Interchangeable Knee Prosthesis Components
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Solution Overview
Problem
Current fixed-bearing knee prostheses are limited in flexibility as they are typically available in matching sizes for femoral and tibial components, which can restrict anatomical compatibility and stability, particularly in cases where soft tissue conditions do not allow for mobile-bearing prostheses.
Innovation Solution
The design of a fixed-bearing knee prosthesis with a femoral component and a tibial tray featuring a Y-shaped or T-shaped posterior and anterior buttress configuration, allowing for secure articulation and interchangeability of differently sized bearings and tibial trays, ensuring a snug fit and reduced micromotion through recesses and tabs, accommodating various patient anatomies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bearing sizes are matched to particular sizes of tibial trays, then manufacturing and inventory management are simplified, but anatomical compatibility and surgical flexibility are restricted
Solution Approach 1:
The tibial tray is designed with a universal interface system comprising a platform with a top surface, a bottom surface, and a vertical side surface connecting them. The platform includes a first recess and a second recess that can accommodate bearings of different sizes. This universal design allows a single tibial tray model to work with multiple bearing sizes, providing surgical flexibility while maintaining manufacturing simplicity.
Solution Approach 2:
The bearing is divided into separate modular components: a bearing body and a reinforcement pin. The reinforcement pin can be selectively inserted into the bearing body to enhance structural support when needed. This segmentation allows the bearing to be customized for different patient anatomies and surgical requirements without requiring different tibial tray designs.
2Stability of the object's composition
If fixed-bearing design is used when soft tissue conditions do not allow mobile bearing, then stability is improved, but anatomical compatibility is restricted
Solution Approach 1:
The bearing is designed with differentiated zones: a reinforcement pin insertion region for enhanced stability and a bearing surface region for articulation. The reinforcement pin can be selectively activated based on patient-specific soft tissue conditions. This local quality differentiation allows the fixed-bearing design to provide stability where needed while maintaining adaptability to various anatomical configurations through the modular interface system.
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.