Effect of magnetic vs sham-magnetic insoles on plantar heel pain: a randomized controlled trial.

Abstract

Despite anecdotal reports, rigorous scientific evidence of the effectiveness of magnetic insoles for the pain of plantar fasciitis is lacking. To determine whether magnetic insoles provide greater subjective improvement for treatment of plantar heel pain compared with identical nonmagnetized insoles. Randomized, double-blind, placebo-controlled trial conducted from February 12, 2001, to November 9, 2001, of a volunteer sample of 101 adults with diagnoses of plantar heel pain for at least 30 days from a multispecialty group practice clinic in Rochester, Minn. Daily pain diaries were kept for 8 weeks. Cushioned insoles, with either active bipolar magnets or sham magnets, which were worn daily by the participants for 8 weeks. Reported average daily foot pain (by metered visual analog scale [VAS] and by categorical response of change from baseline) at 4 and 8 weeks, and impact of insoles on employment performance and enjoyment. No significant between-group differences were found on any outcome variables studied when comparing active vs sham magnets. Both the nonmagnetic and magnetic groups reported significant improvements in morning foot pain intensity, with mean (SD) VAS scores improving from 6.9 (2.3) and 6.7 (2.0), respectively, at baseline to 3.9 (2.6) for each group at 8 weeks (P =.94). At 8 weeks, 33% of the nonmagnetic group and 35% of the magnetic group reported being all or mostly better (P =.78). At baseline, foot pain interfered moderately with participants' employment enjoyment (mean VAS, 4.2) and improved in both groups by 8 weeks (1.3 and 1.5, respectively; P =.68). Static bipolar magnets embedded in cushioned shoe insoles do not provide additional benefit for subjective plantar heel pain reduction when compared with nonmagnetic insoles.