Basic science of articular cartilage and osteoarthritis.

Articular cartilage is a specialized tissue uniquely suited for load distribution with a low-friction articulating surface. Its compressive and tensile properties are determined by its matrix and fluid composition, and are maintained by chondrocytes in the homeostatic joint. Osteoarthritis (OA) is increasingly understood as a family of disorders in which the biomechanical properties of cartilage are altered and ultimately fail as the tissue is degraded by local proteases. Mechanically mediated and cytokine-mediated pathways of cartilage degeneration have been identified in the pathogenesis of OA. Further insight into the basic science of cartilage and OA is necessary to develop diagnostic and treatment strategies for this pervasive disease.