Implantable prostheses fully or partially formed of polymer having a textured or porous outer surface. The surface permits and encourages osteogenesis into the prosthesis and enables it to become firmly and permanently anchored into surrounding bone. The prostheses include a femoral hip stem formed of a metallic core and a polymeric proximal body with a textured or porous surface formed from a laser texturing, machining, or grit blasting.