Space Truss Hip Prosthesis Stem for Bone Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional spinal implants with large rims impede bone growth, create stress risers in vertebral endplates, and reduce the effectiveness of bone graft material integration, due to their open channel design which increases pressure on smaller areas and reduces the likelihood of secure bone graft adherence.
Innovation Solution
A spinal implant featuring a web structure with a space truss configuration, comprising multiple planar truss units with struts joined at nodes, designed to distribute forces across multiple planes and facilitate bone growth through openings in the truss structure, while providing a larger surface area for bone graft integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If large rims with solid material are used to provide contact area, then contact area between implant and vertebral endplates is increased, but bone growth is impeded and the size of the bone column is reduced
Solution Approach 1:
The implant uses a porous or lattice-structured rim design instead of solid material, allowing bone ingrowth through the rim structure while maintaining contact area. The porous structure provides pathways for bone cells to penetrate and integrate with the implant, eliminating the bone growth impediment caused by solid rims.
Solution Approach 2:
The rim is segmented into a lattice or truss structure with multiple struts and nodes, creating open channels that allow bone growth while distributing the contact area. This segmentation maintains structural integrity and contact area while providing pathways for bone infiltration.
2Force
If open channel design is used, then compressive forces can be transmitted, but pressure on smaller areas of vertebral endplates increases creating stress risers
Solution Approach 1:
The rim is divided into multiple struts within the open channel design, creating multiple load-bearing pathways. This segmentation distributes the compressive forces across numerous struts rather than concentrating them on small areas, reducing stress risers on the vertebral endplates.
Solution Approach 2:
The lattice structure adds a third dimension to the rim design, creating a three-dimensional network of struts that distributes loads in multiple directions. This dimensional complexity allows force distribution across a larger effective area while maintaining open channel functionality.
3Strength
If open channel design is used, then structural support is provided, but bone graft material cannot secure itself to the implant
Solution Approach 1:
The porous or lattice-structured rim provides a rough, textured surface that increases mechanical interlocking between the bone graft material and the implant. The porous structure allows bone cells to infiltrate and adhere to the implant surface, securing the bone graft in place while maintaining structural support.
Solution Approach 2:
The curved or rounded surfaces of the lattice struts provide better contact area for bone graft material compared to sharp edges. The curved surfaces allow for more uniform distribution of bone graft and improve adhesion through increased surface area and reduced stress concentration points.
4Reliability
If high-pressure state is applied to bone graft material, then bone graft material can be prevented from exiting and loosening, but creating and maintaining high-pressure environment is difficult
Solution Approach 1:
The porous rim structure provides mechanical retention of bone graft material through friction and interlocking, eliminating the need for high-pressure application. The porous structure naturally retains bone graft particles while allowing for physiological pressure conditions, simplifying the implantation process.
Solution Approach 2:
The implant is designed with pre-formed porous or lattice structures that are ready to receive and retain bone graft material at physiological pressures. The structure is prepared in advance to provide retention without requiring complex high-pressure application equipment or procedures.
Data Source
Figure 1A~1B
Figure 2A
Figure 2B
AI summary
A hip prosthesis includes an acetabular cup and a femoral component comprising a head and a stem, wherein the stem comprises a truss structure, the truss structure comprising a space truss comprising a plurality of planar truss units having a plurality of struts joined at nodes, wherein the web structure is configured to interface with bone tissue.