A systematic review and meta-analysis of the effect of phonophoresis on patients with knee osteoarthritis

This systematic review and meta-analysis investigated the effect of phonophoresis when various gel types were used. Medline (using PubMed), EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) were used to search for relevant studies from the date of their inception to June 28, 2021. We included studies that were randomized controlled trials (RCTs), included patients with a diagnosis of knee osteoarthritis, included treatment with either phonophoresis or therapeutic ultrasound with placebo gel, and reported clinical and functional outcomes. Continuous variables are expressed as standardized mean differences (SMDs) with 95% confidence intervals (CIs). Statistical analysis was performed using RevMan 5.3 software. We initially retrieved 2176 studies and finally analyzed nine RCTs including 423 patients. The intervention group significantly outperformed the control group in pain scores with NSAID gel (SMD = − 0.53, 95% CI [− 1.02, − 0.05], I2 = 73%) and in the Western Ontario and McMaster Universities Arthritis Index (WOMAC) function score with corticosteroid gel (SMD = − 0.96, 95% CI [− 1.47, − 0.44], I2 = 20%). Phonophoresis alleviated pain and improved functional performance. Because of some limitations of this study, additional high-quality, large-scale RCTs are required to confirm the benefits.