Osteoarthritis is diagnosed only when both of these conditions are present:

Joint cartilage is damaged
Joints need healthy cartilage to work properly (see ARTHRITIS INFO No. 1 for more on what joints do). Even minor damage to the thin layers of cartilage that lubricate them can result in osteoarthritis.

Bone structure changes
As joint cartilage wears away, the bones it protects come into direct contact. Over time they become denser and change shape, causing severe pain, stiffness, and inflammation of the surrounding tissue.

To read more: click here