Elsevier

Mayo Clinic Proceedings

Volume 80, Issue 9, September 2005, Pages 1138-1145
Mayo Clinic Proceedings

ORIGINAL ARTICLE
Effect of Magnetic vs Sham-Magnetic Insoles on Nonspecific Foot Pain in the Workplace: A Randomized, Double-Blind, Placebo-Controlled Trial

https://doi.org/10.4065/80.9.1138Get rights and content

OBJECTIVE

To determine whether magnetic insoles are effective for relieving nonspecific subjective foot pain in the workplace, resulting in improved job satisfaction.

SUBJECTS AND METHODS

A prospective, randomized, double-blind, placebo-controlled study of health care employees who experienced nonspecific foot pain for at least 30 days, which occurred more days than not, was conducted between February 2001 and January 2002 at the Mayo Clinic in Rochester, Minn. Participants were asked to wear either magnetic or sham-magnetic cushioned insoles for at least 4 hours daily, 4 days per week for 8 weeks. The primary outcome variable was reported foot pain (by categorical response of change from baseline and by visual analog scale) at 4 and 8 weeks. Secondary outcome variables included graded intensity of pain experienced during various daily activities and the effect of insoles on job performance and enjoyment.

RESULTS

Among 89 enrolled participants, 6 either withdrew before wearing insoles or were noncompliant with follow-up questionnaires; 83 participants remained for full statistical analysis. Participants in both treatment groups reported improvements in foot pain during the study period. No significant differences in categorical response to pain or pain intensity were seen with use of magnetic vs sham-magnetic insoles.

CONCLUSIONS

The magnetic insoles used in this study by a heterogeneous population with chronic nonspecific foot pain were not clinically effective. Findings confirmed that nonspecific foot pain significantly interferes with some employees' ability to enjoy their jobs and that treatment of that pain improves job satisfaction.

Section snippets

Hypotheses and Study Design

The primary hypotheses of this study were that after wearing cushioned insoles for 4 and 8 weeks, participants who wore magnetic insoles as well as those who wore nonmagnetized (sham-magnetic) insoles would report a significant improvement (=2.5-cm reduction from their baseline visual analog scale [VAS] pain score) in intensity of average daily foot pain and that magnetic insoles would provide significantly greater categorical improvement in pain compared with sham-magnetic insoles. We

RESULTS

For this study, 89 participants were enrolled, 52 assigned to receive sham-magnetic insoles and 37 to receive magnetic insoles (Figure 1). Ages of study participants ranged from 19 to 73 years (mean, 44.3 years). Participants were primarily female (79%), with a median foot pain duration of 80 weeks (range, 6 weeks to >20 years). There were no statistical differences in baseline characteristics between the 2 intervention groups (Table 1). Symptomatic treatments at baseline did not differ

DISCUSSION

This study provides convincing evidence that use of static magnets for a total of 8 weeks was not effective in relieving symptoms of nonspecific foot pain in the workplace. The randomized, double-blind nature of this study was chosen to minimize bias and maximize the validity of results, and we are confident that this was accomplished. The sample size used and the absence of anything more than very small differences in outcomes when comparing active to sham magnets in this study make the

CONCLUSIONS

The static magnetic insoles studied were not clinically effective for treatment of chronic nonspecific foot pain. A moderate placebo effect was noted in participants who believed the strongest in the potential of magnets to help their pain. Nonspecific foot pain significantly interferes with some employees' ability to enjoy their jobs, and successful treatment of that pain improves job satisfaction.

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  • Cited by (0)

    This project was funded by an unrestricted educational grant from the Spenco Medical Corp, Waco, Tex. 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 sham-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.

    Individual reprints of this article are not available.

    1

    Dr Billow is now with Northwest Orthopaedic Surgeons, Mount Vernon, Wash.

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