Orthopedic Implant Bone Interface Space Truss Fixation
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Solution Overview
Problem
Current orthopedic implants face issues with inadequate stress distribution and long-term fixation due to insufficient bone-implant interface, leading to implant loosening, instability, and bone density reduction, particularly under dynamic loading conditions.
Innovation Solution
The use of an orthopedic implant with a bone interface structure featuring a space truss design, comprising planar truss units and rod structures that extend from the implant surface at an oblique angle, facilitating effective load transfer and bone integration through bone growth into the truss structure, thereby enhancing initial and long-term fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If porous coating is used to promote bone adhesion, then bone-implant interface is improved, but initial fixation is insufficient due to multidirectional forces
Solution Approach 1:
The implant surface is segmented into multiple protruding rod structures arranged in a space truss configuration, where each rod acts as an independent bone-engaging element. This segmentation allows the implant to distribute multidirectional forces across numerous discrete contact points rather than relying on a continuous porous coating, thereby providing superior initial fixation while maintaining bone interface quality.
Solution Approach 2:
The invention transitions from a two-dimensional porous coating surface to a three-dimensional space truss structure with rods extending in multiple directions. This dimensional change enables the implant to engage bone tissue from multiple angles simultaneously, providing resistance to multidirectional forces and improving both initial fixation and long-term bone integration.
2Ease of manufacture
If traditional fixation techniques are used, then implant installation is simplified, but stress distribution at bone-implant interface becomes inadequate
Solution Approach 1:
The space truss structure provides locally optimized stress distribution through its geometric configuration, where each rod and node is positioned to efficiently transfer loads. This local structural quality ensures that stress is distributed evenly across the bone-implant interface, preventing stress concentrations that would lead to bone density reduction and implant loosening.
Solution Approach 2:
The combination of the solid implant body with the space truss bone interface structure creates a composite system that integrates different structural functions. The solid body provides structural integrity while the space truss provides optimized stress distribution and bone engagement, achieving both ease of installation and superior stress characteristics.
3Volume of moving object
If thin porous coating is applied, then implant size is reduced, but bone tissue in-growth thickness is insufficient
Solution Approach 1:
The space truss structure creates nested void spaces within the implant bone interface, forming a hierarchical structure where bone tissue can grow into and through the truss elements. This nested configuration provides sufficient internal volume for extensive bone in-growth while maintaining a compact overall implant size, as the bone grows within the truss framework rather than requiring a thick external coating.
Solution Approach 2:
The space truss structure inherently creates a porous architecture with interconnected voids that facilitate bone tissue infiltration and growth. This porous design provides adequate thickness and volume for bone in-growth without requiring a thick external coating, as the bone grows into the three-dimensional truss framework, achieving both size efficiency and sufficient bone integration.
4Stability of the object's composition
If screws or posts are used for initial fixation, then implant stability is improved, but bone density reduction occurs due to inadequate stress distribution
Solution Approach 1:
The space truss structure provides dynamic stress distribution that adapts to varying loading conditions, unlike rigid screws or posts that create fixed stress patterns. The geometric configuration of the truss allows it to flex and redistribute forces dynamically, maintaining implant stability while promoting healthy bone remodeling and preventing bone density loss through optimized mechanical stimulation.
Data Source
Figure 1~2B
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Figure 7A~8
AI summary
An orthopedic implant that includes an implant body having a bone contact surface to be in contact or near contact with a bone structure during use, wherein the bone contact surface has a bone interface structure protruding therefrom. The bone interface structure includes a first elongated portion to be at least partially pressed into the bone structure during use, and a second elongated portion to be at least partially pressed into the bone structure during use. The second elongated portion is coupled to the first elongated portion and extends from the first elongated portion at an angle oblique to the first elongated portion.