Arthritis refers to a joint in the body being inflamed. The normal joint has cartilage capped bones that articulate, or move in relation to each other. The cartilage plus the synovial fluid, which lubricates the joint, allows the joint surfaces to move past each other without friction. The cartilage surfaces can wear thin or wear completely through to the underlying bones. This causes irregular surfaces that rub against each other causing pain, inflammation, swellin and often decreased range of motion. Most patients experience wear and tear arthritis, also known as osteoarthritis, but it can be caused by previous injury, auto-immune diseases such as rheumatoid arthritis, gout, infection and psoriasis.