Arthritis is inflammation in the joints or area of the body where two bones come together. Joints are responsible for the movement of body parts. It is a condition that can be experienced all over the body or in a specific area. The types range from those related to wear and tear of cartilage, such as osteoarthritis to those associated with inflammation resulting from an overactive immune system, such as rheumatoid arthritis. The one part of the body that is most affected by arthritis is the knee and it can suffer from both rheumatoid or osteoarthritis.