I have pain from an old sports injury in both my knees and lower back.
I have tried various remedies but they don't seem to work well or they
have some serious drawbacks (pain medications makes me feel dull/
professional acupuncture on a rountine basis is expensive/ ointments
and braces only help for a short periods of time)

I have heard about products that use magnets to "manage" or “block” 
the pain. Can you tell me if these products work.  And, if they do,
how do they work?

If you could include links to any research that would be most helpful.

Thank You!

Virtualprofessor,

There is a lot of debate right now in the medical community about the
efficacy of using magnet therapy to manage pain.  Critics claim that
it is nonsense, and that there is no scientific reason that a magnet
would alleviate pain.  Proponents of magnet therapy point to several
recent studies, which have shown a small but significant improvement
in pain level for participants using magnet therapy.

There are a few theories about how magnets might work to reduce pain:

“Some say that the electrical current created by magnets interrupts
the transmission of pain signals in the central nervous system. Others
claim that magnets increase blood flow to an area, boosting the flow
of oxygen and other nutrients, and ultimately reducing pain and
swelling.”
http://www.wholehealthmd.com/refshelf/substances_view/0,1525,715,00.html

“Magnets might block pain by stimulating nerve endings. Some advocates
ascribe the therapy’s purported benefits to its affects on the nervous
system, which depends on electrical charges to deliver its signals.
Magnets may create charged particles in the blood, producing heat and
dilating blood vessels. Magnets may act on iron in the blood to
increase the blood’s ability to carry oxygen.”
http://www.allaboutarthritis.com/arthritis.cfm/living/281/-1/Treatments

“The lead researcher from the University of Houston study, family
physician Dr. Carlos Vallbona, raised a different possibility. ‘It's
possible the magnetic energy affects the pain receptors in the joints
or muscles or lowers the sensation of pain in the brain,’”
http://www.cnn.com/2000/HEALTH/alternative/02/25/magnets.therapy.wmd/

“Some people believe that magnets may work in part for conditions such
as arthritis because taping them to the affected joint acts like a
splint, limiting movement.”
http://www.wholehealthmd.com/refshelf/substances_view/0,1525,715,00.html


There have been several recent studies on magnetic therapy and pain
management.  Some support the idea that magnets can be an effective
tool for dealing with chronic pain.

“‘I tested magnets on carpal tunnel syndrome but did not get good
results,’ says Dr. Michael Weintraub, a New York Medical College
neurologist. ‘But I did get good results using magnets to help
diabetic foot pain.’ That study, printed in the January 1999 issue of
the American Journal of Pain Management, found that diabetics suffered
less foot pain while wearing low-intensity magnets in their shoes.”
http://webmd.lycos.com/content/article/1668.50166

“Researchers at the Baylor College of Medicine conducted one
significant study in 1997. These scientists produced a double blind,
placebo-controlled study in which a device delivering static magnetic
fields resulted in significant relief in patients with chronic
post-polio pain. Interestingly, the patients treated by placebo
devices also experienced pain relief, but the magnet-treated patients
experienced significantly greater relief, as reported by The National
Council For Reliable Health Information, 2000. Chief researcher Carlos
Vallbona, MD, cautioned NCRHI the study shows that magnet therapy
helped polio patients, but does not suggest any benefits for other
conditions, including arthritis.“
http://www.allaboutarthritis.com/arthritis.cfm/living/281/-1/Treatments

“In 1997, researchers at the Madras Institute of Magnetobiology in
India used pulsing magnetic fields on plantar ulcers in 40 people with
leprosy. After four weeks of treatment, the ulcers shrank at least 40
percent in 89 percent of those receiving the magnetic therapy. A
similar group of patients, receiving only standard care, experienced
no improvement in their ulcers.”
http://my.webmd.com/content/dmk/dmk_article_5963130

“CHARLOTTESVILLE, Feb. 23 -- University of Virginia researchers
published results from one of the first clinical research studies
conducted on magnet therapy for pain in today's issue of the Journal
of Alternative and Complementary Medicine. Although the results of the
study were inconclusive, magnet therapy reduced fibromyalgia pain
intensity enough in one group of study participants to be "clinically
meaningful," the researchers said.”
http://www.newswise.com/articles/2001/2/MAGNET.UVM.html


Other studies record no significant difference between subjects using
magnet therapy and those using placebos.

“Researchers at the Veterans Affairs Medical Center in Prescott,
Ariz., for example, reported recently that magnets offered no
verifiable help to patients with chronic low back pain.”
http://www.healthscout.com/template.asp?page=newsdetail&ap=1&id=109847

“One such study -- which you're unlikely to find on any magnet maker's
web site -- was published in the January 1997 issue of the Journal of
the American Podiatric Medical Association. Nineteen patients with
heel pain wore insoles containing magnetic inserts. Fifteen others
wore identical insoles without the magnets. After four weeks, the two
groups reported the same amount of relief.”
http://webmd.lycos.com/content/article/1668.50166


And yet other studies report a limited affect of magnetic therapy, but
only under very specific conditions.

“Parker and other investigators at the University of Tennessee,
including principal researcher Dr. Candace Brown, say their research
suggests that pain relief is related to the length of exposure to the
magnet. In the clinical trial, there were no significant changes in
the women who had chronic pelvis pain after two weeks. But after three
weeks, 60 percent of the women with active magnets -- and 33 percent
of those with placebo magnets -- reported less pain.

One key to effective magnet therapy could be the strength of the
magnets, says Thomas Skalak, the director of the University of
Virginia's Center for the Engineering of Wound Prevention and Repair.
‘You can't take a single refrigerator magnet and expect it to do
anything. For any potential results, you'd need the equivalent of 10
to 100 refrigerator magnets,’ he adds. “
http://www.lauralee.com/news/magnets.htm 


Magnetic therapy can potentially be harmful for a small subset of the
population.

"People with pacemakers or implanted defibrillators should never use
those new magnet-laced mattress pads touted to ease back pain because
the magnets could temporarily shut off the heart devices."
http://sleepdisorders.about.com/library/weekly/aa052100a.htm

“Magnet makers do advise that pregnant women not use magnets, as no
one knows how the devices might affect a fetus. They also say that
magnets should not be placed over areas of the body that contain
electrical devices like pacemakers or internal insulin pumps”
http://www.cnn.com/2000/HEALTH/alternative/02/25/magnets.therapy.wmd/

And of course it’s always a good idea to check with a doctor that
knows you and the specifics of your medical history before trying a
new therapy.


Regards,
Cindy


Some reference URLs:

Magnetic and Electromagnetic Therapy - by David W. Ramey
http://www.hcrc.org//contrib/ramey/magnet.html

Google Directory: Health > Alternative > Magnetic Therapy
http://directory.google.com/Top/Health/Alternative/Magnetic_Therapy/


Search terms used:

research magnet pain
://www.google.com/search?hl=en&q=research+magnet+pain

"pain management" magnet research
://www.google.com/search?hl=en&q=%22pain+management%22+magnet+research

IMHO, to produce a balanced answer, cindy should have included:
 http://www.quackwatch.com/04ConsumerEducation/QA/magnet.html
which gives a critical analysis of the Baylor College Study.

Thory (I do not mean "in theory") says that change of field, (that
includes
e.g. blood streaming through a static magnetic field) will produce
electric current, and threfore some heat.
 A heating pad or exercise may produce same heating cheaper.

Sice pain is subjective, it may work if you believe it enough to spend
$10
for a querry. You should not spend much more for a magnet. Even
strong,
"rare earth" or ceramic magnets are inexpensive, and one thing we know
for sure
that there aro no "special" magnets with magical properties.

The golden standard of any therapy efficacy test is the "double blind"
study design, where neither the patient nor the evaluating physician
knows if the patient is receiving the experimental therapy under
evaluation, or a sham "placebo" treatment. This is done to eliminate
the possibility that the physician or the patient him/herself
underreport the unabated problems of the patients receiving the
experimental treatment compared to the ones receiving the sham
treatment, based on their (at that time unproven) belief the treatment
should necessarily be better than an inactive control. Studies of this
type have been performed on magnets as well, as already mentioned
elsewhere here.

The trouble with these studies is that the treatment here consists of
attaching either a magnetic or or non-magnetic object to the patient's
joints. Since any patient can easily determine if the object is
magnetic or not with the help of nothing more than a paperclip, there
is no guarantee the patients were indeed "blinded" as to the true
nature of the treatment they underwent, even if they were not told at
the time of the experiment. A physician involved in such a "double
blind" study once demonstrated me the power of those little magnets
with some paperclips; the unmarked "magnets" and "shams" he received
"blinded" were either completely inactive or strong enough for them to
pick up stray paperclips from his desk at some distance. Obviously,
one expects his patients could tell the difference as easily as he
could at their own home office. (Note: I myself was not, and never
have been, involved in these studies either as patient or researcher).

Unlike double blind studies where patients swallow capsules with
either a new drug or inactive "sugar pills" and can't possibly tell
the difference, here the patients can easily tell they have been given
a magnet or not. As such, the ones receiving the magnet are more
susceptible to the autosuggestion it has a beneficial effect.
Conversely, the ones receiving a non-magnetic object can find out
they've been handed a placebo, and most likely won't expect to receive
much improvement from it. They are thus very unlikely to report the
illusionary improvements at least some of the magnet treated patients
will.

I have never seen this problem reported in studies addressing the
magnet efficacy issues. In evaluating the evidence for yourself, you
should realise the "double blind" studies, generally thought to be
most decisive, high quality designed studies possible, have one
problem in common: they're not, and can't be. In this case, the golden
standard of clinical trials simply cannot be upheld properly. Unlike
for other treatments, the results from these "double blind" studies
cannot be taken to be more reliable than unblinded studies.