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2. Trauma MCQs

Practice Set 123 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 2441

Topic: 2. Trauma

A patient presents with a tibia diaphyseal nonunion 8 months after cast treatment. Radiographs show abundant bridging callus that fails to cross the fracture site (elephant foot appearance). What is the primary underlying cause and appropriate treatment?

. Inadequate biology; treat with autologous bone grafting alone
. Inadequate biology; treat with vascularized fibula graft
. Inadequate stability; treat with rigid internal fixation without bone grafting
. Infection; treat with serial debridement and antibiotics
. Metabolic bone disease; treat with high-dose teriparatide

Correct Answer & Explanation

. Inadequate stability; treat with rigid internal fixation without bone grafting

Explanation

A hypertrophic nonunion ('elephant foot') possesses excellent biological healing potential but lacks adequate mechanical stability. Treatment consists of rigid mechanical stabilization (e.g., intramedullary nailing or plating), which typically results in union without the need for bone grafting.

Question 2442

Topic: 2. Trauma

When utilizing a bridge plating technique for a comminuted osteoporotic tibia shaft fracture, what is the biomechanical effect of increasing the working length (leaving empty screw holes over the fracture site)?

. It increases construct stiffness, leading to primary bone healing.
. It decreases construct stiffness, allowing interfragmentary motion to promote secondary bone healing.
. It increases the risk of screw pullout due to higher strain per screw.
. It shifts the neutral axis of the bone, increasing risk of varus collapse.
. It completely eliminates micromotion, causing stress shielding.

Correct Answer & Explanation

. It decreases construct stiffness, allowing interfragmentary motion to promote secondary bone healing.

Explanation

Increasing the working length of a bridge plate decreases the overall stiffness of the construct. This permits controlled interfragmentary strain and micromotion, which promotes secondary bone healing (callus formation).

Question 2443

Topic: 2. Trauma

An 82-year-old female with severe osteoporosis presents with a displaced bimalleolar equivalent ankle fracture. Which fixation strategy provides the best biomechanical advantage to prevent hardware failure in the lateral malleolus?

. Standard one-third tubular plate applied laterally
. Intramedullary fibular nail
. Multiple isolated lag screws
. Tension band wiring of the fibula
. Non-operative casting due to bone quality

Correct Answer & Explanation

. Intramedullary fibular nail

Explanation

An intramedullary fibular nail is a load-sharing device that provides superior biomechanical stability in osteoporotic bone compared to lateral plating. It is placed through a minimal incision, reducing the risk of soft tissue complications.

Question 2444

Topic: 2. Trauma

A 75-year-old female presents with a highly comminuted, bicondylar proximal tibia fracture.

What is the primary advantage of utilizing dual locked plating for this specific injury in this demographic?

. It allows for immediate full weight-bearing post-operatively.
. It eliminates the need for any bone grafting.
. It prevents varus collapse and provides rigid fixed-angle stability in osteoporotic metaphyseal bone.
. It requires smaller incisions than single lateral locked plating.
. It relies purely on the frictional force between the plate and the bone.

Correct Answer & Explanation

. It prevents varus collapse and provides rigid fixed-angle stability in osteoporotic metaphyseal bone.

Explanation

Dual plating in bicondylar plateau fractures, especially in osteoporotic bone, provides rigid, fixed-angle stabilization of both the medial and lateral columns, specifically preventing varus/valgus collapse and hardware pullout.

Question 2445

Topic: 2. Trauma

A patient presents with a proximal tibia fracture associated with a high-energy knee dislocation. Following closed reduction and splinting, vascular assessment is performed. Which Ankle-Brachial Index (ABI) threshold mandates an immediate CT angiogram?

. < 1.1
. < 1.0
. < 0.9
. < 0.7
. < 0.5

Correct Answer & Explanation

. < 0.9

Explanation

In the setting of a knee dislocation or high-energy proximal tibia fracture, an Ankle-Brachial Index (ABI) of < 0.9 is highly suspicious for arterial injury and mandates further advanced vascular imaging, typically a CT angiogram.

Question 2446

Topic: 2. Trauma

Following the treatment of a tibia shaft fracture with a reamed intramedullary nail, a patient complains of persistent anterior knee pain. Current literature suggests this complication is most strongly associated with which factor?

. Use of a paratendinous vs. transtendinous surgical approach
. Prominence of the nail apex above the proximal tibial cortex
. Failure to ream the medullary canal
. Placement of a distal locking screw
. The degree of fracture comminution

Correct Answer & Explanation

. Prominence of the nail apex above the proximal tibial cortex

Explanation

Anterior knee pain is the most common complication following tibia nailing. While approach (paratendinous vs. transtendinous) does not significantly differ in pain rates, proximal nail prominence is a known risk factor for persistent pain.

Question 2447

Topic: 2. Trauma

An 81-year-old female with severe osteoporosis sustains a comminuted bicondylar tibial plateau fracture. During open reduction and internal fixation, the surgeon decides to use calcium phosphate cement in the metaphyseal defect. What is the primary biomechanical advantage of this technique?

. Accelerates secondary bone healing at the fracture site
. Increases the pullout strength of the diaphyseal screws
. Decreases the risk of articular subsidence
. Allows for immediate full weight-bearing
. Prevents thermal necrosis of surrounding bone

Correct Answer & Explanation

. Decreases the risk of articular subsidence

Explanation

Calcium phosphate cement has high compressive strength and provides excellent structural support for articular fragments in osteoporotic bone. It significantly decreases the risk of articular subsidence when used to fill metaphyseal defects in tibial plateau fractures.

Question 2448

Topic: 2. Trauma

A 65-year-old male undergoes intramedullary nailing for a proximal third tibial shaft fracture. To prevent the most common malalignment, Poller (blocking) screws are planned. For a typical apex anterior (procurvatum) and valgus deformity, where should the blocking screws be placed relative to the nail in the proximal fragment?

. Anterior and medial
. Anterior and lateral
. Posterior and medial
. Posterior and lateral
. Directly anterior and distal to the fracture

Correct Answer & Explanation

. Posterior and lateral

Explanation

In proximal tibia fractures, the pull of the patellar tendon causes procurvatum, and the pes anserinus causes valgus. To counteract this, blocking screws should be placed on the concave side of the deformity (posterior and lateral) in the proximal fragment to guide the nail.

Question 2449

Topic: 2. Trauma

An 85-year-old low-demand patient with severe osteopenia and peripheral vascular disease sustains a displaced, comminuted distal tibia and fibula fracture with significant soft tissue compromise. What is the most appropriate surgical intervention?

. Minimally invasive plate osteosynthesis (MIPO) of the tibia
. Open reduction and internal fixation of both bones
. Primary tibiotalocalcaneal (TTC) intramedullary nailing
. External fixation with delayed plating
. Non-operative management in a long leg cast

Correct Answer & Explanation

. Primary tibiotalocalcaneal (TTC) intramedullary nailing

Explanation

In elderly, low-demand patients with severe osteoporosis and poor soft tissues, primary TTC nailing provides rigid, load-sharing fixation while minimizing soft tissue stripping. It avoids the high complication rates associated with plating in this specific demographic.

Question 2450

Topic: 2. Trauma

A 40-year-old male sustains a closed tibial shaft fracture. Four hours post-injury, he is intubated for an associated head injury. His blood pressure is 100/60 mmHg. An intra-compartmental pressure monitor shows an anterior compartment pressure of 40 mmHg. What is the most appropriate next step?

. Elevation of the leg and re-evaluation in 2 hours
. Administration of intravenous mannitol
. Application of a long leg cast
. Immediate four-compartment fasciotomy
. Intramedullary nailing without fasciotomy

Correct Answer & Explanation

. Immediate four-compartment fasciotomy

Explanation

The diagnosis of compartment syndrome in an obtunded patient relies on absolute pressure or the delta P (diastolic BP minus compartment pressure). A delta P of less than 30 mmHg (60 - 40 = 20 mmHg) is an absolute indication for emergent four-compartment fasciotomy.

Question 2451

Topic: 2. Trauma

A 68-year-old female presents with an aseptic oligotrophic nonunion of the tibial diaphysis 9 months after placement of an 8-mm statically locked intramedullary nail. She has mild pain with weight-bearing. The fracture is axially stable but shows minimal callus. What is the most reliable surgical treatment?

. Dynamization by removing the distal locking screws
. Exchange to a larger diameter statically locked reamed intramedullary nail
. Removal of the nail and application of a circular external fixator
. Addition of a bridging compression plate with autograft
. Non-invasive low-intensity pulsed ultrasound (LIPUS)

Correct Answer & Explanation

. Exchange to a larger diameter statically locked reamed intramedullary nail

Explanation

Exchange nailing to a larger diameter reamed nail is the most reliable treatment for aseptic diaphyseal nonunions. Reaming provides autogenous bone graft, and a larger nail increases the biomechanical stability of the construct.

Question 2452

Topic: 2. Trauma

An 82-year-old female with severe osteoarthritis of the knee sustains a displaced, comminuted Schatzker Type II tibial plateau fracture. She was previously active but reports severe pre-injury knee pain. What is the most appropriate definitive management?

. Open reduction and internal fixation with a lateral locking plate
. External fixation
. Primary Total Knee Arthroplasty (TKA) using a stemmed tibial component
. Non-operative management in a hinged knee brace
. Arthroscopic-assisted percutaneous screw fixation

Correct Answer & Explanation

. Primary Total Knee Arthroplasty (TKA) using a stemmed tibial component

Explanation

In elderly patients with pre-existing symptomatic osteoarthritis and a displaced articular fracture, primary TKA with a stemmed tibial component allows for immediate weight-bearing and addresses both the fracture and the underlying arthritis.

Question 2453

Topic: 2. Trauma

In the management of osteoporotic distal tibia fractures using locked plating, which of the following describes the "working length" of the construct?

. The distance between the most proximal and most distal screws
. The distance between the innermost screws on either side of the fracture
. The total length of the plate
. The length of the screw thread engaged in the far cortex
. The distance from the plate to the bone surface

Correct Answer & Explanation

. The distance between the innermost screws on either side of the fracture

Explanation

The working length of a plate is defined as the distance between the two closest screws on opposite sides of the fracture. Increasing the working length in a bridging construct decreases construct stiffness, which is favorable for secondary bone healing.

Question 2454

Topic: 2. Trauma

A 72-year-old female with severe osteoporosis sustains a comminuted distal tibia fracture. The decision is made to proceed with locked plate osteosynthesis. What is the primary biomechanical advantage of using a locked plating construct over conventional plating in this osteoporotic bone?

. It relies on friction between the plate and the bone to maintain stability.
. It promotes primary bone healing by allowing dynamic compression across all fracture fragments.
. It allows for earlier weight-bearing than an intramedullary nail.
. It functions as a fixed-angle construct, relying on the screw-plate interface rather than bone purchase.
. It prevents stress shielding by decreasing the working length of the fracture construct.

Correct Answer & Explanation

. It functions as a fixed-angle construct, relying on the screw-plate interface rather than bone purchase.

Explanation

Locked plates act as internal external fixators, relying on the threaded screw-to-plate interface for stability rather than friction between the plate and bone. This fixed-angle construct significantly reduces the risk of screw pullout, making it highly advantageous in osteoporotic bone.

Question 2455

Topic: 2. Trauma

A 68-year-old male undergoes intramedullary nailing for an osteoporotic proximal third tibia fracture. Intraoperatively, a varus deformity is noted. To correct this malalignment using blocking (Poller) screws, where should the screw be placed relative to the intramedullary nail?

. On the convex side of the deformity in the proximal segment.
. On the concave side of the deformity in the proximal segment.
. Directly anterior to the nail in the distal segment.
. Directly posterior to the nail in the proximal segment.
. In the fracture gap to mechanically block propagation.

Correct Answer & Explanation

. On the concave side of the deformity in the proximal segment.

Explanation

Blocking (Poller) screws should be placed on the concave side of the deformity to direct the path of the intramedullary nail. For a varus deformity, the screw is placed medially in the proximal segment to force the nail laterally and correct the alignment.

Question 2456

Topic: 2. Trauma

A 65-year-old female sustains a bicondylar tibial plateau fracture (Schatzker VI). Dual plating is planned. What is the primary biomechanical rationale for adding a medial anti-glide or buttress plate to a robust lateral locked plate in this patient?

. To prevent apex anterior angulation (procurvatum) of the tibial shaft.
. To allow for immediate unrestricted weight-bearing postoperatively.
. To prevent varus collapse and medial plateau subsidence.
. To decrease the risk of post-operative compartment syndrome.
. To provide a tension band effect on the anterior tibial crest.

Correct Answer & Explanation

. To prevent varus collapse and medial plateau subsidence.

Explanation

In bicondylar tibial plateau fractures, isolated lateral locked plating has a high failure rate in preventing varus collapse of the medial column, especially in osteoporotic bone. The addition of a medial plate restores the medial buttress and prevents this specific mode of failure.

Question 2457

Topic: 2. Trauma

A 75-year-old patient with an osteoporotic tibial shaft fracture presents to the emergency department hypotensive due to concurrent abdominal injuries. How does systemic hypotension alter the evaluation for acute compartment syndrome in this patient?

. It lowers the absolute intracompartmental pressure threshold at which irreversible ischemia occurs.
. It falsely elevates intracompartmental pressure readings.
. It makes physical exam findings of pain out of proportion more reliable.
. It requires a higher Delta P (diastolic pressure minus compartment pressure) to diagnose compartment syndrome.
. It negates the need for continuous compartment pressure monitoring.

Correct Answer & Explanation

. It lowers the absolute intracompartmental pressure threshold at which irreversible ischemia occurs.

Explanation

Compartment syndrome is driven by the perfusion gradient (Delta P). In a hypotensive patient, the diastolic blood pressure is lower, meaning a much lower absolute compartment pressure can cause tissue ischemia (Delta P < 30 mmHg indicates ischemia).

Question 2458

Topic: 2. Trauma

Which of the following describes the optimal bridge plating technique for an osteoporotic, highly comminuted midshaft tibia fracture to maximize construct longevity and promote secondary bone healing?

. A short plate with all holes filled to maximize rigidity.
. A long plate with all holes filled to prevent screw pullout.
. A short plate with widely spaced screws to allow for micro-motion.
. A short plate with eccentric drilling for absolute stability.
. A long plate with a high plate-span ratio and widely spaced screws.

Correct Answer & Explanation

. A long plate with a high plate-span ratio and widely spaced screws.

Explanation

Bridge plating for comminuted fractures relies on relative stability and secondary healing. Using a long plate (high plate-span ratio) with widely spaced screws (low screw density) distributes stresses over a larger area, reducing the risk of implant failure in osteoporotic bone.

Question 2459

Topic: 2. Trauma

When performing intramedullary nailing of a proximal tibia fracture in an elderly patient, the suprapatellar approach is chosen over the standard infrapatellar approach. What is the primary mechanical advantage of the suprapatellar approach?

. It completely avoids penetration of the joint capsule.
. It allows the knee to be positioned in semi-extension, neutralizing the deforming forces of the extensor mechanism.
. It prevents damage to the infrapatellar branch of the saphenous nerve.
. It eliminates the need for intraoperative fluoroscopy.
. It allows for simultaneous prophylactic stabilization of the patella.

Correct Answer & Explanation

. It allows the knee to be positioned in semi-extension, neutralizing the deforming forces of the extensor mechanism.

Explanation

The suprapatellar approach allows intramedullary nailing with the knee in 10-20 degrees of flexion (semi-extension). This relieves tension on the patellar tendon, which otherwise acts as a deforming force causing procurvatum (apex anterior angulation) during standard hyperflexed nailing.

Question 2460

Topic: 2. Trauma

During closed reduction and intramedullary nailing of an osteoporotic distal-third tibia fracture, an intraoperative fluoroscopic image shows an unexpected distal fracture extension. What is the most common cause of this complication?

. Excessive hoop stresses generated during nail insertion into an unreamed stiff metaphysis.
. Premature application of a proximal interlocking screw.
. Use of a dynamically locked intramedullary nail.
. Using an entry point that is too lateral on the tibial plateau.
. Thermal necrosis from excessive reaming of the diaphysis.

Correct Answer & Explanation

. Excessive hoop stresses generated during nail insertion into an unreamed stiff metaphysis.

Explanation

Distal fracture propagation during nailing often results from excessive hoop stresses. This occurs when an oversized nail is impacted into a narrow or insufficiently reamed distal metaphysis, splitting the osteoporotic or stiff bone.

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