Peripheral and central nervous system mechanisms of joint protection.

Although there are many risk factors (such as age, family history, and obesity) associated with the development of osteoarthritis (OA), only trauma is known to cause OA. The neuromuscular system controls the amount and kind of movement occurring at a joint, so it is this system that is uitimately responsible for ensuring that joint tissues are not damaged to the point of developing OA during normal day-to-day activities. In the present paper, we review and critically evaluate some of the current concepts of the role of peripheral and central nervous system mechanisms that might protect joints from excessive excursion and joint tissues from excessive loading and OA. We conclude that a neuromuscular protective model based on central pattern generators (CPGs--subconscious motor programs) can best reconcile much heretofore ambiguous information pertaining to the development and progression of OA in stable and unstable joints.