TiNb Coated Implant Cone Connection

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Solution Overview

Problem

Modular endoprostheses experience crevice corrosion and fretting corrosion in cone connections, leading to potential fatal failures, mechanical abrasion, pain, aseptic loosening, and allergic reactions due to micro-movements and stress between connecting surfaces, especially in metal-metal and metal-ceramic pairings.

Innovation Solution

An implant component with a connecting section partially coated with a TiNb coating, providing biocompatibility, mechanical strength, and a low hardness to ensure a reliable frictional connection and prevent corrosion, applied using PVD or ion implantation methods with a thickness of 1-20 μm, preferably 3-6 μm, to maintain structural integrity and prevent jamming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conical connections are used to join implant components, then a reliable frictional connection is achieved through leverage effect and normal force, but crevice corrosion and fretting corrosion occur due to micro-movements and stresses between connecting surfaces

Engineering Contradiction:
Improvefrictional connection strengthVSAvoidcorrosion resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

A tantalum coating layer is introduced as an intermediary substance between the two metal cones of the conical connection. This coating serves as a mediator that prevents direct metal-to-metal contact, thereby eliminating the electrochemical potential difference that causes crevice corrosion and fretting corrosion, while still allowing the mechanical frictional connection to function effectively

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connection interface is transformed from a homogeneous metal-to-metal contact into a composite structure consisting of three layers: the base metal cone, the tantalum coating layer, and the opposing metal cone. This composite material approach combines the mechanical strength of metal with the corrosion resistance and biocompatibility of tantalum

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If modular design is used with multiple connecting sections, then adaptability to patient anatomy and biomechanical conditions is improved, but the number of potential corrosion interfaces increases

Engineering Contradiction:
Improvecustomization to patient needsVSAvoidcorrosion risk at interfaces
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The tantalum coating is applied specifically to the connecting sections where corrosion occurs, rather than uniformly across the entire implant. This localized treatment addresses the corrosion problem at the critical interfaces while maintaining the modular design's adaptability benefits

Inventive Principle:
Principle #3Local quality

3Strength

If the connecting surfaces are made harder to increase wear resistance, then mechanical durability is improved, but the frictional connection reliability decreases due to reduced ability to maintain conformal contact

Engineering Contradiction:
Improvewear resistanceVSAvoidfrictional connection stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The surface properties of the connecting sections are modified by applying a tantalum coating that changes the friction characteristics and surface compliance. This coating allows the surfaces to maintain conformal contact under load while providing wear resistance, effectively changing the tribological parameters of the interface

Inventive Principle:
Principle #35Parameter changes

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 TiNb coating effectively prevents allergic reactions and corrosion, ensuring a stable and resilient connection while maintaining a frictional force, thereby reducing mechanical abrasion and adverse tissue reactions, and allowing better adaptation to patient anatomy and biomechanics.

Implementation Method 1

the coated connecting section according to the invention not only prevents allergic reactions, but also, with a suitably chosen thickness, provides a reliable frictional connection and leads to better protection against corrosion

Methodology Applied
Scientific EffectCorrosion resistance:

Implementation Method 2

When these connections are joined, the leverage effect created by the cone angle is used to apply a normal force to the conical surfaces, resulting in a friction-fit connection between the two cones

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

applied using PVD or ion implantation methods

Methodology Applied
Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 4

applied using PVD or ion implantation methods

Methodology Applied
Scientific EffectIon implantation: Ion Implantation

Data Source

PatentEP3125829B1Implant connection
Publication Date: 2019.05.08 WALDEMAR LINK GMBH & CO KG

AI summary

The invention relates to an implant component having at least one connection section. The connection section is coated at least partially with a TiNb coating and said coating has a thickness of 1-20 μm, preferably 1-6 μm. The invention also relates to a modular endoprosthesis comprising an implant component of this type.