Ceramic Acetabular Cup Conical Coupling Wear

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Solution Overview

Problem

Current acetabular prostheses with metal-metal couplings face high failure rates due to metal ion release, wear, and positioning issues, leading to adverse effects on tissues and systemic health, necessitating a solution that provides mechanical stability and prevents ion release while maintaining reduced thickness and anatomical compatibility.

Innovation Solution

A ceramic-ceramic acetabular prosthesis with a conical coupling mechanism featuring variable interference along the axis of symmetry, allowing for precise positioning and rotation stability, utilizing ceramic materials for bio-compatibility and reduced wear, and a method for assembly that includes elastic gripping and thermal deformation to achieve a secure fit without metal ion release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If metal-metal coupling is used in acetabular prosthesis, then reduced thickness and anatomical compatibility are achieved, but metal ion release and wear occur leading to high failure rates

Engineering Contradiction:
ImprovethicknessVSAvoidfailure rate
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent changes the material parameter from metal to ceramic, specifically using alumina or zirconia ceramic materials for the insert. This material substitution eliminates metal ion release while maintaining the reduced thickness design, directly resolving the contradiction between achieving thin profile and preventing wear-related failures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The prosthesis employs a composite structure combining ceramic insert material with a metallic or ceramic cup structure. The ceramic insert is specifically designed with optimized thickness while being supported by the cup structure, allowing reduced overall thickness without compromising strength and reliability.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If metal-metal coupling is used in acetabular prosthesis, then anatomical compatibility is maintained, but wear and positioning issues lead to adverse effects on tissues and systemic health

Engineering Contradiction:
Improveanatomical compatibilityVSAvoidmetal ion release and wear
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameter from metal to ceramic (alumina or zirconia), which fundamentally eliminates metal ion release. The ceramic material maintains anatomical compatibility through proper geometric design while providing superior wear resistance, directly addressing the harmful effects of metal-metal coupling.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harm of material wear into a benefit by using ceramic material that exhibits extremely low wear rates. The ceramic-ceramic or ceramic-metal coupling transforms the wear problem into a solution, where the insert provides superior耐磨性 while maintaining anatomical fit.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If conventional coupling methods are used, then assembly is simplified, but mechanical stability and positioning precision are insufficient

Engineering Contradiction:
Improveassembly simplicityVSAvoidpositioning precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent employs a spherical or hemispherical insert design that fits within a corresponding curved cup structure. This spherical geometry provides inherent positioning precision and rotational stability while maintaining ease of assembly through simple insertion, resolving the contradiction between manufacturing simplicity and positioning accuracy.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 ceramic-ceramic conical coupling prosthesis offers enhanced mechanical stability, reduced wear, and bio-compatibility, preventing metal ion release and maintaining anatomical positioning, thereby improving the longevity and safety of hip replacement surgeries.

Implementation Method 1

gripping means made of elastic material

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

thermal deformation to achieve a secure fit

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2911615B9Acetabular prosthesis and corresponding method for production and assembly
Publication Date: 2019.01.23 LIMACORPORATE SPA
  • EP2911615B9 patent drawingFigure 1~2
  • EP2911615B9 patent drawingFigure 3~4
  • EP2911615B9 patent drawingFigure 5~6

AI summary

Acetabular prosthesis comprising an acetabular cup (11), defining a coupling cavity, and an insert (12), able to be inserted inside the coupling cavity. The acetabular cup (11) and the insert (12) have a common coupling axis (Y) and comprise respective clamping means for their reciprocal clamping in an assembled condition.