Abstract
BACKGROUND: There is lack of agreement in the literature about the effectiveness of photobiomodulation (PBM) for reducing pain-related symptoms in patients with knee osteoarthritis (OA). OBJECTIVE: To evaluate whether PBM, when combined to exercises, provides incremental therapeutic benefits for pain, physical function, and quality of life (QoL) in patients with knee OA. METHODS: A six-month double-blind placebo-controlled randomized trial was conducted. Patients with knee OA were randomly assigned to one of three treatment groups: Exercise, Exercise plus Active PBM, or Exercise plus Placebo PBM. Treatment was provided over an eight-week period, three times per week. The primary outcomes were pain at rest and upon movement, assessed by a visual analogue scale (VAS). WOMAC global score, QoL, and a core-set of performance-based tests were measured as secondary outcomes. All outcomes were collected at baseline, immediately after treatment, and after three- and six-month post-treatment. RESULTS: 127 participants were allocated as follows: Exercise, N = 41; Exercise plus Active PBM, N = 44; and Exercise plus Placebo PBM, N = 42. There was no between-groups difference in improvement in pain, physical function, and QoL for all follow-up times. However, all groups presented significant, clinically relevant improvements in pain, physical function, and QoL immediately and three months after treatment compared with baseline measures. CONCLUSION: Patients with knee OA who received a strengthening exercises program did not experience incremental benefits regarding pain, physical function, or QoL when adding PBM to their therapeutic exercises.