Acupuncture for Knee Osteoarthritis: A Systematic Review of Randomized Clinical Trials with Meta-Analyses and Trial Sequential Analyses

BACKGROUND: Knee osteoarthritis (KOA) can cause chronic pain and seriously affect the quality of patient lives. The continued emergence of high-quality RCTS requires us to update the quality of evidence. This study aims to evaluate the efficacy of acupuncture for KOA patients and calculate the required information size (RIS) to determine whether further clinical studies are required. METHODS: We searched PubMed, Embase, WOS, CBM, CNKI, VIP, WHO ICTRP, ChiCTR, and Grey literature to collect randomized controlled trials (RCTs) of acupuncture for KOA from inception to December 2021. A meta-analysis was performed according to the Cochrane systematic review method by using Review Manager 5.4 and TSA 0.9.5.10 beta, and GRADE was used to evaluate the quality of the evidence. Trial sequential analysis was used to control random errors and calculate the required information size. RESULTS: Eleven RCTs with 2484 patients were included in our meta-analysis, meeting the inclusion criteria for the meta-analysis. The meta-analysis indicated that acupuncture had beneficial effect on knee osteoarthritis in reducing pain [n = 2387; SMD = −0.12, 95% CI (-0.20, -0.04); I(2) = 0%] and improved patients function activities [n = 2408; MD = −1.25, 95% CI (-1.97, -0.53); I(2) = 0%], but true acupuncture showed no significant effect in relieve patient's stiffness [n = 1337; MD = −0.07, 95% CI (-0.30, 0.15); I(2) = 0%]. We pooled the studies which found no significant difference in improving the quality life of mental [n = 1462; SMD = 0.02, 95% CI (-0.23, 0.27); I(2) = 78%] and patients physical health (SF-36 or SF-12) [n = 1745; SMD = 1.01, 95% CI (-0.08, 2.11); I(2) = 0%] compared with sham acupuncture. The pain and function TSA graphs indicated that cumulative Z-curves intersected with the traditional level of statistical favoring acupuncture, and more RCTs will required in the future studies. CONCLUSION: Acupuncture has beneficial effect on pain relief and improves function activities, and this treatment can be recommended as a beneficial alternative therapy in patients with KOA, particularly for chronic patients and those currently undergoing long-term pain and help them increasing quality of life. But it should be further verified through more RCTs in function. Available studies suggested that acupuncture was superior to sham acupuncture in reduce pain and function as verified by TSA.