Many people believe that osteoarthritis is a "normal" or natural result of aging. Although age plays an important role in osteoarthritis, the cartilage changes that occur with it are different than those that occur from aging.
As you age, your cartilage is less able to handle the normal stress of day-to-day activity. As a result, your ability to put weight on your joint decreases. Unstable joints, combined with other risk factors, make it easier for osteoarthritis to disrupt the delicate balance between the injury-and-repair process that helps keep joints healthy.