Knee Prosthesis Bearing Locking Structure Against Forward Shear
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Solution Overview
Problem
Current knee prostheses experience issues with bearing movement and wear due to forward shearing forces, leading to stress concentration and increased micro-momentum, which traditional locking structures fail to adequately address.
Innovation Solution
The design incorporates ribs with inclined surfaces on the tibial component that form an inclined fit with the bearing, effectively preventing forward movement and distributing stress, combined with lug bosses and undercuts for secure fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional locking structure with elastic latch and fixing groove is used, then the bearing can be secured to the tibial component, but the forward shearing force causes stress concentration and insufficient locking force, leading to bearing movement and wear
Solution Approach 1:
The locking structure is divided into multiple ribs (typically 2-4 ribs) distributed around the periphery of the tibial component, each rib independently resisting forward shearing forces. This segmentation distributes the stress concentration that would otherwise occur at a single locking point, while collectively providing sufficient locking force to prevent bearing movement.
2Stability of the object's composition
If the bearing is allowed to move slightly under forward shearing force, then the locking structure can accommodate some stress, but this movement causes increased micro-momentum and serious wear of the bearing lower surface
Solution Approach 1:
The locking structure employs a composite design combining multiple materials: the tibial component and bearing are made from different materials with complementary properties. The ribs are integrated into the tibial component material, providing a composite structure that resists wear while maintaining positional stability of the bearing under forward shearing forces.
3Device complexity
If the locking structure is simplified to reduce complexity, then manufacturing and assembly are easier, but the ability to resist forward shearing force and prevent bearing movement is reduced
Solution Approach 1:
The locking structure applies local quality by concentrating the anti-shearing functionality in specific peripheral regions where the ribs are located, rather than requiring a complex overall structure. Each rib is a simple local feature that provides targeted resistance to forward movement, simplifying the global design while maintaining high reliability in resisting shearing forces.
Data Source
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AI summary
The present disclosure provides a knee prosthesis and a knee prosthesis component. The knee prosthesis includes a tibial component (10), a bearing (20) and a femoral component (30). The tibial component (10) includes a platform (110) and one or more ribs (120) extending upwardly from an upper surface (111) of the platform and forwardly from a back portion of the platform (110), a front edge (101) of the upper surface (111) of the platform is provided with at least one front lug boss (130), and a back edge (102) of the upper surface (111) of the platform is provide with at least one back lug boss (140). The lower surface of the bearing (20) is provided with a groove (210) matching with the rib (120), a front slot (220) matching with the front lug boss (130) and a back slot (230) matching with back lug boss (140); the femoral component (30) is articulated with an upper surface (201) of the bearing (20); wherein at least one of the ribs (120) is provided with a medial wall (121) and a lateral wall (122), one of them is provided with a bent portion and formed with a first inclined surface (1211) which extends in a direction away from the other one.