Osteoarthritis is a degenerative arthritis, a condition in which joint cartilage degenerates or breaks down. New tissue, which grows at the ends of bones, now has no cartilage cap to control it. Instead, this new bone forms into strange lips and spurs that grind and grate and get in the way of movement of the joint. Osteoarthritis is common in older people after years of wear-and-tear that thin the cartilage and the bones. Osteoarthritis can also result from diseases in which there is softening of the bone, like Paget's disease in which the long bones of the body curve like a bow, or osteoporosis with its bowing of the shoulder called "dowager's hump," or other bone degeneration. Other forms of arthritis can also cause a secondary osteoarthritis. Osteoarthritis is not an inevitable problem of aging. Those who don't suffer from it may have their heredity and possibly the strength of their immune systems to thank. Medical science is not quite sure of all the factors that come into play in deciding who gets osteoarthritis and who doesn't.
