A systematic review of the published (AMED, CINAHL, MEDLINE, EMBASE, PubMed and the Cochrane Library) and unpublished literature (WHO International Clinical Trials Registry Platform, Current Controlled Trials and the United States National Institute of Health Trials Registry, Open Grey) was undertaken to July 2013. All studies assessing the clinical effects of static magnets as a therapeutic intervention for adults with osteoarthritis were included. Methodological quality was assessed using the PEDro appraisal tool. When appropriate, meta-analysis was conducted to pool data.
From a total of 301 citations, six studies met the eligibility criteria. These included 374 participants, 220 allocated to a magnet group, 154 to a placebo control. The findings indicated that magnets did not significantly reduce pain or medicine requirement nor enhanced function, joint proprioception or muscle strength compared to placebo (p>0.05). There was limited evidence that higher strength magnets may have a greater effect on pain than lower field strength magnets. However, the quality of the current evidence-base was limited and underpowered.
The longer-term outcomes of magnet use and limited control of field strength within the current literature suggests that further, adequately sample-sized, randomised controlled trials to assess dose-response are initially required to begin to rigorously assess the efficacy of this intervention with people with osteoarthritis.