Acupuncture in Knee Osteoarthritis: A Narrative Review of Clinical Efficacy and Neuroimmune-Endocrine Mechanisms.

Purpose: Knee osteoarthritis (KOA) is a leading cause of global pain and disability and warrants complementary therapy. This review provides evidence of the clinical efficacy of acupuncture and the multisystem regulatory mechanisms of KOA. Methods: We analyzed clinical trials and mechanistic studies of acupuncture in the treatment of KOA. Results: Acupuncture-particularly electroacupuncture (EA) significantly reduced pain (VAS/WOMAC) compared with sham acupuncture and conventional care (P < 0.05). Clinical trials demonstrate that combining acupuncture with exercise significantly enhances functional outcomes. Mechanistically, acupuncture modulates neuroendocrine pathways through three key actions: (1) suppressing pro-inflammatory cytokines (eg, TNF-α, IL-1β); (2) activating the Melatonin/cAMP/PKA/CREB signaling cascade; (3) altering functional connectivity in central pain-processing regions. Controversies persist regarding the mechanisms, optimal techniques, and outcome standardization. Conclusion: Acupuncture is an effective complementary therapy for KOA. Future research should prioritize long-term efficacy, personalized protocols, technology integration, and multidisciplinary strategies.