Mechanisms of Peripheral and Central Sensitization in Osteoarthritis Pain

Pain, the primary symptom of osteoarthritis (OA), reduces both the quality and quantity of life for patients. The pathophysiology of OA pain is complex and often difficult to explain solely by radiological structural changes. One reason for this discrepancy is pain sensitization (peripheral sensitization [PS] and central sensitization [CS]) in OA. Thus, an understanding of pain sensitization is important when considering treatment strategies and development for OA pain. In recent years, pro-inflammatory cytokines, nerve growth factors (NGFs), and serotonin have been identified as causative agents that induce peripheral and central sensitization and are becoming therapeutic targets for OA pain. However, the characteristics of the clinical manifestations of pain sensitization elicited by these molecules remain unclear, and it is not well understood who among OA patients should receive the therapeutic intervention. Thus, this review summarizes evidence on the pathophysiology of peripheral and central sensitization in OA pain and the clinical features and treatment options for this condition. While the majority of the literature supports the existence of pain sensitization in chronic OA pain, clinical identification and treatment of pain sensitization in OA are still in their infancy, and future studies with good methodological quality are needed.