Patellofemoral pain is the most common presenting complaint about the knee joint. The explanation for this pain is not entirely clear. The four schools of thought concerning the etiology are divided among explanations based on anatomy, biomechanics, and biochemistry. The treatment for the disease is compromised by the lack of a clear causative agent. Exercises, braces, activity modification, and some medications form the basic protocol for treatment. Until the etiology becomes clear, these approaches represent the only reasonable therapy.