A pilot study carried out to inform the design of a fully-powered pragmatic randomised controlled trial, UK researchers have shown a significant reduction in knee pain at three months for acupuncture compared with usual care. Thirty patients aged over 50 with pain and osteoarthritis of the knee were randomised to acupuncture plus usual care or usual care alone. Although this pilot study was not adequately powered to detect significant changes in outcome, pain scores showed a statistically significant reduction at three months in the acupuncture group compared with usual care. This was not sustained at 12 months. The authors calculated the sample size necessary for a fully powered two-arm trial to be 350. (Acupuncture for pain and osteoarthritis of the knee: a pilot study for an open parallel-arm randomised controlled trial. BMC Musculoskelet Disord. 2009 Oct 24;10:130).