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2. Trauma MCQs

Practice Set 479 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 9561

Topic: 2. Trauma

What characteristic feature on plain radiographs is highly suggestive of a 'columnar' distal humerus fracture pattern, as opposed to a simple supracondylar fracture?

. Anterior displacement of the distal fragment
. Medial or lateral epicondyle avulsion
. Extension of the fracture line into the articular surface, creating separate medial and lateral fragments
. A posterior fat pad sign
. Presence of a greenstick fracture

Correct Answer & Explanation

. Extension of the fracture line into the articular surface, creating separate medial and lateral fragments

Explanation

A columnar distal humerus fracture (e.g., AO Type C) is characterized by a fracture line extending into the articular surface, separating the distal humerus into distinct medial and lateral fragments (columns), often with a separate articular component (T or Y configuration). This distinguishes it from a simple supracondylar fracture (AO Type A) where the fracture is entirely above the articular surface. Anterior displacement is common in supracondylar fractures. Epicondyle avulsion is a specific injury. A posterior fat pad sign indicates intra-articular effusion, not a specific fracture pattern. Greenstick fractures are typically pediatric.

Question 9562

Topic: 2. Trauma

In a patient presenting with an open distal humerus fracture (Gustilo Type II), what is the most critical initial management step once the patient is stable?

. Administer a single dose of oral antibiotics
. Splint the extremity and refer to physical therapy
. Emergent surgical debridement, irrigation, and intravenous antibiotics
. Close the wound primarily with sutures
. Order a comprehensive MRI of the elbow

Correct Answer & Explanation

. Emergent surgical debridement, irrigation, and intravenous antibiotics

Explanation

For an open fracture, emergent surgical debridement and copious irrigation in the operating room, along with the administration of broad-spectrum intravenous antibiotics, is the most critical initial management step once the patient is hemodynamically stable. This aims to minimize contamination and reduce the risk of deep infection, which can be devastating. Oral antibiotics are inadequate. Splinting alone is insufficient. Primary wound closure is typically avoided in open fractures to allow for repeat debridement. MRI is not an emergent imaging modality for acute open fractures.

Question 9563

Topic: 2. Trauma

What is the primary concern when managing a distal humerus fracture in a patient with severe medical comorbidities and a low functional demand?

. Achieving anatomical reduction at all costs
. Minimizing surgical invasiveness and maximizing patient safety
. Preventing heterotopic ossification
. Optimizing bone healing with extensive bone grafting
. Achieving full, pain-free range of motion

Correct Answer & Explanation

. Minimizing surgical invasiveness and maximizing patient safety

Explanation

In patients with severe medical comorbidities and low functional demand, the primary concern shifts from achieving an absolute anatomical reduction (which may require prolonged, complex surgery) to minimizing surgical invasiveness and maximizing patient safety. The goal is often pain relief and obtaining a functional, albeit possibly limited, range of motion, with minimal risk. This might lead to consideration of less invasive fixation, non-operative management if appropriate, or even total elbow arthroplasty, depending on the fracture and patient. The other options are often secondary to patient safety and overall well-being in this specific population.

Question 9564

Topic: 2. Trauma

Which type of screw is typically used in a locking plate system for distal humerus fixation to provide angular stability?

. Lag screw
. Cortex screw
. Cancellous screw
. Locking screw
. Suture anchor

Correct Answer & Explanation

. Locking screw

Explanation

Locking screws are specifically designed to thread into both the plate and the bone, creating a fixed-angle construct. This provides angular stability to the fracture construct, meaning the screws resist toggle and pull-out, which is particularly advantageous in osteoporotic bone or comminuted fractures where screw purchase in the bone may be compromised. Lag screws and cortex screws rely on compression and friction between the plate and bone for stability. Cancellous screws are for metaphyseal bone. Suture anchors are for soft tissue to bone fixation.

Question 9565

Topic: 2. Trauma

What is the primary advantage of a triceps-sparing posterior approach over an olecranon osteotomy for certain distal humerus fractures?

. Better visualization of the entire articular surface
. Elimination of the risk of ulnar nerve injury
. Avoidance of an osteotomy-related complication (e.g., nonunion of the olecranon)
. Allows for earlier weight-bearing on the extremity
. Significantly reduced surgical time

Correct Answer & Explanation

. Avoidance of an osteotomy-related complication (e.g., nonunion of the olecranon)

Explanation

The primary advantage of a triceps-sparing approach (e.g., the triceps-reflecting or triceps-splitting approach) is the avoidance of an olecranon osteotomy. This eliminates the potential complications associated with an osteotomy, such as nonunion, symptomatic hardware, or irritation of the olecranon bursa. While surgical time might be slightly reduced, and ulnar nerve injury is still a risk, the main benefit is avoiding the osteotomy itself. These approaches generally offer less complete visualization of the articular surface compared to an osteotomy, and early weight-bearing is not a direct advantage.

Question 9566

Topic: 2. Trauma

What is the typical management strategy for an acute, stable, non-displaced supracondylar distal humerus fracture (AO 13-A1) in an otherwise healthy adult?

. Immediate surgical ORIF
. Skeletal traction for 4-6 weeks
. Sling immobilization for comfort, followed by early gentle active ROM
. Closed reduction and long-arm cast immobilization for 6 weeks
. Total elbow arthroplasty

Correct Answer & Explanation

. Sling immobilization for comfort, followed by early gentle active ROM

Explanation

For a truly non-displaced and stable supracondylar distal humerus fracture (AO 13-A1) in an adult, non-operative management with a sling for comfort and protection, followed by early gentle active range of motion (AROM) as tolerated, is often appropriate. This helps prevent stiffness while allowing the fracture to heal. Surgical ORIF is for displaced fractures. Skeletal traction is largely historical. Rigid cast immobilization for 6 weeks would likely lead to severe stiffness. TEA is for highly comminuted or unsalvageable intra-articular fractures.

Question 9567

Topic: 2. Trauma

A patient is undergoing ORIF of a distal humerus fracture. During the procedure, the ulnar nerve is found to be severely contused and entrapped within the fracture site. What is the most appropriate action regarding the nerve?

. Bypass the nerve with a nerve graft
. Leave it in situ and close the wound quickly
. Neurolysis and anterior transposition
. Excise the contused segment to prevent pain
. Apply direct electrical stimulation to assess function

Correct Answer & Explanation

. Neurolysis and anterior transposition

Explanation

If the ulnar nerve is found to be contused and entrapped within the fracture site, the most appropriate action is to perform a neurolysis (freeing the nerve from surrounding scar/hematoma/fracture fragments) and an anterior transposition. This decompresses the nerve and moves it to a healthier, less traumatic environment, preventing re-entrapment or further injury. Nerve grafting is for lacerations/gaps. Leaving it in situ would lead to poor recovery. Excising the segment would cause permanent deficit. Electrical stimulation might be done for assessment but doesn't address the pathology.

Question 9568

Topic: 2. Trauma

What is the significance of the 'tie arch' principle in distal humerus fracture fixation?

. It refers to the stability provided by intact collateral ligaments.
. It describes the articular surface bridging the medial and lateral columns, which must be anatomically restored.
. It is a technique for indirect reduction using external fixators.
. It relates to the vascular supply to the distal humerus.
. It's a metaphor for the strength of a tension band wire construct.

Correct Answer & Explanation

. It describes the articular surface bridging the medial and lateral columns, which must be anatomically restored.

Explanation

The 'tie arch' principle describes the articular surface (capitellum and trochlea) as forming an arch that connects and stabilizes the medial and lateral columns of the distal humerus. Accurate anatomical restoration of this articular tie arch is crucial because it dictates the congruity of the elbow joint and subsequent function. If the articular surface is not anatomically reduced, it will lead to incongruity, stiffness, pain, and accelerated arthritis. The columns provide the buttress, and the articular surface provides the connection and exact fit.

Question 9569

Topic: 2. Trauma

When is bone grafting typically considered in the surgical management of distal humerus fractures?

. Routinely for all intra-articular fractures
. When there is significant metaphyseal bone loss or comminution, particularly in nonunions
. Only if the patient is osteoporotic
. As a primary method of fixation instead of plates and screws
. To prevent heterotopic ossification

Correct Answer & Explanation

. When there is significant metaphyseal bone loss or comminution, particularly in nonunions

Explanation

Bone grafting is typically considered when there is significant metaphyseal bone loss or severe comminution that creates a 'void' after reduction, especially in cases of nonunion. The graft (autograft or allograft) helps to restore bone stock, provide structural support, and enhance biological healing. It is not routinely used for all fractures, nor is it a primary method of fixation. While osteoporosis may contribute to bone loss, it's the defect itself, not just the bone quality, that drives the need for graft. Bone grafting does not prevent HO.

Question 9570

Topic: 2. Trauma

A patient undergoes ORIF of a distal humerus fracture. Six months post-op, radiographs show stable hardware but no signs of bony union, and the patient reports persistent pain and limited function. This is most consistent with what complication?

. Malunion
. Heterotopic ossification
. Nonunion
. Chronic infection
. Hardware failure

Correct Answer & Explanation

. Nonunion

Explanation

No signs of bony union at 6 months post-ORIF, coupled with persistent pain and limited function, is highly consistent with a nonunion. A nonunion is defined as a failure of a fracture to heal after a reasonable period, usually 6-9 months, with no further signs of healing. Malunion refers to healing in an unacceptable position. Heterotopic ossification would manifest as stiffness with new bone formation outside the cortex. Chronic infection would typically have signs like drainage, erythema, and systemic symptoms. Hardware failure would be visible on X-rays as broken or loosened implants.

Question 9571

Topic: 2. Trauma

What is a common pitfall when interpreting plain radiographs of a distal humerus fracture, particularly in the immediate post-injury setting?

. Overestimation of comminution
. Underestimation of articular involvement and displacement
. Mistaking a stress fracture for an acute traumatic fracture
. Failure to detect associated nerve injuries
. Difficulty in assessing soft tissue swelling

Correct Answer & Explanation

. Underestimation of articular involvement and displacement

Explanation

A common pitfall in interpreting plain radiographs of distal humerus fractures is the underestimation of articular involvement and displacement, especially in comminuted cases. Subtle coronal shear fractures (e.g., capitellar) or complex T/Y-type patterns may not be fully appreciated on 2D images. This is why a CT scan with 3D reconstructions is often crucial for surgical planning. Radiographs tend to underestimate, not overestimate, comminution. Stress fractures have different radiographic features. Nerve injuries are clinical, not radiographic findings. Soft tissue swelling can be assessed, but the primary pitfall relates to bone detail.

Question 9572

Topic: 2. Trauma

Which factor is NOT typically considered a relative contraindication to total elbow arthroplasty (TEA) for a distal humerus fracture?

. Active infection
. Youth and high demand (e.g., manual laborer)
. Significant bone loss preventing stable implant fixation
. Charcot joint arthropathy
. Poor soft tissue envelope

Correct Answer & Explanation

. Charcot joint arthropathy

Explanation

Charcot joint arthropathy (neuropathic arthropathy) is a destructive joint condition that can severely compromise joint integrity and stability, and is generally considered a contraindication to total joint arthroplasty due to the high risk of implant loosening and failure. Active infection, youth/high demand (due to wear and tear limitations of TEA), significant bone loss, and a poor soft tissue envelope (increasing infection risk and affecting wound healing) are all common relative contraindications for TEA in the context of a fracture. The question asks for what is NOT a relative contraindication, meaning Charcot is usually a strong contraindication.

Question 9573

Topic: 2. Trauma

What is the primary goal of physical therapy in the late phase (e.g., 6 weeks to 3 months) following stable ORIF of a distal humerus fracture?

. Passive stretching to improve ROM without active participation
. Initiating light strengthening exercises and progressing ROM
. Continuous passive motion (CPM) for 8 hours daily
. Maintaining immobilization to ensure full healing
. Addressing scar tissue adhesion only

Correct Answer & Explanation

. Initiating light strengthening exercises and progressing ROM

Explanation

In the late phase (6 weeks to 3 months) following stable ORIF of a distal humerus fracture, the primary goal of physical therapy is to progressively increase range of motion (both active and passive, within limits) and to initiate light strengthening exercises. At this point, fracture healing is typically progressing well, and the focus shifts to restoring strength and full functional mobility. Passive stretching alone is insufficient. CPM is often used earlier if at all, but not as the primary late-phase activity. Maintaining immobilization would lead to stiffness. Addressing scar tissue is part of it, but not the sole focus.

Question 9574

Topic: 2. Trauma

For a distal humerus fracture requiring ORIF, what is the role of an intraoperative fluoroscopy?

. To assess fracture comminution before incision
. To confirm placement of the tourniquet
. To visualize fracture reduction and hardware placement in multiple planes
. To detect potential nerve injuries during dissection
. To measure intra-articular pressure

Correct Answer & Explanation

. To visualize fracture reduction and hardware placement in multiple planes

Explanation

Intraoperative fluoroscopy (image intensifier) is essential during ORIF of distal humerus fractures. It allows the surgeon to visualize the fracture reduction and confirm optimal hardware placement (plates and screws) in multiple planes (AP and lateral views) in real-time. This helps to ensure anatomical reduction, proper screw length, and satisfactory stability before wound closure. CT is for pre-op comminution assessment. Fluoroscopy does not assess tourniquet placement, detect nerve injuries directly, or measure intra-articular pressure.

Question 9575

Topic: 2. Trauma

In a patient with an associated severe ipsilateral forearm fracture (floating elbow), what is the most appropriate approach to managing the distal humerus fracture?

. Non-operative management of the distal humerus fracture to prioritize the forearm
. Perform ORIF of both fractures, prioritizing the more proximal (distal humerus) fracture first
. External fixation of the distal humerus and ORIF of the forearm
. Amputation of the limb due to complexity
. Serial casting for both fractures

Correct Answer & Explanation

. Perform ORIF of both fractures, prioritizing the more proximal (distal humerus) fracture first

Explanation

In a 'floating elbow' injury (ipsilateral distal humerus and forearm fractures), ORIF of both fractures is generally indicated. The current consensus is to prioritize the more proximal injury (distal humerus fracture) first, as its reduction and fixation often dictate the overall limb alignment and length, which then facilitates the reduction and fixation of the forearm fracture. Non-operative management is unlikely to yield good results for two unstable fractures. External fixation for both is a temporizing measure, not definitive. Amputation is excessively drastic. Serial casting is insufficient for complex displaced fractures.

Question 9576

Topic: 2. Trauma

What is a major risk factor for nonunion after ORIF of a distal humerus fracture?

. Early active range of motion
. Age less than 30 years
. Anatomical reduction and stable fixation
. Significant comminution and bone loss
. Ulnar nerve transposition

Correct Answer & Explanation

. Significant comminution and bone loss

Explanation

Significant comminution and bone loss, particularly in the metaphyseal area, are major risk factors for nonunion after ORIF of a distal humerus fracture. Extensive comminution can compromise the fracture biology and stability, making it difficult to achieve and maintain adequate reduction and fixation, thus impeding healing. Early active ROM, age less than 30, and anatomical reduction with stable fixation are generally factors that promote healing. Ulnar nerve transposition is a separate procedure for nerve protection and does not directly cause nonunion.

Question 9577

Topic: 2. Trauma

Which specific type of distal humerus fracture is often associated with high-energy trauma and significant soft tissue injury, leading to a higher risk of complications?

. AO Type 13-A1 (extra-articular, simple)
. AO Type 13-B1 (partial articular, lateral condyle)
. AO Type 13-C3 (complete articular, multifragmentary)
. Capitellar Type I (Hahn-Steinthal)
. Trochlear Type II (Kocher-Lorenz)

Correct Answer & Explanation

. AO Type 13-C3 (complete articular, multifragmentary)

Explanation

AO Type 13-C3 fractures are complete articular, multifragmentary distal humerus fractures. These typically result from high-energy trauma, are often severely comminuted, and involve significant soft tissue injury. This complexity leads to a higher risk of complications such as nonunion, malunion, infection, nerve injury, and post-traumatic arthritis. Type A1, B1, and specific capitellar/trochlear fractures are generally less severe than a C3 complete articular comminuted fracture.

Question 9578

Topic: 2. Trauma

Which imaging modality is considered most useful for diagnosing and assessing the extent of post-traumatic arthrosis and heterotopic ossification after a distal humerus fracture?

. Plain radiographs
. Computed Tomography (CT) scan
. Magnetic Resonance Imaging (MRI)
. Ultrasound
. Bone scintigraphy

Correct Answer & Explanation

. Computed Tomography (CT) scan

Explanation

A Computed Tomography (CT) scan is the most useful imaging modality for diagnosing and assessing the extent of post-traumatic arthrosis (especially articular incongruity, joint space narrowing, and osteophytes) and heterotopic ossification (HO) after a distal humerus fracture. CT provides excellent bony detail and allows for precise localization and quantification of HO, as well as detailed evaluation of the joint surfaces. While plain radiographs can show gross changes, CT offers superior detail. MRI is better for soft tissues. Ultrasound has limited utility here. Bone scintigraphy can show metabolic activity but not anatomical detail.

Question 9579

Topic: 2. Trauma
In a case of chronic nonunion of a distal humerus fracture, what additional surgical component is often necessary alongside revision fixation?
. Application of a continuous passive motion (CPM) device
. Extensive dรฉbridement of normal soft tissue
. Bone grafting (e.g., autograft or allograft)
. Early removal of all existing hardware
. Immediate total elbow arthroplasty

Correct Answer & Explanation

. Bone grafting (e.g., autograft or allograft)

Explanation

For chronic nonunions of distal humerus fractures, revision fixation almost always requires the addition of bone grafting (autograft or allograft). This is because nonunions often have a biological deficit (avascular or sclerotic ends) and/or a mechanical deficit (instability).

Question 9580

Topic: 2. Trauma

What is the primary indication for total elbow arthroplasty (TEA) in the context of a distal humerus fracture?

. Any displaced intra-articular fracture in a young, active patient
. Comminuted, unreconstructible intra-articular fractures in low-demand elderly patients
. Open fractures with minimal soft tissue injury
. Simple supracondylar fractures (AO 13-A1)
. Associated nerve palsy requiring exploration

Correct Answer & Explanation

. Comminuted, unreconstructible intra-articular fractures in low-demand elderly patients

Explanation

The primary indication for total elbow arthroplasty (TEA) for a distal humerus fracture is a comminuted, unreconstructible intra-articular fracture (e.g., severe AO 13-C3) in an elderly patient with low functional demands. In this population, TEA provides immediate stability, allowing early motion and good pain relief, often with better outcomes than attempting ORIF with poor bone quality. For young, active patients, ORIF is almost always preferred to preserve native bone. Open fractures need debridement and ORIF. Simple supracondylar fractures are managed non-operatively or with simpler ORIF. Nerve palsy is a separate issue.

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