Comparative Outcomes of Electroacupuncture, Warm Acupuncture, and Their Combination in Patients Receiving Standard Treatment for Knee Osteoarthritis: A Retrospective Cohort Study

BACKGROUND: Knee osteoarthritis (KOA) causes pain and functional limitation. Electroacupuncture (EA) and warm acupuncture (WA) are widely used, but the comparative effectiveness of their combined use remains unclear. This study compared usual care, EA plus usual care, WA plus usual care, and combined EA + WA plus usual care for KOA. METHODS: In this retrospective cohort, 351 patients with symptomatic KOA were analyzed: usual care (n = 73), EA plus usual care (n = 73), WA plus usual care (n = 87), and EA + WA plus usual care (n = 118). Acupuncture-treated patients received five sessions weekly for 4 weeks. Outcomes included pain, knee function, physical performance, quantitative sensory testing, surface electromyograph, serum inflammatory, oxidative, and cartilage-related biomarkers, and safety. Adjusted models, logistic regression, and correlation analyses were used. RESULTS: All groups improved, with the greatest benefits observed in the EA + WA group. At week 4, EA + WA showed the lowest visual analogue scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, the highest clinical response rate, better physical performance, greater pressure pain threshold (PPT) and conditioned pain modulation (CPM) improvement, greater temporal summation (TS) reduction, and more favorable exploratory inflammatory, oxidative, and cartilage-related biomarker profiles. After multivariable adjustment, EA + WA was associated with more favorable week-4 outcomes than usual care, EA, or WA. No serious adverse events occurred, although minor local or thermal events were more common in acupuncture-treated groups. CONCLUSION: EA + WA plus usual care was associated with greater multidomain improvement and acceptable tolerability in KOA. Prospective randomized, sham-controlled studies are needed to confirm effectiveness, durability, safety, and potential mechanisms.