In a systematic review and meta-analysis, the use of phonophoresis was associated with remarkable improvements in pain and functional performance in people suffering from  osteoarthritis of the knee. This study aimed to investigate the effect of phonophoresis when various gels were used for treating knee osteoarthritis and compared its effects with placebo (nondrug) gel.

For exploring relevant studies, PUBMED/Medline, CENTRAL and EMBASE were comprehensively searched. Studies that were randomized controlled trials (RCTs), encompassed people diagnosed with knee osteoarthritis, encompassed therapy using either phonophoresis or therapeutic ultrasound along with placebo gel, and stated functional and clinical results were incorporated. Rev Man 5.3 software was used for statistical assessment. Using 95% confidence intervals (CIs), the continuous variables were elucidated as standardized mean differences (SMDs).

Initially, 2176 studies were retrieved. After evaluation, 9 RCTs with 423 patients were finally included. As found, phonophoresis group performed substantially better than placebo gel group in scores of Western Ontario and McMaster Universities Arthritis Index (WOMAC) function with corticosteroid gel (SMD = − 0.96) and in scores of pain with NSAID gel (SMD = − 0.53).

For knee osteoarthritis, phonophoresis is an effective and well-tolerated therapy to improve pain and functional ability over a short-term follow-up with either NSAID or corticosteroid gel. However, additional high-quality, robust, large-scale RCTs are needed to substantiate the benefits.