OXIDE CERAMIC COATINGS ON ORTHOPAEDIC IMPLANTS: A REVIEW OF TIO2 AND AL2O3

Abstract

Ceramic coatings like TiO2 and Al2O3 have shown great promise in enhancing the surface properties of metallic orthopaedic implants. This comprehensive review summarises the latest advances in deposition techniques, performance evaluations, and the clinical outcomes of TiO2 and Al2O3 coated implants. Magnetron sputtering enables uniform and adherent TiO2 and Al2O3 coatings, but has limitations in coating complex geometries. Micro-arc oxidation can rapidly produce thick porous oxide layers directly on the implant, but the precise control of coating properties is difficult. Numerous studies demonstrate TiO2 coatings can significantly improve the corrosion resistance, wear resistance, and antibacterial properties of Ti, Co-Cr, and stainless steel implants. TiO2 coatings also appear to promote osseointegration in vitro, but TiO2 evidence is limited. Al2O3 coatings reduce metal ion release and polyethylene wear for alloy implants, but long-term clinical data is sparse. While both coatings have benefits, TiO2 demonstrates better osseointegration potential while Al2O3 is more bioinert. Composite coatings are being explored to harness the synergistic effects. Persistent challenges include coating stresses, thickness uniformity, durability concerns, and long-term clinical evidence.