TRANSPLANTATION OF CARTILAGENOUS TISSUE GENERATED IN-VITRO INTO ARTICULAR JOINT DEFECTS

The purpose of this pilot study was to determine whether isolated rabb it chondrocytes will form cartilagenous tissue in culture and whether this tissue can be used as a cartilage transplant in order to resurfac e damaged joints. Chondrocytes were isolated from rabbit articular car tilage, plated as a monolayer on Millicell-CM(R) filters and maintaine d in cell culture. The cells formed cartilagenous tissue that could be removed from the filter support by two weeks in culture. The chondroc ytes synthesize type II collagen indicating that they maintained their phenotype under these conditions. For the transplant studies, two typ es of articular surface defects, either full thickness into subchondra l bone or intra-chondral, were created in rabbits. The cartilagenous t issue was placed in the defect either without fixation or with the top ical application of an adhesive agent (Cell-Tak or Nexaband(R) Avian). The joints were examined within two weeks following the surgery. No t ransplants remained in the defects in those animals in which tissue fi xation had been attempted with Cell-Tak. Those grafts fixed into the c artilage defect with Nexaband(R) Avian remained in place but consisted of a condensed layer of acellular tissue. However, cartilagenous tiss ue was present and intact in five of the six animals in which the tran splant had been placed, in the absence of adhesive, into a full thickn ess defect. In conclusion, cartilagenous tissue generated in vitro can survive transplantation but an appropriate method to fix grafts into intra-chondral defects is required.