Efficacy of low level laser therapy associated with exercises in knee osteoarthritis: a randomized double-blind study

Authors: Patrícia Pereira Alfredo, Jan Magnus Bjordal, Sílvia Helena Dreyer, Sarah Rúbia Ferreira Meneses, Giovana Zaguetti, Vanessa Ovanessian, Thiago Yukio Fukuda, Washington Steagall Junior, Rodrigo Álvaro õ Lopes Martins, Raquel Aparecida Casarotto and Amélia Pasqual Marques
Source: Clinical Rehabilitation 26(6) 523–533
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To estimate the effects of low level laser therapy in combination with a programme of exercises on pain, functionality, range of motion, muscular strength and quality of life in patients with osteoarthritis of the knee.


A randomized double-blind placebo-controlled trial with sequential allocation of patients to different treatment groups.


Special Rehabilitation Services.


Forty participants with knee osteoarthritis, 2–4 osteoarthritis degree, aged between 50 and 75 years and both genders.


Participants were randomized into one of two groups: the laser group (low level laser therapy dose of 3 J and exercises) or placebo group (placebo laser and exercises).

Main measures

Pain was assessed using a visual analogue scale (VAS), functionality using the Lequesne questionnaire, range of motion with a universal goniometer, muscular strength using a dynamometer, and activity using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) questionnaire at three time points: (T1) baseline, (T2) after the end of laser therapy (three weeks) and (T3) the end of the exercises (11 weeks).


When comparing groups, significant differences in the activity were also found (P 1⁄4 0.03). No other significant differences (P > 0.05) were observed in other variables. In intragroup analysis, participants in the laser group had significant improvement, relative to baseline, on pain (P 1⁄4 0.001), range of motion (P 1⁄4 0.01), functionality (P 1⁄4 0.001) and activity (P < 0.001). No significant improvement was seen in the placebo group.


Our findings suggest that low level laser therapy when associated with exercises is effective in yielding pain relief, function and activity on patients with osteoarthritis of the knees.

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