Effects of pulsed electromagnetic field on knee osteoarthritis: a systematic review

Objective. Many reviews have been previously published on the efficacy of pulsed electromagnetic field (PEMF) in the management of knee OA. However, their results regarding pain and function yielded conflicting conclusions. Therefore this study was conducted to determine the efficacy of PEMF as compared with a placebo. Methods. We reviewed randomized, placebo-controlled trials using electronic databases. We also manually reviewed sources to identify additional relevant studies. Results. Fourteen trials were analysed, comprising 482 patients in the treatment group and 448 patients in the placebo group. When the efficacy of PEMF in treating pain was investigated, no significant effects were observed at any of the time points considered. However, when trials employing high-quality methodology were analysed, PEMF was significantly more effective at 4 and 8 weeks than the placebo. When the efficacy of PEMF was evaluated for function, a significant improvement was observed 8 weeks after the treatment initiation, with a standardized mean difference of 0.30 (95% CI 0.07, 0.53). No significant association was found between the use of PEMF and the occurrence of adverse events, as indicated by a relative risk of 1.47 (95% CI 0.67, 3.20). However, three (21.4%) trials applied electromagnetic field intensity over the levels recommended by the International Commission on Non-Ionizing Radiation Protection. Conclusion. The present study provided suggestive evidence supporting PEMF efficacy in the management of knee OA. Our results further raise the need for more well-controlled trials, employing adequate methodology, to conclusively evaluate the efficacy of PEMF.