3D-Printed Intramedullary Nail With Bone-Matched Stiffness
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Solution Overview
Problem
Current orthopedic intramedullary devices lack universal guidelines for optimal performance, and there is a need for improved mechanical properties that match those of bone, particularly in terms of axial bending and torsional stiffness, to accelerate fracture healing.
Innovation Solution
The development of an orthopedic intramedullary nail manufactured via additive manufacturing using medical-grade powders, with a method involving direct metal laser sintering, heat treatment, and machining to achieve optimal mechanical properties, including a telescopic design and internalized sensor probe channel for adjustable stiffness and monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional machining or molding from isotropic materials is used, then manufacturing precision and reliability are improved, but the mechanical properties (axial bending and torsional stiffness) do not match bone properties
Solution Approach 1:
The patent changes the manufacturing parameters by using additive manufacturing instead of traditional machining, enabling complex porous structures and variable stiffness designs that match bone mechanical properties while maintaining manufacturability through automated processes
Solution Approach 2:
The patent employs composite material structures with varying porosity and density distributions within the implant to achieve mechanical properties that closely match bone, combining different material phases and structures to optimize both strength and bone compatibility
2Adaptability or versatility
If universal guidelines for implant stiffness are established, then device complexity is reduced, but the ability to optimize for specific fracture types is limited
Solution Approach 1:
The patent applies local quality by creating regions of varying porosity and material density within different sections of the implant, allowing each region to have optimized mechanical properties tailored to specific fracture types and locations along the bone
Solution Approach 2:
The patent incorporates dynamic adjustability through telescopic portions that allow post-operative adjustment of implant stiffness, enabling the device to adapt to healing progress and specific patient needs without requiring multiple fixed-design implants
3Reliability
If similar implants are used for both simple and complex fractures to contain costs, then device complexity is reduced, but fracture healing is not accelerated
Solution Approach 1:
The patent achieves universality by designing a single implant platform with adjustable features (telescopic portions, variable porosity) that can be configured for different fracture types, providing customized optimization for both simple and complex fractures without requiring entirely different implant designs
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 provides orthopedic intramedullary nails with mechanical properties comparable to wrought titanium, enabling improved fracture healing by matching the stiffness of bone and allowing for adjustable mechanical loading, thus accelerating the healing process.
Implementation Method 1
forming from a medical grade powder, and via an additive manufacturing process, an additive manufactured orthopedic component
Implementation Method 2
heat treating the additive manufactured orthopedic component
Implementation Method 3
a wall comprising one or more laser sintered layers of a medical grade powder
Data Source
AI summary
An orthopedic device, such as an intramedullary nail for internal fixation of a bone and a method of manufacturing the same. The orthopedic device may be formed from a medical grade powder via an additive manufacturing process. The forming process may include heat treating the additive manufactured component and machining the heat treated additive manufactured component to form the orthopedic device. Further, the orthopedic device may be formed to include an internal sensor probe channel that extends within at least a portion of the wall of the device, but which does not protrude through an outer portion of the wall. Embodiments further include a dynamizing intramedullary nail that accommodate adjustments in the relative axial positions of one or more sections of the orthopedic device. The devise may include features in an inner region of the orthopedic device that may alter an elastic modulus of the orthopedic device.