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2. Trauma MCQs

Practice Set 86 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 1701

Topic: 2. Trauma

A 62-year-old right-hand dominant female presents to the emergency department after a fall onto an outstretched hand. Radiographs confirm a dorsally displaced, comminuted distal radius fracture. Initial closed reduction under hematoma block is performed. Post-reduction radiographs show a residual dorsal tilt of 18 degrees, radial shortening of 5 mm, and an articular step-off of 3 mm. She is otherwise healthy and active. Given these findings, what is the most appropriate next step in management?

. Maintain current immobilization with a long arm cast for 6 weeks.
. Attempt a second closed reduction under conscious sedation.
. Proceed with open reduction internal fixation (ORIF) with a volar locking plate.
. Apply an external fixator as definitive treatment.
. Discharge with a wrist splint and early range of motion exercises.

Correct Answer & Explanation

. Proceed with open reduction internal fixation (ORIF) with a volar locking plate.

Explanation

Correct Answer: CThe patient's post-reduction radiographic parameters (residual dorsal tilt of 18 degrees, radial shortening of 5 mm, and articular step-off of 3 mm) are all outside the generally accepted limits for stable conservative management of a distal radius fracture. Acceptable parameters typically include dorsal tilt <10-15 degrees, radial shortening <3-5 mm, and articular step-off <1-2 mm. Given these unacceptable parameters in an active 62-year-old, the fracture is considered unstable and highly likely to lose reduction or result in a symptomatic malunion if treated conservatively. Therefore, open reduction internal fixation (ORIF) with a volar locking plate is the most appropriate next step to achieve and maintain anatomical reduction, restore articular congruence, and allow for early rehabilitation. A second closed reduction is unlikely to succeed if the first attempt failed to achieve acceptable parameters, especially with comminution. External fixation might be considered, but for this pattern, a volar locking plate often provides more rigid fixation and better articular reduction. Discharging with a wrist splint and early range of motion would lead to severe malunion and functional impairment.

Question 1702

Topic: 2. Trauma

A 48-year-old male presents with severe pain and swelling in his forearm and hand 8 hours after closed reduction and casting of a Colles fracture. He complains of paresthesias in all fingers, and examination reveals severe pain with passive extension of the digits, despite palpable radial and ulnar pulses. What is the most immediate concern?

. Acute carpal tunnel syndrome.
. Complex regional pain syndrome (CRPS) Type I.
. Extensor pollicis longus (EPL) rupture.
. Acute forearm compartment syndrome.
. Loss of fracture reduction.

Correct Answer & Explanation

. Acute forearm compartment syndrome.

Explanation

Correct Answer: DThe constellation of symptoms—severe pain out of proportion to the injury, swelling, paresthesias in all fingers, and critically, severe pain with passive extension of the digits—developing acutely (within hours) after closed reduction and casting, is highly suggestive of acute forearm compartment syndrome. This is a surgical emergency requiring immediate fasciotomy to prevent irreversible muscle ischemia and nerve damage. While acute carpal tunnel syndrome can occur, the diffuse paresthesias and pain with passive extension ofalldigits are more indicative of compartment syndrome. CRPS develops later and has a different clinical course. EPL rupture presents as specific loss of thumb extension. Loss of reduction would cause pain and deformity but not typically these diffuse neurological symptoms and pain with passive stretch.

Question 1703

Topic: 2. Trauma

A 75-year-old patient with osteoporotic bone sustains a highly comminuted, dorsally displaced distal radius fracture (Colles type). She is treated with open reduction internal fixation using a volar locking plate. Which of the following is the primary advantage of using fixed-angle locking screws in this specific patient population and fracture pattern?

. They allow for easier removal of the plate in the future.
. They provide superior compression across the fracture site.
. They resist pullout in osteoporotic bone by creating a fixed-angle construct, independent of bone quality.
. They are compatible with all types of distal radius plates, regardless of design.
. They facilitate more flexible screw trajectories to avoid neurovascular structures.

Correct Answer & Explanation

. They resist pullout in osteoporotic bone by creating a fixed-angle construct, independent of bone quality.

Explanation

Correct Answer: CThe primary advantage of fixed-angle locking screws, especially in comminuted fractures and osteoporotic bone, is their ability to resist pullout. Unlike traditional non-locking screws that rely on compression between the plate and bone for stability, locking screws thread into the plate, creating a 'fixed-angle construct' or 'internal fixator.' This construct provides angular stability independent of bone quality, which is crucial in osteoporotic bone where traditional screws might lose purchase. This rigid fixation allows for earlier mobilization and better maintenance of reduction, preventing collapse in comminuted fractures. While some compression can be achieved, their main strength lies in angular stability and pullout resistance, not necessarily superior compression or easier removal.

Question 1704

Topic: 2. Trauma

A 58-year-old female presents with a Colles fracture. After adequate anesthesia, the orthopedic resident performs a closed reduction. What is the correct sequence of maneuvers to achieve and maintain reduction of a dorsally displaced distal radius fracture?

. Traction, pronation, radial deviation, extension.
. Traction, supination, radial deviation, flexion.
. Traction, exaggeration of deformity, volar translation, supination, ulnar deviation, palmar flexion.
. Traction, direct pressure on the dorsal fragment, pronation, extension.
. Traction, ulnar deviation, supination, extension.

Correct Answer & Explanation

. Traction, exaggeration of deformity, volar translation, supination, ulnar deviation, palmar flexion.

Explanation

Correct Answer: CThe classic sequence for closed reduction of a dorsally displaced Colles fracture (after adequate anesthesia and disimpaction with traction) involves several key steps:Traction:To disimpact the fracture and restore length.Exaggeration of deformity:Briefly dorsiflexing the wrist to unlock the fracture fragments.Volar translation:Applying a direct volar force to the distal fragment to correct dorsal displacement.Supination:To correct the pronated position of the distal fragment, which often accompanies dorsal displacement.Ulnar deviation:To restore radial inclination.Palmar flexion:To correct dorsal angulation and help maintain the reduction.Option C correctly captures these essential maneuvers. The other options either omit critical steps or describe incorrect maneuvers for a Colles fracture.

Question 1705

Topic: 2. Trauma

In the context of an acutely unstable Colles fracture, what is the primary mechanism by which an external fixator achieves and maintains reduction?

. It directly compresses the fracture fragments together.
. It provides indirect reduction and maintains length and alignment through ligamentotaxis.
. It allows for immediate full weight-bearing on the affected limb.
. It is primarily used for definitive internal fixation in comminuted intra-articular fractures.
. Its main purpose is to mobilize the wrist joint immediately post-injury.

Correct Answer & Explanation

. It provides indirect reduction and maintains length and alignment through ligamentotaxis.

Explanation

Correct Answer: BExternal fixation for distal radius fractures primarily achieves indirect reduction and maintains length and alignment through a principle calledligamentotaxis. By applying distraction across the wrist joint, the external fixator tensions the intact soft tissue ligaments (particularly the radiocarpal ligaments) to indirectly pull the fracture fragments into a more anatomical position. It does not directly compress the fracture fragments (though some compression can be applied with specific fixator designs, it's not the primary mechanism of reduction). It does not allow immediate full weight-bearing and is not solely for definitive internal fixation (often used as a temporary measure or in conjunction with limited internal fixation). While dynamic external fixators allow for some controlled motion, the initial purpose is stability and reduction, not immediate full mobilization.

Question 1706

Topic: 2. Trauma

Regarding the management of acute compartment syndrome of the leg, which of the following statements is most accurate?

. Pain out of proportion to injury is a late sign and indicates irreversible muscle damage.
. The most reliable diagnostic tool is clinical examination, particularly assessment of pulselessness.
. Compartment pressure measurements are only indicated when clinical signs are equivocal.
. Elevation of the limb above the heart is crucial to reduce interstitial pressure.
. A delta pressure (diastolic blood pressure - compartment pressure) less than 30 mmHg is an indication for fasciotomy.

Correct Answer & Explanation

. A delta pressure (diastolic blood pressure - compartment pressure) less than 30 mmHg is an indication for fasciotomy.

Explanation

Correct Answer: EPain out of proportion to injury is an early and critical sign of acute compartment syndrome. Pulselessness is a very late sign, indicating arterial compromise, and usually signifies irreversible damage. Clinical examination is key, but compartment pressure measurements are often necessary to confirm the diagnosis, especially in uncooperative or obtunded patients, or when clinical signs are not clear. Elevating the limb reduces arterial inflow, exacerbating ischemia. A delta pressure (diastolic blood pressure - compartment pressure) less than 30 mmHg (or an absolute pressure >30-45 mmHg) is a strong indication for emergent fasciotomy to prevent irreversible muscle and nerve damage.

Question 1707

Topic: 2. Trauma

A 70-year-old female with a history of osteoporosis sustains a displaced, comminuted distal radius fracture. She is relatively active and independent. Which of the following treatment options is generally associated with the best functional outcome in this patient demographic?

. Closed reduction and casting
. External fixation
. Volar locking plate fixation
. Percutaneous pinning
. Total wrist arthroplasty

Correct Answer & Explanation

. Volar locking plate fixation

Explanation

Correct Answer: CFor displaced, comminuted distal radius fractures in active, osteoporotic elderly patients, volar locking plate fixation has demonstrated superior functional outcomes compared to traditional methods like closed reduction and casting, external fixation, or percutaneous pinning. These plates provide stable fixation, allow for earlier mobilization, and can better maintain reduction in osteoporotic bone. Closed reduction and casting often lead to loss of reduction. External fixation can be associated with pin track infections and stiffness. Percutaneous pinning may not provide sufficient stability for comminuted fractures. Total wrist arthroplasty is reserved for severe arthritis or failed complex reconstructive procedures, not acute fractures.

Question 1708

Topic: 2. Trauma

A 24-year-old male with bilateral femur fractures develops a petechial rash across his axillae and conjunctivae, confusion, and tachypnea on hospital day 2. What is the most critical preventative measure for this syndrome?

. Prophylactic administration of corticosteroids
. Therapeutic intravenous heparin infusion
. Early operative stabilization of the long bone fractures
. Aggressive intravenous fluid resuscitation
. Placement of an inferior vena cava filter

Correct Answer & Explanation

. Early operative stabilization of the long bone fractures

Explanation

Fat embolism syndrome classically presents with the triad of hypoxia, neurological abnormalities, and a petechial rash. Early operative stabilization of long bone fractures is the single most effective method to reduce the incidence and severity of this syndrome.

Question 1709

Topic: 2. Trauma

A 78-year-old female taking dabigatran for atrial fibrillation sustains a displaced femoral neck fracture requiring an urgent hemiarthroplasty. Her last dose was 6 hours ago. What is the most appropriate reversal agent to administer prior to surgery?

. Vitamin K
. Fresh frozen plasma
. Prothrombin complex concentrate
. Idarucizumab
. Protamine sulfate

Correct Answer & Explanation

. Idarucizumab

Explanation

Idarucizumab is a monoclonal antibody fragment specifically designed to reverse the direct thrombin inhibitor dabigatran. This targeted reversal agent allows for urgent surgical intervention without excessive bleeding risk.

Question 1710

Topic: 2. Trauma

A 33-year-old polytrauma patient receives 10 units of packed red blood cells, 10 units of plasma, and 2 units of platelets. He subsequently develops a prolonged QT interval on his ECG and perioral numbness. What is the primary underlying mechanism of his electrolyte abnormality?

. Citrate toxicity chelating serum calcium
. Massive intracellular shift of potassium
. Magnesium depletion from injury-induced diuresis
. Dilutional hyponatremia from fluid administration
. Severe metabolic acidosis

Correct Answer & Explanation

. Citrate toxicity chelating serum calcium

Explanation

Massive blood transfusions can lead to hypocalcemia because the citrate used as an anticoagulant in stored blood chelates serum ionized calcium. This presents clinically with a prolonged QT interval, tetany, and perioral numbness.

Question 1711

Topic: 2. Trauma

A 28-year-old male is admitted with an isolated tibial shaft fracture. He complains of increasing pain despite narcotic administration. His diastolic blood pressure is 70 mmHg and his intracompartmental pressure is 45 mmHg. What is his Delta pressure and the most appropriate next step?

. Delta P 25 mmHg; perform a four-compartment fasciotomy
. Delta P 45 mmHg; elevate the leg above the level of the heart
. Delta P 25 mmHg; observe and re-examine in 2 hours
. Delta P 115 mmHg; apply an ice pack and loosen dressings
. Delta P 70 mmHg; administer intravenous mannitol

Correct Answer & Explanation

. Delta P 25 mmHg; perform a four-compartment fasciotomy

Explanation

Delta pressure is calculated as diastolic blood pressure minus intracompartmental pressure (70 - 45 = 25 mmHg). A Delta pressure of 30 mmHg or less confirms acute compartment syndrome and requires emergent fasciotomy.

Question 1712

Topic: 2. Trauma

A 42-year-old male with a history of heavy alcohol use is admitted after a femur fracture. On hospital day 3, he becomes severely agitated, diaphoretic, tachycardic, and experiences visual hallucinations. What is the most appropriate primary pharmacological management?

. Haloperidol
. Dexmedetomidine
. Lorazepam
. Phenytoin
. Propofol

Correct Answer & Explanation

. Lorazepam

Explanation

The patient is exhibiting delirium tremens, a severe and potentially fatal form of alcohol withdrawal that typically peaks at 48-96 hours. Benzodiazepines, such as lorazepam, are the first-line treatment to manage agitation and prevent withdrawal seizures.

Question 1713

Topic: 2. Trauma

A 42-year-old male sustains a closed comminuted tibia fracture and subsequently develops worsening leg pain out of proportion to the injury. Which of the following intracompartmental pressure measurements is the most widely accepted threshold indicating the need for a four-compartment fasciotomy?

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

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The delta pressure (diastolic blood pressure minus the compartment pressure) is the most reliable indicator for acute compartment syndrome. A delta pressure of less than 30 mmHg strongly indicates tissue ischemia and is the accepted threshold for fasciotomy.

Question 1714

Topic: 2. Trauma
A 35-year-old farmer gets his arm caught in a threshing machine, sustaining a heavily contaminated open radius and ulna fracture with extensive soft tissue loss (Gustilo-Anderson Type IIIB). In addition to urgent surgical debridement, what is the most appropriate initial prophylactic antibiotic regimen?
. Intravenous cefazolin alone
. Intravenous cefazolin and gentamicin
. Intravenous cefazolin and clindamycin
. Intravenous cefazolin, gentamicin, and penicillin
. Intravenous vancomycin and ceftriaxone

Correct Answer & Explanation

. Intravenous cefazolin, gentamicin, and penicillin

Explanation

For severe open fractures occurring in agricultural settings with heavy soil contamination, there is a high risk of anaerobic infection (e.g., Clostridium). The recommended regimen is a first-generation cephalosporin, an aminoglycoside, and high-dose penicillin.

Question 1715

Topic: 2. Trauma

A 45-year-old female sustains a high-energy Schatzker VI tibial plateau fracture. Which of the following parameters is the most accurate and validated predictor for diagnosing acute compartment syndrome in this patient?

. Absolute compartment pressure > 30 mmHg
. Absolute compartment pressure > 45 mmHg
. Systolic blood pressure minus compartment pressure < 20 mmHg
. Mean arterial pressure minus compartment pressure < 40 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The Delta P (calculated as the diastolic blood pressure minus the compartment pressure) of less than 30 mmHg is the most reliable threshold for diagnosing acute compartment syndrome.

Question 1716

Topic: 2. Trauma

In which of the following scenarios, as potentially depicted in the image, would surgical intervention (e.g., curettage and bone grafting) be most strongly considered for an otherwise asymptomatic enchondroma?

. A 2 cm lesion in the distal phalanx of the finger
. A 3 cm lesion in the iliac wing
. A 4 cm lesion with significant cortical thinning (>50%) in the distal femur
. A 1 cm lesion in the calcaneus
. A 2.5 cm lesion in the proximal ulna

Correct Answer & Explanation

. A 4 cm lesion with significant cortical thinning (>50%) in the distal femur

Explanation

Correct Answer: CSignificant cortical thinning, especially when it exceeds 50% of the cortical thickness in a weight-bearing long bone like the distal femur, creates a substantial risk of pathological fracture. Even if asymptomatic, prophylactic curettage and bone grafting would be strongly considered in this scenario to prevent a potentially devastating fracture and to restore structural integrity. The other options describe lesions in less mechanically critical locations or without significant fracture risk that would typically be managed with observation if asymptomatic.

Question 1717

Topic: 2. Trauma

A 29-year-old female presents after falling off a horse. Initial radiographs of her left foot are provided.

. A. Non-displaced avulsion fracture of the navicular tuberosity.
. B. Stress fracture of the navicular body.
. C. Displaced, comminuted intra-articular fracture of the navicular body.
. D. Lisfranc injury with associated navicular fracture.
. E. Calcaneal body fracture with subtalar joint involvement.

Correct Answer & Explanation

. C. Displaced, comminuted intra-articular fracture of the navicular body.

Explanation

Correct Answer: CThe candidate's initial assessment of the radiographs states: 'The radiographs of the left foot, AP and oblique show a displaced fracture of the body of navicular bone with comminution. There is overlap of mid-tarsal bones and I can’t exclude fractures of other tarsal bones.' The images clearly demonstrate significant disruption of the navicular body, consistent with a displaced and comminuted intra-articular fracture. Options A and B describe less severe or different types of navicular fractures. Options D and E describe fractures of different anatomical regions, although a Lisfranc injury could be associated, the primary and most evident injury described is the navicular body fracture.

Question 1718

Topic: 2. Trauma

Following initial assessment of a 29-year-old female with a displaced, comminuted navicular body fracture, what is the most appropriate immediate non-operative management?

. A. Immediate weight-bearing in a walking boot.
. B. Application of a short leg cast with the ankle in plantarflexion.
. C. Backslab application with strict elevation, cryotherapy, and analgesia.
. D. Referral for physical therapy to maintain range of motion.
. E. Administration of systemic corticosteroids to reduce swelling.

Correct Answer & Explanation

. C. Backslab application with strict elevation, cryotherapy, and analgesia.

Explanation

Correct Answer: CThe case explicitly outlines the initial non-operative management: 'I would initially treat the injured foot in a backslab, with strict elevation and intermittent cryotherapy, adequate analgesia and close monitoring for evolving compartment syndrome.' This approach aims to control swelling, pain, and protect the injured foot while awaiting definitive management and ruling out acute complications like compartment syndrome. Immediate weight-bearing or range of motion exercises would be contraindicated for an unstable fracture. Systemic corticosteroids are not standard initial management for acute fractures.

Question 1719

Topic: 2. Trauma

A 29-year-old female presents with a navicular body fracture. CT imaging is obtained, as shown below, confirming an unstable, displaced intra-articular fracture.

. A. Non-operative management with serial casting.
. B. Primary talonavicular arthrodesis.
. C. Open reduction and internal fixation (ORIF) to restore articular surface.
. D. Percutaneous screw fixation without formal reduction.
. E. Excision of comminuted fragments and soft tissue interposition.

Correct Answer & Explanation

. C. Open reduction and internal fixation (ORIF) to restore articular surface.

Explanation

Correct Answer: CThe candidate states: 'These coronal and sagittal sections of the CT scan confirm X-ray findings of a displaced fracture of the body of navicular bone with comminution. It is an unstable displaced intra-articular fracture and I would favour operative intervention rather than non-operative. The principles of management are to restore the articular surface, stabilize and hold the fracture to allow early mobilization.' While primary talonavicular arthrodesis (Option B) is mentioned as a consideration forseverecomminution where restoration is not possible, the primary goal and preferred definitive management for an unstable, displaced intra-articular fracture is ORIF to restore the articular surface. Non-operative management is generally not suitable for unstable, displaced intra-articular fractures. Percutaneous fixation without reduction is unlikely to achieve articular congruity in a comminuted fracture.

Question 1720

Topic: 2. Trauma

A 29-year-old female has an unstable, displaced intra-articular navicular body fracture confirmed by CT. The decision is made for operative intervention. What are the primary principles of operative management for this type of fracture?

. A. Achieve immediate full weight-bearing and early return to sport.
. B. Preserve the soft tissue envelope and perform primary talonavicular fusion in all cases.
. C. Restore articular surface, stabilize the fracture, and allow early mobilization.
. D. Perform closed reduction and percutaneous fixation without direct visualization.
. E. Administer prophylactic antibiotics and observe for spontaneous healing.

Correct Answer & Explanation

. C. Restore articular surface, stabilize the fracture, and allow early mobilization.

Explanation

Correct Answer: CThe candidate clearly outlines the principles of management: 'The principles of management are to restore the articular surface, stabilize and hold the fracture to allow early mobilization.' This is the cornerstone of treating intra-articular fractures to minimize post-traumatic osteoarthritis and optimize functional outcomes. Immediate full weight-bearing (A) is generally not advisable. Primary fusion (B) is reserved for severe comminution, not all cases. Closed reduction and percutaneous fixation (D) may not be sufficient for displaced, comminuted fractures. Prophylactic antibiotics (E) are part of perioperative care but not the primary principle of fracture management itself.

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