An implant according to the invention includes first thermoplastic material portions, and second thermoplastic material portions liquefiable by mechanical vibrations and being in contact with the first thermoplastic material portions, wherein the second thermoplastic material portions preferably constitute at least a part of a surface of the implant, and wherein the first thermoplastic material portions have a glass transition temperature above an implantation temperature (about 20° C. to 40° C.), and wherein the second thermoplastic material portions either have a glass transition temperature below said implantation temperature or include means for transforming non-mechanical energy into heat.
