What is osteoarthritis? Osteoarthritis is a common condition affecting millions of people around the world. According to the World Health Organization (WHO), osteoarthritis is one of the ten most disabling diseases in developed countries, affecting 528 million people worldwide. In the United States, the Centers for Disease Control and Prevention (CDC) estimates that over 32 million adults have osteoarthritis, making it the most common form of arthritis. Osteoarthritis is a