Segmented Tibial Prosthesis with Mobile Lateral Bearing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current knee prostheses, especially fixed bearing tibial prostheses, limit the natural articulation of the knee joint due to their fixed nature, preventing the lateral condyle of the femur from rolling off the tibial plateau, and total knee arthroplasty often results in decreased support and stability due to resection of cruciate ligaments.
Innovation Solution
A tibial prosthesis with a fixed medial bearing component and a mobile lateral bearing component, secured by prosthetic ligaments that mimic the natural ligaments, allowing for increased lateral rotation and rollback of the lateral condyle, and provisional ligaments that provide visual and tactile feedback if excessive tension is applied, facilitating accurate replication of natural knee joint articulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed bearing tibial prosthesis is used, then stability is improved, but natural knee joint articulation is limited
Solution Approach 1:
The tibial bearing surface is segmented into two distinct components: a fixed medial bearing component and a mobile lateral bearing component. This segmentation allows each component to serve different functions - the fixed medial component provides stability while the mobile lateral component enables natural articulation and rollback of the lateral condyle.
Solution Approach 2:
Different regions of the tibial prosthesis are given different mobility characteristics. The medial bearing component is fixed to provide stability, while the lateral bearing component is mobile to replicate natural knee articulation. This local differentiation of quality (fixed vs. mobile) resolves the contradiction between stability and natural motion.
2Ease of manufacture
If cruciate ligaments are resected during total knee arthroplasty, then implantation is simplified, but support and stability decrease
Solution Approach 1:
Prosthetic ligaments are introduced as intermediary elements that replicate the function of the natural cruciate ligaments. These prosthetic ligaments provide the necessary support and stability that would otherwise be provided by the natural ligaments, allowing the implantation to proceed without ligament preservation while maintaining joint stability.
Solution Approach 2:
The prosthetic ligaments are designed to copy and replicate the function of the natural cruciate ligaments. By creating artificial substitutes that perform the same mechanical function, the system maintains stability even when the natural ligaments are resected during implantation.
3Adaptability or versatility
If a mobile bearing tibial prosthesis with medial rotation point is used, then lateral rotation increases, but anterior-posterior control is reduced
Solution Approach 1:
The bearing surface is segmented into fixed medial and mobile lateral components, with each having different rotational characteristics. The fixed medial component provides anterior-posterior control while the mobile lateral component allows lateral rotation and rollback, resolving the contradiction between rotational freedom and translational control.
Data Source
AI summary
A knee prosthesis is provided for use in knee arthroplasty. In one exemplary embodiment, the present invention provides a tibial prosthesis having a tibial baseplate with a fixed medial bearing component and a mobile lateral bearing component. In one exemplary embodiment, the lateral bearing component is secured to the lateral portion of the tibial baseplate utilizing at least one prosthetic ligament. Additionally, in one exemplary embodiment, a stop is provided to limit anterior or posterior movement of the lateral bearing component relative to the tibial baseplate. For example, the stop may be defined by cooperating shoulders formed on the lateral bearing and the tibial baseplate.