Effects of static magnets on chronic knee pain and physical function: a double-blind study.
BACKGROUND
Static magnets have become an increasingly popular alternative therapy for individuals with musculoskeletal pain despite limited scientific evidence to support their efficacy or safety.


OBJECTIVE
To determine the effects of static magnets on the pain and functional limitations associated with chronic knee pain due to degenerative joint disease.


METHODS
Double-blind, randomized, controlled clinical trial.


METHODS
Pretests and posttests were conducted in an academic health science center.


METHODS
Forty-three ambulatory subjects with chronic pain in 1 or both knee joints who were recruited from outpatient clinics or who volunteered to participate.


METHODS
Subjects wore pads containing magnets or placebos over their painful knee joints for 2 weeks.


METHODS
Self-administered ratings of pain and physical function using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and a timed 15-m (50-ft) walk.


RESULTS
Multivariate analysis of covariance revealed significantly greater improvements in the group wearing magnets (P=.002). Univariate analyses indicated that comparative changes in self-rated pain and physical function (P=.002 and .001, respectively) were greater than changes in gait speed (P=.042).


CONCLUSIONS
The application of static magnets over painful knee joints appears to reduce pain and enhance functional movement. However, further study is needed to determine the physiological mechanisms responsible for this analgesic effect.
Department of Physical Therapy, University of Texas Medical Branch, Galveston, USA.
Martha R
MR
Hinman
Jennifer
J
Ford
Heather
H
Heyl
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D004311:Double-Blind Method; D004574:Electromagnetic Fields; D005260:Female; D005684:Gait; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000628:therapy*; D007719:Knee Joint / Q000503:physiopathology*; D008280:Magnetics / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000628:therapy*; D010147:Pain Measurement; D016059:Range of Motion, Articular; D012016:Reference Values; D012720:Severity of Illness Index; D016896:Treatment Outcome