BIOMECHANICAL AND MORPHOLOGICAL-STUDIES ON OSSEOINTEGRATION IN IMMUNOLOGICAL ARTHRITIS IN RABBITS

The biomechanics and morphology of the interface between bone tissue a nd threaded, commercially pure titanium implants were studied in an ex perimental model of monoarticular arthritis in New Zealand white rabbi ts (n = 8). Two of the eight rabbits died before evaluation. Immunisat ion with bovine serum albumin (BSA) and repeated intra-articular injec tions with BSA in one knee joint elicited an immune response and clini cal signs of inflammation. The opposite joint was injected with saline . Three implants were inserted intra-articularly in the lateral femora l condyle in each joint. After a period of six weeks the stability of two of the three implants was evaluated by pull-out and torsion tests using a standardised biomechanical model. The rabbits were killed by p erfusion fixation, and the implants and surrounding tissue were retrie ved en bloc for histological analysis. The amount of bane, the degree of bone apposition, and the biomechanical evaluation showed that the a bsolute mechanical capacity of anchorage was not significantly reduced on the arthritic side compared with the control knees. These results indicate that it might be possible to obtain osseointegration in juxta -articular bone despite local joint inflammation.