Magnetic shoe insoles did not effectively relieve foot pain

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Magnetic shoe insoles did not effectively relieve foot pain

http://www.medicalnewstoday.com/medicalnews.php?newsid=31099

25 Sep 2005

Magnetic shoe insoles did not effectively relieve foot pain among

patients in a study, researchers report in the current issue of Mayo

Clinic Proceedings. And the results indicate that patients who

strongly believed in magnets had pain relief even if they were given

false magnets to wear.

" This study provides convincing evidence that use of these static

magnets was not effective in relieving symptoms of nonspecific foot

pain in the workplace, " says Mark Winemiller, M.D., the lead author

of the study and a Mayo Clinic physician.

Dr. Winemiller said adults with foot pain are likely to initiate self-

treatment with magnets based on personal recommendations or belief

systems, often without a specific diagnosis or prescription. That

population was targeted in this study, he said, with the goal of

determining whether magnetic insoles work in the way they are

typically used. He said the randomized, double-blind nature of this

study was chosen to minimize bias and maximize the validity of

results, and he is confident that this was accomplished.

An interesting result in the study relates to " the placebo effect. "

Patients in studies who are given the placebo or false treatment

often report improvement in their conditions when they believe they

are receiving a treatment designed to provide relief. " A moderate

placebo effect was noted in participants who believed the strongest

in the potential of magnets to help their pain, " says Dr. Winemiller.

Otherwise, the fact that magnetic and nonmagnetic insoles provided

nearly identical pain relief suggests that it may have been simply

the cushioning that was effective -- and not the magnets.

In the past decade, the use of magnets for pain relief has increased

substantially. Despite little scientific evidence (and lack of Food

and Drug Administration approval for pain relief), many people have

used magnets to relieve their pain, spending approximately $5 billion

worldwide -- an estimated $500 million in the United States annually -

- on magnetic pain-relieving devices.

Magnetic devices use either static or pulsed magnets. Clinically,

pulsed magnets have been shown effective for treating delayed

fracture healing, for reducing pain in various musculoskeletal

conditions, and for decreasing edema associated with acute trauma,

although other studies have shown no benefit in these situations.

Externally applied static magnets generally are considered safe and

have few adverse effects, but little is known about their mechanism

of action. Most basic scientific research has focused on movement of

tiny electrical voltages that may lead to decreased pain.

The insoles studied were the Active Comfort magnetic insole (Spenco

Medical Corp.), which has a magnetic foil pad located under the arch

of the foot. These insoles were chosen because they are comfortably

cushioned but do not have rigid arch support or acupressure features,

which potentially could confound results if such features provided an

independent effect. The special set of false magnetic insoles also

were produced by the manufacturer, using a nonmagnetized metal foil

embedded identically in the foam insole material.

Along with Dr. Winemiller, Laskowski, M.D., and W.

Harmsen of Mayo Clinic, collaborated on this study, as did

Billow, D.O., who is now with Northwest Orthopaedic Surgeons, Mount

Vernon, Wash.

This project was funded by an unrestricted educational grant from the

Spenco Medical Corp, Waco, Texas. Spenco was not involved in any way

in the study design, data collection, data analyses, or data

interpretation or in manuscript preparation, review or approval. Both

the active and false magnetic insoles were provided at no charge

directly from the manufacturer. None of the authors have any

affiliations or financial involvement with any organization or entity

with a financial interest in the subject matter discussed in this

article.

In an editorial in the same issue, Fillingim, Ph.D., and

Price, Ph.D., of the University of Florida College of Dentistry in

Gainesville noted how the placebo controls of the study was

important.

" Placebo controls are extremely valuable for determining the efficacy

of pain interventions, " the authors write.

Mayo Clinic

http://www.mayo.edu