Patella Component Thickened Superior Edge
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Solution Overview
Problem
Conventional patella components do not adequately address the need for improved stability and articulation with femoral condyles during knee movement, particularly during deep flexion, and suffer from polymer deformation issues.
Innovation Solution
A patella component with a monolithic polyethylene body featuring a thicker superior edge than inferior, medial, and lateral edges, and a curved peak surface offset in the superior direction, which includes pegs for fixation and a posterior bearing surface articulating with femoral condyles, enhancing stability and reducing polymer deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional dome-shaped polymer bearing is used, then the patella component can be manufactured with simple geometry, but it does not provide adequate stability during deep flexion and suffers from polymer deformation
Solution Approach 1:
The patent applies local quality by creating a thickened superior edge on the patella component, where the thickness varies across different regions. The superior edge has greater thickness compared to other edges, providing enhanced stability and resistance to extension during deep knee flexion. This localized thickness variation addresses the specific functional requirement at the superior edge without unnecessarily increasing the entire component size.
Solution Approach 2:
The patent employs asymmetry by designing the patella component with non-uniform edge thicknesses. Specifically, the superior edge is thicker than the inferior, medial, and lateral edges, creating an asymmetric geometry that optimizes performance during deep flexion. This asymmetric design allows the component to resist extension forces more effectively while maintaining appropriate articulation surfaces.
2Reliability
If the superior edge is made thicker to resist extension during deep flexion, then stability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by systematically varying the thickness parameter across different edges of the patella component. The superior edge is designed with a specific thickness greater than other edges, while the inferior, medial, and lateral edges have different thicknesses. This parameter variation is optimized to provide the necessary resistance to extension during deep flexion while remaining manufacturable with standard precision tolerances.
3Reliability
If the curved peak surface is offset in the superior direction, then articulation with femoral condyles is improved, but the device complexity increases
Solution Approach 1:
The patent employs asymmetry by offsetting the curved peak surface in the superior direction from the center of the superior/inferior width. This asymmetric positioning of the peak surface optimizes the articulation between the patella component and the femoral condyles during knee movement, particularly during deep flexion, while maintaining a manageable level of geometric complexity.
Data Source
AI summary
An orthopaedic implant includes a patella component having a posterior bearing surface configured to articulate with the femoral condyles of a femur, and an anterior surface having a number of pegs extending outwardly therefrom. The superior edge of the patella component is thickened relative to conventional dome-shaped patella components.