It seems most unusual that in a review of “all currently available treatments” for knee osteoarthritis (OA) by 21 authorities and “two experts in the field of guidelines methodology”, pulsed electromagnetic field therapy was not mentioned in the text or the 51 references.1 This is particularly troubling because over 2800 publications between 1966 and 1998 were retrieved. An identical search for efficacy of magnetic field therapy during this period listed 31 studies with at least one control group,2 including two double blind trials citing benefits in knee OA from a peer reviewed arthritis journal.3 ,4 In 1999 over 50 000 patients received pulsed signal therapy (PST) prescribed by over 1000 doctors at more than 300 clinics and hospitals in 16 countries, where it is usually reimbursed by fiscal intermediaries because of its proven record of cost effectiveness and safety. A summary of …