Orthopaedic Implant with Different Surface Textures
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Solution Overview
Problem
Current orthopaedic prostheses, particularly those with extensions like pegs and stems, pose challenges during revision surgery due to bone ingrowth, making it difficult to remove them without significant bone resection, which can lead to complications and soft tissue irritation.
Innovation Solution
The development of orthopaedic implant components with a porous metal body bonded to a solid metal portion, featuring a lower static coefficient of friction on certain surfaces to facilitate easier removal and minimize soft tissue irritation, utilizing techniques such as machining and sintering to optimize surface characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If porous metal extensions are used for bone fixation, then bone ingrowth and fixation strength are improved, but removal during revision surgery becomes difficult requiring large bone resection
Solution Approach 1:
The implant component has different surface characteristics in different regions: the first surface (bone-engaging surface) is porous with high friction to promote bone ingrowth and fixation, while the second surface has lower porosity and lower coefficient of friction to facilitate easier removal during revision surgery. This local differentiation resolves the contradiction between strong fixation and easy removal.
2Reliability
If rough porous surfaces are used for bone engagement, then bone ingrowth is promoted, but soft tissue irritation increases
Solution Approach 1:
The implant component differentiates surface properties by location: the first surface maintains rough porous characteristics to promote bone ingrowth, while the second surface has smoother characteristics with lower coefficient of friction to minimize soft tissue irritation. This resolves the contradiction between promoting bone ingrowth and reducing soft tissue irritation.
3Reliability
If uniform porous surfaces are used throughout the implant, then bone ingrowth is maximized, but manufacturing complexity increases
Solution Approach 1:
The implant component has non-uniform surface characteristics with different porosity levels in different regions. The first surface has higher porosity for bone ingrowth while the second surface has lower porosity for easier removal. This local differentiation actually reduces manufacturing complexity compared to making the entire surface uniformly porous, as it allows selective application of porous treatment only where needed.
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 allows for more straightforward removal of prosthetic components during revision surgery, conserving native bone and reducing soft tissue irritation, while maintaining bone ingrowth in desired areas for fixation.
Implementation Method 1
The porous metal body has an outer surface configured for engagement with bone or another portion of the implant component
Implementation Method 2
utilizing techniques such as machining and sintering to optimize surface characteristics
Data Source
Figure 1
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Figure 4~5
AI summary
An orthopaedic implant system comprises an implant component (14) having a bone-engaging surface (28), and an augment component (200) which can be placed selectively against the bone-engaging surface of the implant component. The augment component comprises a porous metal body having a bone-engaging surface (212) and a second surface (250) extending from the bone-engaging surface. The bone-engaging surface has a static coefficient of friction and the second surface has a lower static coefficient of friction, and the body has a void space of at least 60% by volume.