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2. Trauma MCQs

Practice Set 509 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 10161

Topic: 2. Trauma

A 45-year-old male sustains a distal radius fracture after a fall onto an outstretched hand. Radiographs show dorsal displacement and angulation of the distal fragment. Which eponymous fracture does this describe?

. Smith's fracture
. Barton's fracture
. Galeazzi fracture
. Colles' fracture
. Essex-Lopresti fracture

Correct Answer & Explanation

. Colles' fracture

Explanation

A Colles' fracture is a distal radius fracture with dorsal displacement and dorsal angulation of the distal fragment, typically occurring from a fall onto an outstretched hand. A Smith's fracture (or reverse Colles') has volar displacement and angulation. A Barton's fracture is an intra-articular distal radius fracture with either dorsal or volar displacement of the carpus with the associated rim of the radius. A Galeazzi fracture involves a distal radial shaft fracture with associated dislocation of the distal radioulnar joint (DRUJ). An Essex-Lopresti fracture is a radial head fracture with concomitant dislocation of the DRUJ and disruption of the interosseous membrane.

Question 10162

Topic: Lower Extremity Trauma

What is the primary function of the menisci in the knee joint?

. To lubricate the joint surfaces
. To increase the stability of the joint by deepening the articular surface of the tibia for the femoral condyles
. To produce synovial fluid
. To act as a primary shock absorber
. To prevent hyperextension of the knee

Correct Answer & Explanation

. To increase the stability of the joint by deepening the articular surface of the tibia for the femoral condyles

Explanation

The menisci serve multiple functions, but their primary role is to improve the congruence between the incongruent femoral condyles and tibial plateau, thereby increasing the stability of the knee joint. They also act as secondary shock absorbers and play a role in load transmission and joint lubrication. While they contribute to shock absorption and load transmission, 'increasing stability by deepening the articular surface' is their fundamental anatomical contribution to joint mechanics.

Question 10163

Topic: 2. Trauma

A 25-year-old male sustains a high-energy femoral shaft fracture. What is the most appropriate definitive treatment in an otherwise healthy adult?

. Skeletal traction followed by casting
. External fixation
. Open reduction and plate osteosynthesis
. Intramedullary nailing
. Dynamic hip screw

Correct Answer & Explanation

. Intramedullary nailing

Explanation

For most diaphyseal femoral shaft fractures in adults, intramedullary nailing is the gold standard for definitive treatment. It provides excellent biomechanical stability, allows for early weight-bearing, and has high union rates with lower complication rates compared to other methods. Skeletal traction followed by casting is largely historical for adults. External fixation is primarily used for temporary stabilization in polytrauma or open fractures. Plate osteosynthesis is an option but generally considered inferior to IMN for femoral shaft fractures. A dynamic hip screw is used for intertrochanteric hip fractures.

Question 10164

Topic: 2. Trauma

What is the most common type of nonunion in a scaphoid fracture?

. Atrophic nonunion
. Hypertrophic nonunion
. Infected nonunion
. Delayed union
. Malunion

Correct Answer & Explanation

. Atrophic nonunion

Explanation

Scaphoid fractures have a high propensity for nonunion due to their precarious blood supply, especially in the proximal pole. When nonunion occurs, it is most commonly an atrophic nonunion, characterized by a lack of healing potential and a 'pencil-point' appearance on radiographs, often requiring bone grafting. Hypertrophic nonunions show exuberant callus formation but fail to bridge the fracture gap. Infected nonunion is rare in scaphoid fractures. Delayed union means it eventually heals, just slowly. Malunion implies healing in an unsatisfactory position.

Question 10165

Topic: 2. Trauma

What is the most appropriate initial treatment for a stress fracture of the fifth metatarsal (Jones fracture) in an athlete?

. Weight-bearing as tolerated in a walking boot
. Cast immobilization for 6-8 weeks, non-weight bearing
. Intramedullary screw fixation
. Plate and screw fixation
. Percutaneous pinning

Correct Answer & Explanation

. Intramedullary screw fixation

Explanation

A Jones fracture (fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal) is known for its high risk of nonunion due to compromised blood supply. In athletes, especially, early surgical intervention with intramedullary screw fixation is often recommended to ensure union and facilitate a quicker return to sport, especially when compared to prolonged non-weight-bearing immobilization. Non-weight-bearing cast immobilization is an option but has higher nonunion rates in athletes. Plate and screw fixation or percutaneous pinning are not typically used for Jones fractures.

Question 10166

Topic: 2. Trauma
A 50-year-old male presents with severe pain and limited range of motion of the elbow after a fall onto an outstretched hand. Radiographs show a fracture of the radial head with associated dislocation of the distal radioulnar joint (DRUJ) and disruption of the interosseous membrane. Which eponymous injury is this?
. Monteggia fracture-dislocation
. Galeazzi fracture-dislocation
. Essex-Lopresti lesion
. Colles' fracture
. Mason type III radial head fracture

Correct Answer & Explanation

. Essex-Lopresti lesion

Explanation

The description perfectly matches an Essex-Lopresti lesion: a comminuted radial head fracture, rupture of the interosseous membrane, and dislocation of the distal radioulnar joint (DRUJ). This is a severe forearm injury that can lead to significant instability and chronic wrist pain if not recognized and treated appropriately. Monteggia involves an ulna fracture and radial head dislocation. Galeazzi involves a distal radial shaft fracture and DRUJ dislocation. Colles' is a distal radius fracture. Mason classification describes radial head fractures but does not encompass the entire Essex-Lopresti lesion.

Question 10167

Topic: 2. Trauma

What is the most appropriate initial treatment for acute compartment syndrome of the forearm?

. Ice and elevation
. Analgesics and observation
. Splinting and rest
. Emergent fasciotomy
. Tight compression bandage

Correct Answer & Explanation

. Emergent fasciotomy

Explanation

Acute compartment syndrome is a surgical emergency characterized by increased pressure within a confined fascial compartment, leading to impaired blood flow and potential irreversible muscle and nerve damage. The definitive treatment is emergent fasciotomy to decompress the compartment and restore perfusion. Delay in treatment can lead to Volkmann's ischemic contracture. Ice, elevation, analgesics, observation, splinting, rest, and compression bandages are all inappropriate and potentially harmful interventions.

Question 10168

Topic: 2. Trauma

Which of the following describes the classic radiographic appearance of a Colles fracture?

. Volar displacement and angulation of the distal fragment
. Intra-articular fracture of the radial styloid with carpal subluxation
. Dorsal displacement and dorsal angulation of the distal fragment
. Fracture of the radial shaft with minimal displacement
. Compression fracture of the carpal bones

Correct Answer & Explanation

. Dorsal displacement and dorsal angulation of the distal fragment

Explanation

The classic radiographic appearance of a Colles fracture is characterized by dorsal displacement and dorsal angulation (apex volar) of the distal radius fragment. It is typically extra-articular but can have intra-articular extension. Volar displacement and angulation describe a Smith's fracture (reverse Colles). An intra-articular fracture of the radial styloid with carpal subluxation describes a Chauffeur's or Hutchinson's fracture (though not always subluxation), or a Barton's fracture if it's the rim.

Question 10169

Topic: 2. Trauma

A 30-year-old male presents with a minimally displaced, extra-articular Colles fracture. He is active and concerned about returning to sports. Which of the following is the most appropriate initial management?

. Immediate surgical fixation with a volar locking plate
. Closed reduction and sugar tong splint followed by a cast
. External fixation for 6 weeks
. Percutaneous pinning
. Activity modification without immobilization

Correct Answer & Explanation

. Closed reduction and sugar tong splint followed by a cast

Explanation

For a minimally displaced,stableextra-articular Colles fracture, especially in a young, active patient, closed reduction and sugar tong splint followed by a cast is the most appropriate initial management. The question states 'minimally displaced' implying it is not grossly unstable. If closed reduction can achieve and maintain acceptable parameters, conservative management is appropriate. Surgical options are reserved for unstable or irreducible fractures, or those with unacceptable post-reduction parameters. Activity modification alone is insufficient for a fracture.

Question 10170

Topic: 2. Trauma

In the setting of an acutely unstable Colles fracture, what is the role of an external fixator?

. It is primarily used for definitive internal fixation in comminuted fractures.
. It provides indirect reduction and maintains length and alignment through ligamentotaxis.
. It allows immediate full weight-bearing on the affected limb.
. It is indicated only for open fractures with significant soft tissue loss.
. 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

External fixation for distal radius fractures primarily provides indirect reduction and maintains length and alignment through a principle called ligamentotaxis. By distracting across the wrist joint, it tension the intact soft tissue ligaments (radiocarpal ligaments) to indirectly pull the fracture fragments into a more anatomical position. It does not allow immediate full weight-bearing and is not solely for open fractures. It restricts wrist motion initially, though dynamic external fixators aim for controlled motion.

Question 10171

Topic: 2. Trauma

A 55-year-old active female sustains a Colles fracture. Post-reduction radiographs demonstrate acceptable alignment, but she develops severe pain and swelling within 6 hours, with paresthesias in all fingers and pain with passive extension of the digits. Peripheral pulses are present. What is the most immediate concern?

. Loss of reduction
. Median nerve injury
. Compartment syndrome
. Complex regional pain syndrome
. Deep vein thrombosis

Correct Answer & Explanation

. Compartment syndrome

Explanation

The acute onset of severe pain, swelling, paresthesias in all fingers, and critically, pain with passive extension of the digits, within hours of reduction, are classic signs of acute forearm compartment syndrome. Although peripheral pulses may still be present early on, this is a surgical emergency requiring immediate fasciotomy to prevent permanent muscle and nerve damage. Median nerve injury would typically affect only the median nerve distribution. CRPS develops later, and loss of reduction wouldn't typically cause these diffuse neurological and pain symptoms acutely.

Question 10172

Topic: 2. Trauma

In the setting of an open reduction internal fixation of a Colles fracture, what is the primary advantage of fixed-angle locking screws compared to non-locking screws?

. They allow for easier removal of the plate.
. They provide superior compression across the fracture site.
. They resist pullout in osteoporotic bone by creating a fixed-angle construct.
. They are compatible with all types of distal radius plates.
. They allow for more flexible screw trajectories.

Correct Answer & Explanation

. They resist pullout in osteoporotic bone by creating a fixed-angle construct.

Explanation

The primary advantage of fixed-angle locking screws in volar plating, especially in older patients with osteoporotic bone, is their ability to resist pullout. They create a 'fixed-angle construct' or 'internal fixator' where the screws lock into the plate, providing angular stability independent of bone-plate compression. This is highly beneficial in comminuted fractures or poor bone quality where traditional screws might lose purchase. While some compression can be achieved, their main strength lies in angular stability and pullout resistance, not necessarily superior compression (which is achieved by dynamic compression holes in non-locking plates).

Question 10173

Topic: 2. Trauma

Which of the following is an absolute indication for surgical intervention in an acute Colles fracture?

. Associated ulnar styloid fracture
. Frykman Type II fracture in an elderly patient
. Persistent radial shortening of >5mm after closed reduction
. Open fracture with significant contamination
. Positive ulnar variance of 2mm

Correct Answer & Explanation

. Open fracture with significant contamination

Explanation

An open fracture with significant contamination is an absolute indication for surgical intervention (irrigation and debridement followed by stabilization), regardless of the fracture pattern or displacement, due to the high risk of infection. Persistent radial shortening of >5mm after reduction is a strongrelativeindication for surgery (unstable fracture), as is a Frykman Type II in an elderly patient if unstable, but not anabsoluteone. Associated ulnar styloid fracture and 2mm positive ulnar variance are not absolute indications on their own.

Question 10174

Topic: 2. Trauma

A patient presents with a dorsally displaced, comminuted Colles fracture in osteoporotic bone. Which factor is most predictive of early loss of reduction after closed reduction and casting?

. Age greater than 70 years
. Associated ulnar styloid fracture
. Significant dorsal comminution
. Initial radial shortening of less than 3mm
. Ability to pronate and supinate the forearm

Correct Answer & Explanation

. Significant dorsal comminution

Explanation

Significant dorsal comminution (dorsal metaphyseal comminution or the 'dorsal rind' fragment) is the most predictive factor for early loss of reduction after closed reduction and casting of a Colles fracture, especially in osteoporotic bone. The dorsal cortex provides a stable buttress, and its comminution removes this support, making it difficult to maintain the reduction in a cast. While age and ulnar styloid fractures contribute to instability, dorsal comminution directly undermines the stability of the reduced fracture. Minimal initial radial shortening might suggest a more stable fracture, but if comminution is present, it's still at high risk.

Question 10175

Topic: 2. Trauma

In patients undergoing external fixation for a Colles fracture, what is the most common early complication?

. Pin tract infection
. Nonunion
. Reflex sympathetic dystrophy (CRPS Type I)
. Extensor pollicis longus rupture
. Loss of reduction

Correct Answer & Explanation

. Pin tract infection

Explanation

Pin tract infection is the most common early complication associated with external fixation for Colles fractures. While other complications like loss of reduction (if reduction was poor or fixator fails), CRPS, and EPL rupture can occur, pin site issues (infection, loosening) are particularly prevalent and require meticulous pin site care. Nonunion is rare for distal radius fractures.

Question 10176

Topic: 2. Trauma

Which of the following statements about malunion after a Colles fracture is true?

. It is always asymptomatic and requires no further intervention.
. It is defined as a healed fracture with persistent anatomical deformity, which can lead to functional impairment.
. It always requires surgical correction (osteotomy) regardless of symptoms.
. It is less common in fractures treated conservatively compared to surgically.
. It primarily affects the intrinsic muscles of the hand.

Correct Answer & Explanation

. It is defined as a healed fracture with persistent anatomical deformity, which can lead to functional impairment.

Explanation

Malunion is defined as a fracture that has healed in an anatomically unacceptable position, leading to persistent deformity and potentially functional impairment (pain, stiffness, weakness, altered grip strength, DRUJ issues, post-traumatic arthritis). It is not always asymptomatic and often requires further intervention, especially if symptomatic. It does not always require surgical correction; asymptomatic malunions can be observed. It is more common in fractures treated conservatively or with unstable patterns, as opposed to appropriately managed surgical fixation. It affects wrist and forearm mechanics, not primarily intrinsic hand muscles.

Question 10177

Topic: 2. Trauma

What is the typical anesthetic technique used for closed reduction of an uncomplicated Colles fracture in the emergency department?

. General anesthesia with muscle relaxation
. Regional block (e.g., axillary block)
. Hematoma block with local anesthetic
. Spinal anesthesia
. Intravenous sedation without local anesthetic

Correct Answer & Explanation

. Hematoma block with local anesthetic

Explanation

For closed reduction of an uncomplicated Colles fracture in the emergency department, a hematoma block is a common and effective anesthetic technique. This involves injecting a local anesthetic (e.g., lidocaine) directly into the fracture hematoma, which infiltrates the fracture site and provides pain relief. Regional blocks or general anesthesia might be used for more complex or prolonged reductions, or for surgical fixation, but a hematoma block is usually sufficient for acute, simple reductions.

Question 10178

Topic: 2. Trauma
A 25-year-old active male sustains a Colles fracture. Radiographs show a small intra-articular step-off (<1mm) and minimal dorsal angulation (8 degrees). He is anxious to return to sports. What is the most appropriate management plan?
. Open reduction internal fixation with volar plate to achieve anatomical reduction.
. Closed reduction and sugar tong splint followed by a short arm cast for 4-6 weeks.
. External fixation to maintain length.
. Percutaneous pinning as the primary method.
. Immediate full activity with a wrist brace only.

Correct Answer & Explanation

. Closed reduction and sugar tong splint followed by a short arm cast for 4-6 weeks.

Explanation

For a minimally displaced, stable Colles fracture, even with a small intra-articular component, closed reduction (if needed) followed by sugar tong splint for initial swelling control, then a short arm cast for 4-6 weeks, is often appropriate. The parameters (8 degrees dorsal angulation, <1mm articular step-off) are typically within acceptable limits for conservative management, especially if maintained post-reduction. While a younger, active patient might push for anatomical reduction, these specific parameters don't automatically mandate surgery unless reduction is lost or symptoms are refractory. ORIF would be overtreatment for these parameters. Immediate full activity is inappropriate.

Question 10179

Topic: 2. Trauma

What constitutes an 'unstable' Colles fracture that typically warrants surgical consideration after initial closed reduction attempts?

. Any extra-articular fracture regardless of displacement.
. Fractures with less than 5 degrees of dorsal tilt and less than 2mm radial shortening.
. Fractures with persistent dorsal tilt > 10 degrees, radial shortening > 3mm, or significant articular step-off > 2mm after reduction.
. Fractures in patients younger than 20 years old.
. Fractures with an associated minimally displaced ulnar styloid fracture.

Correct Answer & Explanation

. Fractures with persistent dorsal tilt > 10 degrees, radial shortening > 3mm, or significant articular step-off > 2mm after reduction.

Explanation

An unstable Colles fracture, generally defined by unacceptable radiographic parameters after closed reduction, is a strong indication for surgical consideration. These parameters include: persistent dorsal tilt greater than 10-15 degrees, radial shortening greater than 3-5mm (or 2-3mm difference compared to contralateral), significant articular step-off or gap greater than 1-2mm, or significant comminution (dorsal or volar) making maintenance of reduction difficult. A minimally displaced ulnar styloid or extra-articular fracture alone are not typically considered unstable unless associated with other parameters.

Question 10180

Topic: 2. Trauma

Which statement regarding dorsal plating for Colles fractures is generally true?

. Dorsal plating is the preferred method for most Colles fractures due to lower complication rates.
. Dorsal plates are primarily indicated for fractures with significant volar comminution.
. Dorsal plating carries a higher risk of extensor tendon irritation and rupture compared to volar plating.
. The approach for dorsal plating typically involves retracting the radial artery volarly.
. Dorsal plates provide better stability for intra-articular fragments than volar plates.

Correct Answer & Explanation

. Dorsal plating carries a higher risk of extensor tendon irritation and rupture compared to volar plating.

Explanation

Dorsal plating for Colles fractures generally carries a higher risk of extensor tendon irritation and rupture compared to volar plating due to the prominence of hardware beneath the thin dorsal skin and the close proximity of extensor tendons. For this reason, volar plating has become the preferred approach for most dorsally displaced distal radius fractures. Dorsal plates are not primarily indicated for volar comminution (which volar plates address better), and the radial artery is not typically involved in a dorsal approach.

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