Percutaneous Electrolysis and Microelectrolysis for Rotator Cuff Tendinopathy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background/Objectives: Rotator cuff tendinopathy frequently contributes to shoulder pain and functional limitation. This systematic review and meta-analysis examined the effects of percutaneous electrolysis (EL) and microelectrolysis (MEL) on pain, shoulder-related disability, range of motion (ROM), and pressure pain threshold (PPT), and summarized treatment-related adverse events. Methods: Randomized controlled trials (RCTs) were identified through searches of Scopus, PubMed, CINAHL, Web of Science, the Cochrane Library, MEDLINE, Google Scholar, ScienceDirect, and the Physiotherapy Evidence Database (PEDro), from database inception to 14 September 2026. Methodological quality, risk of bias, and certainty of evidence were evaluated using the PEDro scale, Cochrane Risk of Bias 2 tool, and GRADE framework, respectively. Random-effects models were used to pool standardized mean differences (SMDs) or mean differences (MDs) with 95% confidence intervals (CIs). Results: Eight RCTs involving 330 participants were included. The overall post-treatment effect favored electrolysis-based interventions for pain intensity, with a large effect size (SMD = −1.44; 95% CI: −2.21 to −0.67). Pain improvements persisted at the first follow-up within the first 3 months (MD = −2.25; 95% CI: −3.40 to −1.09) and at 6 months (MD = −2.89; 95% CI: −3.68 to −2.10). Shoulder-related disability also favored electrolysis-based interventions (SMD = −0.81; 95% CI: −1.25 to −0.36). Improvements were also observed for selected ROM outcomes, whereas evidence for PPT remained inconclusive. Adverse-event reporting varied across trials; reported events were predominantly transient and non-serious, and no serious treatment-related adverse events were reported. Overall certainty of evidence ranged from low to moderate. Conclusions: Electrolysis-based interventions may improve pain intensity and shoulder-related disability and may provide benefits for selected ROM outcomes in adults with rotator cuff tendinopathy. However, confidence in the pain findings remains limited, with low-certainty evidence for the primary post-treatment analysis and low-to-moderate certainty at follow-up. No serious treatment-related adverse events were reported, although the available RCT evidence was insufficient to estimate adverse-event incidence precisely. Adequately powered RCTs directly comparing EL and MEL are needed to clarify their relative clinical effectiveness.