Hip Endoprosthesis Socket Insert Clamping via Surface Ribs
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Solution Overview
Problem
Existing joint sockets for hip endoprostheses face challenges in achieving a strong clamping effect between the socket shell and insert while maintaining material compatibility and ease of alignment, with existing solutions limiting material choices due to the need for high specific pressure and potential misalignment risks.
Innovation Solution
The introduction of a surface structure with ribs or elevations on the clamping surfaces, reducing deformation resistance and increasing deformability, allowing for a larger contact area and reduced specific pressure without compromising the clamping effect, enabling the use of harder materials like titanium alloys for the socket shell and various materials for the insert.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the contact area between socket insert and socket shell is increased to reduce specific pressure, then material deformation risks are reduced and material compatibility is improved, but the clamping effect may be compromised
Solution Approach 1:
The invention applies a surface structure (ribs or elevations) locally to the clamping surfaces of the socket insert and/or socket shell. This creates zones of reduced deformation resistance at the contact interfaces while maintaining the overall structural integrity and material properties of the components. The local modification allows increased deformability precisely where needed for enhanced clamping without compromising the strength of the core areas.
Solution Approach 2:
The invention changes the physical parameter of deformation resistance by introducing a surface structure with ribs or elevations. This surface structure reduces the deformation resistance of the clamping surfaces compared to the core areas, enabling the surfaces to deform more easily under load. This parameter change allows the contact area to increase and specific pressure to decrease while maintaining or enhancing the clamping effect.
2Strength
If harder materials like titanium alloys are used for the socket shell to improve strength and stability, then material deformation risks increase, but material compatibility and ease of alignment may be compromised
Solution Approach 1:
The surface structure creates a local quality difference between the core area and the clamping surfaces of the socket shell. The core area maintains the high strength and low deformability of titanium alloy, while the clamping surfaces have reduced deformation resistance due to the rib or elevation structure. This allows the use of hard materials without compromising the necessary deformability for proper clamping and alignment.
3Reliability
If additional instruments or fastening means are used to secure the socket insert in the socket shell, then fixation reliability is improved, but device complexity and ease of operation are worsened
Solution Approach 1:
The surface structure with ribs or elevations enables the socket insert and socket shell to self-lock through their own deformation characteristics. When the socket insert is pressed into the socket shell, the surfaces with reduced deformation resistance deform and create a self-locking mechanism that secures the insert without requiring additional fastening means or instruments. The structure serves its own fixation function.
Solution Approach 2:
The invention extracts the fixation function from separate fastening components and integrates it into the surface structure of the clamping surfaces themselves. By incorporating ribs or elevations that create self-locking through deformation, the patent eliminates the need for additional fastening means, reducing device complexity while maintaining fixation reliability.
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 approach enhances the clamping effect between the socket shell and insert, allowing for improved alignment and stability, reduced material deformation risks, and the use of diverse materials, ensuring secure fixation without additional instruments or fastening means.
Implementation Method 1
the deformation resistance of at least one of the mutually corresponding surfaces of the receiving space and the socket insert is reduced compared to that of the core area of these parts by forming a pronounced surface structure
Implementation Method 2
an increased deformability of at least one of the mutually corresponding clamping surfaces is obtained, whereby the contact surface is increased and the specific pressure is correspondingly reduced, without the clamping effect being adversely affected
Data Source
Figure 1
Figure 2~4
AI summary
Joint socket, in particular for a hip endoprosthesis, with a socket shell (18) and a socket insert (20) for accommodating a joint head. The socket insert (20) has a portion (22) with a spherical outer face (28) and can be positioned in a receiving space (24) of the socket shell (18) in such a way that the spherical outer face (28) of the socket insert (20) touches the inner face (30) of the receiving space (24) concentric to the axis of rotation thereof. In the area of the concentric contact, the radius of curvature of the inner face (30) of the receiving space (24) of the socket shell (18) is always greater than the radius of curvature of the spherical portion (22) of the socket insert (20). An irreversible clamping action between socket insert and socket shell is achieved in this way. The deformation resistance of at least one of the mutually corresponding faces (28, 30) is reduced compared to that of the core area of the associated parts, particularly through formation of a surface structure (32, 34).