Chondral defects in animal models: effects of selected repair procedures in canines.

The defect made to the level of the tidemark in a canine model has been used in several prior investigations of various articular cartilage repair procedures. Direct comparison of the repair method, 15 weeks postoperatively, showed a significant correlation between the degree to which the calcified cartilage layer and subchondral bone were disrupted and the amount of tissue filling. Moreover, when it forms, hyaline cartilage most frequently occurs superficial to intact calcified cartilage. Many of the chondrocytic cells and fibroblasts expressed the gene for a contractile muscle actin, alpha-smooth muscle actin. However, the role of this actin isoform is yet in question. These findings may inform future strategies for cartilage repair.