Knee Prosthesis Bushing Hinge Post Anti-Luxation Design
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Solution Overview
Problem
Constrained knee prostheses with hinge posts often face issues with distraction and luxation due to insufficient soft tissue, leading to pain and complications for patients, as existing designs do not adequately limit the movement of the femoral component relative to the tibial baseplate and bearing component.
Innovation Solution
The implementation of a prosthesis assembly that includes a capture element, bushing, and hinge post configuration, where the bushing is designed to engage with the hinge post and limit distraction through various features such as snap-fit connections, retention clips, and threaded engagements, preventing excessive movement and luxation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the femoral component is allowed to move freely relative to the tibial baseplate, then the knee joint has natural range of motion, but distraction and luxation occur due to insufficient soft tissue
Solution Approach 1:
A capture element is introduced as an intermediary component between the femoral component and tibial baseplate. This capture element engages with both components to prevent distraction and luxation while allowing controlled movement, thus mediating between the conflicting requirements of range of motion and joint stability
Solution Approach 2:
The capture element is designed to preemptively counteract the harmful distraction force before it can cause luxation. By engaging with the femoral component and tibial baseplate, it creates a preliminary restraining force that opposes the distracting force generated by insufficient soft tissue
2Reliability
If capture elements are added to limit distraction, then joint stability is improved, but device complexity increases
Solution Approach 1:
The capture element is designed to integrate with existing prosthesis components such as the tibial baseplate and femoral component. By merging the anti-luxation function into the existing structure rather than adding completely separate components, the design achieves enhanced stability while minimizing the increase in overall device complexity
Data Source
AI summary
A prosthesis assembly may include a femoral component, a tibial bearing component engaged by the femoral component and a tibial baseplate. The prosthesis assembly may include a hinge post coupled to the femoral component and at least partially received in a recess in the tibial baseplate. The prosthesis assembly may include a bushing received in a recess in the tibial baseplate. The hinge post is at least partially received by the bushing and the bushing includes one or more engagement features configured to couple the bushing to the hinge post.