Osteoarthritis (OA) is the most common type of arthritis in the United States, with nearly 27 million people affected by it. OA of the knee and hips is the most common cause of arthritis-related disability in the U.S. OA is common in all races and backgrounds.
It most commonly affects middle-aged and older people, with most people getting it after age 45. Men under age 55 are more likely to have OA than women under 55. After age 55, women are more commonly affected; and, overall, more women have OA than men. It is thought that this is because the broader female hips put more long-term stress on the knees. However, age increases your risk for OA.
