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2. Trauma MCQs

Practice Set 462 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 9221

Topic: 2. Trauma

Which of the following describes the most appropriate use of a 'condylar plate' (e.g., DCP-condylar plate or LCP-condylar plate) in lower extremity trauma?

. For bridging comminuted diaphyseal fractures of the femur.
. For achieving interfragmentary compression in a simple transverse patellar fracture.
. For providing buttress support and angular stability in complex distal femoral or proximal tibial fractures.
. For neutralizing torsional forces in a long oblique fibular fracture.
. For tension band fixation of a medial malleolus fracture.

Correct Answer & Explanation

. For providing buttress support and angular stability in complex distal femoral or proximal tibial fractures.

Explanation

Condylar plates are specifically designed with a rigid angled blade or locking screw cluster for fixation of metaphyseal-epiphyseal fractures involving the knee region, such as complex distal femoral fractures or proximal tibial fractures. They provide robust angular stability and buttress support for these often-comminuted and osteoporotic regions, allowing for precise articular reduction and stable metaphyseal fixation. They are not designed for diaphyseal bridging, patellar fixation, fibular torsion, or medial malleolus tension banding, which have their own specific fixation strategies.

Question 9222

Topic: 2. Trauma

When performing open reduction and internal fixation of a forearm fracture (radius and ulna), what is a key principle of plating in this region?

. Always use locking plates to maximize stability in both bones.
. The plates should be placed on the tension side of the radius and ulna.
. A single plate should be used to fix both bones to simplify the procedure.
. The plates should be applied to prevent pronation-supination deformities.
. The plates should be placed on opposing sides of the radius and ulna to minimize stress shielding.

Correct Answer & Explanation

. The plates should be placed on the tension side of the radius and ulna.

Explanation

For forearm fractures (radius and ulna), meticulous anatomical reduction and rigid fixation are paramount to restore the complex biomechanics of pronation and supination. Plates are typically placed on the tension side of the bone (e.g., volar on the radius, dorsal on the ulna for typical fractures), which is often considered the 'convex' side during physiological loading, converting tensile forces into compression. This maximizes stability and aids healing. Separate plates for each bone are essential. Locking plates are not always required; conventional DCPs are often adequate if good reduction and cortical purchase are achieved. Plate placement should restore native anatomy, not necessarily just avoid stress shielding.

Question 9223

Topic: 2. Trauma

Which of the following scenarios would most appropriately indicate the removal of a well-fixed plate in a skeletally mature adult?

. Prophylactic removal to prevent stress shielding after bone healing.
. Routine removal after 12 months for all lower extremity fractures.
. Symptomatic hardware prominence causing irritation or pain.
. Uncomplicated healing of a clavicle fracture after 6 months.
. Concerns about potential future imaging artifact from the implant.

Correct Answer & Explanation

. Symptomatic hardware prominence causing irritation or pain.

Explanation

The most appropriate indication for plate removal in a well-fixed, healed fracture is symptomatic hardware prominence causing pain, irritation, or functional impingement. While prophylactic removal is sometimes considered, and stress shielding is a concern, it's not a universal indication for removal. Routine removal without symptoms is generally not recommended, as it carries surgical risks (infection, refracture, nerve injury). Clavicle plates are often removed due to prominence, but only if symptomatic. Imaging artifact is rarely a primary indication for removal unless it interferes with diagnosis of a critical condition. The risks of removal must always be weighed against the benefits.

Question 9224

Topic: Upper Extremity Trauma

A surgeon is considering the use of a low-profile plate for a subcutaneous bone like the clavicle or distal ulna. What is the primary advantage of a low-profile plate in these locations?

. Increased biomechanical strength due to reduced material volume.
. Facilitates easier removal due to a smaller footprint.
. Minimizes soft tissue irritation and hardware prominence.
. Allows for better visualization during fluoroscopy.
. Promotes faster bone healing by increasing local vascularity.

Correct Answer & Explanation

. Minimizes soft tissue irritation and hardware prominence.

Explanation

In subcutaneous locations (e.g., clavicle, olecranon, distal ulna, distal tibia), hardware prominence is a very common cause of patient discomfort, pain, and irritation, often necessitating plate removal. Low-profile plates are specifically designed to have a thinner and flatter contour to minimize this issue, thus improving patient comfort and potentially reducing the need for subsequent hardware removal. They do not offer increased strength (often less so), faster healing, or better fluoroscopy (can be harder to see if very thin).

Question 9225

Topic: 2. Trauma

What is the primary indication for using a 'blade plate' (e.g., 95-degree condylar blade plate)?

. To bridge a comminuted fracture of the femoral diaphysis.
. To provide absolute stability for an articular fracture of the distal radius.
. To fix an intertrochanteric hip fracture in an osteoporotic patient.
. To provide angular stability for metaphyseal fractures, particularly the distal femur and proximal tibia.
. To buttress a depressed articular segment of the tibial plateau.

Correct Answer & Explanation

. To provide angular stability for metaphyseal fractures, particularly the distal femur and proximal tibia.

Explanation

Blade plates (e.g., the AO 95-degree condylar plate) are used for complex metaphyseal fractures, particularly around the knee (distal femur, proximal tibia). They provide excellent angular stability because the broad blade is driven into the cancellous bone, creating a rigid connection to the bone segment, while the plate itself provides lateral support. While they can be used in the femur, their primary indication is for metaphyseal/epiphyseal fractures requiring angular stability, not typically for bridging diaphyseal fractures, distal radius, or intertrochanteric fractures (for which IM nails or DCS are often preferred). While it provides buttress support, its defining feature is the angular stability provided by the blade.

Question 9226

Topic: 2. Trauma

During the surgical fixation of a tibia fracture with a plate, what is the 'safe zone' for screw placement on the anterior aspect of the tibia?

. There is no true safe zone, as all aspects carry risk.
. The anteromedial surface, due to its thick cortical bone.
. The anterolateral surface, avoiding the neurovascular bundle.
. The anterior crest is generally avoided due to its subcutaneous location and poor blood supply.
. Only the posterior aspect of the tibia is considered safe for plating.

Correct Answer & Explanation

. The anterior crest is generally avoided due to its subcutaneous location and poor blood supply.

Explanation

The anterior crest of the tibia is generally considered a 'watershed' area with relatively poor blood supply and a thin soft tissue envelope. Plating directly on the anterior crest can increase the risk of delayed union, non-union, wound dehiscence, and infection, as well as being prominent hardware. Plates are typically applied to the anteromedial or lateral surfaces, avoiding the crest. The posteromedial aspect is also an option, but the question focuses on the anterior aspect.

Question 9227

Topic: 2. Trauma

What is the principle behind using a 'load screw' in a plate fixation construct?

. It is a locking screw used to distribute axial load evenly.
. It is a conventional screw placed eccentrically in a DCP hole to generate compression.
. It is a cancellous screw used to draw a metaphyseal fragment towards the plate.
. It is a screw used to apply distraction across the fracture site.
. It is a screw used to anchor a bone graft to the plate.

Correct Answer & Explanation

. It is a conventional screw placed eccentrically in a DCP hole to generate compression.

Explanation

A 'load screw' or 'compression screw' in the context of a conventional plate (like a DCP) is a screw placed eccentrically in an oval hole, which, upon tightening, slides down the inclined plane of the hole, pulling the bone fragment towards the fracture and generating interfragmentary compression. This is the mechanism by which conventional plates achieve active compression across a fracture. It is a specific type of conventional screw application, distinct from locking screws or simply anchoring fragments. (Note: The term 'load screw' can sometimes be used more generically, but in the context of 'plate fixation' and 'compression,' eccentric drilling in a DCP is the classic example.)

Question 9228

Topic: 2. Trauma

When a long plate is used to bridge a comminuted diaphyseal fracture, what is the most important consideration for screw placement in the main proximal and distal fragments to optimize biomechanical stability and healing?

. Place as many screws as possible in each fragment to maximize pull-out strength.
. Use only locking screws to ensure absolute stability.
. Distribute screws evenly throughout the plate length, including the comminuted zone.
. Place screws as far away from the fracture site as possible, creating a long working length.
. Prioritize bicortical screw purchase in each fragment, regardless of screw density.

Correct Answer & Explanation

. Place screws as far away from the fracture site as possible, creating a long working length.

Explanation

For bridging comminuted diaphyseal fractures, the goal is relative stability and secondary bone healing. A 'long working length' is desirable, meaning screws should be placed further away from the fracture site in the main fragments, and the screws should be spread out to reduce construct stiffness. This allows for controlled micromotion, which promotes callus formation. Placing too many screws close to the fracture shortens the working length and increases stiffness, which can hinder secondary healing. While bicortical purchase is always preferred, thedistributionof screws to optimize working length is key here. 'Distribute screws evenly throughout the plate length' is not correct for bridging; it should be concentrated at ends to leave fracture zone untouched.

Question 9229

Topic: 2. Trauma

What is the primary role of an 'articular plate' (e.g., T-plate, L-plate, cloverleaf plate) in the treatment of a Pilon fracture?

. To provide dynamic compression across the metaphyseal-diaphyseal junction.
. To act as a tension band against eccentric loading forces.
. To buttress and support reconstructed articular fragments, preventing collapse.
. To achieve absolute stability across the entire fracture by lag screw placement.
. To facilitate minimally invasive percutaneous osteosynthesis.

Correct Answer & Explanation

. To buttress and support reconstructed articular fragments, preventing collapse.

Explanation

Articular plates like T-plates, L-plates, or cloverleaf plates are primarily designed to buttress and support reconstructed articular fragments. In complex intra-articular fractures (like Pilon or tibial plateau), the articular surface needs to be anatomically reduced and then supported against axial loading forces that would cause the fragments to collapse. The plate acts as a scaffold or buttress to maintain this reduction. While they may incorporate locking screws for added stability, their fundamental role is mechanical support against collapse, not primarily dynamic compression or tension banding.

Question 9230

Topic: 2. Trauma

Which biomechanical principle is violated when a surgeon applies a standard DCP without pre-bending to a simple transverse fracture and achieves only near-cortex compression?

. Stress shielding principle.
. Neutralization principle.
. Tension band principle.
. Interfragmentary compression on the far cortex.
. Load-sharing principle.

Correct Answer & Explanation

. Interfragmentary compression on the far cortex.

Explanation

This scenario directly violates the principle of achieving interfragmentary compression on the far (trans) cortex. Without pre-bending, as the screws pull the plate down, the near cortex compresses, but the far cortex can gap open, leading to an unstable construct prone to failure. Pre-bending ensures that as the plate is flattened, it drives the far cortex into compression. While stress shielding and load-sharing are general biomechanical principles, the specific issue here is inadequate compression across the entire fracture plane.

Question 9231

Topic: 2. Trauma

What is the most significant disadvantage of removing a well-healed plate from the midshaft tibia in a skeletally mature adult?

. Increased risk of infection during the removal surgery.
. Refracture through screw holes or the healed fracture site.
. Persistent pain due to soft tissue scarring.
. Loss of bone density around the screw holes.
. Prolonged recovery time compared to the initial surgery.

Correct Answer & Explanation

. Refracture through screw holes or the healed fracture site.

Explanation

The most significant and feared complication of removing a well-healed plate, particularly from a load-bearing bone like the tibia, is refracture through the screw holes or the original fracture site. The empty screw holes create stress risers, and if the bone has been subject to significant stress shielding, it can be temporarily weakened. Patients are typically advised to have a protected weight-bearing period after hardware removal from critical load-bearing bones to allow the bone to remodel and fill in the screw holes, reducing the refracture risk. While infection and pain are risks, refracture is unique and highly problematic.

Question 9232

Topic: 2. Trauma

Which of the following is a biomechanical advantage of using a 'dual plating' technique (e.g., anterior and posterior plates) for fixation of a long bone fracture?

. It allows for earlier full weight-bearing due to increased absolute stability.
. It significantly reduces the risk of stress shielding by distributing loads.
. It provides superior stability against bending and torsional forces in multiple planes.
. It eliminates the need for bone grafting in comminuted fractures.
. It preserves periosteal blood supply better than single plating.

Correct Answer & Explanation

. It provides superior stability against bending and torsional forces in multiple planes.

Explanation

Dual plating, typically applied on different surfaces of a long bone (e.g., anterior and posterior on the humerus, medial and anterior on the tibia), provides significantly superior stability against bending and torsional forces in multiple planes compared to a single plate. This multiplanar fixation is particularly useful for highly unstable fractures, non-unions, or osteotomies requiring very robust constructs. It does not necessarily reduce stress shielding or preserve periosteal blood supply more than a single plate; in fact, it can sometimes increase soft tissue disruption. While it provides increased stability, 'absolute stability' is a specific concept often for primary healing.

Question 9233

Topic: 2. Trauma

What is the key principle for ensuring adequate periosteal blood supply when applying a plate for internal fixation?

. Aggressively stripping the periosteum to ensure direct plate-bone contact.
. Using plates with smooth undersurfaces to minimize friction.
. Maintaining meticulous soft tissue handling and utilizing techniques like MIPO or LC-DCP design.
. Applying the plate tightly to maximize compression and vascularity.
. Drilling all screw holes bicortically to anchor the plate firmly.

Correct Answer & Explanation

. Maintaining meticulous soft tissue handling and utilizing techniques like MIPO or LC-DCP design.

Explanation

Preservation of periosteal blood supply is paramount for biological fracture healing. The periosteum is a critical source of vascularity to the underlying cortical bone. Meticulous soft tissue handling, avoiding aggressive periosteal stripping, and utilizing plate designs that minimize plate-bone contact (e.g., LC-DCPs) or MIPO techniques, are all aimed at preserving this vital blood supply and promoting optimal bone healing. Aggressive stripping, maximizing compression directly, or using only smooth surfaces would be detrimental or irrelevant.

Question 9234

Topic: 2. Trauma

When using a locking plate, what is the primary reason for avoiding over-tightening of the locking screws?

. To prevent screw stripping in the bone.
. To allow for dynamic compression at the fracture site.
. To avoid damaging the threads in the plate and cold welding, potentially making removal difficult.
. To prevent excessive stress shielding of the underlying bone.
. To reduce the risk of infection by minimizing implant friction.

Correct Answer & Explanation

. To avoid damaging the threads in the plate and cold welding, potentially making removal difficult.

Explanation

While locking screws are designed to be tightened firmly, excessive torque can damage the threads in the plate, compromise the screw-plate interface, and potentially lead to cold welding between the screw head and the plate, making subsequent removal extremely difficult or impossible without specialized tools. Locking screws do not rely on bone purchase for primary stability, so stripping in the bone is less of a concern than plate thread damage. Dynamic compression is not achieved with locking screws. Stress shielding is a general feature of rigid constructs, not primarily due to over-tightening specific locking screws.

Question 9235

Topic: 2. Trauma

What is the main advantage of an 'anatomically pre-contoured' locking plate over a straight locking plate?

. It allows for variable screw angles without manual manipulation.
. It has a lower modulus of elasticity, reducing stress shielding.
. It requires less intraoperative bending, preserving plate strength and reducing OR time.
. It can be used for any bone fracture, regardless of geometry.
. It provides superior interfragmentary compression.

Correct Answer & Explanation

. It requires less intraoperative bending, preserving plate strength and reducing OR time.

Explanation

Anatomically pre-contoured plates (e.g., for distal radius, proximal humerus, distal femur) are designed to closely match the complex anatomical shape of specific bone regions. This significantly reduces or eliminates the need for intraoperative plate bending, which can weaken the plate (especially locking plates, where bending can damage the screw holes) and is time-consuming. This makes plate application more efficient and potentially preserves the plate's inherent strength. They don't provide variable screw angles (that's a different plate feature), lower modulus, or universal applicability.

Question 9236

Topic: 2. Trauma
Which of the following fracture types is generally considered a strong contraindication for internal fixation with a plate?
. An open fracture, Gustilo-Anderson Type IIIC with major vascular injury.
. A pathological fracture due to metastatic disease.
. A simple transverse fracture of the humerus.
. A comminuted distal radius fracture in an elderly patient.
. A non-union of the tibia requiring revision surgery.

Correct Answer & Explanation

. An open fracture, Gustilo-Anderson Type IIIC with major vascular injury.

Explanation

An open fracture, Gustilo-Anderson Type IIIC, involves extensive soft tissue damage, significant contamination, and major neurovascular injury. While plates can sometimes be used in open fractures, a Type IIIC fracture often necessitates initial external fixation for stabilization, debridement, and soft tissue management, with definitive internal fixation delayed or sometimes contraindicated altogether due to the high risk of infection and further damage. This represents a scenario where internal fixation with a plate would be highly ill-advised as a primary treatment. Pathological fractures and non-unions are often indications for plating.

Question 9237

Topic: 2. Trauma

What is the biomechanical significance of 'polyaxial' locking screws in a variable-angle locking plate?

. They allow for screw insertion at any desired angle without locking to the plate.
. They provide a fixed angle to the plate but can be inserted at multiple points.
. They enable the surgeon to choose the angle of screw insertion within a limited conical trajectory relative to the plate, enhancing fragment capture.
. They are self-drilling and self-tapping, simplifying surgical technique.
. They convert tensile forces into compression at the screw-plate interface.

Correct Answer & Explanation

. They enable the surgeon to choose the angle of screw insertion within a limited conical trajectory relative to the plate, enhancing fragment capture.

Explanation

Polyaxial (or variable-angle) locking screws, in conjunction with a variable-angle locking plate, allow the surgeon to insert the screw at various angles (within a defined conical range, e.g., +/- 15-20 degrees) relative to the plate. This is extremely valuable for optimizing screw purchase in complex fracture patterns, avoiding critical structures (e.g., articular surface, neurovascular bundles), or bypassing previous hardware. They still 'lock' into the plate, forming a fixed-angle construct once tightened at the chosen angle. Uniaxial locking screws only allow one fixed angle.

Question 9238

Topic: Lower Extremity Trauma

When treating a non-union with plate fixation, what is often a critical adjunct to the plate itself to promote healing?

. Immediate full weight-bearing to stimulate bone remodeling.
. Using a shorter, stiffer plate to maximize compression.
. Aggressive periosteal stripping around the non-union site.
. Application of autogenous bone graft or bone graft substitutes.
. Routinely adding an intramedullary nail in conjunction with the plate.

Correct Answer & Explanation

. Application of autogenous bone graft or bone graft substitutes.

Explanation

Non-unions are often indicative of a biological healing problem. Therefore, in addition to stable mechanical fixation provided by the plate, biological augmentation is frequently critical. Autogenous bone graft (e.g., from the iliac crest) provides osteoinductive, osteoconductive, and osteogenic properties, which are essential for stimulating healing in a non-union. While stability is necessary, biological stimulation is often the missing component. Short, stiff plates might increase stress shielding, and aggressive stripping is detrimental. Immediate full weight-bearing is generally not appropriate for non-unions until early signs of healing. An IM nail with a plate is for specific complex scenarios.

Question 9239

Topic: 2. Trauma

What is the primary concern when considering plate fixation for a clavicle fracture in a patient involved in contact sports?

. High rate of non-union after plate fixation.
. Excessive stress shielding leading to disuse osteopenia.
. Significant risk of hardware prominence and subsequent irritation/reoperation.
. Difficulty achieving anatomical reduction of the clavicle.
. Increased operative time compared to non-operative treatment.

Correct Answer & Explanation

. Significant risk of hardware prominence and subsequent irritation/reoperation.

Explanation

The clavicle is a very subcutaneous bone. While plate fixation offers excellent stability for appropriate clavicle fractures, hardware prominence (palpable plate and screws) causing irritation, discomfort, and impingement is a very common complication, often necessitating a second surgery for plate removal, especially in active individuals or those involved in contact sports. While other options can be concerns, hardware prominence leading to reoperation is a specific and highly frequent issue with clavicle plating.

Question 9240

Topic: 2. Trauma

Which of the following factors would most likely lead to early failure of a plate-screw construct in a comminuted fracture?

. Use of titanium instead of stainless steel.
. Excessive number of screws in the main fragments.
. Inadequate working length of the plate, making the construct too stiff.
. Improper reduction and persistent gapping at the fracture site.
. Early mobilization without weight-bearing.

Correct Answer & Explanation

. Improper reduction and persistent gapping at the fracture site.

Explanation

Improper reduction leading to persistent gapping and instability at the fracture site is a primary cause of early implant failure (pull-out, bending failure, loosening). If the fracture is not adequately reduced, the plate is subjected to excessive and repetitive forces that it was not designed to withstand, leading to premature fatigue or pull-out. While an inadequate working length (too stiff) can also cause problems (e.g., delayed healing or stress shielding), direct gapping means the plate is bridging a larger defect with uncontrolled motion, directly predisposing to early mechanical failure. Titanium vs. stainless steel is less critical for early failure than surgical technique/reduction.

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