Bionic Hip Joint with Curved Bolt and Cortical Integration
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Solution Overview
Problem
Existing bionic artificial hip joints face issues with durability, strength, and susceptibility to deformation due to the straight rod-shaped bolts that require drilling into the femur's medullary cavity, causing damage and a hard-to-hard connection lacking a buffer mechanism, leading to loosening and wear over time.
Innovation Solution
A bionic artificial hip joint design featuring a femoral stem with a convex force-bearing part that integrates with the greater trochanter's cortex, a curved bolt matching the femoral medullary cavity's curvature, and a detachable hard shell for bone cement, providing a stable and durable connection with a buffer mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If straight rod-shaped bolts are used to fix the femoral stem, then the installation process is simple, but the connection strength is insufficient and the femur strength is reduced due to drilling deep holes
Solution Approach 1:
The patent applies curvature by designing the bolt with an arc-shaped main body that matches the physiological curvature of the femoral medullary cavity. This curved bolt design allows it to fit naturally along the cavity's curvature, improving connection strength without requiring excessive drilling that would compromise femur integrity.
Solution Approach 2:
The patent employs composite material strategy by combining the femoral stem, bolt, and bone cement to create a composite fixation system. The bolt acts as a reinforcement element within this composite structure, enhancing overall connection strength while distributing mechanical loads effectively.
2Ease of operation
If deep holes are drilled into the medullary cavity for bolt installation, then the bolts can be inserted, but the overall strength of the femur is reduced
Solution Approach 1:
The curved bolt design follows the natural curvature of the medullary cavity, allowing insertion without requiring deep, destructive drilling. The arc-shaped bolt conforms to the cavity's geometry, enabling secure fixation while preserving more of the original femur structure and maintaining overall strength.
3Ease of manufacture
If the femoral head, neck and cortex on greater trochanter are removed for installation, then the artificial joint can be installed, but the connection between corpus femoris and artificial hip joint is weakened
Solution Approach 1:
The patent applies preliminary action by providing a force-bearing part on the femoral stem that abuts against the inner side of the cortex on the greater trochanter before final cementation. This preliminary mechanical support maintains connection strength during installation and prevents excessive removal of cortical bone.
Solution Approach 2:
The patent changes the mechanical parameters of the connection by introducing a force-bearing part that provides initial structural support. This modifies the load-bearing characteristics from relying solely on cemented fixation to a combination of mechanical abutment and cemented fixation, thereby strengthening the overall connection.
4Device complexity
If a hard-to-hard connection is used between artificial hip joint and corpus femoris, then the structure is simple, but the connection is susceptible to wear and tear and deformation over time
Solution Approach 1:
The patent introduces an intermediary buffer mechanism consisting of the bolt and bone cement that mediates between the hard artificial hip joint and the living corpus femoris. This intermediary layer absorbs mechanical shocks and reduces rigid stress transmission, preventing wear and deformation while maintaining connection integrity over time.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating the bone cement and curved bolt as buffer elements before the prosthesis is subjected to full mechanical loading. These elements provide shock absorption and stress distribution from the beginning, preventing premature wear and deformation of the hard-to-hard connection interfaces.
Data Source
AI summary
The invention discloses a bionic artificial hip joint. The artificial hip joint includes a femoral stem located above corpus femoris, and a convex force-bearing part is provided on the femoral stem. The force-bearing part abuts against the inner side of the cortex on greater trochanter and bears a part of the longitudinal stress; its hollow design is convenient for bone grafting, so that the prosthesis and the greater trochanter can be integrated. Replacement surgery can preserve the hard cortex on the greater trochanter, providing another focus point for the femoral stem and further improving the stability of the connection between the bionic artificial hip joint and corpus femoris.