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Electromagnetic energy for knee osteoarthritis

Systematic review
Results
Comment

The pages of our newspapers offer all sorts of quackery for all sorts of medical conditions. One suggested treatment is pulsed electromagnetic field therapy, in which magnetic fields are pulsed on and off to supposedly promote tissue healing, to relieve pain, and inflammation. Some reviews have been produced, with equivocal results, perhaps due in part to the variable quality of trials included. A new systematic review [1] provides a clearer picture.

Systematic review


The review used a Cochrane search strategy to find randomised trials of pulsed electromagnetic field therapy in adults with knee osteoarthritis who had clinical or radiological diagnosis. Any type of pulsed electromagnetic field therapy was accepted, using validated patient-reported pain and function as the outcomes.

Results


Five studies with 276 patients met the inclusion criteria. They had good reporting quality, all scoring 3 out of 5 points or better on a standard scale. Duration of treatment was two to six weeks, with two using a visual analogue scale for pain, and three using the WOMAC scale.

All five trials reported pain outcomes (Figure 1). No single trial showed any benefit of pulsed electromagnetic field therapy over placebo for pain, nor was there any difference overall. Four trials measured function. One showed a trivial improvement, but there was no improvement overall.


Figure 1: Individual trial results of pulsed electromagnetic energy (PEME) compared with placebo, showing actual pain scores on whatever scale used






Comment


Despite the small number of small trials, there was not a smidgen of clinical benefit. It is good, though, that people have taken the trouble to test pulsed electromagnetic field therapy in properly randomised trials.

Reference:

  1. CJ McCarthy et al. Pulsed electromagnetic energy treatment offers no clinical benefit in reducing the pain of knee osteoarthritis: a systematic review. BMC Musculoskeletal Disorders 2006 7:51 (www.biomedcental.com/1471-2474/7/51).

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