Osteoarthritis is a degenerative arthritis, a condition in which joint cartilage 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 the breakdown of other bones. 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.
Rheumatoid arthritis is an inflammatory arthritis. It is second only to osteoarthritis in the number of its victims. It affects primarily the small joints in the hands and feet and the synovium, causing crippling deformities. This is an arthritis that usually starts in middle age or earlier. Estimates of the incidence of rheumatoid arthritis run as high as one person in every hundred, and females are two to three times as likely to suffer from it. It seems to start more in the winter and after some siege of sickness, but it is not considered an infective arthritis. Nobody knows what causes rheumatoid arthritis. There may be some hereditary trait, and there seems to be some connection to viral infections like German measles and serum hepatitis, the liver disease brought on by an injection of one kind or another. Because of this, scientists