Pathophysiology

In joint diseases, pain most commonly occurs during exercise or even during normal daily activities (see “Clinical
Features” below). This heightened pain sensitivity is attributed to:
· Peripheral sensitization: enhancement of the sensitivity of joint nociceptors to mechanical stimuli applied
to the joint. It is induced by inflammatory mediators such as bradykinin, prostaglandins, and cytokines.
· Central sensitization: enhancement of the sensitivity of nociceptive neurons with joint input in spinal cord
and brain areas to mechanical stimuli applied to the joint. It is induced by the input from sensitized joint
nociceptors and furthered by central amplification mechanisms.