Background and objective: Photobiomodulation has been shown to modulate cellular protein production and stimulate tendon healing in a dose-dependent manner. Previous studies have used class IIIb lasers with power outputs of less than 0.5 W. Here we evaluate a dual wavelength (980/810 nm) class IV laser with a power output of 10 W for the purpose of determining the efficacy of class IV laser therapy in alleviating the pain and dysfunction associated with chronic epicondylitis.
Methods: Sixteen subjects volunteered for laser therapy, or an identically appearing sham instrument in a randomized, placebo-controlled, double-blinded clinical trial. Subjects underwent clinical examination (pain, function, strength, and ultrasonic imaging) to confirm chronic tendinopathy of the extensor carpi radialis brevis tendon, followed by eight treatments of 6.6 ± 1.3 J/cm(2) (laser), or sham over 18 days. Safety precautions to protect against retinal exposure to the laser were followed. The exam protocol was repeated at 0, 3, 6 and 12 months post-treatment.
Results: No initial differences were seen between the two groups. In the laser treated group handgrip strength improved by 17 ± 3%, 52 ± 7%, and 66 ± 6% at 3, 6, and 12 months respectively; function improved by 44 ± 1%, 71 ± 3%, and 82 ± 2%, and pain with resistance to extension of the middle finger was reduced by 50 ± 6%, 93 ± 4%, and 100 ± 1% at 3, 6 and 12 months, respectively. In contrast, no changes were seen until 12 months following sham treatment (12 months: strength improved by 13 ± 2%, function improved by 52 ± 3%, pain with resistance to extension of the middle finger reduced by 76 ± 2%). No adverse effects were reported at any time.
Conclusions: These findings suggest that laser therapy using the 10 W class IV instrument is efficacious for the long-term relief of the symptoms associated with chronic epicondylitis. The potential for a rapidly administered, safe and effective treatment warrants further investigation.
Copyright © 2013 Wiley Periodicals, Inc.