RABBIT ARTICULAR-CARTILAGE DEFECTS TREATED WITH AUTOLOGOUS CULTURED CHONDROCYTES

Adult New Zealand rabbits were used to transplant autologously harvest ed and in vitro cultured chondrocytes into patellar chondral lesions t hat had been made previously and were 3 mm in diameter, extending down to the calcified zone, Healing of the defects was assessed by gross e xamination, light microscope, and histological-histochemical scoring a t 8, 12, and 52 weeks, Chondrocyte transplantation significantly incre ased the amount of newly formed repair tissue compared to that found i n control knees in which the lesion was solely covered by a periosteal flap, In another experiment, carbon fiber pads seeded with chondrocyt es were used as scaffolds, and repair significantly increased at both 12 and 52 weeks compared to knees in which scaffolds without chondrocy tes were implanted, The histologic quality scores of the repair tissue were significantly better in all knees in which defects were treated with chondrocytes compared to knees treated with periosteum alone and better at 52 weeks compared to knees in which defects were treated wit h carbon scaffolds seeded with chondrocytes. The repair tissue, howeve r, tended to incomplete the bonding to adjacent cartilage, This study shows that isolated autologous articular chondrocytes that have been e xpanded for 2 weeks in vitro can stimulate the healing phase of chondr al lesions. A gradual maturation of the hyalinelike repair with a more pronounced columnarization was noted as late as 1 year after surgery.