Cam Post Mechanism for Anterior Stabilization in Knee Implants
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current total knee arthroplasty (TKA) procedures sacrifice the anterior cruciate ligament (ACL), leading to instability and potential meniscus and cartilage damage, as existing TKA implants lack anterior stabilization.
Innovation Solution
A total knee implant prosthesis design that includes a femoral component with a cam mechanism and a tibial component with a post, allowing for anterior stabilization without the ACL, while accommodating a retained posterior cruciate ligament (PCL).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the anterior cruciate ligament (ACL) is sacrificed in traditional TKA procedures, then the implant structure is simplified and easier to manufacture, but joint stability deteriorates and risk of meniscus and cartilage damage increases
Solution Approach 1:
The patent introduces a cam mechanism as an intermediary structure between the femoral and tibial components. This cam acts as a mediator that provides anterior stabilization without requiring the ACL, thereby maintaining joint stability while keeping the implant structure relatively simple and manufacturable.
Solution Approach 2:
The implant is divided into distinct functional components: a femoral component, a tibial component, and a separate cam mechanism. This segmentation allows the cam to specifically address anterior stabilization needs without complicating the overall implant design, enabling targeted functionality while maintaining ease of manufacture for each individual component.
2Reliability
If a cam mechanism is added to provide anterior stabilization, then joint stability is improved, but device complexity increases
Solution Approach 1:
The cam mechanism is integrated with the existing femoral and tibial components rather than being a completely separate addition. The cam is positioned to engage with the post on the tibial component, merging the stabilization function into the overall implant structure. This reduces the increase in device complexity compared to a fully separate mechanism.
Solution Approach 2:
The cam mechanism serves multiple functions: it provides anterior stabilization, guides femoral rollback during flexion, and works in conjunction with the retained PCL. This multi-functionality means that a single additional structure addresses multiple stabilization needs, reducing the overall complexity increase compared to adding separate mechanisms for each function.
Data Source
AI summary
A total knee implant prosthesis is disclosed. The total knee implant prosthesis includes a tibial component including a pair of bearing surfaces and a post positioned between the bearing surfaces, and a femoral component configured to rotate relative to the tibial component. The femoral component includes a pair of condyles sized and shaped to articulate on the bearing surfaces and a cam positioned between the pair of condyles. The cam engages the post at a first contact point when the femoral component is at 0 degrees of flexion and engages the post at a second contact point located lateral of the first contact point when the femoral component is at a first degree of flexion greater than 0 degrees. The cam is disengaged from the post when the femoral component is at a second degree of flexion greater than the first degree of flexion.