Low Level Laser Therapy for Osteoarthritis and Rheumatoid Arthritis: A Metaanalysis ABSTRACT.Osteoarthritis (OA) and rheumatoid arthritis (RA) affect a large proportion of the population. Low level laser therapy (LLLT) was introduced as an alternative non-invasive treatment for RA and OA about 10 years ago, but its effectiveness is still controversial. We assessed the effectiveness of LLLT in the treatment of RA and OA. Objective. Methods.A systematic review was conducted, following an a priori protocol, according to the methods recommended by the Cochrane Collaboration. Trials were identified by a literature search of Medline, Embase, and the Cochrane Controlled Trials Register. Only randomized controlled...