the invention is directed to a method of forming an implant having a porous surface using an organic binder compound to enhance the bonding between the porous surface layer and implant . preferably , the binder is formed from a water - soluble protein that carbonizes during the sintering process to alloy with the metal of the porous surface layer . the porous surface layer may be in the form of beads or of fiber metal and can be preformed to fit with an implant or formed over the surface of the implant .