Coping with patellofemoral syndrome.

Patellofemoral syndrome (PFS) is one of the most common causes of knee pain in active patients and stems from problems with the kneecap (patella) as it moves over the front of the knee. PFS causes pain in the front of one or both knees, especially after either exercising or sitting for prolonged periods. Some patients will experience minor swelling and the feeling that their knee "catches" or gives way.