Photobiomodulation does not provide incremental benefits to patients with knee osteoarthritis who receive a strengthening exercises program: a randomized controlled trial

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.