Validation of weak magnets as a credible placebo in trials of magnetic therapies

INTERVENTION: Randomised controlled trial, comparing belief in magnetic status between 2 groups. CONDITION: Musculoskeletal Diseases ; Musculoskeletal Diseases PRIMARY OUTCOME: Added 21 July 2008: ; Based on the magnet assigned to the participant, responses to the question "Which kind of magnet do you think you have been given?" [Active /Inactive /Don?t know]. SECONDARY OUTCOME: Added 21 July 2008: ; Based on the magnet assigned to the participant, responses to the question ?How convinced are you that wearing this bracelet on your wrist for 3 months would help to relieve pain in your joints?? [visual analogue scale from 0=Not at all to 10 = Totally convinced].; INCLUSION CRITERIA: 108 osteoarthritis patients who do not currently use magnetic bracelet therapy.