Eccentric Prosthetic Knee Fastening Device for Gait Optimization
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Solution Overview
Problem
Prosthetic knee joints attached to patients with knee exarticulations often result in an uneven gait and reduced mobility due to the increased distance from the hip joint to the prosthetic knee axis, causing discomfort in walking and sitting, especially in spaces with limited legroom.
Innovation Solution
A fastening device with a distal holder and strut system that allows the prosthetic shaft to be attached eccentrically to the prosthetic knee joint axis, utilizing a power transmission element to pivot the upper part of the knee joint, enabling natural segment lengths and minimizing thigh extension, while maintaining standard knee joint designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the prosthetic knee joint is attached directly to the distal end of the prosthesis shaft, then the connection is simple and direct, but the distance from the hip joint to the prosthetic knee joint axis becomes significantly larger, causing uneven gait and reduced mobility
Solution Approach 1:
The patent introduces a fastening device with a strut that extends in the proximal direction beyond the prosthetic knee joint axis, creating an additional spatial dimension for attachment. This allows the prosthetic shaft to be positioned at an optimized distance from the hip joint, effectively reducing the overall length parameter while maintaining proper mechanical alignment and gait function.
2Ease of operation
If a fastening device with strut is used to reduce the distance from hip joint to knee joint axis, then gait behavior improves, but the device complexity increases
Solution Approach 1:
The fastening device is segmented into distinct functional components: a holder for attachment to the lower part or lower leg tube, a strut extending in the proximal direction beyond the knee joint axis, and a receptacle for the prosthetic shaft. This segmentation allows each component to perform its specific function efficiently while keeping the overall design manageable and adaptable to standard knee joint designs.
Solution Approach 2:
The fastening device is designed to be compatible with standard prosthetic knee joint designs without requiring constructive changes to the knee joint itself. The holder can attach to various lower part configurations, and the receptacle accommodates the prosthetic shaft, making the device universally applicable to different knee joint models while maintaining improved gait behavior.
3Length of stationary object
If the prosthetic shaft is attached at a reduced distance from the hip joint, then thigh extension while sitting is minimized, but the fastening device requires additional components
Solution Approach 1:
The fastening device merges multiple functions into a single integrated structure: the holder provides attachment to the lower part, the strut creates the necessary proximal extension to reduce thigh length, and the receptacle secures the prosthetic shaft. This merging reduces the need for separate components and simplifies the overall assembly while achieving the goal of minimizing thigh extension during sitting.
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
This solution allows for improved gait behavior and reduced thigh extension while sitting, providing prosthetic segment lengths similar to healthy legs without requiring constructive changes to the knee joint, facilitating easier adaptation and use with long thigh stumps.
Implementation Method 1
at least one power transmission element (5) is attached to a proximal bearing point (15) to transmit a pivoting movement of the prosthesis shaft (10). The power transmission element (5) is coupled to a distal bearing point (25) with the upper part (21) such that a pivoting movement of the prosthesis shaft around the shaft swing axis (14) causes a pivoting movement of the upper part of the prosthesis sheet joint about the prosthesis knee joint axis (23)
Data Source
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AI summary
The invention relates to a fastening device (1) for fastening a prosthesis shaft (10) to a prosthetic knee joint (20) that has a proximal top part (21) and a distal bottom part (22), which are mounted on one another to pivot about a prosthetic knee joint axis (23). The fastening device (1) has a distal bracket (2) for attachment to the bottom part (22) or to a lower-leg tube (30). At least one strut (3) extends in the proximal direction from the holder (2) beyond the prosthetic knee joint axis (23) and on the strut (3) a receptacle (4) is arranged proximally to the prosthetic knee joint axis (23) for pivotally mounting the prosthesis shaft (10) about a shaft pivot axis (14). At least one force transfer element (5) is fastened offset to the shaft pivot axis (14) at a proximal bearing point (15) to transfer a pivoting movement of the prosthesis shaft (10). The force transfer element (5) is coupled to the top part (21) at a distal bearing point (25) in such a way that a pivoting movement of the prosthesis shaft (10) about the shaft pivot axis (14) causes a pivoting movement of the top part (21) about the prosthetic knee joint axis (23).