Interchangeable Knee Prosthesis Bearing and Tibial Tray Locking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fixed-bearing knee prostheses have limited flexibility in sizing, as they are typically provided in matching sizes for femoral and tibial components, which can restrict their adaptability to varying patient anatomies, and lack a secure locking mechanism to prevent movement and micromotion.
Innovation Solution
The design incorporates a tibial tray with a Y-shaped posterior buttress and an anterior buttress featuring S-shaped profiles and undercuts, allowing for a snap-fit mechanism with the bearing, providing a secure fixation and enabling interchangeability across different sizes, with the bearing's recesses and tabs ensuring a tight fit and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fixed-bearing knee prostheses are provided in matching sizes for femoral and tibial components, then manufacturing and inventory management are simplified, but adaptability to varying patient anatomies is restricted
Solution Approach 1:
The locking mechanism features a standardized interface design where the bearing recess and locking protrusion geometry are consistent across different bearing sizes, allowing any bearing to be interchangeably mounted on any tibial tray. This universal interface enables a single tibial tray design to work with multiple bearing sizes, resolving the contradiction between simplified manufacturing and enhanced adaptability.
2Reliability
If a secure locking mechanism is implemented to prevent movement and micromotion, then joint stability is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is segmented into distinct functional elements: a locking protrusion on the bearing, a corresponding recess on the tibial tray, and an interference fit interface. This segmentation allows each element to be optimized independently while maintaining overall simplicity, achieving reliable locking without excessive complexity.
Solution Approach 2:
The locking interface utilizes curved or rounded geometric features rather than sharp angular transitions, which distributes contact stresses more evenly and prevents stress concentration. This curved geometry simplifies the manufacturing of the locking features while ensuring reliable engagement and preventing micromotion.
3Stability of the object's composition
If bearing size is restricted to match specific tibial tray sizes, then component compatibility is ensured, but surgical flexibility is reduced
Solution Approach 1:
The tibial tray incorporates a universal locking interface that can accommodate multiple bearing sizes through a standardized recess geometry. This allows surgeons to select from various bearing sizes based on patient anatomy and surgical requirements while using the same tibial tray, thereby maintaining component compatibility while enhancing surgical flexibility.
Data Source
AI summary
A fixed-bearing prosthesis includes a femoral component having a medial condyle surface and a lateral condyle surface. The knee prosthesis also includes a bearing having a medial bearing surface configured to articulate with the medial condyle surface of the femoral component, and a lateral bearing surface configured to articulate with the lateral condyle surface of the femoral component. A tibial tray is secured to the bearing. The tibial tray has a platform with an elongated stem extending downwardly from a lower surface thereof. A posterior buttress extends along a posterior section of the perimeter of the tray's platform, and an anterior buttress extends along an anterior section of the perimeter of the tray's platform. Differently-sized tibial trays are interchangeable with differently-sized bearings.