But medical information is always changing, and some information given here may be out of date. For regularly updated information on a variety of health topics, please visit familydoctor.org , the AAFP patient education Web site. An article on this topic is available in this issue of AFP . Osteoarthritis is a painful knee problem.
Arthritis is what happens when the tissue that protects the bones wears away.
Doctors don't know what causes joint cartilage to wear away. But they do know that osteoarthritis is more common as you get older or if you are very overweight. Sometimes a serious knee injury can bring on arthritis after a few years. Your doctor can find out if you have osteoarthritis by asking you questions about how your knee feels and by giving your knee an exam. Your doctor may want to take x-rays of your knee.