The Definition of Osteoarthritis
Osteoarthritis is the name for a group of similar diseases that affect the joints. Sometimes, the condition also is called degenerative joint disease (DJD), osteoarthrosis, atrophic arthritis, arthrosis, or hypertrophic arthritis.
Osteoarthritis is diagnosed when the cartilage that covers the bones and forms the surface of the joints changes its structure—becoming thinner, rougher, and less protective of the underlying bone. As the disease worsens, the bone surfaces become exposed, irregular, and rough. The joint surfaces no longer glide smoothly, and instead, grind against each other. The result is usually joint pain and difficulty moving the joint and limbs.
Osteoarthritis can occur in any joint, but it most often affects the hands, hips, knees, and spine. The condition develops slowly over months or years and symptoms begin almost always after the age of 40.
