The most common cause of knee pain is patellofemoral pain syndrome (PFPS) and usually presents with anterior knee pain. It is common in people who participate in sports and symptoms are usually aggravated by activities such as running, jumping, standing up from a chair or going up and down stairs.   Why does this happen? The control of the knee joint is completely dependent on the surrounding structures, which includes the iliotibial band (ITB) that runs down the outer edg...