Osteoarthritis (OA) is the most common type of arthritis, affecting up to 70 million Americans, and 1 out of 2 people over the age of 50.  Osteoarthritis has fast become the most common cause of disability, and by 2050 will outpace cancer and heart disease combined. Osteoarthritis is usually caused by either wear and tear on the joints or follows several years after an injury…