Public Funding for Corin Limited

Awaiting Public Project Summary

Additive Manufacture (AM) is being increasingly investigated within the orthopaedic industry for the production of optimised implant designs. The technology enables complex geometries to be generated which can also be better matched to the properties of bone. Such implants can minimise bone resorbtion and facilitate improved bone ingrowth, thus improving the survivorship of the joint replacement. To date, only one US company is known to have brought AM technology to market. One of the key hurdles to enable commercialisation of existing AM designs is cleaning. Post-manufacture cleaning is required to remove unsintered material/entrapped powder and manufacturing lubricants and it is ultimately of importance to ensure patient safety. Cleaning poses a significant challenge due to the complex, porous implant geometries created by AM. The objective of this project is to develop cleaning methods to enable commercialisation of existing device designs and custom implants.

Clinical studies have shown that hip resurfacings provide improved patient function over total hip replacements (THR) with reduced recovery times; however, since 2008 there has been a large fall in the number of resurfacings performed. This is due to concern over ion release from metal-on-metal (MoM) implants leading to ALVAL (aseptic lymphocytedominated vasculitis associated lesion, also termed pseudotumors) and chromosomal changes.The aim of this project is to develop a metal-on-polymer (MoP) bearing couple on a large diameter resurfacing device. The MoP bearing couple consists of an acetabular component assembled from an innovative metal shell and polymer liner, and a metal femoral head. ECiMa (vitamin E cold irradiated mechanically annealed) is a next generation advanced bearing developed by Corin and Massachusetts General Hospital, and is proven to be a low wearing polymer with enhanced fatigue resistance. ECiMa is currently used as a bearing surface in THRs. This project will combine the current technical advances in polymer bearings with the clinical benefits of resurfacing to produce a next generation device suitable for young, active patients. The innovative MoP hip resurfacing will have a direct positive impact, especially on younger patients for the treatment of arthritis. Lower wear rates, improved function, increased range of motion and a return to an active lifestyle, mean that a resurfacing procedure is preferential to THR for sections of the patient demographic. Patients thought to benefit from hip resurfacing, but not currently recommended for a MoM device as they are considered at high risk from metal ion release, will be able to take advantage of the bone conserving treatment. The device will help address the NHS drive for an eighteen week referral to a treatment admitted pathway as hip resurfacings have a shorter recovery time and so can help reduce the current backlog of orthopaedics waiting times.

The objective of project BERTI (Biomedical implant with Exceptional Resistance to Tribo-bio-corrosion and with Inherent antimicrobial properties) is to develop an innovative joint replacement with a coating that minimises polyethylene and metal wear debris, prevents metal ion release and promotes the release of antimicrobial agents. The project will determine a method that establishes drivers for the detrimental responses to wear debris observed in patients. This information will be used to optimise a recently develop physical-vapour deposition coating that minimises wear and tribo-bio-corrosion while delivering an antimicrobial agent. In addition, the project will establish a test for patient susceptibility to ions release from implants. This will help identify patient cohorts who would benefit most from the novel coated implants, and will deliver to them, and to the wider population, a world-leading joint replacement with exceptional biocompatibility, longevity and antimicrobial properties. Project BERTI will ultimately increase the longevity of orthopaedic implants, reducing the number of revision surgeries, benefiting the UK and wider economy, and the patient.

Acetabular and femoral bone resorption is one of the few remaining clinical challenges to be addressed when considering the long term success of orthopaedic joint replacements, particularly in hip prostheses. Bone resorption around the proximal femoral stem and acetabular cup due to stress shielding contributes to bone loss and reduced bone mineral density, ultimately leading to clinical complications such as periprosthetic fracture, aseptic loosening, joint pain and the loss of bone. The aim of project SHIELD is to develop novel acetabular and femoral components that minimise bone resorption. This will be achieved through a combination of component design and material optimisation by which the load transfer from prosthesis to bone will attempt to mimic bone stress levels pre-operation. Bone resorption during the ageing process will be predicted through finite element models of the physiological scenario derived from in-vivo CT/MRI images. These models will allow state-of-the-art optimisation algorithms to be employed for the implant design and subsequent analyses. Structural integrity will be tested through a series of laboratory tests including cadaveric studies, that will validate predictions from finite element models and evaluate clinical viability. Tribological performance and biocompatibility studies will be evaluated through state-of-the-art methodologies.

Metal on metal prostheses are currently an exciting new area for resurfacing and total hip replacements, reducing problems of osteolysis associated with standard metal on polymer prostheses. However, problems have been identified related to the biological response to the metal particles and metal ion release. The objective of this project is to develop and test the properties of new nanocomposite, wear and ion release resistant PVD coatings, to meet the rigorous demands of the hip joint application. Performance will be assessed on a hip wear simulator to evaluate the longevity of the surface modifications, whilst the nanoparticles generated will be evaluated using state-of-the-art analytical methods. In addition to reducing wear and ion release, the coatings will be designed to offer novel multifunctional benefits of self-lubrication, antimicrobial properties & improved bedding in of bearing surfaces.