Metal implants

A method for treating a metallic titanium implant for use in a surgical procedure, to form a surface layer that is integral with the metal substrate and which incorporates a biocidal material, by anodising the implant to form a surface layer and then performing ion exchange so as to incorporate a biocidal metal ions in the surface layer, characterized in that the method comprises anodising the implant at a voltage above 50 V for a period of at least 30 minutes, to generate the surface layer, wherein the current density, the electrolyte concentration, the duration of anodising and the magnitude of the voltage of anodization are such that the anodising generates a hard surface layer dense and surface holes in the surface layer filled with a somewhat softer and more porous material porous.