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Double-blind placebo-controlled
trial of static magnets for the treatment of osteoarthritis of the knee: results
of a pilot study.
Wolsko PM, Eisenberg DM, Simon LS, Davis RB, Walleczek J, Mayo-Smith M, Kaptchuk
TJ, Phillips RS.
Division for Research and Education, Harvard Medical School, Boston, MA, USA.
CONTEXT: Outpatient clinical
studies of magnet therapy, a complementary therapy commonly used to treat
osteoarthritis (OA), have been limited by the absence of a credible placebo
control.
OBJECTIVE: Our objective
was to assess the feasibility and promise of studying static magnetic therapy
for knee OA and determine the ability of a new placebo-magnet device to provide
concealment of group assignment.
DESIGN: Randomized, double-blind,
placebo-controlled clinical trial.
SETTING: Academic teaching
hospital in Boston. PARTICIPANTS: We enrolled 29 subjects with idiopathic
or post-traumatic OA of the knee.
INTERVENTIONS: Subjects
received either high-strength magnetic (active) or placebo-magnetic (placebo)
knee sleeve treatment for 4 hours in a monitored setting and self-treatment
6 hours daily for 6 weeks.
MAIN OUTCOME MEASURES:
Primary outcomes were change in knee pain as measured by the WOMAC Osteoarthritis
Index Pain Subscale at 6 weeks and extent of group concealment at study end.
RESULTS: At 4 hours, VAS
pain scores (+/- SE) on a 5-item scale (0-500, 500 worst) decreased 79 +/-
18 mm in the active group and 10 +/- 21 mm in the placebo group (P < 0.05).
There were no significant differences in any primary or secondary measure
of efficacy between the treatment groups at 6 weeks. Despite widespread testing
for magnetic properties, at study end, 69% of the active group and 77% of
the placebo group (P > 0.2) believed that they had been assigned to the
active treatment group.
CONCLUSION: Despite our
small sample size, magnets showed statistically significant efficacy compared
to placebo after 4 hours under rigorously controlled conditions. The sustained
efficacy of magnetic therapy for knee osteoarthritis could be assessed in
an adequately powered trial utilizing an appropriate control such our new
placebo-magnet device.
Publication Types:
Clinical Trial
Randomized Controlled Trial
PMID: 15055092 [PubMed - indexed for MEDLINE]
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