Expandable Foot Prosthesis With Screw-Linkage Size Adjustment
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Solution Overview
Problem
Current prosthetic devices for foot/ankle injuries, disorders, and deformities lack adequate structural support and are time-consuming to shape during surgery, with limited size and shaping potential of autogenous bone tissue, and alternative materials do not provide sufficient structural support.
Innovation Solution
An expandable prosthetic device with a drive block, linkage block, drive screw, and linkages that allow for controlled expansion and contraction, featuring a drive screw that rotates within openings in the blocks, enabling movement of endplates and linkages to adjust the device's size and shape, with optional graft windows for bone and tissue growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If intra-operative shaping of autogenous bone tissue is used, then the prosthetic device can be customized to patient anatomy, but the process is time-consuming and the bone tissue has limited size and shaping potential
Solution Approach 1:
The prosthetic device is pre-formed with specific geometries and configurations before surgery. The device includes pre-configured linkages, endplates, and structural elements that are prepared in advance, eliminating the need for time-consuming intra-operative shaping of bone tissue while maintaining customization through selection of appropriate pre-formed device variants.
Solution Approach 2:
The prosthetic device incorporates expandable and adjustable components that can be modified intra-operatively through controlled expansion mechanisms. The device transitions from a compact transport configuration to an expanded functional configuration, allowing size and shape adjustment without requiring extensive surgical shaping time.
2Productivity
If granular and/or putty-like materials are used for bone grafting, then the void can be filled quickly, but adequate structural support is not provided
Solution Approach 1:
The prosthetic device incorporates porous structural elements and lattice frameworks that provide both mechanical strength and porosity for bone ingrowth. The porous titanium or metal alloy structures offer adequate structural support while allowing biological integration, eliminating the need for weak granular graft materials.
Solution Approach 2:
The device combines different materials with complementary properties - strong metal alloys for structural components, porous materials for bone integration, and potentially bioactive coatings. This composite approach provides both the required structural support and the biological functionality that granular materials alone cannot achieve.
3Adaptability or versatility
If the prosthetic device is made expandable with drive mechanisms, then size and shape flexibility is improved, but device complexity increases
Solution Approach 1:
The prosthetic device is divided into modular segments connected by linkages. Each segment can be independently positioned or adjusted, and the modular design allows the device to be assembled from standardized components, reducing overall complexity while maintaining flexibility.
Solution Approach 2:
The expansion and adjustment mechanisms utilize simple mechanical principles such as threaded rods, cam mechanisms, or shape memory alloys rather than complex motorized systems. These passive or semi-passive mechanisms reduce the number of active components while achieving the desired size and shape flexibility.
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
Provides improved structural support and flexibility during surgery, allowing for precise shaping and integration with bone and tissue, enhancing surgical efficiency and effectiveness.
Implementation Method 1
The drive screw is rotatably coupled at least partially in the drive block opening or linkage block opening and is threadingly disposed within the other of the linkage block opening or the drive block opening
Implementation Method 2
the body of the drive screw includes threading that is threadedly connected to at least a portion of the threading in the linkage block opening
Data Source
AI summary
An expandable prosthetic device used as a prosthesis during surgery. The expandable prosthetic device is configured for use in the extremities of a body such as, but not limited to, use in the expansion of the lateral or medial column of a foot. The expandable prosthetic device includes a drive block, a linkage block, a drive screw, a first endplate, a second endplate, and first and sets of linkages. Rotation of the drive screw causes movement of the linkage block relative to the drive block and/or movement of the first endplate relative to the second endplate.