Flexible Spacer Metatarsophalangeal Joint Implant
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Solution Overview
Problem
Conventional metatarsophalangeal joint replacement devices often result in stiffness, discomfort, and unnatural feel due to being too stiff or loose, with inadequate coupling to the bone and invasive implantation procedures, failing to replicate natural joint flexibility and stability.
Innovation Solution
A prosthetic joint device comprising a flexible spacer connected by elongate fibers between two porous metallic anchors, allowing for flexible attachment to the bones without invasive intramedullary operations, replicating natural joint flexibility and stability through additive manufacturing and osseointegration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid components are used in the joint replacement device, then structural strength is improved, but joint flexibility and natural movement are worsened
Solution Approach 1:
The patent employs a flexible spacer component made of elastomeric material with embedded reinforcement fibers. This flexible shell structure provides the necessary structural strength through the reinforcement while maintaining joint flexibility and natural movement through the elastomeric matrix, directly resolving the contradiction between strength and flexibility.
Solution Approach 2:
The device uses a composite structure combining rigid porous metallic anchors for bone attachment with a flexible elastomeric spacer containing embedded reinforcement fibers. This composite material approach allows the rigid components to provide structural strength while the flexible components maintain joint adaptability, resolving the strength-flexibility contradiction.
2Strength
If intramedullary inserts are used to attach the pad between bones, then attachment strength is improved, but implantation complexity and invasiveness are worsened
Solution Approach 1:
The patent extracts the intramedullary insert functionality from the device, eliminating the need for invasive bone tunnel creation. The anchors attach to bone surfaces through compression and friction without requiring intramedullary insertion, simplifying the implantation procedure while maintaining adequate attachment strength.
Solution Approach 2:
The flexible spacer acts as an intermediary component that transfers and distributes loads between the anchors and bone surfaces, enabling secure attachment without the need for invasive intramedullary fixation. This mediator approach maintains attachment strength while reducing implantation complexity.
3Strength
If the spacer is made too stiff to provide structural support, then load-bearing capacity is improved, but natural joint flexion is worsened
Solution Approach 1:
The flexible spacer is constructed as a flexible shell structure made of elastomeric material that can bend and deform to accommodate natural joint flexion. The embedded reinforcement fibers provide load-bearing capacity while the elastomeric matrix maintains flexibility, resolving the contradiction between load-bearing capacity and natural joint movement.
Solution Approach 2:
The spacer uses a composite structure combining elastomeric material with embedded reinforcement fibers. The elastomeric component provides flexibility for natural joint flexion while the reinforcement fibers contribute to load-bearing capacity, resolving the contradiction between these two requirements.
4Adaptability or versatility
If the device is made too loose to allow movement, then joint flexibility is improved, but joint stability is worsened
Solution Approach 1:
The flexible spacer shell provides a balance between flexibility and stability. The elastomeric material allows joint movement and flexibility while the embedded reinforcement fibers prevent excessive loosening and maintain joint stability, resolving the contradiction between these two opposing requirements.
Solution Approach 2:
The composite construction of the spacer with elastomeric matrix and reinforcement fibers creates a structure that is flexible enough to allow natural joint movement but stable enough to prevent hypermobility and maintain proper joint alignment, resolving the flexibility-stability contradiction.
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 device provides improved comfort and performance by securely attaching to bones, allowing for natural flexion and stability, reducing pain and discomfort associated with osteoarthritis while simplifying the implantation process.
Implementation Method 1
two porous metallic anchors, allowing for flexible attachment to the bones without invasive intramedullary operations, replicating natural joint flexibility and stability through additive manufacturing and osseointegration
Implementation Method 2
A prosthetic joint device comprising a flexible spacer connected by elongate fibers between two porous metallic anchors, allowing for flexible attachment to the bones
Data Source
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AI summary
A device for the repair of a phalangeal joint comprises a first anchor, a second anchor, and a flexible spacer connecting the first and second anchors. The flexible spacer comprises a plurality of elongate fibers extending axially or criss-crossed between the first and second anchors and a polymeric matrix interspersed with the plurality of elongate fibers. Specifically, a prosthetic metatarsophalangeal joint device comprises a porous metallic metatarsal bone anchor, a porous metallic phalangeal bone anchor, and a polymeric spacer element comprising parallel or criss-crossed elongate fibers that can connect the metatarsal bone anchor and the phalangeal bone anchor. Methods for manufacturing prosthetic joint devices comprise using three-dimensional printing processes or molding processes. Methods for implanting prosthetic joint devices comprise positioning porous metallic anchor components adjacent resected bones at planar interfaces and between which a polymeric spacer having axial aligned elongate fibers embedded in a matrix can be disposed.