Randomised Controlled Trial of Magnetic Bracelets for Relieving Pain in Osteoarthritis of the Hip and Knee
Dr. Tim Harlow (Dec 2004)
The study was structured as a randomized, placebo controlled trial consisting of 3 parallel groups, which took place in 5 rural general medical practices. The study consisted of 94 participants between the ages of 45 and 80 years old, who suffered from osteoarthritis of the hip or knee. Osteoarthritis was diagnosed by an orthopedic surgeon or rheumatologist, or by a general medical practitioner. Confirmatory radiological evidence was required for study participants didn’t have any recorded in their medical notes. Participants had to score between 8 and 20 points on the Western Ontario and McMaster Universities osteoarthritis index upon entry into the study. People with a cardiac pacemaker, current magnetic bracelet, surgery to the index joint, or hemophilia, and women who were pregnant or breast feeding were excluded from the study.
Participants wore either a standard strength static bipolar magnetic therapy bracelet, a weaker magnetic therapy bracelet, or a fake magnetic bracelet for a period of 12 weeks.
Some research studies on permanent static magnets have confirmed measurable pain reduction; other studies have reported little to no effect. However, major differences exist in both the type and strength of the magnets used, the types of medical conditions treated, and length of treatment. Also, there exist methodological concerns regarding sample sizes that are too small and difficulties in maintaining blinding. Therefore, this study had the goal of conducting an adequately powered trial which tested the hypothesis that magnetic therapy bracelets, like those commonly worn by consumers, reduce pain associated with osteoarthritis of the hip and knee.
The study found evidence regarding the beneficial effects of magnetic therapy bracelets on the pain of osteoarthritis of the hip and knee. These findings were consistent with previous research studies on magnetic therapy and pain. Studies that did not show a reduction in pain generally utilized weaker magnets (19 to 50 mTesla). On the other hand, studies that resulted in pain reduction utilized stronger magnets (47 to 180 mTesla), which are comparable with our standard strength magnets. Taken together, these results suggest that magnet field strength is an important factor.
The mean pain scores reported by participants were reduced more in the standard magnet group than in the dummy magnet group (a mean difference of 1.3 points, 95% confidence interval 0.05 to 2.55). The study concludes that pain from osteoarthritis of the hip and knee decreases while wearing magnetic therapy bracelets. However, it is indeterminate whether this is the result of specific or placebo effects.
The study was cited in the December 2004 edition of the British Medical Journal. Dr Tim Harlow has recommended additional study of magnetic therapy for longer periods of time in order to determine the longevity of the results.