Non-Invasive Radiofrequency Therapy for Musculoskeletal, Neurological, and Vascular Conditions of the Lower Limb: A Systematic Review and Meta-Analysis

<b>Background/Objectives</b>: Non-invasive radiofrequency (NIRF) therapy is increasingly used in physical rehabilitation. However, its efficacy across different lower limb pathologies remains unclear. This study aimed to evaluate the effects of NIRF on pain intensity and functional status in patients with musculoskeletal, neurological, and vascular conditions of the lower limb. <b>Methods</b>: A systematic review with meta-analysis of randomized controlled trials (RCTs) was conducted following PRISMA guidelines. The PubMed, Scopus, Web of Science, PEDro, and Cochrane Library databases were searched for RCTs comparing NIRF with sham, standard care, or other physical modalities. Methodological quality was assessed using the PEDro scale. Statistical analysis was performed using RevMan 5.4 to calculate Mean Differences (MD) and Standardized Mean Differences (SMD). <b>Results</b>: Nineteen RCTs comprising 911 participants were included in the qualitative review, of which 14 were included in the quantitative meta-analysis. The mean methodological quality was 7.78/10. The meta-analysis revealed favorable results for NIRF in reducing pain intensity compared to control groups (MD = -2.04; 95% CI = -3.14 to -0.93; <i>p</i> = 0.0003; I² = 96%). Functional outcomes also showed significant improvement in favor of the experimental group (SMD = -0.51; 95% CI: -0.85 to -0.16; <i>p</i> = 0.004; I² = 78%). Additionally, narrative synthesis indicated benefits for spasticity management (stroke) and limb volume reduction (lipedema/lymphedema). <b>Conclusions</b>: The results suggest a trend favoring NIRF for reducing pain and improving function in lower limb musculoskeletal conditions, particularly when used as an adjunct to active therapy. Evidence also suggests preliminary beneficial effects for neurological and vascular disorders. However, these findings must be interpreted with caution due to the high statistical heterogeneity observed, the broad diversity of the clinical populations included, and the wide variability in the treatment protocols applied. Further rigorous research with standardized protocols is highly recommended.