Shape-Changing Bone Implant for Segment Compression
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Solution Overview
Problem
Existing bone fixation implants lack the ability to lock into bone segments and simultaneously shorten to pull them together, requiring heating, cooling, expensive equipment, and complex manufacturing processes, and often fail to provide consistent compression forces during bone healing.
Innovation Solution
A shape-changing implant made from elastic materials like nitinol, titanium, or polymers that stores mechanical energy and automatically changes shape to compress bone segments without temperature dependence, allowing for easy insertion and consistent load transfer, with a mechanism that locks into bone and adjusts to maintain contact even if it loosens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid stainless steel or titanium wires and screws are used for bone fixation, then the implant provides structural support, but it cannot change shape to pull together and compress bone segments
Solution Approach 1:
The patent employs shape memory alloys (such as nitinol) that can change their physical parameters (shape, length, diameter) in response to temperature or mechanical stimuli. The implant is manufactured in a temporary configuration and then transformed in situ to its functional configuration, enabling it to both provide structural support and adapt to pull together bone segments.
Solution Approach 2:
The implant transitions from a static rigid structure to a dynamic shape-changing structure. The use of elastic materials and shape memory alloys allows the implant to dynamically adjust its shape and apply compressive forces, enabling it to both support and actively compress bone segments during healing.
2Adaptability or versatility
If shape changing nitinol implants are used, then the implant can expand to lock into bone, but it requires heating or cooling to activate the shape change
Solution Approach 1:
The implant is pre-formed in a temporary, constrained configuration that is easy to insert. The shape change to the functional configuration is then activated in situ through mechanical means (such as expanding against bone walls or using self-expanding features) rather than requiring pre-heating or cooling, eliminating temperature dependence while maintaining adaptability.
Solution Approach 2:
The patent replaces thermal activation mechanisms with mechanical activation mechanisms. Instead of using heat or cold to trigger shape change, the implant uses mechanical expansion, elastic deformation, or self-expanding features that convert insertion energy into the desired shape change and bone compression.
3Reliability
If expanding implants are used to lock into bone, then fixation is achieved, but the implant cannot simultaneously shorten to pull together bone segments
Solution Approach 1:
The implant is divided into functional segments: an expansion mechanism for locking into bone, a compression mechanism for shortening, and a structural backbone for support. This segmentation allows each function to be independently optimized and activated in sequence, enabling both reliable locking and subsequent shortening to compress bone segments.
Solution Approach 2:
The implant incorporates dynamic elements that allow it to first expand radially to lock into bone, then axially shorten to compress bone segments. The use of elastic materials and shape memory alloys enables this sequential dynamic transformation, providing both fixation and compression functions.
4Manufacturing precision
If complex manufacturing processes are used to set staple shape and transition temperatures, then precise shape changing properties are achieved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent uses shape memory alloys with transition temperatures that are either body-temperature activated or can be set through relatively simple heat treatment processes. This eliminates the need for complex multi-step manufacturing to precisely control transition temperatures, as the materials naturally exhibit the desired properties or can be adjusted through standard metallurgical processes.
Solution Approach 2:
The implant is designed as a single-use, disposable device that is pre-formed in a temporary configuration. This eliminates the need for complex adjustment and reconfiguration procedures, simplifying manufacturing while ensuring consistent performance. The implant is manufactured in its final functional configuration (or close to it) and simply deployed as-is.
5Measurement precision
If ancillary equipment is used to manipulate the implant during insertion, then precise placement is achieved, but the procedure complexity and cost increase
Solution Approach 1:
The implant is designed to be self-manipulating and self-positioning to a large extent. It may include self-expanding features, self-locking mechanisms, and guidance features that allow it to insert and position itself with minimal external manipulation equipment, reducing procedural complexity while maintaining placement precision.
Solution Approach 2:
The implant is pre-formed with guidance features, alignment markers, and self-positioning characteristics that enable accurate placement without requiring complex ancillary equipment. The preliminary configuration includes features that guide the implant into the correct position and orientation during insertion.
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 implant provides reliable, temperature-independent compression forces that promote bone healing by locking into bone segments and adjusting to maintain contact, reducing the need for ancillary equipment and complex procedures, while minimizing the risk of implant-induced fractures and infection.
Implementation Method 1
The embodiments of the subject invention describe an improved within bone fixation implant that stores recoverable mechanical energy in its structure and changes shape to pull together and compress the bone fixation interface. Any biocompatible that has structural properties and behaves elastically when deformed such as but not limited to nitinol, titanium, and stainless steel
Implementation Method 2
These implants are commonly placed along the centerline of bone and thus reside within the bone's intra-medullary canal. The early rigid bone fixation devices were commonly threaded or drilled into bone where the more modern devices are implanted in drilled holes and expand through mechanical means to lock into bone
Data Source
AI summary
A new shape changing bone implant and instrument for the fixation of structures to include bone tissue. This new implant stores elastic mechanical energy to exert force on fixated structures to enhance their security and in bone affect its healing response. This unique implant locks into bone and then simultaneously expands and shortens to lock into bone and then pull the bone segments together. This implant once placed changes shape in response to geometric changes in the implant's and bone's materials structure. The implant may be fabricated from any biocompatible material that acts elastically when deformed including but not limited to nitinol, stainless steel, titanium, and their alloys as well as polymers such as polyetheretherketone, silicone elastomer and polyethylene. The implant is advanced over prior devices due to its: (1) method of operation, (2) high strength, (3) method of insertion, (4) compressive force temperature independence, (5) energy storing implant retention and delivery system, (6) compatibility with reusable or single use product configuration, (7) ability to act as a scaffold to conduct healing bone through the implant, (8) efficient and cost effective manufacturing methods, and (9) reduction in the steps required to place the device.