Ceramic Joint Implant Locking Ring for Screw Stress Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ceramic materials used in joint prostheses are prone to cracking or breaking due to localized mechanical stresses during screw tightening, posing risks during and after operations, and are prohibited by regulatory standards due to potential toxicity.
Innovation Solution
A ceramic joint prosthesis implant with a main body and an added ring that distributes mechanical stresses homogeneously, using a clamping screw and a ring assembly with locking mechanisms to prevent separation and deformation, ensuring robustness and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic material is used for the joint prosthesis implant, then biocompatibility and friction properties are improved, but mechanical strength and resistance to cracking are worsened
Solution Approach 1:
The implant is divided into two distinct parts: a ceramic main body providing biocompatibility and articular surface, and a metal added element providing mechanical strength and stress distribution. This segmentation allows each material to发挥 its optimal properties without compromise.
Solution Approach 2:
The invention creates a composite structure combining ceramic and metal materials. The ceramic main body maintains biocompatibility and friction properties, while the metal added element provides tensile strength and stress distribution capability, achieving a composite material system that overcomes the limitations of pure ceramic.
2Strength
If tightening screw is used to secure the implant, then fixation strength is improved, but mechanical stress concentration and cracking risk are worsened
Solution Approach 1:
The added element is designed with specific local properties: a bearing surface that contacts the screw head to distribute stress, and a geometry that creates a chamber for the screw. This local quality enhancement at the stress-concentration zone prevents cracking while maintaining fixation strength.
Solution Approach 2:
The added element acts as an intermediary between the tightening screw and the ceramic main body. It receives the mechanical stress from the screw and redistributes it homogeneously across the ceramic structure, preventing stress concentration and cracking.
3Strength
If added element is used to distribute stress, then cracking risk is reduced, but holding reliability and deformation resistance are worsened
Solution Approach 1:
The added element combines multiple functions in a single component: stress distribution through its bearing surface, structural support through its chamber geometry, and deformation resistance through its material properties. This merging ensures both stress distribution and holding reliability are achieved simultaneously.
Solution Approach 2:
The added element features a curved bearing surface that contacts the screw head, creating a distributed stress pattern. The spherical or curved geometry naturally distributes point loads across a larger area, preventing stress concentration while maintaining structural integrity and resistance to deformation.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
The invention relates to a joint prosthesis implant (1) comprising: - a main body (2) mainly of ceramic and comprising an external articular surface (8) of ceramic of concave or convex shape, - at least one clamping screw (5) configured to allow clamping of the main body (2) on the patient's bone or on an intermediate element (3) fixed to said bone, - at least one added ring (4) in the main body (2; 200) configured to distribute the mechanical stresses from the tightening of the clamping screw (5) homogeneously within the main body (2), said added ring (4) comprising a first organ (41) and a second organ (42) distinct from each other.