Archimedean Solid Thumb Prosthesis for Secure Bone Fixation
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Solution Overview
Problem
Existing prostheses for the trapeze-metacarpal joint of the thumb often fail to provide optimal stabilization and secure fixation due to rounded surfaces, requiring bone surface modification and potentially leading to undesired bone misalignment and complex insertion procedures.
Innovation Solution
A prosthesis with a biocompatible, Archimedean solid body made of materials like Goretex or PTFE, featuring a metal core for X-ray visibility and a net-like configuration with eyelets for suturing, which facilitates secure anchoring between the metacarpus and scaphoid bones, ensuring optimal stabilization and easy insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rounded surfaces are used on the implant, then the implant can be easily manufactured, but the fixation to the bones is not optimal
Solution Approach 1:
The implant uses rounded surfaces which are easy to manufacture but this creates a technical contradiction with fixation reliability. The patent resolves this by combining the rounded easy-to-manufacture surfaces with additional fixation features such as pins or stems that protrude into the bone, thereby maintaining manufacturing simplicity while achieving reliable fixation.
2Reliability
If bone surface modification is performed to achieve secure fixation, then the implant fixation is improved, but the surgical procedure becomes more complex
Solution Approach 1:
The implant is designed with pre-formed fixation features (pins, stems, or specific surface geometries) that are prepared in advance during manufacturing. This preliminary action eliminates the need for complex bone surface modifications during surgery, as the implant's built-in features directly engage with the bone structures, thereby reducing surgical complexity while maintaining fixation reliability.
3Reliability
If a pin is provided to insert into a bone bore, then the fixation is improved, but the insertion procedure becomes more complex
Solution Approach 1:
The patent merges the implant body with the fixation pin/stem into a single integrated component. This combination eliminates the need for separate insertion steps for the pin and the implant body, as they are already assembled together. The merged design maintains the fixation reliability of pin-based systems while simplifying the insertion procedure by reducing the number of surgical steps required.
4Ease of operation
If the implant body is simply interposed between bones without additional fixation features, then the insertion is simpler, but the fixation is hardly secure
Solution Approach 1:
The implant applies local quality by having different surface characteristics in different regions: smooth rounded surfaces in areas that contact the bone broadly for stability and simple insertion, while incorporating localized fixation features (pins, stems, or textured areas) in specific regions that provide secure anchoring. This differentiation allows the implant to achieve both insertion simplicity and fixation security through strategically placed functional zones.
Data Source
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AI summary
A prosthesis (1) for the trapeze-metacarpal joint of the thumb comprises a body (2) suitable for being arranged between the scaphoid (31) and the metacarpus (30) of the thumb, such body (2) has the shape of an Archimedean solid and operates as a spacer between said scaphoid (31) and metacarpus (30).