Comparison of the bony ingrowth into an osteochondral defect and an artificial osteochondral composite device in load-bearing joints

Abstract

In order to preserve as much subchondral cancellous bone as possible in the repair of damaged joint surfaces, we have attempted to develop an artificial articular cartilage, using polyvinyl alcohol hydrogel, a rubber-like gel. In this study, osteochondral defects were made and an osteochondral composite device was implanted in the weight-bearing portions of medial and lateral femoral condyles of dogs. Cancellous bone ingrowth into the pores of titanium-fiber mesh and osteochondral defect and bone remodeling under loading conditions were observed histologically and roentgenologically for 24 weeks after implantation. Cancellous bone ingrowth into the titanium-fiber mesh could be observed as early as 4 weeks in the study. Bone ingrowth was abundant and increased with time after implantation. These findings were similar to the cancellous bone repair and remodeling observed in the osteochondral defects. Interstitial cancellous bone ingrowth resulted in the complete integration of this implant and the viable host bone. Moreover, both the polyvinyl alcohol hydrogel itself and the tibial joint surface that bore against the polyvinyl alcohol hydrogel surface of this implant remained intact, which suggests this composite is a very promising biomaterial for use in joint prostheses. Thus, we conclude that this artificial osteochondral composite device could reconstitute and achieve the shock-absorbing effect lost after total joint replacement or hemiarthroplasty.