Osteoarthritis is more common than rheumatoid arthritis, but both affect the joints and impede their function, causing pain and stiffness. Rheumatoid arthritis affects about one-tenth as many people as osteoarthritis.
The main difference between osteoarthritis and rheumatoid arthritis is the cause behind the symptoms. Osteoarthritis is caused by mechanical wear and tear on joints. Rheumatoid arthritis is an autoimmune disease; it makes your body’s own immune system attack the joints.
While both rheumatoid arthritis and osteoarthritis can affect the small joints of the hand, there are differences. Rheumatoid arthritis tends to affect the middle joints of the fingers and the joints where the fingers attach to the hand. Osteoarthritis more commonly affects larger, weight-bearing joints like the hips and knees. In some cases, osteoarthritis can affect the joints at the ends of the fingers and at the base of the thumb.
In rheumatoid arthritis, the same joints usually are affected on both sides of the body. This symmetry doesn’t typically occur in osteoarthritis, so it’s common for only one hand or knee to be painful.
Another difference is that joints damaged by osteoarthritis may be stiff in the morning, but they usually feel better in about 20 minutes. Joints affected by rheumatoid arthritis, on the other hand, often hurt for more than 45 minutes after you get out of bed.
While osteoarthritis is typically a disease of maturity, associated with years of wear and tear, rheumatoid arthritis can come on quickly at any age, even in children (juvenile RA). The inflammation caused by rheumatoid arthritis can lead to heart, lung, and eye damage.
In the U.S., about 27 million arthritis cases are osteoarthritis and 1.3 million are rheumatoid arthritis (RA). Rheumatoid arthritis affects three times as many women as men. Osteoarthritis affects women and men equally, except after age 55, when it affects more women than men.