Orthopedic Implant Surface Erosion for Bone-Growth Topography
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Solution Overview
Problem
Orthopedic implants produced using additive methods have not fully realized their potential in promoting bone integration and fusion, as they lack the necessary surface structures to enhance bone growth and integration with the surrounding bone tissue.
Innovation Solution
The method involves additively building orthopedic implants and then eroding their surfaces using mechanical or chemical processes to create micro-scale and nano-scale structures, which facilitate bone growth by allowing new bone to grow on the implant surfaces over time, rather than immediately contacting bone or bone graft material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If additive manufacturing is used to produce orthopedic implants, then manufacturing complexity is reduced and customization is enabled, but the implant surfaces lack the necessary micro-scale and nano-scale structures to promote bone integration
Solution Approach 1:
The manufacturing process is segmented into distinct stages: additive manufacturing to create the implant geometry, followed by separate mechanical erosion and chemical etching steps to create surface structures. This segmentation allows each process to optimize for its specific function without compromising the other.
Solution Approach 2:
The additive manufacturing process is used to preliminarily form the implant with its basic geometry and internal architecture before subsequent surface treatment steps. This preliminary structuring enables complex geometries that would be difficult to achieve with traditional manufacturing followed by surface modification.
2Manufacturing precision
If conventional subtractive methods are used to manufacture implants, then surface structures can be created, but manufacturing complexity increases and customization capability is reduced
Solution Approach 1:
The invention merges additive manufacturing with subsequent mechanical and chemical surface treatment processes to achieve both geometric complexity and surface structure quality in a single integrated manufacturing workflow, rather than requiring separate manufacturing steps.
Solution Approach 2:
The additive manufacturing process serves multiple functions: creating the implant geometry, establishing internal architecture, and providing a substrate for subsequent surface treatment. This multi-functionality reduces the need for separate specialized processes.
3Ease of manufacture
If implant surfaces are left smooth from additive manufacturing, then manufacturing is simpler, but bone integration and osseointegration are compromised
Solution Approach 1:
The surface parameters are changed through controlled mechanical erosion and chemical etching processes that modify the surface topography, creating micro-scale and nano-scale structures with specific roughness values (Ra 1-10 μm) that promote bone cell attachment and osseointegration.
Solution Approach 2:
The invention replaces purely mechanical surface finishing methods with a combination of mechanical erosion followed by chemical etching, where the chemical process enhances the surface structures created by mechanical means, providing superior bone integration promotion compared to mechanical methods alone.
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 osteoinduction and osseointegration by creating a bioactive surface topography that supports mesenchymal stem cell differentiation and bone growth, even in the absence of direct contact with bone, leading to improved implant integration and stability.
Implementation Method 1
additively building an orthopedic implant... may comprise successive layering and melting of powder, particles, granules, wires, fragments, or combinations thereof of the metal
Implementation Method 2
The additive build may comprise successive layering and sintering of powder, particles, granules, wires, fragments, or combinations thereof of the metal
Implementation Method 3
The mechanical eroding may comprise eroding the one or more surfaces with an organic or inorganic media
Implementation Method 4
The chemical erosion may comprise chemically eroding the one or more surfaces of the orthopedic implant, for example, with an acid or with a base
Data Source
AI summary
Orthopedic implants produced by additive manufacture, followed by refinement of exterior and interior surfaces trough mechanical erosion, chemical erosion, or a combination of mechanical and chemical erosion. Surface refinement removes debris, and also produces bone-growth enhancing micro-scale and nano-scale structures.