A background for the management of osteoarthritic knee pain.

Knee osteoarthritis (KOA) is the most common degenerative arthritis and is treated by a wide range of practitioners. Treatment planning requires knowledge of the knee joint components and the influence of systemic and environmental factors. The treatment of KOA has changed little in 50 years. We are entering a new stage where KOA is now being viewed as an organ in failure. Neurotransmission of pain is both peripheral and central. Medical treatment can influence both pathways. Current guidelines for treatment have more rigid criteria based on the literature. In the future, the use of genetic-based biomarkers, clinical patterns of response and imaging characteristics will likely create subgroups of individuals who could benefit from improved designer therapies.