Magnetic bracelets for relieving pain in lower-limb osteoarthritis: a randomised controlled trial

Objective To conduct a trial of the effectiveness of magnetic bracelets as used in the consumer market for pain control in osteoarthritis of hip and knee. Design Randomised, placebo-controlled trial with three parallel groups. Setting Primary care study set in five rural general practices in Mid Devon, UK. Subjects 194 men and women aged 45 to 80 years with osteoarthritis of the hip or knee. Intervention Wearing a standard-strength static bipolar magnetic bracelet (group A), a weak magnetic bracelet (group B), or a non-magnetic (dummy) bracelet (group C) for 12 weeks. Main outcome measures Change in WOMAC A osteoarthritis lower-limb pain scale between group A and group C after 12 weeks were predefined as the primary endpoint. Secondary outcomes included change in WOMAC B and C scales and a visual analogue scale for pain. Results Mean pain scores were reduced more in group A than in the group C (mean difference 1.3 points, 95%CI: 0.05 to 2.55). There was, however, no significant difference between group A and group B. Self-reported blinding status did not affect the results. However, beliefs about bracelet type were the strongest predictor of changes in WOMAC scale. The scores for secondary outcome measures were consistent with the WOMAC A scores. Conclusion Pain from osteoarthritis of hip and knee decreases when wearing magnetic bracelets. It is uncertain whether this response is due to specific or non-specific effects.