Retrograde Hammer Toe Implant with Flexible Expansion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional implants for treating hammer toe deformity face issues such as difficulty in installation, tendency to separate, and temperature-sensitive materials that deploy prematurely, leading to pain and limited shoe wearability.
Innovation Solution
An implant system featuring an elongate threaded member with a flexible portion and a core pin for driving into bone, allowing for reversible compression and secure fixation of adjacent bones, enabling improved alignment and fusion of joints without the drawbacks of existing methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pin or rod is placed in the distal, middle, and proximal phalanxes to fuse joints, then the hammer toe deformity is corrected, but the patient cannot wear closed toe shoes and experiences pain from the exposed end of the rod
Solution Approach 1:
The implant uses a nested configuration where the flexible portion with prongs is inserted through the elongate threaded member, allowing the rod to be fully contained within the toe bone structure. This eliminates the exposed end of the rod that causes pain and limits shoe wearability, while maintaining the joint fusion function.
Solution Approach 2:
The flexible portion made of shape memory alloy provides a soft, compliant structure that can be compressed during insertion and then expands to engage the bone. This flexible component replaces the rigid exposed rod end, allowing the patient to wear closed toe shoes without pain while maintaining the fixation function.
2Ease of manufacture
If threaded members are coupled through male-female connection mechanism, then the implant can be installed, but the installation is difficult and the connection tends to separate
Solution Approach 1:
The implant merges the threaded member and flexible portion into a single integrated unit, eliminating the need for separate male-female connection mechanisms. The flexible portion is permanently attached to the threaded member, providing a stable connection that is difficult to separate while maintaining ease of installation through the retrograde approach.
Solution Approach 2:
The implant uses a retrograde approach where the flexible portion is inserted first through the bone, and then the elongate threaded member is threaded over it. This inverted sequence of insertion simplifies the installation process compared to traditional antegrade methods, while the integrated connection prevents separation.
3Force
If temperature sensitive material is used for the implant, then the implant can expand to provide outward force on bone, but the implant may deploy or expand prior to installation requiring a new implant
Solution Approach 1:
The flexible portion is pre-compressed to a compact configuration before insertion, and the shape memory alloy is cooled to a low-temperature state to prevent premature expansion. The material is only activated to its expanded state after insertion into the bone, ensuring controlled deployment at the correct time while providing the necessary outward force on the bone for fusion.
Solution Approach 2:
The implant utilizes temperature-dependent phase changes in the shape memory alloy to control expansion. By controlling the temperature parameter, the implant remains compressed during storage and insertion, then expands when warmed in the body to provide the necessary outward force on the bone, preventing premature deployment.
4Ease of operation
If the flexible portion is compressed toward the axis, then the implant can be inserted through the bone, but the prongs must be reversibly compressed
Solution Approach 1:
The flexible portion is designed with dynamic properties that allow it to be compressed during insertion and then automatically expand to its full configuration after insertion. The shape memory alloy provides this dynamic behavior through temperature-induced phase changes, eliminating the need for complex mechanical compression mechanisms while enabling easy insertion through the bone.
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 system effectively fuses adjacent bones with improved alignment and stability, reducing pain and allowing for the use of closed-toe shoes, while avoiding the installation challenges and material issues of conventional implants.
Implementation Method 1
The flexible portion includes a plurality of prongs configured to be reversibly compressed toward an axis defined by the elongate threaded member
Data Source
AI summary
A system includes and implant and an elongate device. The implant includes a first bone engaging portion and a flexible portion coupled to an end of the first bone engaging portion at an engagement portion. The flexible portion is configured to be compressed toward a longitudinal axis defined by the flexible portion. The elongate device includes an engagement end that is sized and configured to engage the engagement portion of the implant.