This condition is an irritation of the cartilage on the back of the patella (the kneecap) that causes pain in one or both knees.
Although the exact cause is unknown, patellofemoral pain syndrome can develop because of overuse, typically as a result of high-impact athletic activities that require running and jumping, or because of improper tracking of the patella on the femur. These activities can place severe stress on the cartilage that covers the underside of the patella as it slides against the knee joint, particularly in people whose patellas are slightly misaligned.
The most common symptom is a dull aching sensation under and around the kneecap that becomes most noticeable after long periods of sitting, squatting or walking down stairs. The knee may also catch, grind or pop.
Treatment options include rest, ice, medications, physical therapy, taping, knee sleeve, and in severe cases, surgery.