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2. Trauma MCQs

Practice Set 402 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 8021

Topic: 2. Trauma

A 28-year-old intubated male with a closed tibial shaft fracture develops a tense, swollen leg. His blood pressure is 110/70 mmHg. Direct compartment pressure measurement of the anterior compartment yields an absolute pressure of 45 mmHg. Which of the following defines the accepted pressure threshold indicating the need for a four-compartment fasciotomy in this scenario?

. Delta pressure < 30 mmHg
. Absolute pressure > 30 mmHg regardless of blood pressure
. Delta pressure > 30 mmHg
. Delta pressure < 45 mmHg
. Absolute pressure > 45 mmHg regardless of blood pressure

Correct Answer & Explanation

. Delta pressure < 30 mmHg

Explanation

A delta pressure (diastolic blood pressure minus absolute compartment pressure) of less than 30 mmHg is the most reliable indicator for surgical fasciotomy. In this patient, the delta pressure is 25 mmHg (70 - 45), indicating inadequate perfusion.

Question 8022

Topic: 2. Trauma

A 45-year-old female sustains a severe crush injury to her lower extremity, resulting in a Grade IIIA open tibial diaphyseal fracture. According to current evidence-based literature, which of the following variables is most significantly associated with a decreased risk of deep infection?

. Time to initial antibiotic administration
. Time to definitive surgical fixation
. Volume of normal saline used for initial lavage
. Use of high-pressure pulsatile lavage instead of gravity flow
. Addition of local antibiotic beads at the primary surgery

Correct Answer & Explanation

. Time to initial antibiotic administration

Explanation

Early administration of systemic antibiotics is the single most critical factor in reducing infection rates in open fractures. Delaying antibiotics significantly increases the risk of deep infection.

Question 8023

Topic: 2. Trauma

A 22-year-old male sustains bilateral closed femoral shaft fractures and a severe bilateral pulmonary contusion following a motor vehicle collision. Initial resuscitation reveals a serum lactate of 5.5 mmol/L and a pH of 7.21. After initial fluid resuscitation, his lactate remains 4.0 mmol/L. What is the most appropriate initial orthopedic management of his femur fractures?

. Bilateral reamed intramedullary nailing
. Bilateral external fixation
. Unilateral reamed intramedullary nailing of the more displaced side
. Skeletal traction until definitive plating can be performed
. Primary bilateral plate osteosynthesis

Correct Answer & Explanation

. Bilateral reamed intramedullary nailing

Explanation

This patient meets the criteria for a borderline/unstable polytrauma patient with evidence of persistent hypoperfusion (elevated lactate). Damage control orthopedics (DCO) utilizing bilateral external fixation is indicated to minimize the second hit associated with reamed intramedullary nailing.

Question 8024

Topic: 2. Trauma

A 32-year-old male is 8 weeks status post open reduction and internal fixation of a displaced talar neck fracture. Routine follow-up radiographs demonstrate a distinct band of subchondral radiolucency in the talar dome. What is the most likely clinical significance of this radiographic finding?

. Avascular necrosis of the talar body
. Revascularization and an intact blood supply
. Developing osteomyelitis
. Nonunion at the fracture site
. Early post-traumatic osteoarthritis

Correct Answer & Explanation

. Avascular necrosis of the talar body

Explanation

This subchondral radiolucency is known as the Hawkins sign. It indicates intact vascularity to the talar body, as it represents subchondral osteopenia secondary to normal hyperemic revascularization.

Question 8025

Topic: 2. Trauma

A 40-year-old male sustains a high-energy complex bicondylar tibial plateau fracture (Schatzker VI). CT imaging reveals a large, medially displaced, and coronally oriented posteromedial fragment. What is the optimal surgical approach to safely and directly reduce and stabilize this posteromedial fragment?

. Anterolateral approach only with a laterally applied locking plate
. Dual incision utilizing an anterolateral and a posteromedial approach
. Median parapatellar approach
. Posterior approach with prone positioning
. Extended lateral approach with fibular osteotomy

Correct Answer & Explanation

. Anterolateral approach only with a laterally applied locking plate

Explanation

A coronally oriented posteromedial fragment in a bicondylar plateau fracture cannot be adequately reduced or buttressed from a purely anterolateral approach. A dual incision technique (anterolateral and posteromedial) is standard for direct visualization and buttress plating.

Question 8026

Topic: 2. Trauma

A 55-year-old male is treated with a lateral locked plating construct for a supracondylar femur fracture (AO 33-A3). Six months later, he presents with pain and radiographic evidence of a nonunion. Retrospective review of his surgical construct reveals high screw density near the fracture site and the use of all locking screws. What mechanical factor most likely contributed to this nonunion?

. The plate construct was too rigid, suppressing secondary bone healing
. The use of a titanium plate instead of stainless steel
. The plate length was too long
. Inadequate over-contouring of the plate
. Proximal locking screws were placed too far from the fracture

Correct Answer & Explanation

. The plate construct was too rigid, suppressing secondary bone healing

Explanation

Comminuted extra-articular distal femur fractures heal primarily via secondary bone healing (callus formation), which requires controlled interfragmentary motion. A construct that is too rigid (e.g., high screw density, all locking screws) prevents this micro-motion, increasing the risk of nonunion.

Question 8027

Topic: 2. Trauma

A 35-year-old male sustained a highly comminuted, displaced intra-articular calcaneus fracture (Sanders Type III) after a fall from a roof. The surgeon plans an open reduction internal fixation via an extensile lateral approach. Which of the following is the most reliable clinical indicator that the soft tissue envelope is ready for surgery?

. Presence of blood-filled fracture blisters
. Resolution of all ecchymosis
. Presence of a positive wrinkle sign
. Exactly 21 days post-injury
. Normalization of the erythrocyte sedimentation rate

Correct Answer & Explanation

. Presence of blood-filled fracture blisters

Explanation

The extensile lateral approach to the calcaneus carries a high risk of wound healing complications. Surgery must be delayed until soft tissue swelling has subsided, reliably indicated by the presence of a positive wrinkle sign on the lateral hindfoot.

Question 8028

Topic: 2. Trauma

A 19-year-old male presents with a midshaft diaphyseal femur fracture caused by a low-velocity handgun bullet. There is no active bleeding, normal distal pulses, and intact neurological function. What is the most appropriate management strategy for the fracture?

. Formal irrigation and debridement of the bullet tract followed by IM nailing
. Immediate reamed intramedullary nailing without formal tract debridement
. Immediate external fixation
. Skeletal traction for 2 weeks followed by delayed IM nailing
. Open reduction and internal fixation with a broad dynamic compression plate

Correct Answer & Explanation

. Formal irrigation and debridement of the bullet tract followed by IM nailing

Explanation

Low-velocity gunshot wounds to the diaphyseal femur without neurovascular compromise or massive contamination do not require formal operative debridement of the bullet tract. They are safely and effectively managed with standard reamed intramedullary nailing.

Question 8029

Topic: 2. Trauma

A 30-year-old man presents with a high-energy grade IIIA open tibia shaft fracture. Which of the following factors is the most critical and reliable predictor for preventing a deep surgical site infection in this patient?

. Time from injury to surgical debridement
. Time from injury to the administration of systemic antibiotics
. Use of high-pressure pulsatile lavage during debridement
. Choice of wound closure technique in the emergency department
. Immediate intramedullary nailing over external fixation

Correct Answer & Explanation

. Time from injury to surgical debridement

Explanation

The most critical factor in decreasing infection rates in open fractures is the early administration of systemic antibiotics. Delaying antibiotic administration significantly increases the risk of deep infection.

Question 8030

Topic: 2. Trauma

A 25-year-old intubated polytrauma patient with a comminuted tibial shaft fracture is suspected of having acute compartment syndrome. Which of the following criteria is the most reliable threshold for diagnosing acute compartment syndrome and indicating fasciotomy?

. Mean Arterial Pressure minus Compartment Pressure < 40 mmHg
. Systolic Blood Pressure minus Compartment Pressure < 30 mmHg
. Diastolic Blood Pressure minus Compartment Pressure <= 30 mmHg
. Absolute Compartment Pressure > 20 mmHg
. Absolute Compartment Pressure > 25 mmHg

Correct Answer & Explanation

. Mean Arterial Pressure minus Compartment Pressure < 40 mmHg

Explanation

The Delta P (diastolic blood pressure minus compartment pressure) is the most reliable metric for diagnosing acute compartment syndrome. A Delta P of <= 30 mmHg signifies critical local ischemia and is a strict indication for fasciotomy.

Question 8031

Topic: Pelvic & Acetabular Trauma

A hemodynamically unstable patient arrives with an anterior-posterior compression (APC-III) pelvic ring injury. A pelvic binder is ordered to reduce pelvic volume. Over which anatomic landmark must the binder be centered to effectively achieve mechanical stabilization?

. Iliac crests
. Anterior superior iliac spines (ASIS)
. Greater trochanters
. Symphysis pubis
. Subtrochanteric femoral diaphysis

Correct Answer & Explanation

. Iliac crests

Explanation

To effectively reduce pelvic volume and stabilize the pelvic ring, a pelvic binder must be centered over the greater trochanters. Placement over the iliac crests is incorrect and can worsen the rotational displacement of an open-book fracture.

Question 8032

Topic: 2. Trauma

A polytrauma patient with a severe chest injury and a closed femoral shaft fracture is admitted to the ICU. Which of the following laboratory parameters is the best indicator that the patient is adequately resuscitated and cleared for Early Total Care (ETC) of the femur?

. Base deficit > 8 mmol/L
. Serum lactate < 2.0 mmol/L
. Platelet count < 90,000/mcL
. IL-6 levels > 500 pg/mL
. Arterial pH < 7.2

Correct Answer & Explanation

. Base deficit > 8 mmol/L

Explanation

Normalization of serum lactate (< 2.0 mmol/L) and correction of base deficit are reliable indicators of adequate physiological resuscitation. This stability permits a safe transition from damage control to Early Total Care.

Question 8033

Topic: 2. Trauma

The Sanders classification is widely used for preoperative planning of intra-articular calcaneus fractures. This classification system is fundamentally based on the number and location of primary fracture lines extending through which specific anatomic structure?

. Anterior facet
. Middle facet
. Posterior facet
. Sustentaculum tali
. Calcaneocuboid joint

Correct Answer & Explanation

. Anterior facet

Explanation

The Sanders classification for intra-articular calcaneus fractures is based on the number and location of primary fracture lines running through the posterior facet. This is evaluated using a coronal view on a computed tomography (CT) scan.

Question 8034

Topic: 2. Trauma

A 28-year-old woman is brought to the trauma bay after a high-speed motorcycle crash. Chest radiographs reveal severe lateral displacement of the scapula relative to the chest wall, complete acromioclavicular separation, and a displaced clavicle fracture. The high acute mortality associated with this specific injury complex is primarily driven by:

. Tension pneumothorax
. Subclavian artery and vein disruption
. Complete brachial plexus root avulsion
. Secondary cardiac tamponade
. Unstable cervical spine fracture

Correct Answer & Explanation

. Tension pneumothorax

Explanation

This patient has a scapulothoracic dissociation, a massive closed traction injury to the shoulder girdle. The extremely high acute mortality rate is predominantly driven by massive, often uncontainable hemorrhage from subclavian vascular disruptions.

Question 8035

Topic: 2. Trauma

A 42-year-old male is brought in after a severe crush injury. He has an open book pelvic fracture with a perineal laceration exposing the fracture. He remains hemodynamically unstable despite a pelvic binder and initial massive transfusion protocol. FAST exam is negative. What is the most appropriate next step in his acute management?

. Preperitoneal pelvic packing and mechanical stabilization
. CT angiography with pelvic vessel embolization
. Diverting colostomy and washout
. Immediate internal fixation of the pubic symphysis
. Retrograde urethrogram and Foley catheter placement

Correct Answer & Explanation

. Preperitoneal pelvic packing and mechanical stabilization

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and negative FAST, mechanical stabilization and preperitoneal pelvic packing are urgently indicated. This is especially critical in open pelvic fractures where the tamponade effect is lost, making angiography less effective as a first-line intervention.

Question 8036

Topic: 2. Trauma

A 30-year-old male presents after an MVA with bilateral closed femoral shaft fractures, a severe pulmonary contusion, and a Glasgow Coma Scale of 7. His initial serum lactate is 4.8 mmol/L and pH is 7.15. What is the most appropriate initial orthopedic management of his femoral fractures?

. Bilateral reamed intramedullary nailing
. Bilateral unreamed intramedullary nailing
. Unilateral reamed nailing and unilateral external fixation
. Bilateral external fixation
. Skeletal traction and delayed nailing at 3 weeks

Correct Answer & Explanation

. Bilateral reamed intramedullary nailing

Explanation

This patient is in extremis with a head injury, pulmonary contusion, and profound acidosis. Damage control orthopedics with rapid provisional bilateral external fixation is indicated to minimize the second hit phenomenon associated with reaming and intramedullary nailing.

Question 8037

Topic: 2. Trauma

A 45-year-old obtunded male is admitted after a motorcycle collision with a closed, comminuted midshaft tibia fracture. Intracompartmental pressure monitoring shows an absolute pressure of 45 mmHg. The patient's blood pressure is 110/65 mmHg. What is the most appropriate next step in management?

. Immediate four-compartment fasciotomy
. Removal of splint and elevation of the leg above the heart
. Administration of intravenous mannitol
. Repeat compartment pressure measurement in 4 hours
. Emergent CT angiogram of the lower extremity

Correct Answer & Explanation

. Immediate four-compartment fasciotomy

Explanation

The diagnosis of acute compartment syndrome in an obtunded patient relies on objective pressure measurements. A delta P (diastolic blood pressure minus compartment pressure) of less than 30 mmHg (65 - 45 = 20 mmHg) is an absolute indication for an emergent four-compartment fasciotomy.

Question 8038

Topic: 2. Trauma

An 82-year-old female with severe osteoporosis presents with a closed, displaced, comminuted intra-articular distal femur fracture (OTA/AO 33-C2). She has a known history of severe symptomatic knee osteoarthritis. Which surgical option provides the most reliable earliest return to full weight-bearing for this patient?

. Retrograde intramedullary nailing
. Open reduction and internal fixation with a lateral locking plate
. Distal femoral replacement
. Ilizarov external fixation
. Closed reduction and long leg casting

Correct Answer & Explanation

. Retrograde intramedullary nailing

Explanation

Distal femoral replacement (megaprosthesis) in elderly patients with comminuted intra-articular distal femur fractures and pre-existing osteoarthritis allows for immediate full weight-bearing. Osteosynthesis in the presence of severe osteoporosis carries a high risk of hardware failure and typically requires prolonged restricted weight-bearing.

Question 8039

Topic: 2. Trauma

A 32-year-old male sustained a displaced talar neck fracture and underwent open reduction and internal fixation. At his 8-week follow-up visit, mortise radiographs of the ankle reveal a distinct subchondral radiolucent band in the dome of the talus. What does this radiographic finding indicate?

. Avascular necrosis of the talar body
. Impending nonunion of the talar neck
. Deep infection of the tibiotalar joint
. Preserved vascularity to the talar body
. Early post-traumatic osteoarthritis

Correct Answer & Explanation

. Avascular necrosis of the talar body

Explanation

The presence of a subchondral radiolucent band in the talar dome, known as Hawkins sign, indicates subchondral osteopenia. This bone resorption requires an intact blood supply, signifying that the talar body is viable and avascular necrosis is highly unlikely.

Question 8040

Topic: 2. Trauma

A patient sustains a displaced vertical fracture through the sacrum that extends medial to the sacral foramina, involving the central spinal canal. According to the Denis classification, what zone is this injury, and what is the associated risk?

. Zone 1, high risk of L5 nerve root injury
. Zone 2, low risk of neurologic deficit
. Zone 3, highest risk of bowel and bladder dysfunction
. Zone 1, highest risk of bowel and bladder dysfunction
. Zone 3, low risk of neurologic deficit

Correct Answer & Explanation

. Zone 1, high risk of L5 nerve root injury

Explanation

Denis Zone 3 sacral fractures involve the central sacral canal (medial to the foramina). They carry the highest risk (>50%) of neurologic deficit, specifically affecting bowel, bladder, and sexual function due to sacral root involvement.

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