Osteoarthritis is a condition that affects millions of Americans. It is the most common form of arthritis and is caused by years of wear and tear on the joints. Other forms of the disease, like Rheumatoid and Psoriatic Arthritis, are autoimmune disorders in which your body’s immune system attacks your joints. Rheumatoid and Psoriatic arthritis progress differently than Osteoarthritis, which develops slowly and usually begins later in life. Osteoarthritis typically affects middle aged to elderly individuals.