Over the last 30 years, orthopaedic surgery has immeasurably improved the lives of millions of people, restoring their mobility, bringing pain relief and ultimately giving them a better quality of life. However, orthopedic implants, especially hip and knee joint replacements, have a limited lifetime because of implant failure and the need for revision surgeries within certain time periods in patients who might require frequent, complicated, and expensive surgeries. For this reason, lengthening the life span of implants for several decades would prevent considerable patient suffering and save health care costs. Long-term survival and favorable outcome of orthopedic implant use are mainly determined by bone–implant osseointegration and absence of infection near the implants.
Most commonly recorded indications for these revisions are aseptic loosening and infection while other indications include pain, dislocation, fracture, etc. An ideal orthopaedic implant material is thus expected to promote osseointegration and inhibit bacterial attachment, enabling a better treatment procedure with less risk of infection while still accelerating the bone healing process. Development of novel surface modification techniques to endow these capabilitiescto biomaterials has recently surged and is of great clinical promise; it is viewed as one of the most promising future directions in orthopaedics. However, currently available surface modification techniques do not satisfactorily combines ease of processing complex shapes with inhibition of bacteria and support of bone matrix production. Based on this context, the overall aim of EDiMplant project was set to develop a competent surface modification approach suitable for enhanced osseointegration and antibacterial capabilities of biomaterials. In this project, electrical discharge machining (EDM) based surface modification approach was proposed for fabrication of surfaces exhibiting anti-bacterial and osteogenic characteristics through surface alloying, metal oxide globule formation, and controlled surface texturing mechanism of EDM. Following objectives were set for the project:
(i) To characterise the properties of hydroxyapatite (HA) powder mixed dielectric and their influence on surface modifications during powder mixed electrical discharge machining (PM-EDM) of Ti alloys:
(ii) To fabricate novel Zn-Ag electrodes and characterise their properties and analyse their appropriateness for EDM applications in biomaterial treatment (WP2):
(iii) To evaluate the influence of Zn-Ag electrodes in PM-EDM on osseointegration and antibacterial resistance of Ti alloys (WP3)
(iv) Demonstrate the competence of EDM to process implants quickly, accurately, to achieve the treatment of complex shapes, to a high quality.
