Chronic pain is a major health problem affecting approximately 20% of the population resulting in marked reduced quality of life for the individual, as well as extensive costs for society. A large-scale survey undertaken in 15 European countries showed that 40% of the people who reported persistent pain (>6 months) had joint pain and that osteoarthritis (OA) and rheumatoid arthritis (RA) combined was the most common cause of pain (42%). 1 Preclinical studies of pain mechanisms in RA have …