Anterior knee pain (pain in the front of the knee under the knee cap) is a very common problem. Patients who present with this complaint are usually active and healthy and have irritation which limits their ability to exercise. The condition is more common in women and most common in the 30-40 year old age group. Common complaints are intermittent, sharp pain under the knee cap with sport activities such as running or hiking that is more pronounced walking down hill or downstairs. The condition is caused by irritation of the cartilage on the underside of the kneecap (patella). Evaluation includes physical examination of the knee to assess the kinematics (the way the joint moves) of the patella-femoral joint and an x-ray to evaluate or degenerative changes. This can be a frustrating and stubborn problem. Treatment focuses on activity modification, anti-inflammatory medication, physical therapy, rest and occasionally corticosteroid injection. Surgery is rarely indicated unless the kneecap dislocates and symptoms do not improve.