Stabilized Ankle Prosthesis Lip Constraint
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ankle joint replacement prostheses face challenges in providing adequate range of motion and stability, especially in patients with compromised soft tissues, due to issues like high wear rates, ambulatory constraint, loosening, and edge loading, which can lead to further joint damage and pain in surrounding joints.
Innovation Solution
A two-component ankle prosthesis design that mimics the natural anatomy of the talus and tibia, with complementary contours and a lip feature to constrain movement in compromised soft tissue directions, ensuring congruence and stability, and using suitable materials to minimize friction and promote osseointegration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed-bearing prosthesis design is used, then implant stability is improved, but wear rate increases and ambulatory freedom is constrained
Solution Approach 1:
The prosthesis transitions from a fixed-bearing design to a mobile-bearing design where the bearing surface can move relative to the implant components. This dynamic configuration allows the bearing to self-adjust and distribute loads more evenly, reducing wear rates while maintaining implant stability through the mobile bearing mechanism.
2Adaptability or versatility
If soft tissue-dependent stabilization is used, then implant flexibility is improved, but reliability decreases in patients with compromised soft tissues
Solution Approach 1:
The prosthesis employs asymmetric design features including a lip extending from one component that selectively constrains movement in specific directions. This asymmetric configuration provides inherent stability in compromised soft tissue directions while preserving flexibility and range of motion in other directions, making the implant suitable for patients with compromised soft tissues.
3Reliability
If articulation surfaces restrict varus/valgus and rotation motions, then implant stability is improved, but range of motion is reduced
Solution Approach 1:
The prosthesis divides the articulation into separate functional zones: one zone allows varus/valgus and rotation motions through the mobile bearing mechanism, while another zone maintains stability through the lip constraint. This segmentation enables independent optimization of stability and range of motion in different movement planes.
4Ease of operation
If edge loading is permitted, then range of motion is increased, but stress on implant ridge increases causing retraction
Solution Approach 1:
The lip structure acts as a preventive constraint that stops the bearing from migrating to edge-loaded positions before excessive stress can develop on the implant ridge. This beforehand cushioning prevents the harmful edge loading condition while still allowing adequate range of motion through the constrained movement path.
Data Source
AI summary
The present invention relates to a stabilized ankle prosthesis configured for use in patients with compromised soft tissue in the ankle. The prosthesis of the present invention is a two-component design comprising a stabilizing lip configured to constrain movement in the general direction of compromised soft tissue.