Proximal/Distal Locking Screw Fully Threaded

Description

Proximal/Distal Locking Screws (Fully Threaded): Maximum Grip for Specific Fracture Fixations

Proximal/Distal Locking Screws (Fully Threaded) are a specialized variation of screws used in orthopedic surgery for securing bone fixation plates during femoral fracture treatment. While half-threaded locking screws are more common, fully threaded versions offer an alternative solution in specific scenarios requiring the strongest possible hold:

• Proximal and Distal Variations: Similar to standard locking screws, these come in proximal and distal variations for targeted placement within the femur (near the hip or knee joint), ensuring proper fit and functionality based on the anatomical location.
• Full-Threaded Design for Maximum Grip: Unlike half-threaded screws, these screws have threads along their entire length. This design provides the strongest possible purchase within bone compared to other locking screw options. This enhanced grip can be beneficial in specific situations requiring maximum stability, such as:
  • Fractures with very poor bone quality
  • Complex fracture patterns with a high risk of displacement during healing
  • Revision surgery for fractures with hardware failure or non-union

Locking Mechanism Compatibility:

Despite their full threads, Proximal/Distal Locking Screws (Fully Threaded) 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.

Selective Use in Femoral Fracture Fixation:

Due to their focus on maximum grip, Proximal/Distal Locking Screws (Fully Threaded) are used more selectively compared to half-threaded options. Their applications may include:

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

Important Considerations:

While offering superior grip, using Proximal/Distal Locking Screws (Fully Threaded) requires careful surgeon evaluation due to potential drawbacks:

• Reduced Bone Purchase in Specific Areas: While strong overall, the threads along the entire screw shaft can limit purchase within the softer bone cortex (outer layer) compared to half-threaded varieties. 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:

Given these 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. Here are some factors they will consider:

• 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:

• Proximal/Distal Locking Screws (Fully Threaded) 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.