Novel 3D coating of bioactive glass and metallic composites

Lead Research Organisation: University of Sheffield
Department Name: Materials Science and Engineering

Abstract

The orthopaedic implant market is consistently projected to show strong growth, particularly in the joint reconstruction
sector. At a time where healthcare budgets are under severe pressure, there is a need for novel hip implants that deliver a
better quality of clinical outcome, but at the same or reduced cost. Implants are coated to aid implant bone-integration, and
the composition and structure of these coating is critical to the speed and strength of implant-bone integration and hence
the clinical outcome. The current coating is a combination of titanium (for strength) and bioactive glass (to facilitate bone
ingrowth), materials which have very different thermal properties and therefore must be laid down in two-stages if using a
conventional coating process. The ability to apply these materials by a novel 3D printing process, potentially in one-step,
will transform design and manufacture of orthopaedic implants. It will provide much greater design freedom to create new
functionally optimised material combinations and structures not achievable by a conventional process. This project
integrates the capabilities of SMEs operating end-to-end from design to product supply and the expertise of the University
of Sheffield in end-to-end simulation. Using a range of simulation methodologies developed by UoS in a series of
previously funded programmes (e.g. IMMPETUS EPSRC grants, EP/E063497 and EP/F023464), the Mercury Centre will
apply these to design and simulate the end-to-end manufacturing of the novel 3D coating of bioactive glass and metallic
composites. We will use phase field modelling to simulate the melting, fluid dynamics, solidification and phase
transformations during AM to optimise the process conditions for this application. We will use our unique combined finite
element/discrete element modelling to simulate the heat transfer, residual stresses and interaction between the metal and
bioglass. Multi-scale modelling will be used to link microstructure and properties throughout the manufacturing process.
This will extended to include the behaviour of the novel composite in vivo. It will deliver from design to supply a novel
additive manufacturing (AM) process to apply novel interpenetrating 3D glass and metallic composite coatings onto 3D
surfaces initially for orthopaedic (hip) implants. The coatings will enable design and manufacture of smaller (minimally
invasive) implants with 'large implant' performance having better mechanical stability and faster integration with bone thus
improving long-term clinical performance and a reduced revision rate. This delivers a significantly better clinical outcome
for patients and savings for the health service. The envisaged AM process has the potential to be faster and lower cost
than current two-stage deposition and to enable the manufacture (possibly in near-patient areas) of implants matched to
the patient using pre-operative bone scans. Transferability to other sectors will be demonstrated by the manufacture of a
solar diffuser material.

Planned Impact

The orthopaedic implant market is consistently projected to show strong growth, particularly in the joint reconstruction
sector, with a total market size estimated at $36.7bn p.a.. At a time where healthcare budgets are under severe pressure,
there is a need for novel hip implants that deliver a better quality of clinical outcome, but at the same or reduced cost. This
project brings together partners with expertise in multiscale modelling, additive manufacturing, glass technology and orthopaedic implants. The aim is to develop the next generation of coatings for orthopaedic implants such as hip
replacements. The new combination glass and metal coatings will have better mechanical stability and faster integration
with bone thus improving long-term clinical performance and reducing the revision rate. This will deliver a significantly
better clinical outcome for patients and savings for the health service. The partners provide end-to-end supply chain, from
simulation and design, through manufacturing, through to the market place. The technology developed during this project
has the potential to transform the manufacture of orthopaedic implants and has applications in other fields requiring
specialist combinations of glass and metal.

Publications

10 25 50
 
Description A new way of using additive layer manufacturing to produce a bioactive glass component for hip joint replacements has been developed. Models for the manufacturing process have been developed.
Exploitation Route The results will be used by a number of companies to manufacture new components. This includes JRI (who make hip joint orthopaedics), Glass Technology International, 3T.
Sectors Manufacturing, including Industrial Biotechology

 
Description A new manufacturing method for making acetabular cups with bioactive glass for hip joint replacements is being developed. The project produced a computer model that predicts the optimum process conditions for this application and explains the observed product output.
First Year Of Impact 2014
Sector Manufacturing, including Industrial Biotechology
Impact Types Economic

 
Description JRI 
Organisation JRI Orthapaedics
Country United Kingdom 
Sector Private 
PI Contribution Modelling the additive layer deposition of glass powders onto a metal substrate Understanding of the tribology of hip joints
Collaborator Contribution Expert knowledge
Impact Model to predict optimum process conditions for ALM
Start Year 2014
 
Title Bioactive glass coating acetabular cup 
Description The product is being developed from a laboratory proof of concept to a product that can undergo clinical trials. 
Type Therapeutic Intervention - Surgery
Current Stage Of Development Initial development
Year Development Stage Completed 2016
Development Status Under active development/distribution
Impact The acetabular cup will integrate with bone more rapidly and provide a superior joint that should allow for longer life in the patient.