Osteoarthritis: the genesis of pain.

OA is a painful joint disease that predominantly affects the elderly. Pain is the primary symptom of OA, and it can present as either intermittent or constant. OA pain mechanisms are complex and have only recently been determined. Both peripheral and central processes are involved in creating the OA pain experience, making targeted therapy problematic. Nociceptive, inflammatory and neuropathic pains are all known to occur in OA, but to varying degrees in a patient- and time-specific manner. A better understanding of these multifactorial components of OA pain will lead to the development of more effective and safer pain treatments.