Orthopedic Implant Finned Locking for Polyaxial Screw Stability
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Solution Overview
Problem
Existing orthopedic implants with locking screws provide limited angular fixation, restricting the insertion angle of fasteners, while non-locking screws offer versatility but lack stability, and current polyaxial systems fail to maintain secure engagement under physiological loads.
Innovation Solution
The orthopedic implant features finned openings with alternating configurations of upper and lower fins in vertically stacked rows, allowing fasteners to be inserted at various angles and securely engaged through deformable fins that alternate in length and thickness, enhancing polyaxial rotation and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If locking screws are used to provide stable fixation, then stability and reliability are improved, but the range of fixation angles is limited
Solution Approach 1:
The locking mechanism is segmented into multiple independent locking elements (first locking element and second locking element) that can engage at different angles. This segmentation allows the fastener to be locked at multiple angular positions, providing both stability through locking and versatility through angular variation.
Solution Approach 2:
The locking mechanism transitions from a static fixed-angle design to a dynamic multi-angle design. The fastener can be inserted at various angles and then locked into position, allowing the system to adapt to different surgical needs while maintaining stability once locked.
2Adaptability or versatility
If non-locking screws are used to increase angular flexibility, then adaptability is improved, but stability and rigidity are reduced
Solution Approach 1:
The system allows dynamic adjustment during insertion (polyaxial movement for angular flexibility) followed by static locking (for stability). This dynamic-to-static transition enables the fastener to achieve both angular flexibility during positioning and stable fixation once locked.
Solution Approach 2:
The locking mechanism is divided into separate locking elements that can engage independently at different angles, allowing the system to provide stability only when needed (when locked) while maintaining flexibility during insertion.
3Ease of manufacture
If a single locking angle is provided, then manufacturing simplicity is maintained, but surgical versatility is limited
Solution Approach 1:
The locking mechanism uses multiple simple locking elements (such as cam locks or set screws) that can be replicated at different angular positions. This segmentation allows multiple locking angles to be achieved using repeated simple components rather than complex mechanisms.
Solution Approach 2:
The same basic locking element design is used multiple times at different angular positions, making the locking mechanism universal and multi-functional. This approach maintains manufacturing simplicity by reusing the same component design while providing surgical versatility through angular variation.
Data Source
AI summary
An orthopedic implant including an outer surface and at least one opening extending through the outer surface for receiving a fastener for coupling the implant to a patient's bone or bone portion/fragment. The opening including a plurality of fins circumferentially disposed about the opening for engaging threads formed on a head portion of the fastener to secure the fastener to the implant. The plurality of fins being arranged and configured in first and second vertically spaced rows of fins. At least one of the fins including a different configuration, property, etc. relative to at least one of the other plurality of fins. In one embodiment, each of the first and second fins in a vertically stacked relationship includes a different configuration from the other of the first and second fins in that stack. In one embodiment, the different configuration includes a different length, a different thickness, or a combination thereof.