Wrist Prosthesis Complementary Convex-Concave Surfaces
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Solution Overview
Problem
Existing wrist prostheses suffer from loosening, wear, and restricted mobility, leading to painful and reduced movement due to anchoring mechanisms that cause bone removal and wear on the radius.
Innovation Solution
A wrist prosthesis design comprising a proximal and distal body with complementary convex-concave surfaces, eliminating anchoring means to allow for relative movement and minimize wear, enabling improved mobility and tension distribution without bone removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anchoring means are used to fix the radiar component in the radius, then the prosthesis provides stable fixation, but bone removal is required causing wear and loosening
Solution Approach 1:
The invention removes the anchoring means from the prosthesis design entirely. The radiar component is no longer fixed to the radius through anchoring, but instead moves freely relative to the radius while maintaining functional stability through the complementary convex-concave surface design between proximal and distal components.
Solution Approach 2:
Instead of fixing the prosthesis to bone through anchoring (traditional approach), the invention inverts the approach by allowing free movement between the radiar component and radius, while creating stability through the articulated surface geometry between prosthesis components themselves.
2Reliability
If anchoring means are used to secure the prosthesis, then fixation is achieved, but the degree of mobility is restricted
Solution Approach 1:
The prosthesis is divided into separate movable components (radiar component, intermediate component, carpal component) that can move relative to each other through complementary convex-concave surfaces, enabling multi-degree-of-freedom wrist motion while maintaining overall structural integrity.
Solution Approach 2:
The invention transitions from a static fixed prosthesis to a dynamic articulated structure where components move relative to each other, mimicking natural wrist kinematics through the complementary surface geometry that guides motion while maintaining stability.
3Stability of the object's composition
If the proximal prosthesis body is fixed to the radius, then stable positioning is achieved, but wear and loosening occur over time
Solution Approach 1:
The invention removes the fixation interface between the radiar component and radius, eliminating the source of bone wear and loosening. The radiar component floats relative to the radius and is positioned and stabilized through its articulation with the distal prosthesis body via complementary surfaces.
Solution Approach 2:
The complementary convex-concave surfaces between proximal and distal components act as intermediaries that transfer and distribute loads, replacing the direct bone-implant fixation interface and eliminating wear at the bone-prosthesis interface.
4Adaptability or versatility
If conventional wrist prosthesis design is used, then basic functionality is provided, but wear and loosening reduce functionality over time
Solution Approach 1:
The prosthesis is segmented into multiple articulated components with complementary surfaces that enable complex wrist movements while distributing mechanical loads across multiple contact points, reducing wear on any single interface and maintaining functionality over time.
Solution Approach 2:
The articulated design with complementary convex-concave surfaces creates a dynamic system that adapts to natural wrist motion patterns, providing versatile functionality while reducing stress concentrations that lead to wear and loosening in conventional fixed designs.
Data Source
Figure 1a~1c
Figure 2a~3
AI summary
The invention relates to a wrist prosthesis (1), comprising a proximal prosthesis body (21) and a distal prosthesis body (11), wherein, at least in a deployed state of the wrist prosthesis, a portion of the proximal prosthesis body that faces away from the distal prosthesis body is provided with a convexly curved surface (22). Additionally, a portion of the distal prosthesis body that faces away from the proximal prosthesis body is furthermore provided with a convexly curved surface(12). Furthermore, the surfaces of the proximal prosthesis body and the distal prosthesis body that are facing each other are provided with complementary convex-concave curved surfaces (13, 23). The invention further relates to a set of components for such a wrist prosthesis, which allows the wrist prosthesis to be placed in a wrist, without anchoring means, and with a high degree of adaptation to the specific situation.