What is pigmented villonodular synovitis?

Pigmented villonodular synovitis (called PVNS for short) is a joint problem that usually affects the hip or knee. It can also occur in the shoulder, ankle, elbow, hand or foot.

When you have PVNS, the lining of a joint becomes swollen and grows. This growth harms the bone around the joint. The lining also makes extra fluid that can cause swelling and make the joint hurt.

Who gets PVNS and why?

PVNS isn't common. It usually affects people 20 to 45 years old, but it can also occur in children and people over 65 years old. It may happen slightly more often in men.

Doctors don't know exactly what causes PVNS. It doesn't seem to run in families. It doesn't seem to be caused by certain jobs or activities. Some people with PVNS remember that they hurt their joint at some time in the past.

What are the symptoms of PVNS?

If you have PVNS, you'll notice swelling and stiffness in a joint, most often your knee. The joint may hurt. You may have a “popping” feeling when you move the joint. The symptoms usually start slowly and may come and go over time.

How will my doctor test for PVNS?

PVNS can look like arthritis and some other conditions. Your doctor may use tests to check for these conditions. After a physical exam, your doctor may want x-rays of the joint that hurts.

Your doctor may also want to draw some fluid from the joint and test it. Another test, magnetic resonance imaging (also called MRI), takes a “picture” of the joint.

How is PVNS treated?

The best way to treat PVNS is to remove the lining of the joint. This can be done with regular surgery (sometimes called “open” surgery) or with arthroscopy. In arthroscopy, the doctor makes a tiny cut in the skin over your joint. Then a thin tube is put into the joint to remove the lining.

Even with treatment, PVNS comes back about half of the time. If the pain comes back again and again, radiation therapy may help. Sometimes, the joint must be replaced.

If the pain comes back, what can I do to feel better?

You can ease the pressure on the joint that hurts by resting it. For example, you might use crutches to keep weight off of your sore knee or hip. Or you might need to stay off of your feet. This may also let the swelling go down. You can take a medicine called ibuprofen (brand names: Advil, Motrin, and others) to help with the pain and swelling. Most people with PVNS have times when they have no pain and can do their normal activities.