Joint Spacer Wear-Resistant Capping Abrasion Reduction

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Solution Overview

Problem

In patients with joint endoprostheses, infections in hard-to-reach areas can lead to complications, and existing spacers cause abrasion due to interaction with the remaining prosthesis, risking premature failure of the revision prosthesis.

Innovation Solution

A spacer with a wear-resistant capping made of materials like stainless steel, designed for low friction and secure attachment to the joint head, reducing wear and preventing abrasion by doubling friction surfaces and using a twist-proof attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spacer is used to maintain joint length and deliver drug substance, then the joint length is maintained and infection is treated, but abrasion occurs between the spacer and remaining prosthesis causing foreign material to enter surrounding tissue

Engineering Contradiction:
Improvejoint function maintenanceVSAvoidabrasion and foreign material
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A capping element made of wear-resistant material is introduced as an intermediary between the joint piece and the joint piece receptacle. This capping prevents direct contact and abrasion between the spacer material and the prosthesis, eliminating the harmful foreign material generation while maintaining the joint length and function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The spacer is constructed with composite materials: the main body is made of drug-delivering material while the capping is made of wear-resistant material. This composite structure allows the spacer to simultaneously deliver drug substance and prevent abrasion, resolving the contradiction between therapeutic function and mechanical durability.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If patient mobility is promoted during spacer implantation, then mobility is maintained, but abrasion between spacer and prosthesis increases

Engineering Contradiction:
Improvepatient mobilityVSAvoidabrasion
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The wear-resistant capping acts as a protective intermediary that allows patient mobility and movement training while preventing the abrasion that would otherwise occur between the spacer and prosthesis. This enables mobility promotion without the harmful consequences.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the joint piece is made for mobile interaction, then joint function is enabled, but friction and wear occur at the interaction surface

Engineering Contradiction:
Improvejoint mobilityVSAvoidfriction and wear
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The joint piece is constructed with composite materials: the main body uses drug-delivering material while the outer capping uses wear-resistant material. This allows the joint piece to maintain mobility and joint function while the wear-resistant capping prevents friction and wear during movement.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3388030B1Spacer as a temporary joint prosthesis for dispensing a medical agent
Publication Date: 2020.03.04 WALDEMAR LINK GMBH & CO KG
  • EP3388030B1 patent drawingFigure 1~3b
  • EP3388030B1 patent drawingFigure 4~6

AI summary

The invention relates to a spacer for a joint endoprosthesis for temporary implantation, comprising a main body (1) for attachment to a bone and a joint piece (3). The main body (1) consists of a material such as bone cement in which a drug substance (8) is embedded for release into the surrounding tissue. According to the invention, a separate capping (4) of the joint piece (3) is provided. The capping (4) itself consists of a wear-resistant material. It is fixed against rotation relative to the joint head (3). This allows the patient's mobility to be promoted even during the period in which the spacer is implanted, while avoiding dangerous abrasion. The invention thus eliminates the existing conflict between the need for mobility on the one hand and the associated risk of complications (due to abrasion) on the other.