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2. Trauma MCQs

Practice Set 481 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 9601

Topic: 2. Trauma

A pilon fracture of the distal radius is characterized by:

. An extra-articular fracture with dorsal displacement
. An intra-articular fracture with a large volar fragment
. A comminuted intra-articular fracture involving the articular surface and metaphysis
. A fracture of the radial styloid
. A metaphyseal fracture with an intact articular surface

Correct Answer & Explanation

. A comminuted intra-articular fracture involving the articular surface and metaphysis

Explanation

A pilon fracture of the distal radius is analogous to a tibial pilon fracture, referring to a high-energy, comminuted intra-articular fracture of the distal radius involving both the articular surface and the metaphysis, often with significant impaction. These are typically AO/OTA Type C fractures, particularly C3.

Question 9602

Topic: 2. Trauma

What is the most common cause of nonunion in distal radius fractures?

. Inadequate immobilization
. Poor vascularity of the distal fragment
. Smoking
. Severe open injury with bone loss
. Nonunion is extremely rare in the distal radius.

Correct Answer & Explanation

. Nonunion is extremely rare in the distal radius.

Explanation

Nonunion of the distal radius is exceedingly rare due to its robust blood supply. While contributing factors like inadequate immobilization, smoking, or severe open injury with bone loss can increase the risk, the overall incidence is very low. Malunion is a far more common complication than nonunion in the distal radius.

Question 9603

Topic: 2. Trauma

Which of the following describes a volar Barton's fracture?

. An extra-articular fracture with dorsal displacement of the distal fragment.
. A fracture of the radial styloid with scaphoid impaction.
. An intra-articular fracture of the dorsal rim of the distal radius.
. An intra-articular fracture of the volar rim of the distal radius with volar carpal displacement.
. A comminuted intra-articular fracture with significant metaphyseal involvement.

Correct Answer & Explanation

. An intra-articular fracture of the volar rim of the distal radius with volar carpal displacement.

Explanation

A volar Barton's fracture is an intra-articular fracture of the distal radius involving the volar rim, with the carpus and the volar fragment displacing volarly and proximally. It is an inherently unstable fracture-dislocation. A Colles' fracture is extra-articular with dorsal displacement. A Hutchinson/Chauffeur's fracture is a radial styloid fracture. A dorsal Barton's fracture involves the dorsal rim.

Question 9604

Topic: 2. Trauma

Which type of distal radius fracture is most commonly associated with rupture of the Extensor Pollicis Longus (EPL) tendon?

. Volar Barton's fracture
. Smith's fracture
. Colles' fracture
. Chauffeur's fracture
. Die-punch fracture

Correct Answer & Explanation

. Colles' fracture

Explanation

EPL rupture, often delayed, is a recognized complication of dorsally displaced distal radius fractures, classically Colles' fractures. The tendon can rupture due to attrition over a sharp, irregular dorsal fracture fragment or a prominent Lister's tubercle, especially after a period of swelling and healing. It can also occur as a complication of dorsal plating for these fractures. Volar Barton's and Smith's are volar-displaced fractures. Chauffeur's is a radial styloid fracture. Die-punch is a compression articular fracture.

Question 9605

Topic: 2. Trauma
Regarding coronoid fractures in the context of elbow dislocations, which type according to the Regan and Morrey classification is MOST commonly associated with persistent elbow instability and typically requires surgical fixation?
. Type I (tip fracture).
. Type II (involving less than 50% of the coronoid height).
. Type III (involving more than 50% of the coronoid height).
. Type IV (comminuted fracture of the coronoid base).
. Type V (avulsion of the sublime tubercle).

Correct Answer & Explanation

. Type III (involving more than 50% of the coronoid height).

Explanation

Regan and Morrey Type III coronoid fractures, involving more than 50% of the coronoid height, are most commonly associated with persistent elbow instability and typically require surgical fixation. These larger fragments significantly compromise the anterior buttress effect of the coronoid.

Question 9606

Topic: 2. Trauma

Which of the following conditions is an absolute contraindication to closed reduction of an elbow dislocation?

. Concomitant radial head fracture.
. Ulnar nerve paresthesia.
. Open dislocation with gross contamination.
. Delayed presentation (>24 hours).
. Significant soft tissue swelling.

Correct Answer & Explanation

. Open dislocation with gross contamination.

Explanation

An open dislocation with gross contamination (Option C) is an absolute contraindication to closed reduction. Open dislocations require formal surgical debridement, irrigation, and reduction in the operating room to prevent infection. While a radial head fracture (Option A), ulnar nerve paresthesia (Option B), delayed presentation (Option D), and significant swelling (Option E) all complicate management, they are not absolute contraindications to attempting closed reduction (with caution for neurovascular status in B). For example, a radial head fracture may still allow closed reduction of the elbow, with subsequent management of the fracture. A delayed presentation may make closed reduction more difficult, but not absolutely contraindicated, though the risk of iatrogenic fracture increases.

Question 9607

Topic: 2. Trauma

A patient presents with a posterior Monteggia equivalent lesion (type I variant) involving a fracture of the coronoid and radial head dislocation without an ulnar shaft fracture. What is the MOST appropriate initial management?

. Immediate closed reduction of the radial head followed by long arm casting.
. Surgical open reduction and internal fixation of the coronoid fracture and radial head stabilization.
. Radial head excision to facilitate reduction.
. External fixation of the elbow joint.
. Observation and physiotherapy without reduction.

Correct Answer & Explanation

. Surgical open reduction and internal fixation of the coronoid fracture and radial head stabilization.

Explanation

A Monteggia equivalent lesion involves a radial head dislocation and an ulnar fracture or fracture equivalent (like a coronoid fracture), but without a frank ulna shaft fracture. These are unstable injuries. While a true Monteggia typically involves an ulnar shaft fracture, a coronoid fracture combined with a radial head dislocation is a variant. Given the inherent instability of the radial head dislocation, surgical open reduction and internal fixation of the coronoid fracture and stabilization of the radial head is generally required. Closed reduction of the radial head alone is unlikely to be stable due to the associated coronoid fracture. Radial head excision (Option C) is destabilizing. External fixation (Option D) is reserved for severe soft tissue injury or highly comminuted, unstable fractures. Observation (Option E) would lead to chronic dislocation.

Question 9608

Topic: 2. Trauma

A 45-year-old male with an elbow dislocation presents with significant swelling and a tense forearm compartment. His fingers are extended, and he reports severe pain on passive stretching of the fingers. What is the MOST critical immediate action?

. Elevate the arm and apply ice packs.
. Administer opioid analgesia and observe.
. Perform urgent compartment pressure measurements.
. Order an immediate MRI of the forearm.
. Attempt manual reduction of the elbow dislocation.

Correct Answer & Explanation

. Perform urgent compartment pressure measurements.

Explanation

The described symptoms (tense forearm compartment, severe pain on passive stretch, fingers extended, severe swelling) are highly suggestive of acute compartment syndrome of the forearm. This is a surgical emergency. The MOST critical immediate action is to perform urgent compartment pressure measurements to confirm the diagnosis, followed by emergent fasciotomy if pressures are elevated. Elevating the arm or applying ice (Option A) might worsen ischemia. Opioid analgesia (Option B) would mask symptoms. MRI (Option D) is too slow. Attempting reduction (Option E) might be necessary for the dislocation but addressing compartment syndrome is the priority for limb salvage once suspected.

Question 9609

Topic: 2. Trauma

Which of the following describes a 'transolecranon fracture-dislocation'?

. A radial head fracture with concomitant elbow dislocation.
. An olecranon fracture combined with an elbow dislocation.
. A coronoid fracture with a radial head dislocation.
. A Monteggia fracture variant with posterior radial head dislocation.
. An elbow dislocation with an associated medial epicondyle avulsion.

Correct Answer & Explanation

. An olecranon fracture combined with an elbow dislocation.

Explanation

A transolecranon fracture-dislocation is an injury where an olecranon fracture is combined with an elbow dislocation, typically anterior displacement of the forearm relative to the humerus through the fracture site. This is a complex injury often requiring ORIF of the olecranon to restore joint stability and congruity. Options A, C, D, and E describe other distinct elbow injuries.

Question 9610

Topic: 2. Trauma

Which of the following factors is considered the MOST significant predictor of a poor outcome (stiffness, pain, or instability) after an elbow dislocation?

. Patient age over 60 years.
. Body mass index (BMI) > 30.
. Presence of a concomitant radial head fracture.
. Duration of immobilization post-reduction.
. Associated nerve injury (e.g., ulnar nerve palsy).

Correct Answer & Explanation

. Presence of a concomitant radial head fracture.

Explanation

The presence of a concomitant radial head fracture (Option C), especially as part of a terrible triad injury, significantly complicates elbow dislocations and is a strong predictor of a poor outcome, including persistent pain, stiffness, and instability. These injuries are inherently more unstable and challenging to manage. While duration of immobilization (Option D) is critical for stiffness, it is a modifiable factor. Age (Option A), BMI (Option B), and nerve injury (Option E) can influence outcomes but are not as profoundly predictive of overall poor outcome and complexity as an associated radial head fracture, particularly in the context of a terrible triad.

Question 9611

Topic: 2. Trauma

What specific injury pattern is characterized by a posterior elbow dislocation with an associated fracture of the medial epicondyle and a radial head fracture?

. Terrible Triad.
. Monteggia fracture-dislocation.
. Essex-Lopresti lesion.
. Transolecranon fracture-dislocation.
. This is not a recognized specific named injury pattern.

Correct Answer & Explanation

. This is not a recognized specific named injury pattern.

Explanation

The terrible triad injury specifically refers to a posterior elbow dislocation with an associated radial head fracture and a coronoid process fracture, combined with lateral ulnar collateral ligament disruption. A posterior elbow dislocation with an associated fracture of the medial epicondyle and a radial head fracture is not a single, universally recognized specific named injury pattern like the terrible triad or Monteggia. It is a complex elbow dislocation with multiple fracture components, and each component would need to be addressed. Thus, 'This is not a recognized specific named injury pattern' is the correct answer.

Question 9612

Topic: 2. Trauma

Which of the following associated injuries is most commonly missed in the initial evaluation of an isolated radial head fracture?

. Medial collateral ligament tear
. Coronoid process fracture
. Capitellum chondral injury
. Distal radio-ulnar joint (DRUJ) instability
. Olecranon fracture

Correct Answer & Explanation

. Distal radio-ulnar joint (DRUJ) instability

Explanation

While all listed injuries can occur with radial head fractures, DRUJ instability, indicative of an Essex-Lopresti lesion or other forearm axis disruption, is often missed initially. It presents as insidious wrist pain and instability that becomes apparent days or weeks after the initial injury to the radial head. Coronoid and MCL injuries are typically associated with terrible triad injuries involving elbow dislocation. Capitellum chondral injuries are less common and often only seen on arthroscopy or MRI. Olecranon fractures are usually obvious on initial X-rays.

Question 9613

Topic: 2. Trauma

Following open reduction and internal fixation (ORIF) of a radial head fracture, what is the primary goal of early rehabilitation?

. Achieve full strength immediately
. Prevent heterotopic ossification
. Restore range of motion while protecting fixation
. Return to sports within 2 weeks
. Maintain a fixed flexion deformity

Correct Answer & Explanation

. Restore range of motion while protecting fixation

Explanation

The primary goal of early rehabilitation after ORIF of a radial head fracture is to restore range of motion while protecting the internal fixation. Early, controlled motion helps prevent stiffness, which is a common complication of elbow injuries. Full strength comes later. While preventing heterotopic ossification is a goal, it's typically addressed with medication or radiation in high-risk cases, not solely through early rehab. Returning to sports within 2 weeks is unrealistic, and maintaining fixed flexion deformity is undesirable.

Question 9614

Topic: 2. Trauma
What is the typical indication for non-operative management of a radial head fracture?
. Mason-Johnston Type III fracture with comminution
. Fracture with a palpable mechanical block to rotation
. Associated elbow dislocation
. Mason-Johnston Type I fracture without mechanical block
. Essex-Lopresti lesion

Correct Answer & Explanation

. Mason-Johnston Type I fracture without mechanical block

Explanation

Non-operative management, typically involving a brief period of immobilization followed by early active range of motion, is the standard for Mason-Johnston Type I radial head fractures, which are non-displaced or minimally displaced without a mechanical block to forearm rotation.

Question 9615

Topic: 2. Trauma
In the modified Mason-Johnston classification, what defines a Type II fracture?
. Non-displaced fracture
. Displaced single fragment involving >30% of the articular surface or with >2mm displacement, but non-comminuted
. Comminuted fracture
. Fracture with associated elbow dislocation
. Fracture with a palpable mechanical block to motion

Correct Answer & Explanation

. Displaced single fragment involving >30% of the articular surface or with >2mm displacement, but non-comminuted

Explanation

The modified Mason-Johnston classification refines the original. A Type II fracture is defined as a displaced fracture involving a single fragment that is usually amenable to fixation. It typically involves more than 2mm displacement or more than 30% of the articular surface, but is not significantly comminuted.

Question 9616

Topic: 2. Trauma

What is the recommended timing for initiation of active range of motion exercises following non-operative management of a Mason-Johnston Type I radial head fracture?

. Immediately post-injury, as tolerated
. After 3 weeks of strict immobilization
. Once radiographic healing is complete (typically 6-8 weeks)
. Only if pain has completely resolved
. After 6 months

Correct Answer & Explanation

. Immediately post-injury, as tolerated

Explanation

For Mason-Johnston Type I radial head fractures (non-displaced, no mechanical block), early active range of motion exercises should be initiated almost immediately post-injury, as tolerated by the patient. A brief period of sling immobilization (e.g., a few days for comfort) is acceptable, but prolonged immobilization should be avoided to prevent elbow stiffness, which is a common and debilitating complication of elbow injuries. Waiting for radiographic healing is too long.

Question 9617

Topic: 2. Trauma

Which of the following conditions is an absolute contraindication for conservative management of a radial head fracture?

. Patient age > 65 years
. Mason-Johnston Type I fracture
. Associated interosseous membrane injury
. Tobacco smoking history
. Body mass index (BMI) of 35

Correct Answer & Explanation

. Associated interosseous membrane injury

Explanation

An associated interosseous membrane injury, particularly as part of an Essex-Lopresti lesion, is an absolute contraindication for conservative management of a radial head fracture. The radial head is crucial for longitudinal forearm stability, and its disruption combined with IOM injury necessitates surgical restoration of radial length and stability, usually via radial head replacement, to prevent proximal radial migration and DRUJ disruption. Other options are relative considerations but not absolute contraindications.

Question 9618

Topic: 2. Trauma

In the context of radial head fractures, what does the term 'terrible triad' refer to?

. Radial head fracture, olecranon fracture, and capitellum fracture
. Radial head fracture, coronoid fracture, and medial epicondyle fracture
. Posterior elbow dislocation, radial head fracture, and coronoid process fracture
. Anterior elbow dislocation, radial head fracture, and MCL rupture
. Radial head fracture, interosseous membrane disruption, and DRUJ dislocation

Correct Answer & Explanation

. Posterior elbow dislocation, radial head fracture, and coronoid process fracture

Explanation

The 'terrible triad' of the elbow is a specific and severe injury pattern characterized by a posterior elbow dislocation, a radial head fracture, and a coronoid process fracture. This combination often results in significant instability requiring surgical intervention to restore joint stability and function. Option E describes an Essex-Lopresti lesion.

Question 9619

Topic: 2. Trauma

Which radiographic sign on a lateral elbow view might suggest an occult radial head fracture, even if the radial head itself appears intact?

. Olecranon fracture
. Medial epicondyle avulsion
. Anterior and/or posterior fat pad sign
. Distal humerus fracture
. Coronoid process fracture

Correct Answer & Explanation

. Anterior and/or posterior fat pad sign

Explanation

The anterior and/or posterior fat pad sign on a lateral elbow radiograph is a classic indicator of an intra-articular effusion, which strongly suggests an occult fracture in the absence of obvious bony injury. In an adult, a visible posterior fat pad is always abnormal, and an anterior fat pad (sail sign) that is elevated and prominent is also indicative of effusion. In the setting of trauma, this should prompt suspicion for a radial head or capitellum fracture, even if not directly visualized.

Question 9620

Topic: 2. Trauma

A 25-year-old male sustains a radial head fracture after a fall. On examination, he has pain with palpation over the radial head and limited pronation/supination. Radiographs show a Mason-Johnston Type II fracture with a single displaced fragment. Which of the following is the most important factor in deciding between non-operative and operative management for this patient?

. Patient's activity level
. Presence of a mechanical block to forearm rotation
. Patient's age
. Number of fragments
. Fracture location (neck vs. head)

Correct Answer & Explanation

. Presence of a mechanical block to forearm rotation

Explanation

For a Mason-Johnston Type II radial head fracture, the presence of a mechanical block to forearm rotation is themost importantfactor in deciding for operative management. Even a minimally displaced fragment causing a block will lead to persistent pain and stiffness if not addressed surgically. While activity level and age are considerations, a mechanical block is a direct indication for surgical intervention to restore motion. The number of fragments (single vs. comminuted) influences thetypeof surgery but the block indicates surgery is needed. Location matters more for fracture type (e.g., radial neck vs. head).

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