Electroacupuncture for knee osteoarthritis: a multicentre randomised controlled trial assessing symptomatic and structural efficacy

Background While electroacupuncture (EA) alleviates pain in knee osteoarthritis (KOA), high-quality evidence from large trials is limited, and its potential to influence structural progression is unknown. We investigated whether EA confers structural benefits beyond symptom relief. Methods In this multicentre, randomised, parallel-group, sham-acupuncture (SA)-controlled trial at six Shanghai hospitals, eligible participants were assigned (1:1) to EA or SA, administered three times/week for six weeks, with 30-week follow-up. Patient enrolment occurred from November 30, 2021, to April 26, 2024, and the final follow-up was completed on November 22, 2024. The primary outcome was the change in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) global score (0–240) at week 6. The minimal clinically important improvement (MCII) was predefined as a ≥12% relative improvement from baseline in the WOMAC global score. Key secondary outcomes included the WOMAC pain, stiffness, and function subscales, the Visual Analogue Scale (VAS), the Lequesne index, the Lysholm score, and the 6-Minute Walk Test (6MWT). Exploratory outcomes included artificial intelligence (AI)-based knee magnetic resonance imaging (MRI) measures of cartilage morphology and synovial inflammation. This trial was prospectively registered with the Chinese Clinical Trial Registry (ChiCTR2000036292). Findings Of 686 assessed, 480 participants were randomised (EA: n=240; SA: n=240). At week 6, the EA group showed a significantly greater reduction in WOMAC global score than the SA group (adjusted mean change 65.35 vs 24.76, mean difference [MD]: 40.56, 95% CI 36.35–44.77; P < 0.001; Cohen's d = 1.21), exceeding the prespecified MCII threshold. Consistent benefits were observed across all key secondary symptomatic outcomes, including WOMAC pain (MD: 11.98, P < 0.001), WOMAC stiffness (MD: 3.12, P < 0.001), WOMAC function (MD: 25.47, P < 0.001), VAS (MD: 2.04, P < 0.001), Lysholm score (MD: −7.36, P < 0.001), Lequesne index (MD: 1.23, P < 0.001), and 6MWT (MD: −41.95, P < 0.001). In exploratory MRI analyses at week 6, EA was associated with signals of reduced synovial inflammation and less cartilage loss in several compartments, with effect sizes ranging from very small to moderate (Cohen's d range −0.03 to 0.64). No serious adverse events occurred. Interpretation In patients with KOA, a 6-week course of EA provided substantial and durable symptomatic relief, representing a clinically meaningful therapeutic benefit. Exploratory MRI findings suggest that EA might have anti-inflammatory and cartilage-protective effects, but these structural signals require confirmation in trials specifically designed and powered for imaging endpoints. Funding This work was supported by the National Natural Science Foundation of China (Key Program, Grant No. 82530121; General Program, Grant No. 82474534), the Shanghai Municipal Health Commission (Health Youth Talent Project, Grant No. 2022YQ025), the Science and Technology Commission of Shanghai Municipality (Medical Innovation Research Special Project, Grant Nos. 25Y12800800 and 23Y31920100), the Shanghai Oriental Talents Program (Leading Talent Project), the Traditional Chinese Medicine Innovation Team and Talent Support Program-National Traditional Chinese Medicine Multidisciplinary Cross-Innovation Team Project (ZYYCXTD-D-202401), and the Shanghai Triennial Initiative for Promoting Clinical Proficiency and Innovation Capabilities in Municipal Hospitals (Grant No. SHDC2020CR1010A).