3D Porous Bone Ingrowth Structures With Controlled Pore Geometry
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Solution Overview
Problem
Current methods in additive manufacturing for porous metal structures lack precise control over pore size distribution and porosity, limiting their effectiveness for bone ingrowth applications, particularly in orthopaedic prosthetics, due to the minimum strut diameter limitations of existing 3D printers.
Innovation Solution
The development of geometric structures with modified strut lengths and diameters to achieve desired geometric features, allowing for improved control over pore size, porosity, and homogeneity in porous structures, such as rhombic dodecahedrons and trigonal trapezohedrons, which are manufactured using additive manufacturing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional additive manufacturing techniques are used to produce porous metal structures, then the manufacturing process is feasible with current technology, but the pore size distribution and porosity cannot be precisely controlled
Solution Approach 1:
The patent divides the porous structure into repeating unit cells, each with controlled internal geometry. By segmenting the overall structure into manageable unit cells with specific strut configurations, the invention achieves precise control over pore size distribution and porosity while maintaining manufacturability through standardized production processes
Solution Approach 2:
The patent systematically varies geometric parameters of the unit cells, including strut diameter, strut length, and unit cell dimensions, to achieve desired pore size distributions and porosity levels. This parameter optimization enables precise control over structural properties while remaining compatible with conventional additive manufacturing capabilities
2Manufacturing precision
If the minimum lattice strut diameter is reduced to achieve smaller pore sizes, then pore size control improves, but the structural integrity and self-supporting capability deteriorate
Solution Approach 1:
The patent introduces internal struts within the unit cell structure that extend in multiple dimensions, providing additional load paths and structural support. This dimensional enhancement allows the use of thinner outer struts for smaller pore sizes while maintaining overall structural integrity through the reinforced internal geometry
Solution Approach 2:
The patent places internal struts and secondary geometric structures within the outer unit cell framework, creating a nested configuration where inner elements provide reinforcement. This nesting allows smaller pore sizes at the outer boundary while maintaining structural strength through the nested internal support elements
3Reliability
If porosity is increased to promote bone ingrowth, then bone ingrowth capability improves, but the mechanical strength and structural stability deteriorate
Solution Approach 1:
The patent applies different strut diameters and densities at different locations within the unit cell structure. By creating local variations in structural density, the invention achieves high porosity in regions that contact bone tissue to promote ingrowth, while maintaining higher structural density in load-bearing regions to preserve mechanical strength
Solution Approach 2:
The patent creates a composite geometric structure combining elements of high porosity (for bone ingrowth) and high structural density (for mechanical strength) within the same unit cell. This composite approach integrates both low-density and high-density regions, achieving simultaneous optimization of bone ingrowth capability and mechanical strength
4Manufacturing precision
If homogeneous pore size distribution is achieved through geometric modification, then bone ingrowth uniformity improves, but the manufacturing complexity increases
Solution Approach 1:
The patent designs a universal unit cell geometry that can be repeated throughout the entire porous structure with consistent strut configurations. This universal design achieves homogeneous pore size distribution through standardization, reducing manufacturing complexity by eliminating the need for varied geometric patterns across different regions of the structure
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 solution enables the production of robust porous structures with optimized pore sizes and porosities, promoting better bone ingrowth and structural integrity, independent of the manufacturing technology used, by maintaining a uniform gap between pore and window sizes.
Implementation Method 1
depositing and scanning successive layers of metal powders with a beam to form a porous three-dimensional structure
Implementation Method 2
depositing and scanning successive layers of metal powders with a beam to form a porous three-dimensional structure
Data Source
AI summary
An orthopaedic prosthetic component is provided. The orthopaedic prosthetic component comprises a porous three-dimensional structure shaped to be implanted in a patient's body. The porous three-dimensional structure comprises a plurality of unit cells. At least one unit cell comprises a first geometric structure having a first geometry and comprising a plurality of first struts, and a second geometric structure having a second geometry and comprising a plurality of second struts connected to a number of the plurality of first struts to form the second geometric structure.