Hip Prosthesis Socket Isoelastic Load Distribution

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Solution Overview

Problem

Current hip joint endoprostheses face significant challenges in long-term durability, material aging, wear particle toxicity, osseointegration, and stress shielding, leading to decreased survival rates beyond the first decade after implantation.

Innovation Solution

A joint socket made from a composite material with a modulus of elasticity adapted to spongy bone, featuring a porous surface with titanium or calcium phosphate particles, and stabilized UHMWPE with antioxidants, ensuring long-term mechanical stability, osseointegration, and reduced wear, while maintaining physiological load distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional materials are used for joint sockets, then initial survival rate is high (90%+ after 10 years), but failure rate increases drastically in the second decade

Engineering Contradiction:
Improvelong-term survival rateVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The joint socket employs a composite structure combining a metal base body with a ceramic insert material. This composite approach allows the socket to achieve both the required mechanical strength for initial stability and the wear resistance needed for long-term durability, resolving the contradiction between initial survival rate and long-term service life.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The ceramic insert features a porous surface structure that promotes osseointegration with surrounding bone tissue. This porous configuration enables direct bone bonding to the implant surface, significantly improving long-term reliability and preventing loosening over decades, thereby addressing the failure rate increase in the second decade.

Inventive Principle:
Principle #31Porous materials

2Strength

If rigid materials are used for load-bearing structure, then mechanical strength is improved, but stress shielding causes bone regression

Engineering Contradiction:
Improvemechanical strengthVSAvoidstress shielding
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The ceramic insert material is specifically selected to have a modulus of elasticity that matches the surrounding spongy bone tissue. This parameter matching ensures that the implant and bone experience similar mechanical stresses, preventing stress shielding and bone regression while maintaining sufficient load-bearing capacity through the composite structure.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional articulation materials are used, then initial wear resistance is achieved, but wear particles cause tissue damage over time

Engineering Contradiction:
Improvewear resistanceVSAvoidwear particle toxicity
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The porous ceramic insert surface provides excellent wear resistance while the ceramic material itself generates benign wear particles that do not cause tissue damage. The porous structure allows for bone ingrowth that further stabilizes the articulation, eliminating the harmful wear particle effect associated with conventional metals and polymers.

Inventive Principle:
Principle #31Porous materials

4Ease of manufacture

If smooth surface is used for joint socket, then manufacturing is easier, but bone integration is insufficient

Engineering Contradiction:
Improvesurface processingVSAvoidosseointegration
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The ceramic insert incorporates a porous surface structure that is specifically designed to promote bone integration. The porous configuration provides anchoring points for osteoblasts and facilitates direct bone bonding to the implant surface, achieving superior osseointegration while remaining manufacturable through standard ceramic processing techniques.

Inventive Principle:
Principle #31Porous materials

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 solution provides a joint socket that remains functional and biocompatible for over two decades, preventing material degradation, promoting stable bone integration, and minimizing wear particles, thus enhancing the long-term success rate of hip joint endoprostheses.

Implementation Method 1

The material on the surface of the socket joint should bond with the surrounding bone material in a long-term and stable manner

Methodology Applied
Scientific EffectOsseointegration:

Implementation Method 2

The material of the joint socket should distribute the mechanical load evenly into the surrounding bone material

Methodology Applied
Scientific EffectStress distribution:

Implementation Method 3

stabilized UHMWPE with antioxidants

Methodology Applied
Scientific EffectOxidation resistance: Oxidation

Data Source

PatentEP2296584B1Socket having physiological load transmission
Publication Date: 2019.04.10 MATHYS AG BETTLACH
  • EP2296584B1 patent drawingFigure 1
  • EP2296584B1 patent drawingFigure 2~3

AI summary

The invention relates to a socket (1) for a hip joint endoprosthesis (2), wherein the socket (1) is made of non-aging materials and forms a low-abrasion tribological pairing with a ball (3). The socket (1) comprises an implant surface (4) formed of a material having a porous surface, wherein an isoelastic structure of the socket (1) according to the invention and the ball brings about a physiological load transmission by means of specially concepted materials, the elastic modulus of said materials being matched to the values of a spongy bone material.