The word arthritis literally means "joint inflammation". Arthritis refers to a group of more than 100 rheumatic and other diseases that cause pain, stiffness, and swelling in the joints. Rheumatoid arthritis is a disease that damages the lining around our joints while destroying our bones, tissues and joints over time. Osteoarthritis is a progressive disease that slowly damages the cartilage around the ends of bones and is common in the hip, knee or spine.