Variable Stiffness Orthopedic Prosthetics for Reduced Insertion Force
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Solution Overview
Problem
Current bone fracture repair methods face challenges in efficiently and safely inserting and fixing prosthetics due to high installation forces, which can lead to bone damage and complications, particularly in traumatic injuries, where conventional systems require multiple steps and materials that do not accurately mimic the mechanical properties of bone.
Innovation Solution
The development of a system and method using anisotropic and viscoelastic components with asymmetric surface treatments and manufacturing techniques, such as additive manufacturing, to create prosthetics with variable stiffness profiles that facilitate easier insertion and secure fixation, allowing for reduced force insertion and enhanced bone healing by mimicking the mechanical properties of bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional prosthetics with uniform stiffness are used for bone fracture repair, then the prosthesis provides structural support, but it causes high installation forces that can lead to bone damage
Solution Approach 1:
The prosthesis incorporates variable stiffness elements with different stiffness values in different regions, allowing the structure to have high strength where needed while reducing local stiffness in areas that contact bone during insertion. This spatial variation in material properties enables the prosthesis to maintain overall structural integrity while minimizing peak insertion forces.
Solution Approach 2:
The prosthesis uses adjustable stiffness mechanisms that allow the mechanical properties to be modified after implantation. The stiffness can be dynamically adjusted from a lower initial value during insertion to a higher value for long-term structural support, transforming a static structure into a dynamically adaptable one that responds to different operational phases.
2Reliability
If high installation forces are applied to secure the prosthesis, then the fixation is secure, but bone damage and complications occur
Solution Approach 1:
The prosthesis employs material parameters that change over time or under different conditions. The variable stiffness elements are designed to exhibit different mechanical properties during insertion versus during load-bearing, allowing secure fixation to be achieved through controlled parameter transitions rather than consistently high forces that would damage bone.
Solution Approach 2:
The prosthesis utilizes composite material structures combining materials with different mechanical properties. This allows the construction of a fixation system that achieves reliable bonding and secure attachment without requiring excessively high installation forces, as the composite structure distributes and manages insertion forces more effectively.
3Ease of manufacture
If conventional materials are used that do not mimic bone mechanical properties, then manufacturing is simpler, but osseointegration and bone healing are less effective
Solution Approach 1:
The prosthesis applies different material properties to different regions, with surface areas contacting bone having mechanical properties that closely match bone tissue. This localized optimization of material characteristics promotes osseointegration in critical areas while maintaining manufacturing feasibility through targeted application of complex materials only where needed.
Solution Approach 2:
The prosthesis incorporates porous material structures that mimic the trabecular architecture of natural bone. These porous regions facilitate bone ingrowth and enhance osseointegration by providing a scaffold that encourages biological integration, while the overall manufacturing process remains viable through established porous material fabrication techniques.
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 reduces the magnitude of forces required for insertion, minimizes bone damage, and promotes effective osseointegration, enabling safer and more efficient bone fracture repair with the ability to adjust stiffness over time for optimal healing.
Implementation Method 1
The development of a system and method using anisotropic and viscoelastic components with asymmetric surface treatments and manufacturing techniques, such as additive manufacturing, to create prosthetics with variable stiffness profiles
Implementation Method 2
The development of a system and method using anisotropic and viscoelastic components with asymmetric surface treatments and manufacturing techniques
Implementation Method 3
asymmetric surface treatments and manufacturing techniques, such as additive manufacturing, to create prosthetics with variable stiffness profiles that facilitate easier insertion
Implementation Method 4
promotes effective osseointegration, enabling safer and more efficient bone fracture repair with the ability to adjust stiffness over time for optimal healing
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.