Compliant Polymer Hinge Joint Implant for Arthritis

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Solution Overview

Problem

Current hinge joint implants are invasive, cause discomfort, and fail to restore natural joint kinematics, leading to pain and limited mobility, especially in small joints like fingers and toes, with high revision rates and bone absorption issues.

Innovation Solution

A minimally invasive, self-lubricating, compliant implant designed to fit between articulating surfaces, allowing motion solely within the device, preserving natural joint kinematics and ligaments, and manufactured using rapid prototyping techniques to ensure precise fit and minimal bone reshaping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional hinge joint implants are used, then joint replacement is achieved, but bone absorption, implant loosening, and osteophyte formation occur

Engineering Contradiction:
Improveimplant stabilityVSAvoidbone absorption
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces traditional metal mechanical implants with a compliant polymer implant that deforms elastically under load. This substitution of mechanical system changes the interaction mechanism from rigid contact to compliant deformation, eliminating stress shielding and bone resorption while maintaining joint function and implant stability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If metal hinged implants are used, then joint replacement is achieved, but residual metal is transferred to the bloodstream

Engineering Contradiction:
Improveimplant durabilityVSAvoidmetal transfer to bloodstream
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent employs a composite material approach by using a compliant polymer rather than metal, thereby eliminating metal transfer to bloodstream while maintaining implant durability through the polymer's wear resistance and mechanical properties.

Inventive Principle:
Principle #40Composite materials

3Reliability

If invasive surgical procedures are used for implant insertion, then joint replacement is achieved, but patient trauma and recovery time increase

Engineering Contradiction:
Improvejoint function restorationVSAvoidsurgical trauma
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The implant is designed as a segmented structure with multiple lobes that can be inserted through a minimally invasive approach. The segmented design allows the implant to be delivered through a small incision and then deployed within the joint space, reducing surgical trauma while restoring joint function.

Inventive Principle:
Principle #1Segmentation

4Reliability

If existing implants are used, then joint replacement is achieved, but natural joint kinematics are not restored

Engineering Contradiction:
Improvejoint stabilityVSAvoidnatural joint movement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The implant features a dynamic design where the compliant polymer deforms elastically in response to joint movement, allowing the implant to adapt to the natural kinematics of the joint. This dynamic compliance restores natural joint movement patterns while maintaining stability through the polymer's elastic properties.

Inventive Principle:
Principle #15Dynamics

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 reduces trauma, recovery time, and risk of complications, maintaining joint integrity and mobility, suitable for all ages, and can be used under local anesthesia, effectively treating small joint arthritis with low friction and no external wear, thus improving quality of life.

Implementation Method 1

self-lubricating, compliant implant designed to fit between articulating surfaces, allowing motion solely within the device

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

self-lubricating, compliant implant designed to fit between articulating surfaces, allowing motion solely within the device

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4069150B1implant
Publication Date: 2024.05.01 AURORA MEDICAL LTD
  • EP4069150B1 patent drawingFigure 1A~2
  • EP4069150B1 patent drawingFigure 3~5A
  • EP4069150B1 patent drawingFigure 5B~6H

AI summary

The present invention is directed to a hinge joint implant (40) configured to fit in a joint cavity and which can comprise, when in situ, an at least hemi-spherocylindrical configuration, and further a hinge joint implant configured to fit in a joint cavity wherein the implant can extend around the sides of a joint component which may be a bone and/or cartilage. The invention further provides the use of a hinge joint implant according for treating arthritis, and/or torn cartilage, and a method for manufacturing a hinge joint implant from one or more pieces.