Effectiveness of Percutaneous Needle Electrolysis (PNE) and Intramuscular Electrical Stimulation (IMES) in the Management of Myofascial Pain Syndrome and Tendinopathies: A Systematic Review

Objectives: Myofascial pain syndrome (MPS) is a common musculoskeletal condition, and while percutaneous needle electrolysis (PNE) and intramuscular electrical stimulation (IMES) are emerging therapies for myofascial pain syndrome and tendinopathies, their effects remain unclear. This systematic review aimed to characterize the methodological features and synthesize the evidence on the clinical improvement and adverse events rates of PNE and IMES in treating MPS and tendinopathies. Data Sources: PubMed, Scopus, Web of Science, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform, Google Scholar, and reference lists. Searches were carried out on 10 July 2025 and repeated on 16 March 2026, just before final analysis. New results found during final searches were screened for inclusion to ensure currency of the review. Methods: We selected studies based on the PICOS framework and predefined selection criteria: Population: adults with MPS or active myofascial trigger points (TrPs), or tendinopathies; Intervention: PNE or IMES; Comparator: sham procedures, other interventions, or no intervention; Outcomes: pain intensity (e.g., Visual Analogue Scale or Numeric Pain Rating Scale), pressure pain threshold (PPT), and functional measures; and Study Design: experimental studies. Studies focused exclusively on post-surgical or neuropathic pain, studies without a relevant comparator, and studies not reporting clinically meaningful outcomes were excluded. We assessed the risk of bias of included studies and performed a narrative synthesis. Results: From 737 identified records, 30 studies met the selection criteria. PNE was generally effective in reducing pain and improving function in tendinopathies and MPS, although results varied across outcomes and follow-ups. IMES showed moderate evidence for reducing pain and enhancing function, particularly cervical range of motion and PPT. However, both interventions had inconsistent clinical improvement and adverse events rates on disability indices and quality of life. Most studies had a high risk of bias due to challenges in blinding. Reported adverse events were minor and self-limiting, indicating that both therapies are generally safe when performed by trained clinicians. Conclusions: PNE and IMES may improve pain and some functional outcomes in MPS and tendinopathies; however, these findings should be interpreted cautiously because most included studies had a high risk of bias.