INFLUENCE OF METAL IMPLANTS ON INFECTION - AN EXPERIMENTAL-STUDY IN RABBITS

We implanted cylinders of cobalt-chrome or titanium, with smooth or po rous surfaces, into rabbit bones which had been inoculated with suspen sions of Staphylococcus aureus in various doses. The bacterial concent ration required to produce infection of porous-coated titanium implant s was 2.5 times smaller than that necessary to infect implants with po lished surfaces. Porous-coated cobalt-chromium implants required bacte rial concentrations that were 40 times smaller than those needed to in fect implants with polished surfaces, and 15 times smaller than those required to infect porous-coated titanium implants. The other advantag es and disadvantages of the various implants, such as improved osseoin tegration, larger ion-release surfaces, surface wear and relative stif fness, must be weighed against the higher infection rates in the porou s-coated implants, and particularly in the cobalt-chromium implants.