An attempt has been made to measure the bonding capability of bone with implanted materials which have open pores on their surfaces. The results of experimental work in dogs with ceramics, Vitallium with satin surface, and a new type of porous surface finish for Vitallium implants is presented. Firm bonding of bones with the porous-surfaced metal was established by the active infiltration of the porous structure by new bone. Bonding of the metal with methylmethacrylate cement was also greatly enhanced by this porous surface. Some suggestions have been made as to the possible surgical use of such material.