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2. Trauma MCQs

Practice Set 39 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 761

Topic: 2. Trauma

The patient's fasciotomy wounds were initially left open and managed with negative pressure wound therapy (NPWT). A planned 'second look' surgery was performed at 48-72 hours. By postoperative day 7, the anterolateral wound still exhibited a 4 cm gap and required a split-thickness skin graft (STSG). What is the primary reason for leaving fasciotomy wounds open and delaying definitive closure?

. A. To allow for continuous drainage of serosanguinous fluid and prevent hematoma formation.
. B. To facilitate serial debridement of necrotic muscle and prevent infection.
. C. To prevent recreation of compartment syndrome by accommodating persistent soft tissue edema.
. D. To allow for easier application of topical antibiotics and wound dressings.
. E. To promote secondary intention healing, which results in stronger scar tissue.

Correct Answer & Explanation

. C. To prevent recreation of compartment syndrome by accommodating persistent soft tissue edema.

Explanation

Correct Answer: COption C is correct. The case explicitly states, 'The fasciotomy wounds were left open. Primary closure is absolutely contraindicated as it recreates the compartment syndrome.' The primary reason for leaving fasciotomy wounds open is to accommodate the significant post-ischemic edema and swelling that persists for several days. Attempting primary closure too early, before the edema has resolved, would re-elevate intra-compartmental pressures and lead to a recurrence of compartment syndrome, negating the entire purpose of the fasciotomy.Option A is incorrect. While drainage of exudate is a benefit, it is not the primary reason for leaving the wounds open. NPWT helps manage exudate, but the fundamental reason is pressure relief.Option B is incorrect. While serial debridement of necrotic muscle (if present) is a crucial part of the 'second look' surgery, the initial decision to leave the wounds open is primarily driven by the need to prevent recurrent compartment syndrome from edema, not solely for debridement. The case notes that in this patient, all muscle bellies remained viable.Option D is incorrect. While open wounds allow for easier dressing changes and topical treatment, this is a practical consideration, not the primary physiological reason for leaving them open.Option E is incorrect. While secondary intention healing can occur, the goal for fasciotomy wounds is typically delayed primary closure or skin grafting once edema resolves, to minimize scar burden and improve functional outcomes, rather than specifically promoting secondary intention healing for stronger scar tissue.

Question 762

Topic: 2. Trauma

The patient's injured extremity was elevated strictly at the level of the heart postoperatively. What is the rationale behind this specific positioning strategy in the management of acute compartment syndrome?

. A. Elevation above the heart promotes venous return and reduces edema more effectively.
. B. Dependent positioning enhances arterial inflow and improves tissue perfusion.
. C. Elevation at the level of the heart optimizes the balance between venous drainage and arterial perfusion pressure.
. D. Elevation above the heart is contraindicated as it increases the risk of deep vein thrombosis.
. E. Dependent positioning is preferred to maximize lymphatic drainage and reduce swelling.

Correct Answer & Explanation

. C. Elevation at the level of the heart optimizes the balance between venous drainage and arterial perfusion pressure.

Explanation

Correct Answer: COption C is correct. The case states, 'The injured extremity was elevated strictly at the level of the heart. Elevation above the heart decreases the local arterial perfusion pressure, which can exacerbate ischemia in borderline perfused tissues, while dependent positioning increases venous congestion and edema.' This highlights the delicate balance required. Elevating the limb too high (above the heart) can compromise arterial inflow, especially in tissues that are already borderline ischemic. Conversely, allowing the limb to be dependent (below the heart) increases venous congestion and edema, which can counteract the decompression achieved by fasciotomy and potentially increase intra-compartmental pressure.Option A is incorrect. While elevation generally promotes venous return, elevatingabovethe heart can compromise arterial inflow, which is detrimental in a limb recovering from ischemia.Option B is incorrect. Dependent positioning (below the heart) increases hydrostatic pressure, which can increase venous congestion and edema, not necessarily enhance arterial inflow in a beneficial way for ACS recovery.Option D is incorrect. While DVT is a concern, the primary reason for avoiding elevation above the heart is the risk of exacerbating ischemia by reducing arterial perfusion pressure, not primarily DVT risk.Option E is incorrect. Dependent positioning increases edema and venous congestion, which is counterproductive to reducing swelling and promoting recovery after fasciotomy.

Question 763

Topic: 2. Trauma

The patient's initial presentation included a 2 cm transversely oriented laceration over the anterior aspect of the distal third of the tibia. This was classified as a Gustilo-Anderson Type II open fracture. Given the high-energy mechanism and the rapid development of compartment syndrome, which of the following statements regarding the Gustilo-Anderson classification is most accurate in predicting the severity of soft tissue injury?

. A. The Gustilo-Anderson classification accurately quantifies the extent of muscle necrosis and nerve damage.
. B. A Type II classification reliably indicates minimal soft tissue damage, precluding the development of severe complications like ACS.
. C. The Gustilo-Anderson classification primarily describes the size of the skin wound and the degree of contamination, not necessarily the underlying soft tissue energy absorption.
. D. A Type II open fracture, by definition, implies adequate fascial decompression, preventing ACS.
. E. The classification is primarily used to guide the choice between reamed and unreamed intramedullary nailing.

Correct Answer & Explanation

. C. The Gustilo-Anderson classification primarily describes the size of the skin wound and the degree of contamination, not necessarily the underlying soft tissue energy absorption.

Explanation

Correct Answer: COption C is correct. The Gustilo-Anderson classification primarily focuses on the size of the skin wound, the presence of contamination, and the extent of periosteal stripping. While it provides a general guide to the severity of the open injury, it does not fully quantify the underlying soft tissue energy absorption or the potential for deep tissue damage, especially in high-energy injuries. The case highlights this by stating, 'the high-energy mechanism (70 km/h MVC) suggested significant underlying soft tissue injury not immediately visible at the skin level, which was corroborated by the rapid onset of compartment syndrome.'Option A is incorrect. The Gustilo-Anderson classification does not directly quantify muscle necrosis or nerve damage. These are clinical findings that evolve and are assessed separately.Option B is incorrect. As demonstrated in this case, a Type II classification (laceration >1 cm without extensive soft tissue damage) does not reliably preclude severe complications like ACS, especially in high-energy trauma. The superficial wound may not reflect the deep tissue injury.Option D is incorrect. This is a dangerous misconception, as discussed in the case. An open fracture, regardless of its Gustilo-Anderson type, does not guarantee adequate fascial decompression and does not prevent ACS.Option E is incorrect. While the Gustilo-Anderson classification influences overall management (e.g., timing of definitive fixation, need for soft tissue coverage), it is not the primary determinant for choosing between reamed and unreamed intramedullary nailing. That decision is more influenced by factors like patient stability, presence of ACS, and surgeon preference regarding endosteal blood supply preservation.

Question 764

Topic: 2. Trauma

The patient's pain was described as a deep, throbbing, and constant pressure, completely unrelieved by repositioning, elevation, or immobilization, and noticeably worse than initial assessment despite high-dose opioids. This pain profile is a hallmark of acute compartment syndrome. Which of the following characteristics of pain is considered the most sensitive and specific clinical sign for diagnosing acute compartment syndrome?

. A. Pain that is localized directly over the fracture site.
. B. Pain that improves significantly with limb elevation.
. C. Pain that is relieved by standard doses of intravenous analgesia.
. D. Pain out of proportion to the injury and exacerbated by passive stretch of the involved muscles.
. E. Pain described as a sharp, shooting sensation radiating distally.

Correct Answer & Explanation

. D. Pain out of proportion to the injury and exacerbated by passive stretch of the involved muscles.

Explanation

Correct Answer: DOption D is correct. The case emphasizes, 'The patient reported excruciating, unremitting pain in his right lower leg, rated as 10/10 on the Visual Analog Scale. This pain severity persisted despite the administration of 10 mg of intravenous morphine sulfate by EMS en route, followed by an additional 50 mcg of intravenous fentanyl in the trauma bay. The patient described the pain as a deep, throbbing, and constant pressure that was completely unrelieved by repositioning, elevation, or immobilization... This pain profile was noticeably worse and out of proportion to the initial assessment... The most critical and diagnostic finding was the assessment of pain with passive stretch of the ischemic muscle groups.' This 'pain out of proportion' and severe pain with passive stretch are the most sensitive and specific clinical signs for ACS.Option A is incorrect. Pain localized over the fracture site is expected with any fracture and is not specific to ACS.Option B is incorrect. Pain that improves with limb elevation is typical for venous congestion or simple edema, but ACS pain is often unrelieved or even worsened by elevation if it compromises arterial inflow.Option C is incorrect. ACS pain is classically described as 'unrelieved by standard doses of analgesia' or 'out of proportion' to the injury, meaning it persists despite significant pain medication.Option E is incorrect. Sharp, shooting pain radiating distally is more characteristic of nerve impingement or direct nerve injury, not the deep, throbbing, pressure-like pain of ischemic muscle in ACS.

Question 765

Topic: 2. Trauma

Which of the following best describes the initiating pathophysiological mechanism that leads to irreversible muscle ischemia in acute compartment syndrome?

. Arterial occlusion resulting in immediate cessation of nutrient blood flow
. Venous hypertension directly causing endothelial apoptosis and microvascular thrombosis
. Decreased local arteriovenous gradient leading to capillary collapse
. Lymphatic obstruction causing rapid accumulation of extracellular proteinaceous fluid
. Direct mechanical compression of the local motor nerve terminals

Correct Answer & Explanation

. Decreased local arteriovenous gradient leading to capillary collapse

Explanation

Acute compartment syndrome occurs when elevated tissue pressure decreases the local arteriovenous gradient. This leads to capillary collapse when tissue pressure exceeds capillary perfusion pressure, resulting in cellular hypoxia and irreversible muscle ischemia if uncorrected.

Question 766

Topic: 2. Trauma

A 25-year-old male is undergoing a two-incision four-compartment fasciotomy of the lower leg for acute compartment syndrome. During the medial approach, the surgeon makes an incision 2 cm posterior to the medial tibial margin. To adequately decompress the deep posterior compartment, which of the following structures must be meticulously released from its origin?

. The medial head of the gastrocnemius
. The soleus bridge from the posteromedial tibia
. The flexor retinaculum at the medial malleolus
. The tibialis posterior tendon sheath
. The interosseous membrane

Correct Answer & Explanation

. The soleus bridge from the posteromedial tibia

Explanation

To adequately release the deep posterior compartment via a medial incision, the soleus muscle must be detached from its origin on the posteromedial aspect of the tibia. Failure to release the soleus bridge is the most common reason for an incomplete decompression of the deep posterior compartment.

Question 767

Topic: 2. Trauma
Based on the findings of the Lower Extremity Assessment Project (LEAP) study, which of the following factors has the strongest correlation with a poor long-term functional outcome following a severe, mangled lower extremity injury?
. The decision to amputate rather than attempt limb salvage
. An initial Mangled Extremity Severity Score (MESS) greater than 7
. The presence of a Gustilo-Anderson Type IIIB open fracture
. Poor patient psychosocial status and lack of social support
. The utilization of a free tissue transfer for soft tissue coverage

Correct Answer & Explanation

. Poor patient psychosocial status and lack of social support

Explanation

The LEAP study demonstrated that there was no significant difference in functional outcomes between amputation and limb salvage at 2 years. The strongest predictors of poor functional recovery were poor psychosocial status, low socioeconomic status, and lack of social support networks.

Question 768

Topic: 2. Trauma

A 34-year-old construction worker sustains a severe crush injury to his dominant right hand. Compartment pressures are measured at 45 mmHg. To perform a complete fasciotomy of the hand, how many individual compartments must be released?

. 4
. 6
. 8
. 10
. 12

Correct Answer & Explanation

. 10

Explanation

The hand contains 10 distinct fascial compartments: 4 dorsal interossei, 3 volar interossei, the thenar compartment, the hypothenar compartment, and the adductor pollicis compartment. All 10 must be released in a complete hand fasciotomy.

Question 769

Topic: 2. Trauma
A 45-year-old obtunded trauma patient with a tibial shaft fracture has tense lower leg compartments. Continuous intracompartmental pressure monitoring is initiated. Which of the following pressure parameters represents the most accurate absolute indication for emergent fasciotomy?
. Absolute compartment pressure > 30 mmHg
. Absolute compartment pressure > 45 mmHg
. Mean arterial pressure (MAP) minus compartment pressure < 30 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Systolic blood pressure minus compartment pressure < 40 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The delta P (ΔP) is the most reliable indicator for fasciotomy, defined as the diastolic blood pressure minus the intracompartmental pressure. A ΔP of less than 30 mmHg is the widely accepted threshold for performing an emergent fasciotomy.

Question 770

Topic: 2. Trauma

A patient presents with a severely displaced pilon fracture and multiple blood-filled fracture blisters overlying the anterolateral ankle. What is the primary histological characteristic of blood-filled fracture blisters compared to clear fluid-filled blisters, and what is the implication for surgical timing?

. They represent an intra-epidermal cleavage plane; surgery can proceed immediately through the blisters.
. They represent complete epidermal separation from the dermis with deeper dermal injury; incisions through them should be avoided.
. They represent superficial venous thrombosis; they mandate immediate deep vein thrombosis prophylaxis.
. They are caused by lymphatic obstruction; elevation for 24 hours will clear them completely.
. They indicate deep space infection; emergent irrigation and debridement are required.

Correct Answer & Explanation

. They represent complete epidermal separation from the dermis with deeper dermal injury; incisions through them should be avoided.

Explanation

Blood-filled fracture blisters represent deeper injury with a cleavage plane below the dermo-epidermal junction, essentially leaving no intact epidermis. Surgical incisions through blood-filled blisters carry a significantly higher risk of wound complications and infection, so surgery is typically delayed until re-epithelialization occurs.

Question 771

Topic: 2. Trauma
According to the principles of Damage Control Orthopedics (DCO), which of the following initial laboratory or clinical findings is the strongest indication for temporary external fixation of a femoral shaft fracture rather than early total care with intramedullary nailing?
. Arterial pH of 7.36
. Serum lactate of 1.8 mmol/L
. Serum base deficit of > 6 mEq/L
. Core body temperature of 36.5°C
. Platelet count of 150,000/μL

Correct Answer & Explanation

. Serum base deficit of > 6 mEq/L

Explanation

Parameters favoring Damage Control Orthopedics (DCO) over Early Total Care (ETC) in a polytrauma patient include a base deficit > 6 mEq/L, serum lactate > 4 mmol/L, core temperature < 35°C, and coagulopathy. These indicate a patient in extremis or a borderline state who may not tolerate the physiological hit of intramedullary reaming and nailing.

Question 772

Topic: 2. Trauma
A 29-year-old male sustains a Gustilo-Anderson Type IIIB open tibia fracture. Following meticulous serial debridement, a free tissue transfer is required for soft tissue coverage. According to Godina's classic principles, performing the free flap within what timeframe is associated with the lowest rates of flap failure and deep infection?
. Within 12 hours
. Within 24 hours
. Within 72 hours
. Between 7 and 10 days
. After 3 weeks

Correct Answer & Explanation

. Within 72 hours

Explanation

Godina's classic 1986 study demonstrated that free tissue transfer for Type IIIB open lower extremity fractures performed within 72 hours of injury resulted in significantly lower rates of flap failure, infection, and nonunion compared to delayed coverage.

Question 773

Topic: 2. Trauma

A 60-year-old patient is found in his apartment 4 days after a drug overdose with a prolonged period of unconsciousness on a hard floor. His right lower extremity is swollen, flaccid, and cool, with absent distal pulses, absent sensation, and dense motor paralysis. Intracompartmental pressures are 60 mmHg. What is the most appropriate orthopedic management?

. Supportive care, avoidance of fasciotomy, and possible delayed amputation
. Emergent single-incision four-compartment fasciotomy
. Emergent two-incision four-compartment fasciotomy
. Emergent popliteal artery exploration and thrombectomy
. Application of a hyperbaric oxygen chamber and delayed fasciotomy

Correct Answer & Explanation

. Supportive care, avoidance of fasciotomy, and possible delayed amputation

Explanation

This is a classic presentation of a missed, late compartment syndrome (>48-72 hours) with dead, non-viable muscle. Performing a fasciotomy in this setting exposes necrotic tissue to hospital pathogens, carrying a high risk of overwhelming, often fatal, sepsis. Non-operative management or delayed amputation is preferred.

Question 774

Topic: 2. Trauma

A trauma surgeon is applying a temporary knee-spanning external fixator for a highly comminuted proximal tibia fracture. When placing the anterolateral half-pins into the distal femur, what is the most critical anatomical consideration to avoid iatrogenic septic arthritis of the knee?

. The pins must be placed anterior to the vastus lateralis.
. The pins must be placed at least 2 cm proximal to the superior pole of the patella.
. The pins must be placed at least 6 cm proximal to the superior pole of the patella.
. The pins must be angled 30 degrees posteriorly.
. The pins must avoid the iliotibial band insertion at Gerdy's tubercle.

Correct Answer & Explanation

. The pins must be placed at least 6 cm proximal to the superior pole of the patella.

Explanation

The suprapatellar pouch (recess) of the knee joint can extend up to 6 cm proximal to the superior pole of the patella. Distal femoral external fixation pins placed within this zone risk intracapsular penetration, potentially causing iatrogenic septic arthritis.

Question 775

Topic: 2. Trauma

Volkmann's ischemic contracture is a severe sequela of untreated compartment syndrome of the forearm. In the classic presentation of this contracture, which of the following muscle groups is most severely affected due to its deep central anatomical location?

. Flexor carpi radialis and flexor carpi ulnaris
. Flexor digitorum profundus and flexor pollicis longus
. Flexor digitorum superficialis and palmaris longus
. Brachioradialis and extensor carpi radialis brevis
. Extensor digitorum communis and extensor indicis proprius

Correct Answer & Explanation

. Flexor digitorum profundus and flexor pollicis longus

Explanation

The flexor digitorum profundus (FDP) and flexor pollicis longus (FPL) are located in the deep volar compartment of the forearm. Due to their deep location and vulnerable blood supply, they are the first and most severely affected muscles in forearm compartment syndrome, leading to Volkmann's contracture.

Question 776

Topic: 2. Trauma

Following successful fasciotomy for acute compartment syndrome, the patient experiences a severe exacerbation of local tissue edema and acute systemic inflammatory response. This reperfusion injury is primarily mediated by which of the following cellular mechanisms?

. Mast cell degranulation of histamine
. Platelet aggregation leading to microvascular thrombosis
. Generation of reactive oxygen species and subsequent neutrophil activation
. Irreversible binding of carbon monoxide to myoglobin
. Inhibition of the sodium-potassium ATPase pump by extracellular potassium

Correct Answer & Explanation

. Generation of reactive oxygen species and subsequent neutrophil activation

Explanation

Reperfusion injury is characterized by the return of oxygen to ischemic tissues, which leads to a burst of reactive oxygen species (ROS). These ROS cause lipid peroxidation, endothelial damage, and massive neutrophil activation, paradoxically worsening tissue damage and systemic inflammation.

Question 777

Topic: 2. Trauma



A 42-year-old male sustains a distal third femoral shaft fracture. Radiographs typically demonstrate an apex posterior angulation of the distal fragment. Which of the following muscles is the primary deforming force responsible for this specific angulation?

. Quadriceps femoris
. Gastrocnemius
. Biceps femoris
. Adductor magnus
. Tibialis anterior

Correct Answer & Explanation

. Gastrocnemius

Explanation

In distal third femur fractures, the gastrocnemius muscle (which originates on the posterior aspect of the femoral condyles) acts as the primary deforming force, pulling the distal fragment posteriorly and resulting in apex posterior angulation.

Question 778

Topic: 2. Trauma

A 22-year-old gang member presents with a low-velocity gunshot wound to the right thigh. Radiographs reveal a comminuted fracture of the femoral metaphysis with a retained bullet fragment. Under which of the following circumstances is operative removal of the bullet definitively indicated?

. The bullet is lodged within the muscle belly of the vastus lateralis.
. The bullet is located within the medullary canal of the femur.
. The bullet has fractured the femur but is located deep in the subcutaneous fat.
. The bullet is lodged within the joint capsule of the knee.
. The patient requests removal for cosmetic reasons.

Correct Answer & Explanation

. The bullet is lodged within the joint capsule of the knee.

Explanation

Retained intra-articular bullets must be surgically removed. Synovial fluid dissolves the lead over time, leading to severe lead arthropathy, joint destruction, and potentially systemic lead poisoning.

Question 779

Topic: 2. Trauma

A 7-year-old child sustains a completely displaced supracondylar humerus fracture. Upon presentation, the child is anxious and requires escalating doses of IV morphine. Which of the following clinical signs is considered the most sensitive early indicator of developing compartment syndrome in this patient?

. Pain out of proportion to the injury exacerbated by passive finger extension
. Absence of a palpable radial pulse
. Dense anesthesia in the median nerve distribution
. Capillary refill time greater than 3 seconds
. Cyanosis of the digits

Correct Answer & Explanation

. Pain out of proportion to the injury exacerbated by passive finger extension

Explanation

Pain out of proportion to the injury, particularly pain exacerbated by passive stretch of the ischemic muscles (e.g., passive finger extension for volar forearm compartments), is the earliest and most sensitive clinical sign of impending compartment syndrome. Pulselessness and pallor are very late and unreliable signs.

Question 780

Topic: 2. Trauma
A polytrauma patient presents with an anteroposterior compression (APC) Type III pelvic ring injury and severe hemorrhagic shock. A pelvic binder is appropriately applied in the trauma bay, but the patient remains hypotensive (BP 70/40 mmHg) despite massive transfusion protocols. The FAST exam is negative. What is the most appropriate next step in management?
. Immediate placement of an external pelvic fixator in the ER
. Bilateral lower extremity fasciotomies
. Preperitoneal pelvic packing and/or angioembolization
. Exploratory laparotomy with bowel run
. Administration of high-dose vasopressors

Correct Answer & Explanation

. Preperitoneal pelvic packing and/or angioembolization

Explanation

In a hemodynamically unstable patient with a mechanically unstable pelvic ring injury (APC III) and no other identified source of bleeding (negative FAST), the next immediate lifesaving step is direct hemorrhage control via preperitoneal pelvic packing and/or pelvic angiography with embolization.

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