To evaluate the effects of pulsed electromagnetic field (PEMF) and exercises in reducing pain and improving function and muscle strength in patients with shoulder impingement syndrome (SIS).
Double-blind, randomized controlled trial with a 3-month posttreatment follow-up.
Outpatient rehabilitation of a public hospital.
Patients (N=56) between 40 and 60 years of age, with a diagnosis of SIS, were randomly assigned to receive active PEMF (n=26; mean age, 50.1y) or placebo PEMF (n=30; mean age, 50.8y).
After 3 weeks of active or placebo PEMF, both groups performed the same program of exercises that focused on shoulder strengthening.
Main Outcome Measures
A visual analog scale, the University of California/Los Angeles shoulder rating scale, the Constant-Murley shoulder score, and handheld dynamometry for muscle strength were used as outcome measures at baseline (pretreatment), at 3 weeks (after active or placebo PEMF), at 9 weeks (postexercise), and at 3 months posttreatment.
Patients in the active PEMF group had a higher level of function and less pain at all follow-up time frames compared with baseline (P<.05). However, the placebo PEMF group had increased function and reduced pain only at the 9-week and 3-month follow-ups (P<.05)—that is, after performing the associated exercises. For the shoulder dynamometry, the active PEMF group had increased strength for lateral rotation at 9 weeks (P<.05), and increased strength for medial rotation at 9 weeks and 3 months (both P<.05) when compared with baseline. There was no significant difference for shoulder strength in the placebo PEMF group (P>.05), as well as no significant differences (P>.05) for all outcome measures.
The combination of PEMF and shoulder exercises is effective in improving function and muscle strength and decreasing pain in patients with SIS. However, these results should be carefully interpreted because of the lack of differences between groups.
List of abbreviations:ICC (intraclass correlation coefficient), MCID (minimal clinically important difference), PEMF (pulsed electromagnetic field), SIS (shoulder impingement syndrome), VAS (visual analog scale), UCLA (University of California/Los Angeles)
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Published online: October 17, 2013
Clinical Trial Registration No.: NCT01452204.
No commercial party having a direct financial interest in the results of the research supporting this article has conferred or will confer a benefit on the authors or on any organization with which the authors are associated.
© 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.