Arthritis is a condition that causes pain and inflammation in a joint. There are two common types; osteoarthritis and rheumatoid arthritis. Osteoarthritis is the more common of the two affecting 8 million people in the UK. It starts with the thinning out of the cartilage lining of the joint, making movement more difficult than usual resulting in stiffness and pain. Rheumatoid arthritis (RA) affect more than 400,000 people in the UK, with women being more likely to be affected with RA than men. RA happens when the immune system of the body affects the joints, which leads to pain and swelling. In this case, the outer covering (synovium) is the first place to be affected with the potential to spread across the joint.