ACL-Substituting Knee Prosthesis Post Design
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Solution Overview
Problem
Traditional knee replacement surgeries lack a mechanism for substituting the function of the anterior cruciate ligament (ACL), leading to abnormal motion patterns and the need for more invasive procedures, as existing prostheses either require additional surgeries for ACL reconstruction or total joint replacement, even when the ACL is functional.
Innovation Solution
The development of knee joint replacement devices and methods that include a tibial implant, a femoral implant, and a post configured to simulate the ACL, allowing for its substitution during partial or total knee replacement surgeries, ensuring optimal soft-tissue balancing and component placement without the need for additional procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional knee replacement prostheses are used without ACL substitution mechanism, then the procedure is simpler and less invasive, but the knee shows abnormal motion patterns and reduced functionality
Solution Approach 1:
The ACL substitution post is nested within the tibial implant structure, with the post extending from the superior surface of the tibial implant near an edge. This integrates the ACL substitution function into the existing prosthesis design without requiring separate external components, thereby improving motion pattern normality while controlling device complexity.
Solution Approach 2:
The prosthesis is designed to perform multiple functions: replacing damaged knee joint surfaces and simultaneously substituting ACL function through the integrated post structure. This multi-functionality allows a single implant to address both knee replacement and ACL substitution needs, improving reliability without proportionally increasing complexity.
2Reliability
If additional ACL reconstruction surgery is performed before partial knee replacement, then ACL function is restored, but the number of surgical procedures increases and patient trauma is increased
Solution Approach 1:
The invention merges ACL substitution with knee replacement surgery into a single integrated procedure. The post structure is incorporated into the tibial implant, allowing both ACL function restoration and knee replacement to be achieved in one surgical intervention, thereby eliminating the need for separate ACL reconstruction surgery and reducing overall treatment time and patient trauma.
Solution Approach 2:
The ACL substitution mechanism is built into the knee replacement prosthesis design beforehand, allowing ACL function to be restored as part of the primary knee replacement procedure rather than requiring preliminary separate ACL reconstruction surgery.
3Reliability
If total joint replacement is performed instead of partial replacement for patients with absent ACL, then knee stability is improved, but healthy elements are replaced and surgical invasiveness increases
Solution Approach 1:
The invention applies local quality by providing ACL substitution only in the specific region where it is needed (through the post structure on the tibial implant) while leaving the rest of the knee joint elements intact. This allows partial knee replacement to be performed with improved stability rather than requiring total joint replacement, thereby reducing surgical invasiveness while maintaining necessary stability.
Solution Approach 2:
The post structure changes the mechanical parameters of the knee joint by providing anterior-posterior stability that mimics native ACL function. This parameter change enables partial knee replacement to achieve adequate stability without requiring the more invasive total joint replacement procedure.
4Reliability
If CR prosthesis is used with both ACL and PCL present, then PCL function is retained, but optimal soft-tissue balancing and component placement is difficult to achieve
Solution Approach 1:
The invention extracts the ACL function substitution capability from separate reconstruction surgery and integrates it into the CR prosthesis design itself. The post structure on the tibial implant provides ACL substitution while the PCL remains intact and functional, thereby achieving both PCL function retention and improved ease of soft-tissue balancing in a single procedure.
Data Source
AI summary
Methods and devices are provided for knee joint replacement with anterior cruciate ligament (ACL) substitution. Generally, the methods and devices can allow a knee joint to be partially or totally replaced in conjunction with substitution of the knee joint's ACL. In one embodiment, a knee replacement prosthesis can include a medial or lateral femoral implant, a femoral intercondylar notch structure, a medial or lateral tibial insert, and an ACL-substitution member. The ACL-substitution member can be configured to engage with the femoral intercondylar notch structure during a full range of knee motion and/or during only early knee flexion.