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.