title: The effectiveness of therapeutic class IV (10 W) laser treatment for epicondylitis.
abstract: 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.
authors.affiliation: Selkirk College, Castlegar, British Columbia, Canada, V1N 4L3. droberts@selkirk.ca
authors.forename: Delia B
authors.initials: DB
authors.lastname: Roberts
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Kruse
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Stoll
mesh_terms: D000328:Adult; D000368:Aged; D004311:Double-Blind Method; D005260:Female; D018737:Hand Strength; D006801:Humans; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000517:prevention & control*; D020127:Recovery of Function; D052256:Tendinopathy / Q000150:complications / Q000628:therapy*; D013716:Tennis Elbow / Q000150:complications / Q000628:therapy*; D016896:Treatment Outcome