Loose Prosthetic Cup Spacers for Gas Plasma Sterilization

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Solution Overview

Problem

The existing cement spacers on prosthetic cups pose challenges during gas plasma sterilization, as the gas cannot penetrate behind and along the sides of the spacers due to their interference fit design, leading to incomplete sterilization.

Innovation Solution

The spacers are designed to be loosely carried on the cup with a surrounding clearance gap, allowing sterilizing gas to penetrate, and are secured in place with a snap-fit mechanism once cement is used to lock the assembly, ensuring effective sterilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If spacers are pressed into drilled holes to create an interference fit, then the spacers are held rigidly in position, but the sterilizing gas cannot penetrate behind and along the sides of the spacers

Engineering Contradiction:
Improvespacer position stabilityVSAvoidsterilization completeness
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The spacer is divided into two functional parts: a location portion that provides a clearance gap for gas penetration, and a retentive flange that provides retention after cement insertion. This segmentation allows the spacer to simultaneously enable sterilization gas access while maintaining position stability through the flange-cement-retention mechanism.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If spacers are loosely carried on the cup with a clearance gap, then sterilizing gas can penetrate behind and along the sides of the spacers, but the spacers are not rigidly held in position

Engineering Contradiction:
Improvesterilization completenessVSAvoidspacer position stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The retentive flange is designed in advance to engage with the undercut in the recess, creating a preliminary retention mechanism. This allows the spacer to be loosely carried during sterilization while ensuring it remains retained after cement insertion, as the flange prevents removal once the cement sets.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If spacers are made as separate items pressed into openings, then they can be easily manufactured, but gas plasma sterilization cannot reach all surfaces

Engineering Contradiction:
Improvespacer manufacturing simplicityVSAvoidsterilization completeness
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The spacer design applies local quality by creating a specific clearance gap geometry at the location portion while maintaining a retentive flange structure. This localized structural differentiation allows the spacer to be easily manufactured as a single piece while enabling gas plasma sterilization access through the clearance gap region.

Inventive Principle:
Principle #3Local quality

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

This design allows for complete sterilization of the prosthetic cup and spacers, ensuring the integrity and safety of the surgical implant by ensuring the sterilizing gas can reach all areas, including behind and alongside the spacers.

Implementation Method 1

cups made from, for example, polyethylene can be sterilized with a gas plasma sterilization process

Methodology Applied
Scientific EffectGas plasma sterilization: Plasma

Data Source

PatentEP2042130B1Cement spacer for use in prosthetic cup
Publication Date: 2014.05.14 STRYKER IRELAND LTD
  • EP2042130B1 patent drawingFigure 1~4
  • EP2042130B1 patent drawingFigure 5~6

AI summary

A prosthetic cup adapted to be held in place in a receptive opening in a bone by cement, and having an outer surface provided with one or more projecting spacers to space said outer surface away from the surface of said receptive opening and in which said spacer or spacers is or are loosely carried on said cup with a surrounding clearance gap to allow loose relative movement in all directions.