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2. Trauma MCQs

Practice Set 343 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 6841

Topic: 2. Trauma

A 28-year-old polytrauma patient sustains bilateral closed femoral shaft fractures. He has a GCS of 14, pulmonary contusions, and is hemodynamically stable after initial fluid resuscitation. Which of the following parameters is the most reliable indicator that the patient has been adequately resuscitated to safely undergo definitive early total care (intramedullary nailing) rather than damage control orthopedics?

. Serum lactate < 2.5 mmol/L
. Hemoglobin > 10 g/dL
. Urine output > 0.5 mL/kg/hr
. Platelet count > 100,000/mcL
. Systolic blood pressure > 100 mmHg

Correct Answer & Explanation

. Serum lactate < 2.5 mmol/L

Explanation

Serum lactate (< 2.5 mmol/L) and base deficit are the most reliable indicators of adequate tissue perfusion and resuscitation in trauma. Normalizing these parameters prior to early total care reduces the risk of "second hit" phenomena such as ARDS and systemic inflammatory response syndrome.

Question 6842

Topic: 2. Trauma

A 25-year-old man undergoes reamed intramedullary nailing of a closed midshaft tibial fracture. Twelve hours postoperatively, he complains of severe, escalating leg pain that is not relieved by intravenous narcotics. On examination, the leg is tense, and passive plantar flexion of the great toe elicits excruciating pain. Which muscle compartment is most likely primarily involved?

. Anterior
. Lateral
. Superficial posterior
. Deep posterior
. Peroneal

Correct Answer & Explanation

. Anterior

Explanation

The anterior compartment of the leg contains the extensor hallucis longus (EHL). Passive stretch of the EHL by plantar flexing the great toe elicits severe pain, which is the classic sign of anterior compartment syndrome.

Question 6843

Topic: 2. Trauma



A 40-year-old man presents after a tonic-clonic seizure. His right arm is locked in internal rotation and adduction. An initial anteroposterior (AP) radiograph demonstrates a symmetric "lightbulb" appearance of the humeral head without obvious fracture. Which of the following is the most appropriate next step in imaging to confirm the suspected diagnosis?

. Magnetic resonance imaging (MRI)
. Computed tomography (CT) scan
. Axillary lateral radiograph
. Stryker notch view
. Diagnostic ultrasound

Correct Answer & Explanation

. Axillary lateral radiograph

Explanation

The clinical presentation and "lightbulb" sign on AP radiograph strongly suggest a posterior shoulder dislocation. An axillary lateral (or Velpeau) radiograph is the most appropriate next step to definitively confirm posterior displacement of the humeral head.

Question 6844

Topic: 2. Trauma

A 35-year-old male sustains a high-energy trauma resulting in a coronal plane fracture of the lateral femoral condyle (Hoffa fracture). When performing open reduction and internal fixation, which of the following lag screw configurations provides the most biomechanically stable construct?

. Anterior-to-posterior directed lag screws
. Posterior-to-anterior directed lag screws
. Medial-to-lateral directed lag screws
. Lateral-to-medial directed lag screws
. Inferior-to-superior directed lag screws

Correct Answer & Explanation

. Posterior-to-anterior directed lag screws

Explanation

Biomechanical studies have demonstrated that posterior-to-anterior (PA) lag screw placement is significantly stronger for Hoffa fractures than anterior-to-posterior placement. This is due to the denser bone in the posterior condyle and the trajectory being more perpendicular to the fracture plane.

Question 6845

Topic: 2. Trauma

A 45-year-old woman is struck by a car, sustaining a lateral tibial plateau fracture with both a split and central depression (Schatzker Type II). There is 8 mm of joint depression. Which of the following is the most appropriate surgical management?

. Closed reduction and long leg casting
. Spanning external fixation as definitive treatment
. Open reduction, joint elevation, bone grafting, and lateral buttress plating
. Medial buttress plating alone
. Intramedullary nailing

Correct Answer & Explanation

. Open reduction, joint elevation, bone grafting, and lateral buttress plating

Explanation

Schatzker Type II fractures require open reduction, elevation of the depressed articular fragment, filling of the metaphyseal void with bone graft or substitute, and support with a lateral buttress plate. This prevents late valgus collapse and post-traumatic arthritis.

Question 6846

Topic: 2. Trauma
A 30-year-old construction worker sustains a Gustilo-Anderson Type IIIB open tibia fracture with a 10 x 5 cm anterior soft tissue defect requiring a free tissue transfer. Assuming the patient is hemodynamically stable and the wound is adequately debrided, what is the optimal timing for definitive soft tissue coverage to minimize infection rates?
. Within 24 hours
. Within 72 hours
. Between 7 to 14 days
. Between 14 to 21 days
. After 21 days when granulation tissue forms

Correct Answer & Explanation

. Within 72 hours

Explanation

Early soft tissue coverage, ideally within 72 hours (or up to 5-7 days), is associated with the lowest rates of deep infection and flap failure in Type IIIB open tibia fractures. Delays beyond this window significantly increase complication rates.

Question 6847

Topic: 2. Trauma

During the intramedullary nailing of a proximal third tibial shaft fracture using a standard infrapatellar approach, the surgeon notes a post-reduction malalignment. What is the most common deformity encountered during this specific procedure?

. Apex anterior (procurvatum) and valgus
. Apex posterior (recurvatum) and varus
. Apex anterior (procurvatum) and varus
. Apex posterior (recurvatum) and valgus
. Pure rotational malalignment

Correct Answer & Explanation

. Apex anterior (procurvatum) and valgus

Explanation

The most common deformity when nailing proximal third tibia fractures is apex anterior (procurvatum) and valgus. This is caused by the unopposed pull of the patellar tendon and the anterior approach of the nail pushing the proximal fragment into extension.

Question 6848

Topic: 2. Trauma

A 35-year-old male is involved in a high-speed motor vehicle collision and sustains an ipsilateral basicervical femoral neck fracture and a midshaft femur fracture. What is the standard priority and sequence of fixation for these injuries?

. Retrograde nailing for the shaft, followed by sliding hip screw for the neck
. Anatomic reduction and fixation of the femoral neck first, followed by shaft fixation
. Fixation of the femoral shaft first to establish length, followed by the neck
. Use of a single cephalomedullary nail to treat both simultaneously as the first step
. External fixation for the shaft and immediate hemiarthroplasty for the neck

Correct Answer & Explanation

. Anatomic reduction and fixation of the femoral neck first, followed by shaft fixation

Explanation

In ipsilateral femoral neck and shaft fractures, the priority is precise anatomic reduction and stable fixation of the femoral neck to minimize the risk of avascular necrosis and nonunion. The shaft fracture is addressed subsequently.

Question 6849

Topic: 2. Trauma

A 45-year-old male sustains a high-energy tibial pilon fracture. On presentation, the ankle is grossly swollen with hemorrhagic fracture blisters over the medial and lateral malleoli. What is the most appropriate initial management strategy?

. Immediate open reduction and internal fixation with dual plating
. Spanning external fixation across the ankle joint with delayed definitive ORIF
. Primary ankle arthrodesis
. Immediate intramedullary nailing of the tibia
. Closed reduction and casting until the soft tissues heal completely

Correct Answer & Explanation

. Spanning external fixation across the ankle joint with delayed definitive ORIF

Explanation

High-energy pilon fractures with severe soft tissue compromise are best managed with a staged protocol: initial spanning external fixation ("span and scan"). Definitive ORIF is delayed until soft tissue swelling resolves and the "wrinkle sign" appears, typically 10-21 days later.

Question 6850

Topic: 2. Trauma

A 28-year-old male presents with a "floating knee" injury (ipsilateral fractures of the femoral and tibial shafts) after a motorcycle collision. Which of the following factors is most predictive of a poor long-term functional outcome in this patient?

. Use of intramedullary nails for both fractures
. Intra-articular extension of the fractures into the knee joint
. Delayed fixation greater than 24 hours
. Concomitant fibular shaft fracture
. Development of a fat embolism syndrome

Correct Answer & Explanation

. Intra-articular extension of the fractures into the knee joint

Explanation

The most significant prognostic factor for poor functional outcome in floating knee injuries is intra-articular involvement (Fraser Type II). Intra-articular fractures lead to much higher rates of arthrofibrosis, post-traumatic arthritis, and permanent knee stiffness.

Question 6851

Topic: 2. Trauma

A 32-year-old man presents with a comminuted closed midshaft tibial fracture. Two hours after admission, he develops severe, unrelenting leg pain exacerbated by passive stretch of the hallux. The most reliable diagnostic parameter for acute compartment syndrome is a difference of less than 30 mmHg between:

. Systolic blood pressure and compartment pressure
. Diastolic blood pressure and compartment pressure
. Mean arterial pressure and compartment pressure
. Capillary refill pressure and compartment pressure
. Venous pressure and compartment pressure

Correct Answer & Explanation

. Diastolic blood pressure and compartment pressure

Explanation

The delta P (diastolic blood pressure minus compartment pressure) is the most reliable threshold for diagnosing acute compartment syndrome. A delta P of less than 30 mmHg is an indication for immediate four-compartment fasciotomy to prevent irreversible muscle and nerve necrosis.

Question 6852

Topic: 2. Trauma

A 28-year-old multiple trauma patient sustains bilateral femoral shaft fractures and a severe closed head injury. On arrival, his lactate is 6.5 mmol/L, pH is 7.1, and core temperature is 34.0°C. What is the most appropriate initial management of the femoral fractures?

. Bilateral reamed intramedullary nailing
. Bilateral unreamed intramedullary nailing
. Bilateral external fixation
. Open reduction and internal fixation with plates
. Skeletal traction until definitive fixation in 2 weeks

Correct Answer & Explanation

. Bilateral external fixation

Explanation

This patient is physiologically unstable (in extremis) with severe acidosis, hypothermia, and elevated lactate. Damage control orthopedics (DCO) using rapid temporary external fixation is indicated to minimize the physiologic "second hit" associated with prolonged intramedullary nailing.

Question 6853

Topic: 2. Trauma

During intramedullary nailing of a proximal third tibial shaft fracture, the surgeon notes a persistent apex anterior and valgus deformity. Where should a blocking (Poller) screw be placed relative to the intended nail path to correct this deformity?

. Anterior and lateral to the nail in the proximal fragment
. Posterior and medial to the nail in the proximal fragment
. Anterior and medial to the nail in the proximal fragment
. Posterior and lateral to the nail in the proximal fragment
. Directly into the fracture site

Correct Answer & Explanation

. Posterior and medial to the nail in the proximal fragment

Explanation

Blocking screws are placed on the concave side of the deformity to narrow the metaphyseal corridor and force the nail to the center of the medullary canal. For an apex anterior (procurvatum) and valgus deformity, the blocking screw should be placed posterior and medial to the nail in the proximal segment.

Question 6854

Topic: 2. Trauma

A 35-year-old man sustains a subtrochanteric femur fracture. During closed reduction for intramedullary nailing, the proximal 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 proximal fragment is subjected to distinct deforming forces that complicate reduction. The iliopsoas flexes the fragment, the abductors (gluteus medius and minimus) abduct it, and the short external rotators externally rotate it.

Question 6855

Topic: 2. Trauma
A 42-year-old pedestrian is struck by a car and sustains a pure centrally depressed fracture of the lateral tibial plateau with an intact lateral cortical rim (Schatzker type III). What is the optimal surgical approach and fixation strategy?
. Medial approach with a buttress plate
. Lateral cortical window with elevation, bone grafting, and raft screws
. Posterior approach with anti-glide plating
. Bilateral spanning external fixation only
. Intramedullary nailing

Correct Answer & Explanation

. Lateral cortical window with elevation, bone grafting, and raft screws

Explanation

A Schatzker type III fracture is a pure depression of the lateral tibial plateau, typically seen in softer, osteopenic bone. The optimal treatment involves a lateral approach with a cortical window to elevate the depressed articular fragment, followed by bone grafting and subchondral raft screw support.

Question 6856

Topic: 2. Trauma

A 28-year-old man sustains a proximal third tibial shaft fracture. He undergoes intramedullary nailing via a standard infrapatellar approach. Which of the following deformities is most commonly seen postoperatively in this specific fracture pattern?

. Procurvatum and valgus
. Recurvatum and varus
. Procurvatum and varus
. Recurvatum and valgus
. Shortening and internal rotation

Correct Answer & Explanation

. Procurvatum and valgus

Explanation

Proximal third tibia fractures treated with infrapatellar intramedullary nails classically drift into procurvatum (apex anterior) and valgus. This malalignment is driven by the anterior pull of the patellar tendon and the wide metaphysis preventing tight cortical fit of the nail.

Question 6857

Topic: 2. Trauma
A 32-year-old man sustains a Pauwels type III (vertical) femoral neck fracture in a motor vehicle collision. Which of the following biomechanical constructs provides the most stable fixation for this specific fracture pattern?
. Three parallel cancellous lag screws
. Sliding hip screw with an anti-rotation screw
. Short cephalomedullary nail
. Dynamic condylar screw
. Cannulated screws in an inverted triangle configuration

Correct Answer & Explanation

. Sliding hip screw with an anti-rotation screw

Explanation

Pauwels type III fractures are highly vertically oriented (angle > 50 degrees), which subjects them to extreme shear forces. A sliding hip screw combined with an anti-rotation screw provides superior biomechanical stability against shear compared to multiple parallel cancellous screws.

Question 6858

Topic: 2. Trauma
A 35-year-old construction worker sustains a Gustilo-Anderson Type IIIB open tibia fracture. Following initial thorough debridement and stabilization with an external fixator, what is the optimal timing for definitive soft-tissue coverage to minimize infection rates?
. Within 24 hours
. Within 72 hours
. Between 5 and 7 days
. Between 2 and 3 weeks
. Only after clear granulation tissue has formed over the bone

Correct Answer & Explanation

. Within 72 hours

Explanation

Early soft-tissue coverage of Type IIIB open tibia fractures, ideally within 72 hours, significantly reduces the rate of deep infection and promotes fracture healing. Delays in coverage beyond 5 to 7 days are associated with markedly higher infection rates.

Question 6859

Topic: 2. Trauma

A 78-year-old woman sustains a reverse obliquity intertrochanteric femur fracture. Which of the following best describes the biomechanical rationale for using a cephalomedullary nail rather than a sliding hip screw (SHS) for this fracture?

. The SHS allows excessive controlled collapse leading to medialization of the femoral shaft.
. A cephalomedullary nail entirely prevents femoral neck shortening.
. A cephalomedullary nail has a higher failure rate due to lateral wall blowout.
. The SHS provides superior compression across the reverse obliquity fracture gap.
. The nail has a longer lever arm, reducing stresses on the implant head.

Correct Answer & Explanation

. The SHS allows excessive controlled collapse leading to medialization of the femoral shaft.

Explanation

In reverse obliquity fractures, the primary fracture line exits lateral to the shaft, rendering the lateral wall incompetent. A sliding hip screw allows the femoral shaft to medialize and the proximal fragment to slide laterally, commonly leading to construct failure.

Question 6860

Topic: 2. Trauma

A 25-year-old male is brought in after a high-speed motorcycle crash. He has bilateral closed midshaft femur fractures and a pulmonary contusion. After initial fluid resuscitation, his serum lactate is 4.2 mmol/L. What is the most appropriate initial orthopedic management of the femur fractures?

. Bilateral reamed intramedullary nailing
. Bilateral unreamed intramedullary nailing
. Bilateral temporary external fixation
. Open reduction and internal fixation with plates
. Non-operative management in bilateral skeletal traction

Correct Answer & Explanation

. Bilateral temporary external fixation

Explanation

This patient is an "unstable" or "borderline" polytrauma patient, indicated by pulmonary injury and inadequately cleared lactate (> 2.5 mmol/L). Damage Control Orthopedics (DCO) using temporary external fixation is indicated to prevent the systemic "second hit" associated with intramedullary nailing.

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