Infection adjacent to titanium and bone cement implants: an experimental study in rabbits

A pure titanium cylinder or a piece of bone cement was implanted in each upper tibial metaphysis of 20 rabbits. After 4 months radiograms were taken and 104, 106, or 108 Staphylococcus aureus were injected into each leg through central holes in the implants in three groups of animals. Four weeks later new radiograms, bacteriological and histological biopsies were obtained. Three animals died before the end of the experiment. In animals which received 106 or 108 S. aureus radiographic signs of infection were found in 11/22 legs with both titanium and bone cement implants. No radiolucent zones developed around the implants. Bacteriological cultures from bone close to the implants were negative in all legs with titanium implants and positive in four legs with cement implants. Seven cultures were negative in spite of radiographic changes. It is concluded that after a proper time for wound healing the bone around unloaded implants of both titanium and bone cement is fairly resistant to infection. In some cases, healing of an infection in the surrounding bone seems possible.