3D-Printed Orthopedic Implant Surfaces for Bone Integration
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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 features to enhance osteoinduction and osseointegration.
Innovation Solution
The method involves additively building orthopedic implants in a vertical direction, followed by mechanical or chemical erosion of surfaces to create micro-scale and nano-scale structures, which facilitate bone growth by removing debris and imparting bioactive topography, and may include stress-relieving steps like hot isostatic pressing.
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 structures to promote bone integration and fusion
Solution Approach 1:
The patent applies preliminary action by incorporating surface erosion features directly into the additive manufacturing process parameters. The build orientation, layer thickness, and infill patterns are pre-configured to create surfaces that will naturally erode to the desired micro-scale topography during post-processing, eliminating the need for separate surface modification steps while ensuring bone integration capability.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying additive manufacturing parameters (build orientation, layer height, infill density) and post-processing erosion parameters (media type, particle size, duration) to transform the implant surface from a smooth manufactured state to a micro-scale roughened state that promotes osteoinduction and osseointegration.
2Manufacturing precision
If conventional subtractive methods are used to manufacture implants, then surface finish can be controlled, but manufacturing complexity increases and customization is limited
Solution Approach 1:
The patent applies inversion by reversing the traditional approach: instead of using subtractive methods to achieve surface finish control, it uses additive manufacturing to create the bulk geometry and incorporates surface erosion characteristics directly into the additive process parameters, thereby achieving both manufacturing simplicity and surface control through the opposite methodology.
3Reliability
If implant surfaces are eroded to create micro-scale structures, then osteoinduction and osseointegration are enhanced, but manufacturing time and process complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring the additive manufacturing parameters (build orientation, layer thickness, infill patterns) to create surfaces that require minimal post-processing erosion. The initial additive structure is designed to naturally develop the desired micro-scale topography with reduced erosion time, thereby promoting bone growth while minimizing additional manufacturing time.
Solution Approach 2:
The patent applies partial action by using controlled erosion that removes only the necessary amount of material to create micro-scale structures without over-eroding. The erosion process is optimized to achieve the minimum required surface modification for osteoinduction, avoiding excessive processing time while still enhancing bone integration potential.
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 surfaces that support mesenchymal stem cell differentiation and bone growth, even without direct contact with bone, improving initial stability and cellular response.
Implementation Method 1
additive methods where materials in crystal or granular form are melted by energy sources and layered or applied while liquid to each other to form growing structures
Implementation Method 2
The additive build may comprise successive layering and sintering of powder, particles, granules, wires, fragments, or combinations thereof of the metal into the shape of the orthopedic implant
Implementation Method 3
mechanically eroding (e.g., blasting the surfaces with an organic or inorganic medium, which is preferably dissolvable, and may be particulate)
Implementation Method 4
chemically eroding (e.g., treating the surfaces with an acid or base)
Implementation Method 5
The method may further comprise heating the implant and compressing the heated implant under hot isostatic pressure (HIP)
Data Source
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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.