Objectives This study aims to evaluate (1) the effect and safety of acupuncture in patients with knee osteoarthritis (KOA) and explore (2) whether the effect of acupuncture differed according to acupuncture type, acupuncture dose and follow-up time. Design Systematic review and pairwise and exploratory network meta-analysis. Setting PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, VIP Database for Chinese Technical Periodicals and Wanfang from inception to 13 November 2023. Participants Randomised controlled trials comparing acupuncture with sham acupuncture, non-steroidal anti-inflammatory drugs (NSAIDs), usual care or waiting list groups, intra-articular (IA) injection and blank groups in patients with KOA. Interventions Eligible interventions included manual acupuncture (MA) and electroacupuncture (EA). Main outcomes measures The primary outcome was pain intensity at the end of treatment. Results 80 trials (9933 participants) were included. Very low certainty evidence suggested that acupuncture may reduce pain intensity compared with sham acupuncture (standardised mean difference, SMD −0.74, 95% CI −1.08 to −0.39, corresponded to a difference in Visual Analogue Scale of −18.50 mm, −27.00 to −9.75), NSAIDs (SMD −0.86 to –1.26 to −0.46, corresponded to −21.50 mm, −31.50 to −11.50), usual care or waiting list groups (SMD −1.01, –1.47 to −0.54, corresponded to −25.25 mm, −36.75 to −13.50) and blank groups (SMD −1.65, –1.99 to −1.32, corresponded to −41.25 mm, −49.75 to −33.00), but not IA injection. Similar results were also found in other outcomes. For most of the subgroup analyses, acupuncture type, acupuncture dose and follow-up time did not show a significant relative effect. Only when compared with NSAIDs, a higher dose of acupuncture may provide greater pain relief (interaction p<0.001). The network meta-analysis revealed that electroacupuncture (SMD −0.75, 95% CI −1.34 to −0.17) had a greater effect on pain relief in patients with KOA compared with manual acupuncture. Conclusions The findings suggest that acupuncture may provide clinically important effects in reducing pain and improving physical function in patients with KOA, but the certainty of evidence was very low. Electroacupuncture and higher dose of acupuncture probably are two potential contributing factors. PROSPERO registration number CRD42021232177.

Introduction Knee osteoarthritis (KOA) is one of the leading causes of disability. The effectiveness of acupuncture for treating KOA remains controversial. This protocol describes the method of a systematic review and meta-analysis evaluating the effectiveness and safety of acupuncture for treating KOA. Methods and analysis Four English databases (PubMed, Embase, Cochrane Library databases and Web of Science) and four Chinese databases (China National Knowledge Infrastructure, Chinese Biomedical Literature Database, VIP Database for Chinese Technical Periodicals, and Wanfang) will be searched from the database inception to 1 September 2021. All randomised controlled trials related to acupuncture for KOA will be included. Extracted data will include publication details, basic information, demographic data, intervention details and patient outcomes. The primary outcome will be pain intensity. Risk of bias will be assessed using the Cochrane Collaboration’s tool for assessing risk of bias. Article selection, data extraction and risk of bias assessment will be performed in duplicate by two independent reviewers. If the meta-analysis is precluded, we will conduct a descriptive synthesis using a best-evidence synthesis approach. The strength of recommendations and quality of evidence will be assessed using the Grading of Recommendations Assessment Development and Evaluation working group methodology. Ethics and dissemination Ethics approval is not required because individual patient data are not included. This protocol was registered in the international Prospective Register of Systematic Reviews on 25 February 2021. The systematic review and meta-analysis will be submitted for publication in a peer-reviewed journal. The findings will also be disseminated through conference presentations. Trial registration number CRD42021232177.