CHONDROCYTE-LADEN COLLAGEN SCAFFOLDS FOR RESURFACING EXTENSIVE ARTICULAR-CARTILAGE DEFECTS

Chondrocyte-collagen composites were evaluated for resurfacing of larg e articular defects. Isolated chondrocytes were cultured in expanded c ollagen scaffolds for 7-10 days to provide a composite containing 3.6 x 10(4) cells/mm(3). The graft was transplanted into 15 mm full thickn ess articular defects in the femoropatellar joint of 12 horses using a rthroscopic techniques. Ungrafted defects in the opposite femoropatell ar joint served as controls. Synovial fluid, clinical progress and pai n responses were evaluated in groups of 6 horses over 4-month and 8-mo nth periods. Following termination, gross, histochemical and histologi c evaluations of the repair tissues and synovial membrane were perform ed. Arthroscopic defect debridement and chondrocyte implantation resul ted in minimal post-operative effusion or pain, and synovial fluid con stituents were not significantly different in grafted and ungrafted jo ints. Gross differences in grafted defects were not apparent. Increase d chondrocyte numbers and cartilage histochemical staining were eviden t in the deeper layers of grafted defects, whereas ungrafted defects w ere almost entirely fibrous tissue. The surface layers of grafted defe cts were fibrous tissue. There were no synovial fluid cellular respons es, synovial membrane histiocytic reaction or subchondral bone infiltr ates to suggest imimune-related reaction to the allograft cells. Chond rocyte-collagen grafts were arthroscopically implanted and resulted in improved cartilage healing in extensive defects. However, the structu ral organization of the surface layers was inadequate and suggested po or long-term durability.