Current Status and Research Gaps of Neuromodulation in the Rehabilitation of Knee Osteoarthritis: A Scoping Review

Background: Knee osteoarthritis (KOA) is a highly prevalent degenerative joint disease with a growing global disease burden, yet traditional interventions have limited efficacy. Neuromodulation has emerged as a promising non-pharmacological rehabilitation strategy for KOA, but existing reviews have not systematically synthesized the clinical protocols, efficacy characteristics, and full spectrum of research gaps for mainstream neuromodulation techniques. This scoping review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines, aiming to describe the current application status and identify critical research gaps. Methods: A systematic search was performed in PubMed and Web of Science databases for clinical studies on neuromodulation for KOA published between May 13, 2021 and May 13, 2026. Two researchers independently completed literature screening, data extraction, and cross-verification according to pre-specified inclusion and exclusion criteria. Results: A total of 131 records were initially retrieved. After deduplication, title/abstract screening, and full-text evaluation, 23 studies were finally included, comprising 18 randomized controlled trials, 3 self-controlled before-after trials, 1 retrospective case series, and 1 cross-sectional study. The included studies covered three core categories of neuromodulation: peripheral neuromodulation (TENS, NMES, PNS, electroacupuncture, electrical dry needling, tVNS), central neuromodulation (tDCS), and combined neuromodulation (TENS + tDCS). All techniques demonstrated certain efficacy in pain relief and functional improvement, but intervention protocols varied widely, and optimal parameters have not been standardized. Conclusion: Neuromodulation, as a non-pharmacological rehabilitation strategy, has broad application prospects in KOA treatment. However, existing studies still have deficiencies in intervention standardization, long-term efficacy evaluation, and mechanism exploration. Future high-quality, large-sample studies are needed to optimize clinical protocols and clarify mechanisms of action, providing evidence support for the standardized application of neuromodulation in KOA rehabilitation.