Background Osteoarthritis (OA) of the knee is a destructive joint disease, causing degeneration of cartilage, damage to the underlying bone and morphological changes to the joint1. It is a major public health concern due to the increased life expectancy of the ageing population2,3. No approved medical treatment that reverses the morphological changes currently exists. Conventional treatment includes physiotherapy, pain killers, braces and in end-stage OA surgical knee replacement4.