Locking Screw (Proximal / Distal) Fully Threaded

Description

Locking Screws (Proximal/Distal, Fully Threaded): Alternative Fixation for Femoral Fractures

Locking Screws (Proximal/Distal, Fully Threaded) are another variation of specialized screws used in orthopedic surgery for femoral fracture fixation with bone plates. While half-threaded locking screws are more common, fully threaded versions offer an alternative solution in specific scenarios:

• Proximal and Distal Variations: Similar to half-threaded screws, these screws come in proximal and distal variations for targeted placement within the femur, ensuring proper fit and functionality based on the anatomical location (near the hip or knee joint).
• Full-Threaded Design: Unlike half-threaded screws, these screws have threads along their entire length. This design provides a stronger purchase within the bone compared to half-threaded varieties. This enhanced grip can be beneficial in situations requiring maximum stability, such as fractures with poor bone quality or complex fracture patterns with a high risk of displacement.
• Locking Mechanism Compatibility: Fully threaded locking screws are still designed to work with locking bone plates. They thread through the plate hole and into the bone, achieving fixation through the head-locking mechanism within the plate, similar to half-threaded screws.

Applications in Femoral Fracture Fixation (Selective Use):

Locking Screws (Proximal/Distal, Fully Threaded) are used more selectively compared to half-threaded screws. Their applications may include:

• Fixation with locking bone plates for complex fractures with poor bone quality or high risk of displacement, particularly around the hip joint (proximal).
• Revision surgery for fractures with hardware failure or non-union, where additional stability is desired.

Important Considerations:

Locking Screws (Proximal/Distal, Fully Threaded) can be valuable tools in specific situations. However, their use requires careful consideration by the surgeon due to potential downsides:

• Reduced Bone Purchase in Certain Areas: While offering strong overall grip, the threads along the entire screw shaft can limit purchase within the softer bone cortex (outer layer) compared to half-threaded options. This may be less ideal for fractures in the femoral shaft where both cortical and cancellous (spongy) bone fixation is desired.
• Potential for Screw Cut-Out: In situations with very weak bone, the full threads may increase the risk of the screw pulling out entirely from the bone due to the lack of a smooth gliding surface within the plate hole.

Surgeon Expertise and Patient Selection:

Due to the potential trade-offs, using fully threaded locking screws requires careful surgeon expertise and patient selection. Consulting with a qualified orthopedic surgeon is crucial to determine if fully threaded screws are the most appropriate option for your individual case. They will consider factors like:

• Type and severity of the femoral fracture
• Bone quality at the fracture site
• Chosen method of fracture fixation (plate type and screw selection)
• Patient’s overall health and medical history

Additional Notes:

• Locking screws come in various sizes, thread diameters, and lengths to accommodate different bone sizes, fracture patterns, and specific implant systems.
• The material of locking screws is typically stainless steel or titanium.