Osteoarthritis is first and foremost the ongoing destruction of the articular cartilages of joints. Therefore, the extracellular matrix and the cells of the articular cartilages are the primary targets of osteoarthritis therapy. This tries to inhibit enzymatic destruction of the extracellular cartilage matrix as well as the modification of the cellular phenotype of the chondrocytes: cell degeneration and cell death are alongside anabolic activation and stabilization of the cellular phenotype of major interest. However, apart from the cartilage and its cells, other tissues of the joints are also important for the symptoms of the disease, which basically all originate outside the articular cartilage. In addition, changes in the subchondral bone as well as the synovial capsule and membrane are important at least for the progression of the disease process.
All the named tissues offer different directions and ways for therapeutic intervention.