What is it? Osteoarthritis is focal (small areas of) cartilage loss with a bony ‘reaction’, such as development of osteophytes (bone spurs), cyst formation, sclerosis. It typically causes pain at the knee, and sometimes in the leg, with stiffness, loss of strength, swelling, and reduced mobility. Epidemiology One of the challenges in understanding the causes and issues in relation to knee arthritis is that many people with osteoa...