Clinical applications of growth factors for articular cartilage repair.

Articular cartilage injuries and degeneration present a challenge for orthopedic surgeons. Chondrocytes have limited regenerative and reparative abilities. Healing of a defect results in a fibrocartilaginous repair tissue that lacks the structural and biomechanical properties of hyaline cartilage and that degrades over time. Polypeptide growth factors have an important role in regulating the behavior of all cells, including articular chondrocytes. Our understanding of growth factor effects on and interactions with chondrocytes is progressing rapidly. The most prominent growth factors identified for articular cartilage include insulin-like growth factor, fibroblast growth factor, the transforming growth factor-beta superfamily, hepatocyte growth factor, platelet-derived growth factor, Indian hedgehog and parathyroid hormone-related peptide, bone morphogenetic proteins, and the interleukin-1 receptor antagonist. Orthopedic surgeons need to be familiar with the properties of these growth factors, as they hold great therapeutic promise. In-progress clinical studies are examining how growth factors may have applications in treatments of bone.