Effects of low-intensity pulsed ultrasound on knee osteoarthritis: A systematic review and meta-analysis of randomized controlled trials

Objective To systemically review the effects of low-intensity pulsed ultrasound (LIPUS) on pain relief and functional recovery in patients with knee osteoarthritis (KOA). Data sources PubMed, Web of Science, Cochrane Library, Physiotherapy Evidence Database (PEDro), and China National Knowledge Infrastructure (CNKI) were used from inception to 18 March 2022. Review Methods Meta-analysis was performed to evaluate pain and function recovery between control and LIPUS groups. Standardized mean difference (SMD) or mean difference (MD) and 95% confidence interval (CI) were calculated, and data were combined using the fixed or random-effect model. Results Thirteen studies involving 807 patients with KOA were included. Patients' outcomes treated by LIPUS were improved significantly, including Visual analog scale (VAS) score (MD = -0.95, 95% CI: -1.43 to -0.48?P < 0.001), Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) score (MD = -4.35, 95% CI: -8.30 to -0.40, P = 0.0309), Lysholm score (SMD = 1.59, 95% CI: 1.29 to 1.90, P < 0.001), Lequesne index (MD = -1.33, 95% CI: -1.69 to -0.96, P < 0.001), Range of motion (ROM) (MD = 2.43, 95% CI: 0.39 to 4.46, P = 0.0197) and 50 meter walking time (SMD = 1.48, 95% CI: 0.46 to 2.49, P = 0.0044). Subgroup analyses showed monotherapy of LIPUS produced a better effect on reducing VAS score (P = 0.0213), and the shorter therapeutic period (<= 4 weeks) produced a more significant effect on raising the WOMAC score (P = 0.0083). Conclusion LIPUS was beneficial for pain relief and functional knee recovery and maybe as an alternative therapy in KOA rehabilitation.