Anisotropic Prosthetic Implants for Stiffness Mismatch and Stress Shielding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current orthopedic implantation techniques face challenges in efficiently and safely inserting and securing prosthetic components into bone tissue, particularly due to issues like trunnionosis and the need for reduced force insertion, which can lead to increased wear and mechanical insufficiency at modular junctions, and the stiffness mismatch between metal implants and bone.
Innovation Solution
The development of prosthetic implants with anisotropic and viscoelastic properties, utilizing additive manufacturing techniques to create surface treatments that provide asymmetric force profiles for easier insertion and enhanced osseointegration, along with the use of programmable smart composites that can adjust stiffness profiles over time to promote bone healing and reduce stress shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional isotropic metal implants are used, then structural strength is ensured, but stiffness mismatch with bone causes stress shielding and impaired bone healing
Solution Approach 1:
The patent applies local quality by creating anisotropic structures with directionally dependent mechanical properties. The implant contains a first region with higher stiffness matching cortical bone and a second region with lower stiffness matching cancellous bone, allowing each region to provide appropriate mechanical support while promoting stress distribution that facilitates bone healing throughout the implant-bone interface
Solution Approach 2:
The patent employs composite materials by combining materials with different mechanical properties in a single implant structure. The composite construction includes cortical bone-mimicking regions and cancellous bone-mimicking regions with varying elastic moduli, creating a gradient structure that eliminates stiffness mismatch and promotes physiological stress distribution for enhanced bone healing
2Strength
If high insertion force is applied to secure prosthetic components, then initial fixation is achieved, but wear and mechanical insufficiency occur at modular junctions
Solution Approach 1:
The patent utilizes mechanical vibration through a vibratory tool during the impaction process. The vibratory tool applies controlled vibrations to the prosthetic component during insertion, reducing friction and allowing the component to be secured with lower insertion forces while maintaining strong initial fixation and preventing damage to modular junctions
Solution Approach 2:
The patent applies parameter changes by modifying the friction characteristics at the implant-bone interface through vibratory treatment. The vibrations temporarily alter the friction coefficient, enabling easier insertion with reduced forces while maintaining secure fixation once positioned, thereby protecting modular junctions from excessive mechanical stress
3Reliability
If anisotropic structures with cortical and cancellous bone-mimicking regions are created, then stress distribution is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating anisotropic structures with directionally dependent mechanical properties. The implant contains a first region with higher stiffness matching cortical bone and a second region with lower stiffness matching cancellous bone, allowing each region to provide appropriate mechanical support while promoting stress distribution that facilitates bone healing throughout the implant-bone interface
Solution Approach 2:
The patent achieves multi-functionality by designing a single implant structure that simultaneously mimics both cortical and cancellous bone properties. This universal design approach allows the implant to provide both structural support and stress distribution functions in one component, eliminating the need for separate implant types for different bone densities
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 allows for safer, more controlled insertion of prosthetic components with reduced force requirements, improved osseointegration, and enhanced bone healing by mimicking the mechanical properties of bone, thereby reducing complications like trunnionosis and stress shielding.
Implementation Method 1
Anisotropic structures with a first region having a first stiffness profile matching a stiffness profile of cortical bone and a second region having a second stiffness profile matching a stiffness profile of cancellous bone
Implementation Method 2
The collection of incorporated references includes multiple embodiments of multiple inventions, with some of these embodiments including a use of vibratory force/energy that disclosed as important for addressing problems with application of impaction forces
Implementation Method 3
prosthetic implants with anisotropic and viscoelastic properties
Data Source
AI summary
A system and method for improving upon an ability of a surgeon to repair traumatic bone injury using new materials, components, and structures. A structure may be used as an implant or a component of an external fixator for a fractured long bone with that structure having anisotropic and viscoelastic properties, such as through additive manufacturing techniques.