Osteoarthritis is the degenerative joint disease that often occurs due to age and wearing of the joint tissues. Cartilage serves as a padding for the joints, preventing the bones from rubbing each other. This Arthritis causes the top layer of cartilage to wear away, allowing for the bones under the cartilage to rub against one another. This causes pain, irritation, and swelling of the joint, leading to limited movement. This is the most common type of arthritis and affects only the joints, not the organs.