Orthopedic Implants with Roughened Surfaces via Particulate Impact
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Solution Overview
Problem
Existing orthopedic implants lack inherent surface roughness necessary for stable bone integration and friction, relying on external coatings which increase costs and complexity.
Innovation Solution
A method of processing compacted metal powder green bodies by impacting them with a particulate material to create inherent surface roughness, characterized by high static friction coefficients and specific surface roughness parameters, eliminating the need for external coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external coatings are applied to implant surfaces to provide roughness and friction, then bone integration and stability are improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The green body itself serves as the substrate for surface roughening, eliminating the need for separate coating materials. The impacting process directly modifies the green body surface to create the required roughness and friction characteristics, making the system self-sufficient without external coating materials.
Solution Approach 2:
The surface roughening function is merged with the green body formation process. By impacting the green body while it is still in its compacted metal powder state, the patent combines the structural formation and surface modification steps into a single integrated process, eliminating the need for separate coating application.
2Reliability
If external coatings are applied to implant surfaces to provide roughness and friction, then bone integration and stability are improved, but manufacturing cost increases
Solution Approach 1:
The green body itself serves as the substrate for surface roughening, eliminating the need for separate coating materials. The impacting process directly modifies the green body surface to create the required roughness and friction characteristics, making the system self-sufficient without external coating materials.
Solution Approach 2:
The patent extracts and removes the space holder material from the green body before impacting, creating voids that enhance surface roughness. This extraction step is integrated into the manufacturing process to eliminate the need for expensive external coating materials while achieving the desired surface characteristics.
3Ease of manufacture
If conventional smooth implant surfaces are used, then manufacturing is simpler and cheaper, but friction and stability against bone are insufficient
Solution Approach 1:
The green body is impacted while still in its compacted metal powder state, before sintering and final manufacturing. This preliminary surface roughening action creates the required friction characteristics early in the process, and the roughness is preserved through subsequent sintering without requiring additional coating steps.
Solution Approach 2:
The patent changes the physical state of the metal powder from compacted green body to sintered structure through controlled heating. This parameter change (temperature-induced sintering) preserves the surface roughness created during impacting while transforming the material properties to achieve the final implant characteristics.
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
The method enhances implant stability and biological fixation through increased friction and surface roughness, reducing costs by integrating the surface characteristics directly into the implant material.
Implementation Method 1
impacting the green body with a particulate material under conditions effective to displace a portion of the metal powder from the green body
Implementation Method 2
The porous matrix material is then sintered to further strengthen the matrix structure
Data Source
AI summary
Provided are methods for processing a green body that includes compacted metal powder, comprising impacting the green body with a particulate material for a time and under conditions effective to displace a portion of the metal powder from the green body. The present methods can be used to prepare green bodies that have “roughened” surfaces and that can be used to make orthopedic implants displaying low movement relative to bone when installed in situ, which corresponds to higher stability upon implantation and decreases the time required for biological fixation of the implant. Also provided are implants comprising a metallic matrix, and methods comprising surgically installing an implant prepared from a “surface roughened” green body in accordance with the present invention.