Osteoarthritis is usually a slowly progressive degenerative disease in which the joint cartilage gradually wears away. Your joint cartilage, also called articular cartilage, is a smooth glistening surface that allows your joint to move smoothly with low friction.

Osteoarthritis most often affects middle-aged and older people. However, if can also affect young people if the joint cartilage has been damaged or weaked, such as in an injury.