Association of photobiomodulation therapy (PBMT) and exercises programs in pain and functional capacity of patients with knee osteoarthritis (KOA): a systematic review of randomized trials

Knee osteoarthritis (KOA) is a common degenerative disease in which several treatments and treatment associations have been investigated. This review analyzed the efficacy of the association of photobiomodulation therapy (PBMT) and exercises for people with KOA in randomized controlled clinical trials. PubMed, Scopus, and EMBASE databases were searched using the following terms: “knee osteoarthritis,” “laser,” “low-level laser,” “photobiomodulation,” “phototherapy,” and “exercise.” Seven RCT studies involving humans that examined PBMT treatment in association with were found. Most studies used mainly near-infrared PBMT irradiation, with a fluence ranging from 610 mJ/cm² to 200 J/cm², 23.55 J to 2400 J total energy per knee, and number of treatment sessions from 10 to 24. In addition, all the protocols included exercises to increase lower limb muscle strength that were performed alone or in association with other types of exercises. However, only 2 studies, considered as a high quality, showed the additional effect of PBMT (lower doses) on an exercise program (involving warming-up, motor learning, balance coordination and strengthening exercises, and stretching) for improvement of pain and functional capacity in people with KOA. This review demonstrates that there is a controversy on the effects PBMT associated with exercises for pain and functional capacity improvement for people with KOA, because there is a heterogeneity between studies in related to PBMT parameters, as dose, number of therapy sessions and the type of PBMT (either LLLT and HILT), and the exercise protocols proposed.