Knee Joint Endoprosthesis Transverse Coupling Mechanism
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Solution Overview
Problem
Existing knee joint endoprostheses face challenges in securely coupling the femoral and tibial components without unintentionally loosening the tibial component during implantation, particularly due to the need for a joint pin extension and locking cones that can cause unintended force impacts.
Innovation Solution
A knee joint endoprosthesis design featuring a connecting device with first and second connecting elements that move transversely to the rotational axis for coupling, allowing independent implantation of components and eliminating the need for locking cones, ensuring a secure connection without force impact on the tibial component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If locking cones are used to couple the femoral and tibial components, then the connection is secure, but the tibial component may unintentionally loosen during implantation due to force impact
Solution Approach 1:
The coupling mechanism is divided into two independent stages: first the tibial component is implanted and secured independently, then the femoral component is coupled to it through a separate connecting device. This segmentation eliminates the risk that coupling forces will affect the already-secured tibial component, resolving the contradiction between achieving secure connection and maintaining tibial component stability.
Solution Approach 2:
The tibial component is implanted and secured to the tibia before the coupling operation with the femoral component takes place. By performing the tibial implantation as a preliminary action and securing it independently first, the subsequent coupling operations cannot cause unintended loosening, thus maintaining reliability while still achieving strong connection.
2Strength
If the femoral and tibial components are coupled during a single operation, then the connection is secure, but the complexity of the implantation procedure increases
Solution Approach 1:
The implantation procedure is segmented into distinct independent steps: tibial component implantation, then femoral component coupling. The connecting device is designed to facilitate this segmented approach, allowing each component to be implanted and secured independently while maintaining overall connection strength.
3Device complexity
If the connecting elements move parallel to the rotational axis, then the coupling mechanism is simple, but the connecting device cannot be fully separated in the assembly position
Solution Approach 1:
The connecting elements are designed to move transversely (perpendicularly) to the rotational axis during coupling, rather than parallel to it. This dimensional change in the movement direction allows the connecting device to be fully separated in the assembly position while still achieving secure engagement in the connected position, resolving the contradiction between simplicity and separability.
Data Source
AI summary
The present invention relates to a knee joint endoprosthesis having a tibial component and a femoral component and a hinge joint for coupling the tibial component and the femoral component so as to be pivotal about a rotational axis, which hinge joint comprises a first joint element and a second joint element coupled therewith so as to be rotatable about the rotational axis, wherein a connecting device is provided having at least one first connecting element and at least one second connecting element for connecting the first joint element to the femoral component, which connecting device defines a connecting position, in which the at least one first connecting element and the at least one second connecting element are engaged in a at least one of non-positive- and positive-locking manner, and an assembly position, in which the first joint element and the femoral component are fully separated from each other.