Magnetic Knee Prosthesis Joint Design for Low-Friction Stability
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Solution Overview
Problem
Existing total knee prostheses lack the biomechanical complexity of natural knee joints, resulting in an unnatural feel and increased wear, friction, and potential damage to surrounding tissues.
Innovation Solution
Incorporation of magnetic repulsion forces between components of the prosthesis, simulating the viscoelastic properties of natural joints by using opposing, distance-dependent magnetic fields to counteract compressive forces and reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic repulsion forces are incorporated into the prosthesis, then the natural feel and reduction of wear and friction are improved, but the device complexity increases
Solution Approach 1:
The patent replaces traditional mechanical lubrication and contact mechanisms with magnetic repulsion forces. Magnets are embedded in the femoral and tibial components to create repulsive forces that reduce direct contact and friction between articulating surfaces, eliminating the need for complex mechanical lubrication systems while improving joint stability and reducing wear.
Solution Approach 2:
The patent changes the physical parameters of the joint by introducing magnetic fields as a new force parameter. By adjusting magnet strength, position, and orientation, the repulsive force can be optimized to match the compressive forces of natural knee joints, creating a more physiological loading environment without adding mechanical complexity.
2Object-generated harmful factors
If magnetic fields are used to counteract compressive forces, then friction and wear are reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent divides the magnetic field generation into discrete magnet segments embedded in specific locations within the femoral and tibial components. This segmentation allows for standardized manufacturing of individual magnet housings that can be precisely positioned during assembly, reducing the overall manufacturing precision requirements compared to a single complex magnetic structure.
Solution Approach 2:
The patent introduces non-magnetic spacers or housings as intermediaries between the magnets and the articulating surfaces. These intermediaries serve as precision positioning features that guide magnet placement during manufacturing while isolating the magnetic field from direct contact with biological tissues, thereby reducing sensitivity to exact magnet positioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the natural feel and reduces wear and friction, minimizing particulate generation and heat, while decreasing stress on surrounding tissues and improving joint stability.
Implementation Method 1
the first pole and the second pole are in sufficient proximity to each other such that a magnetic repulsive force is present, the repulsive force configured to subtract from compressive forces that are applied between the femoral component and the tibial bearing
Data Source
AI summary
An orthopedic knee prosthesis includes a femoral component, a tibial bearing, a tibial component, a first magnetic portion associated with the femoral component and including a first pole having a first pole polarity the first magnetic portion not physically interrupting any articulating portion of the curved medial condyle surface or curved lateral condyle surface, and a second magnetic portion associated with one or both of the tibial bearing and/or the tibial component and including a second pole having a second pole polarity, the second pole polarity the same as the first pole polarity, the second magnetic portion not physically interrupting any articulating portion of the concave medial bearing surface or concave lateral bearing surface, wherein the first pole and the second pole are in sufficient proximity to each other such that a magnetic repulsive force is present therebetween.