This paper examines the condition of anterior knee pain known as patellofemoral pain syndrome. It describes the functional anatomy and biomechanics of the knee including normal movement, and factors which may destabilize the knee, and predispose it to injury. The controversial ‘‘Q’’ angle is discussed, as is its relationship to patellofemoral pain. The importance of balanced musculature to the integrity of the knee is emphasized as are the potential consequences of weak, or overly tight, muscles. Examination of the knee including patient history, standard orthopedic testing, observation of posture and gait, and palpation are summarized. Treatment protocols for the acute phase, recovery, and maintenance phases of treatment are described. These include gentle mobilization techniques, home exercises, and the occasional use of knee bracing and foot orthotics. & 2003 Elsevier Ltd. All rights reserved.