Curved Toe Implant Fixation for Stable MTP Joint Motion
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Solution Overview
Problem
Current surgical implants for treating articular cartilage damage in the first metatarsophalangeal (MTP) joint often cause unwanted side-effects such as failure, loosening, subsidence, and limited joint motion, and do not adequately maintain joint mobility and relieve symptoms in patients with advanced cartilage damage.
Innovation Solution
A toe implant with a bearing member having a curved interface surface and a fixation member with a non-porous barrier and tapered portion, along with a surgical kit and method for precise implantation, including a guide, reamer, and tamper, to replicate normal anatomy and secure the implant in the joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing implants are used to treat articular cartilage damage, then some symptom relief may be achieved, but unwanted side-effects occur including failure, loosening, subsidence, and limited joint motion
Solution Approach 1:
The implant is divided into three distinct components: a bearing member with curved interface surface, a fixation member with porous structure, and a non-porous barrier layer. This segmentation allows each component to perform its specific function optimally - the bearing member maintains joint space and motion, the porous fixation member promotes bone integration, and the non-porous barrier prevents fibrous tissue formation, thereby eliminating the side-effects of monolithic implants while maintaining reliability
Solution Approach 2:
Different regions of the implant have different material properties tailored to local requirements. The bearing member has a curved interface surface for smooth joint motion, the fixation member has porous structure for bone ingrowth, and the barrier has non-porous properties to prevent soft tissue penetration. This local differentiation of material properties resolves the contradiction by ensuring each region performs its specific function without causing harmful effects
2Strength
If current surgical techniques are applied, then cartilage repair may be achieved, but patients experience limited joint motion and recurrence of deformity
Solution Approach 1:
The bearing member features a curved interface surface that replicates the natural spherical geometry of the MTP joint. This curvature allows for smooth, multi-directional joint motion while maintaining stable articulation, thereby providing both strong joint support and preserved mobility, resolving the contradiction between strength and ease of operation
3Reliability
If traditional implants are used, then joint replacement may be achieved, but patients develop plantar keratosis, tenderness, and metatarsalgia
Solution Approach 1:
The porous fixation member enables self-service bone integration through osteoconduction, where bone tissue naturally grows into the porous structure to secure the implant. This biological fixation method eliminates the need for aggressive mechanical fixation that causes surrounding tissue damage, thereby achieving reliable joint replacement without patient discomfort
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 improved joint motion and symptom relief by recreating the MTP joint space and promoting bone integration, reducing the risk of implant failure and side-effects.
Implementation Method 1
a fixation member coupled to the bearing member, where the fixation member includes a porous structure
Implementation Method 2
the fixation member includes a first portion having a non-porous barrier
Data Source
AI summary
Disclosed herein is a toe implant for replacing a portion of a human toe joint, as well as a related kit, surgical method, and method of manufacturing. Specifically, the toe implant may include a bearing member having a curved interface surface and a fixation member coupled to the bearing member. The fixation member may include a first portion having a non-porous barrier, and a tapered second portion.