Osteoarthritis, or OA for short, is a common joint disease of the middle-aged and elderly. Some doctors used to call osteoarthritis “degenerative joint disease”, “degenerative arthritis” or “osteoarthrosis”, which is often referred to as “osteophytes” or “long bone spurs”. To be precise, osteoarthritis is a disease of cartilage, not bone. The main problem with osteoarthritis is that the articular cartilage covering the joint surfaces degenerates, and as a response of the body, bone spurs can form around the joints. In contrast to other types of arthritis, osteoarthritis rarely causes inflammation. Almost all vertebrates other than humans suffer from this disease, including dolphins and whales, and even long-extinct and hastily passing species like dinosaurs. The joints serve to flex and extend, support, stabilize and protect. In a normal state of painless activity, these functions are provided primarily by cartilage and synovial membranes. There is no blood supply to the articular cartilage; it is the synovial fluid secreted by the synovial membrane that provides nutrient circulation and oxygen to the cartilage. The cartilage itself has a high water content, up to 85% in young people and about 70% in the elderly. This high water content is caused by the hydration properties of the large molecules of proteoglycan (one of the main structures of cartilage). The other major component of cartilage is collagen (collagen is the main protein in all connective tissues in the body such as muscles, ligaments and tendons), which forms a meshwork structure that provides support and flexibility to the joints. The collagen mesh structure and high water content are tightly bound together by proteoglycans, which form an elastic, smooth cushion (cartilage) within the joint that resists the pressure between bones during muscle movement. Articular cartilage is the protective cushion that surrounds the bone ends in the joint. If the cartilage in the joint degenerates and progressive damage occurs, osteoarthritis can occur. In the early stages of the disease, the cartilage surface swells and loses some proteoglycan and other tissue components, and fissures and small depressions appear within the cartilage. Once the cartilage layer is peeled off and the “dress” is broken, the bone ends are exposed and the bone rubs against each other, resulting in damage to the bone and subplate tissue, causing painful joint symptoms. The cause of this change is not well understood and may be hereditary or due to metabolic problems or injury to the joint. Inflammation of the synovium also occurs in some patients. As the disease progresses, more tissue is damaged and the cartilage loses its elasticity, and this damage is further exacerbated by repeated use and injury. Eventually a large amount of cartilage is destroyed, leaving the bony ends of the joint unprotected. The next problem is that the body tries to repair the damage by creating bone protrusions on the edges of the joint with abnormal new cartilage growths that form so-called “bone spurs”. Unlike some other types of arthritis, such as rheumatoid arthritis, osteoarthritis is not systemic and is not distributed throughout the body, but rather is concentrated in one or several degenerated joints. Osteoarthritis is common in the joints of the fingers, feet, knees, hips and spine, and less commonly in the wrists, elbows, shoulders and temporomandibular joints.