Objectives:

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.

Design:

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

Setting:

Special Rehabilitation Services.

Subjects:

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

Intervention:

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

Results:

When comparing groups, significant differences in the activity were also found (P=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=0.001), range of motion (P=0.01), functionality (P=0.001) and activity (P<0.001). No significant improvement was seen in the placebo group.

Conclusion:

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.