Hemiarthroplasty Implant Ring Fixation for Metatarsal Joint
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Solution Overview
Problem
Current treatments for arthritic metatarsal phalangeal joints, such as hydrogels and silicone joints, fail to effectively correct joint motion issues and provide long-term pain relief, often leading to subsidence and joint collapse.
Innovation Solution
A hemiarthroplasty device with a joint-facing surface and a bone-facing surface forming a body member, featuring a ring member extending from the bone-facing surface for insertion into a bone recess, and a dorsal member for affixing to the metatarsal bone, designed to preserve bone structure and promote fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If joint fusion is performed to stop pain, then pain relief is achieved, but mobility is limited
Solution Approach 1:
The implant is divided into distinct functional segments: a joint-facing surface for articulation, a bone-facing surface for fixation, and a dorsal member for stabilization. This segmentation allows the device to provide pain relief through proper joint alignment while preserving mobility through controlled articulation surfaces.
Solution Approach 2:
The implant extends from the bone head to the dorsal region, utilizing the third dimension (depth/length along the bone axis) to achieve stable fixation without limiting joint motion. The dorsal member extends along the dorsal surface, providing stabilization in a dimension perpendicular to the joint articulation plane.
2Object-affected harmful factors
If hydrogels are placed in the joint to provide pain relief, then pain relief is achieved, but the treatment is not strong enough to correct joint motion issues and leads to subsidence and joint collapse
Solution Approach 1:
The implant uses curable adhesive material with adjustable viscosity and bonding strength parameters. The adhesive can be applied in a softer state for easy application and then cured to achieve high bonding strength, providing both ease of implantation and reliable joint stabilization.
Solution Approach 2:
The implant combines multiple materials with different properties: the adhesive material provides bonding and stabilization, while the implant structure itself provides mechanical support and motion correction. This composite approach overcomes the weakness of single-material solutions like hydrogels.
3Ease of operation
If silicone joints are used as an alternative treatment, then joint replacement is achieved, but they do not perform well long term
Solution Approach 1:
The implant uses curable adhesive material that transitions from a workable state to a permanently bonded state. This parameter change ensures strong, durable fixation that maintains joint replacement functionality over the long term, overcoming the degradation issues of silicone joints.
Solution Approach 2:
The adhesive material cures in situ within the implant structure, creating self-contained, permanent bonds that do not require external reinforcement or maintenance. This self-service bonding mechanism ensures long-term durability without compromising the joint replacement function.
4Loss of substance
If a ring member is inserted into a bone recess to preserve bone structure, then bone preservation is achieved, but implant fixation complexity increases
Solution Approach 1:
The implant is segmented into a main body and an extending dorsal member, allowing the dorsal member to specifically target the bone recess for fixation while the main body addresses the joint surface. This segmentation enables bone preservation without requiring complex overall implant design.
Solution Approach 2:
The dorsal member extends from the bone-facing surface along the dorsal surface of the metatarsal bone, utilizing the longitudinal dimension of the bone to achieve stable fixation in the bone recess. This dimensional approach simplifies the implant design by using the bone's existing geometry rather than adding complex multi-directional fixation elements.
Data Source
AI summary
An implant having a joint facing surface and a bone facing surface forming a body member and a dorsal member therebetween. The implant further having a ring member extending out from the bone facing surface to a free end disposed for insertion into a bone recess. The body member and the dorsal member include a concave curvature on the bone facing surface and a convex curvature on the joint facing surface.