tibia fracture in a motor vehicle accident. What is the most critical initial factor in preventing deep infection?
. Time to definitive soft tissue coverage
. Time to operative debridement
. Time to administration of systemic antibiotics
. Modality of bone fixation
. Use of negative pressure wound therapy

Correct Answer & Explanation

. Time to administration of systemic antibiotics

Explanation

The most critical factor in reducing infection rates in open fractures is the early administration of systemic antibiotics, ideally within 1 hour of injury. While early debridement is also important, timely antibiotic administration has the strongest correlation with reduced infection risk.

Question 8884

Topic: 2. Trauma

A 25-year-old man with a closed tibial shaft fracture complains of severe leg pain out of proportion to the injury. Which of the following pressure measurements is an absolute indication for emergency four-compartment fasciotomy?

. Absolute compartment pressure of 20 mmHg
. Absolute compartment pressure of 25 mmHg
. Diastolic blood pressure minus compartment pressure of 20 mmHg
. Mean arterial pressure minus compartment pressure of 40 mmHg
. Systolic blood pressure minus compartment pressure of 30 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure of 20 mmHg

Explanation

A delta pressure (Diastolic Blood Pressure minus Compartment Pressure) of less than 30 mmHg is the diagnostic threshold for acute compartment syndrome. Delta pressure is a more reliable indicator for fasciotomy than absolute compartment pressure alone as it accounts for tissue perfusion.

Question 8885

Topic: 2. Trauma
A 30-year-old female sustains a displaced, vertically oriented (Pauwels type III) femoral neck fracture. Which of the following internal fixation constructs offers the highest biomechanical stability for this specific fracture pattern?
. Three parallel cancellous screws
. Sliding hip screw (SHS) alone
. Sliding hip screw with an anti-rotation screw
. Two crossed cancellous screws
. Cephalomedullary nail

Correct Answer & Explanation

. Sliding hip screw with an anti-rotation screw

Explanation

For vertically oriented (high shear angle/Pauwels type III) femoral neck fractures in young adults, a sliding hip screw combined with a derotational screw provides superior biomechanical stability. This construct best resists the high vertical shear forces compared to multiple cancellous screws.

Question 8886

Topic: 2. Trauma

An 82-year-old osteoporotic woman sustains a highly comminuted, intra-articular distal femur fracture (OTA/AO 33-C3). She has severe pre-existing osteoarthritis of the same knee. What is the most appropriate definitive management?

. Retrograde intramedullary nailing
. Spanning external fixation
. Distal femoral replacement
. Nonoperative management with a hinged knee brace
. Dual plating (medial and lateral)

Correct Answer & Explanation

. Distal femoral replacement

Explanation

In elderly patients with severe osteopenia, pre-existing symptomatic knee osteoarthritis, and highly comminuted intra-articular distal femur fractures, distal femoral replacement is preferred. It addresses the baseline arthritis and allows for immediate weight-bearing, avoiding the high failure rates of internal fixation.

Question 8887

Topic: 2. Trauma

A 45-year-old pedestrian is struck by a car and sustains a displaced medial tibial plateau fracture (Schatzker IV). Which of the following associated injuries must be evaluated with high clinical suspicion?

. Common peroneal nerve palsy
. Anterior tibial artery avulsion
. Popliteal artery injury
. Patellar tendon rupture
. Superficial peroneal nerve entrapment

Correct Answer & Explanation

. Popliteal artery injury

Explanation

Schatzker IV (medial plateau) fractures are typically high-energy injuries resulting from varus and hyperextension forces, representing a knee dislocation equivalent. They carry a significant risk of popliteal artery injury or disruption of the peroneal nerve.

Question 8888

Topic: 2. Trauma

A 50-year-old male sustains a high-energy closed tibial pilon fracture with severe soft tissue swelling and extensive fracture blisters. What is the most appropriate initial management strategy?

. Immediate open reduction and internal fixation
. Spanning external fixation and delayed definitive ORIF
. Minimally invasive plate osteosynthesis (MIPO) within 24 hours
. Nonoperative treatment in a cast
. Primary below-knee amputation

Correct Answer & Explanation

. Spanning external fixation and delayed definitive ORIF

Explanation

High-energy pilon fractures with severe soft tissue compromise are best managed with a staged approach. Immediate spanning external fixation restores length and alignment, followed by definitive ORIF once the soft tissues heal and the "wrinkle sign" appears.

Question 8889

Topic: 2. Trauma

In a polytrauma patient, which of the following laboratory parameters is the most reliable indicator of adequate physiologic resuscitation prior to converting from damage control orthopedics to definitive fracture fixation?

. Serum potassium < 4.5 mEq/L
. Hemoglobin > 10 g/dL
. Lactate < 2.0 mmol/L
. Platelet count > 150,000
. White blood cell count < 10,000

Correct Answer & Explanation

. Lactate < 2.0 mmol/L

Explanation

Serum lactate clearance (< 2.0 mmol/L) and correction of base deficit are reliable markers of restored tissue perfusion. Normalizing these parameters indicates the patient is physiologically optimized to withstand the surgical stress of definitive fixation.

Question 8890

Topic: 2. Trauma

A 65-year-old woman on long-term alendronate presents with a completely displaced transverse fracture of the proximal femoral diaphysis after a simple fall. Which characteristic radiographic feature is typically seen prior to displacement in these atypical injuries?

. Medial cortical spiking
. Lateral cortical thickening or "beaking"
. Diffuse osteopenia
. Lytic lesion
. Multiple periosteal reactions

Correct Answer & Explanation

. Lateral cortical thickening or "beaking"

Explanation

Atypical femur fractures related to prolonged bisphosphonate use typically begin as a stress fracture on the tension (lateral) side of the femur. This appears radiographically as focal lateral cortical thickening or "beaking" before progressing to a complete fracture.

Question 8891

Topic: 2. Trauma

A 35-year-old hypotensive polytrauma patient is brought into the trauma bay with an anteroposterior compression (APC) pelvic ring injury. The trauma team decides to place a non-invasive circumferential pelvic binder. To effectively reduce the pelvic volume and stabilize the fracture, the binder must be centered over which of the following anatomic landmarks?

. The anterior superior iliac spines
. The iliac crests
. The greater trochanters
. The pubic symphysis specifically
. The mid-thighs bilaterally

Correct Answer & Explanation

. The greater trochanters

Explanation

Pelvic binders must be placed centered over the greater trochanters to generate an effective internal rotational force through the femurs to close the pelvic ring. Placement over the iliac crests is a common error that can paradoxically widen the pelvis and worsen instability.

Question 8892

Topic: 2. Trauma

A 22-year-old male sustains a closed tibia shaft fracture. Four hours post-admission, he complains of severe leg pain refractory to intravenous narcotics. You suspect acute compartment syndrome. When utilizing continuous intracompartmental pressure monitoring, which of the following parameters is the most reliable threshold for diagnosing compartment syndrome and indicating the need for immediate fasciotomy?

. Absolute compartment pressure greater than 15 mmHg
. Absolute compartment pressure greater than 20 mmHg
. Mean arterial pressure minus compartment pressure less than 40 mmHg
. Diastolic blood pressure minus compartment pressure less than 30 mmHg
. Systolic blood pressure minus compartment pressure less than 50 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure less than 30 mmHg

Explanation

The Delta P (diastolic blood pressure minus the intracompartmental pressure) is the most reliable physiologic threshold for diagnosing compartment syndrome. A Delta P of less than 30 mmHg correlates with critical tissue ischemia and is an absolute indication for fasciotomy.

Question 8893

Topic: 2. Trauma
A 40-year-old male construction worker sustains a Gustilo-Anderson Type IIIB open tibia fracture requiring a free tissue transfer for soft tissue coverage. According to established orthopedic trauma literature, early definitive soft tissue coverage is associated with decreased infection rates. Flap coverage should ideally be performed within what maximum timeframe to optimize outcomes?
. Within 24 hours
. Within 7 days
. Within 14 days
. Within 21 days
. After the fracture shows clinical signs of union

Correct Answer & Explanation

. Within 7 days

Explanation

For Gustilo Type IIIB open tibia fractures, soft tissue coverage within 7 days (early coverage) is associated with the lowest rates of deep infection and flap failure. Delaying coverage beyond this window significantly increases complication rates.

Question 8894

Topic: 2. Trauma

A 65-year-old female sustains a severe proximal humerus fracture.

Which of the following radiographic findings is considered the most reliable predictor of subsequent avascular necrosis (AVN) of the humeral head according to Hertel criteria?

. A medial metaphyseal head extension (calcar length) of 12 mm
. Greater tuberosity displacement of greater than 5 mm
. An intact posteromedial periosteal hinge
. A varus angulation of the head-shaft angle of 10 degrees
. A medial metaphyseal head extension (calcar length) of less than 8 mm combined with a disrupted medial hinge

Correct Answer & Explanation

. A medial metaphyseal head extension (calcar length) of less than 8 mm combined with a disrupted medial hinge

Explanation

Hertel identified specific predictors of ischemia in proximal humerus fractures. The combination of a disrupted medial hinge and a short medial calcar segment (less than 8 mm) is highly predictive of disruption of the blood supply to the articular segment, leading to AVN.

Question 8895

Topic: 2. Trauma

A 45-year-old male sustains a severe closed high-energy distal tibia fracture extending into the ankle joint (pilon fracture). He presents with profound soft tissue swelling, fracture blisters, and skin ecchymosis. The decision is made to perform a staged protocol starting with a spanning external fixator. What is the primary advantage of this staged management approach?

. Significant reduction in the rate of wound healing complications and deep infection
. Superior final functional range of motion of the ankle joint
. Increased likelihood of anatomic articular reduction at the time of final surgery
. Decreased incidence of post-traumatic osteoarthritis
. Prevention of deep vein thrombosis by allowing early weight-bearing

Correct Answer & Explanation

. Significant reduction in the rate of wound healing complications and deep infection

Explanation

Staged management of high-energy pilon fractures (spanning external fixation followed by delayed definitive ORIF 1-3 weeks later) allows the soft tissue envelope to recover. This approach has drastically reduced the historically high rates of severe wound complications and deep infections.

Question 8896

Topic: 2. Trauma
A 30-year-old male sustains a vertically oriented (Pauwels type III) basicervical femoral neck fracture. To minimize the risk of varus collapse, nonunion, and implant failure in this high-shear angle fracture in a young adult, what is the biomechanically optimal internal fixation construct?
. Three parallel cancellous lag screws in an inverted triangle configuration
. A fixed-angle sliding hip screw device supplemented with a derotational cancellous screw
. A cephalomedullary nail locked dynamically
. Multiple fully threaded cortical screws used in a lag technique
. Primary total hip arthroplasty

Correct Answer & Explanation

. A fixed-angle sliding hip screw device supplemented with a derotational cancellous screw

Explanation

Pauwels type III fractures exhibit high shear forces that frequently cause failure of standard multiple cancellous screw constructs. A fixed-angle device, such as a sliding hip screw, provides superior resistance to varus collapse, often supplemented by a derotational screw for rotational control.

Question 8897

Topic: 2. Trauma

A 19-year-old male cyclist falls directly onto his left shoulder, sustaining a displaced midshaft clavicle fracture. While many of these injuries can be treated non-operatively, which of the following clinical or radiographic findings represents an absolute indication for operative fixation?

. Shortening of the clavicle by 1.5 centimeters
. Complete displacement of the fracture fragments without bony apposition
. Skin tenting with progressive skin blanching and ischemia
. Presence of a Z-deformity on the anteroposterior radiograph
. Associated undisplaced fracture of the ipsilateral scapular body

Correct Answer & Explanation

. Skin tenting with progressive skin blanching and ischemia

Explanation

Absolute indications for open reduction and internal fixation of a clavicle fracture include open fractures, progressive neurovascular deficits, and significant skin tenting causing skin blanching and impending necrosis. Shortening and displacement are relative indications.

Question 8898

Topic: 2. Trauma

A severely injured polytrauma patient is resuscitated in the trauma bay following a high-speed motorcycle crash. He has bilateral femur fractures and a severe pelvic injury. The surgical team is debating between Early Total Care (ETC) and Damage Control Orthopedics (DCO). Which of the following physiologic parameters is an established trigger indicating the need for a DCO approach?

. Core body temperature of 36.5 degrees Celsius
. Base deficit of less than 2.0 mmol/L
. Systolic blood pressure maintained strictly above 100 mmHg
. Platelet count of 150,000 per microliter
. Serum lactate level greater than 4.0 mmol/L

Correct Answer & Explanation

. Serum lactate level greater than 4.0 mmol/L

Explanation

Damage Control Orthopedics (DCO) is indicated in physiologically unstable or borderline patients to prevent the fatal triad of trauma. Triggers for DCO instead of Early Total Care include prolonged hypothermia (< 35 C), severe acidosis (pH < 7.2), coagulopathy, and a serum lactate > 4.0 mmol/L.

Question 8899

Topic: 2. Trauma

A 75-year-old osteoporotic patient undergoes distal femur fracture stabilization with a lateral locking bridge plate. Six months post-operatively, radiographs demonstrate failure of the plate with breakage at the fracture level and a clinical nonunion. Assuming appropriate reduction, what technical error regarding plate construct stiffness most commonly predisposes to this failure?

. Placing screws too close to the fracture site, resulting in a significantly decreased working length
. Using a plate spanning the entire length of the femur
. Placing screws exclusively in the most proximal and distal ends of the plate
. Using unicortical locking screws instead of bicortical screws
. Achieving absolute anatomic reduction of the comminuted metaphyseal segment

Correct Answer & Explanation

. Placing screws too close to the fracture site, resulting in a significantly decreased working length

Explanation

In bridge plating techniques, utilizing a short working length (placing screws too close to the fracture gap) creates an excessively stiff construct. This stiffness concentrates stress on a short segment of the plate, leading to fatigue failure and fracture nonunion.

Question 8900

Topic: 2. Trauma

A 45-year-old male presents with a high-energy transverse subtrochanteric femur fracture. To achieve an anatomic reduction intraoperatively using an intramedullary nail, the surgeon must overcome significant deforming forces acting on the proximal fracture fragment. Which combination of muscles represents the primary deforming forces on the proximal fragment?

. Adductor magnus (adduction), rectus femoris (extension), and gluteus maximus (internal rotation)
. Hamstrings (shortening), adductor longus (varus), and piriformis (extension)
. Vastus lateralis (abduction), psoas (flexion), and tensor fasciae latae (internal rotation)
. Iliopsoas (flexion), gluteus medius/minimus (abduction), and short external rotators (external rotation)
. Gastrocnemius (flexion), gluteus maximus (extension), and adductor brevis (internal rotation)

Correct Answer & Explanation

. Iliopsoas (flexion), gluteus medius/minimus (abduction), and short external rotators (external rotation)

Explanation

The proximal fragment in a subtrochanteric fracture is classically displaced into flexion, abduction, and external rotation. This classic deformity is driven by the unopposed pull of the iliopsoas, the gluteus medius/minimus, and the short external rotators respectively.

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