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This study shows the efficacy of
phototherapy in DOA in late middle-aged
and elderly patients. Patients treated
with red or infrared light emitters
reported more than 50% pain relief after
10 days of treatment. Pain relief
continued for an average of 4 to 6
months after the treatment. Our results
are similar to those reported by Trelles
et al.17
They studied the impact of infrared
diode laser (860 nm, 60 mW, CW) on pain,
inflammation, joint mobility, and
treatment tolerance in patients with
DOA. Their study showed significant
improvement immediately after 4 weeks of
twice weekly treatments and 4 months
later.
The exact mechanism of pain reduction by
phototherapy is not completely
understood. Many investigators have
observed an anti-inflammatory effect of
phototherapy in studies conducted in
patients with rheumatoid arthritis.18-20
A recent histochemical study has shown a
marked increase of prostaglandin I2
following phototherapy, and consequently
inhibition of platelet aggregation and
vasodilation.21
Improvement of local circulation leads
to reduction of edema and better
oxygenation of tissues and thus may
result in reduction of pain. Lack of
Na-K-ATPase activity seems to increase
nociceptive impulse transmission; an
increase in Na-K-ATPase following
phototherapy may be a factor in pain
attenuation.22
Thus, phototherapy could produce pain
relief by one or a combination of these
mechanisms: anti-inflammatory effect,
circulation enhancement, and analgesic
effect.
We observed the same degree of
improvement in pain relief and
functional ability in the red and
infrared treated groups. Patients
treated with placebo emitters did not
report any changes in pain, except for a
small (10%) and statistically
insignificant (P = 0.163) degree
of pain relief reported in the affective
component of the SF-MPQ.
The red and infrared treated groups
showed significant improvement in
functional disability, more than 40%,
perhaps due to the reduction in pain
intensity and possibly also contributed
to by a direct effect of phototherapy on
knee mobility. The placebo treated
patients did not show significant
functional improvement, and the observed
slight improvement (7%) probably
reflected a placebo effect (use of the
emitters).
In conclusion, this study showed that
short-time application of phototherapy
is effective in pain relief and in
improvement of functional ability in
elderly patients with DOA. Thus,
phototherapy can be an important adjunct
in treatment of this disease, especially
in patients with adverse side effects to
drug treatment. Our personal experience
suggests that phototherapy can be used
conjointly with analgesics to reduce
their dosage. These encouraging results
might prompt further, long-term studies
to validate this treatment and to
establish more detailed indications for
the use of phototherapy in DOA. |
