Osseointegrated knee prostheses. An experimental study in rabbits

Osseointegration, defined as direct bone-to-implant contact, has been suggested as an approach for improving the results of arthroplasties of the major joints. An experimental investigation in femoral-patellar joint of the rabbit was performed to evaluate whether osseointegration could be achieved in a one-stage surgical procedure. After three months, it was found that the screws used for anchorage of the prosthesis showed an average direct bone-to-implant contact of 60% in three selected consecutive threads on each side. The range was 40-90%. These figures correspond well with previously reported ones from bone anchored titanium fixtures. It was therefore concluded that osseointegration of dynamically loaded screws used for anchorage of a femoral-patellar joint prosthesis may be achieved in spite of the fact that no controlled healing period for the screws was observed.