Composite Ball Head for Artificial Hip Joint
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Solution Overview
Problem
Conventional artificial hip joints with metal ball heads and non-metallic liners suffer from reduced joint mobility, increased wear, and high contact stress due to the limited size of the ball head, leading to premature failure and the need for revision surgery.
Innovation Solution
An artificial hip joint with a composite ball head where a metal ball head is wrapped with a non-metallic shell, allowing for a larger accommodation space and increased joint mobility, reducing contact stress, and enhancing the bearing capacity and durability of the joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a non-metallic liner is used in the acetabulum, then the bearing capacity is improved, but the ball head diameter is reduced and contact area is decreased
Solution Approach 1:
The invention uses a composite ball head structure combining metal and non-metallic materials. The metal core provides structural strength and bearing capacity, while the non-metallic outer layer provides wear resistance and biocompatibility. This composite structure allows the ball head to maintain high strength while increasing its diameter to improve contact area with the acetabulum, resolving the contradiction between bearing capacity and contact area.
2Ease of operation
If the ball head diameter is increased, then joint mobility is improved, but the liner thickness requirement increases and wear increases
Solution Approach 1:
The composite ball head with metal core and non-metallic outer layer allows for increased ball head diameter to improve joint mobility while the non-metallic material provides excellent wear resistance. The metal core maintains structural integrity at larger sizes, while the non-metallic surface reduces wear on the acetabular liner, resolving the contradiction between joint mobility and wear resistance.
3Ease of operation
If a metal ball head with metal shell is used, then joint mobility is improved, but metal ions are generated and harm the human body
Solution Approach 1:
The composite ball head uses a metal core for structural strength and mobility, but covers it with a non-metallic outer layer that prevents metal ion release. This non-metallic coating acts as a barrier between the metal core and the biological environment, eliminating harmful metal ions while preserving the mechanical benefits of the metal structure, thus resolving the contradiction between joint mobility and biocompatibility.
Data Source
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AI summary
An artificial hip joint with a composite ball head includes an artificial acetabulum (1) and a composite ball head (2); wherein an internal surface of the artificial acetabulum (1) cooperates with an external surface of the composite ball head (2), and the composite ball head (2) can rotate within the artificial acetabulum (1); the internal surface of the artificial acetabulum (1) is directly in contact with the composite ball head (2) without a liner therebetween; the composite ball head (2) comprises a metal ball head (22) and a non-metallic shell (21) wrapped around an external surface of the metal ball head (22). For the composite ball head (2), the metal ball head (22) is wrapped with a non-metallic shell (21), which has large supporting force capability, has strong bearing capacity, effectively reduces the contact stress of the non-metallic shell (21), is stable and reliable, and is not easy to be damaged. Liner is not used in the artificial acetabulum, so that the size of the composite ball head (2) can be increased, thereby increasing the joint mobility, reducing the collision between boundaries of the femoral stem and the acetabular shell, reducing the risk of dislocation of the artificial acetabulum (1) and the composite ball head (2), thereby effectively extending the service life of artificial joints, and enhancing the use of artificial joints.