Authors in China have undertaken a systematic review of trials of electro-acupuncture for knee osteoarthritis. They examined 11 randomised controlled trials involving a total of nearly 700 participants. Meta-analysis suggested electro-acupuncture was more effective than medication, and standard acupuncture alone. It reduced pain intensity and improved physical function without any serious adverse events reported. The results implied electro-acupuncture should be given for at least four weeks, for 20-30 minutes per session.