[Biology of articular cartilage repair--present status and prospects]

The cartilage response to injury differs from the classic wound healing because of two important features of the cartilage structure; lack of vascular system and rich matrix preventing chondrocyte from migration to the injury site. Three distinct types of cartilage injuries can be identified based on the depth of injury and the repair response: microdamage, chondral injury, and osteochondral injury. There have been numerous attempts to repair cartilage injury, however their results have reinforced that articular cartilage has limited potential to repair itself. However, current research is helping to clarify the mechanism of cartilage injury and repair based on its gene expression. Biology, gene therapy, and tissue engineering may provide a breakthrough to treat cartilage injury.