Does the laser in combination with exercises improve pain and function of patients with knee osteoarthritis?

INTERVENTION: E02.594.540 G11.427.410.698.277 Therapeutic exercises: a supervised progressive resistance exercise. The session includes warm‐up (10 min); resistance exercise training with additional load (elastic band and free weights) and weight‐bearing exercises (40 min); and cool‐down with static stretching of the muscles (10 min). Low‐Level Laser Therapy (LLLT) ‐ complementary intervention: performed immediately after exercise. Laser 808 nm, output power of 100 mW, 6J/point, 8 points (4 on the medial face and 4 on the lateral face) on the articular line of the most symptomatic knee. The therapeutic intervention will be conducted in 8 consecutive weeks, 3 times a week (Monday/Wednesday/Friday), at total of 24 sessions. 3 groups: Experimental group (N=40): Therapeutic exercises Experimental group (N=40): Therapeutic exercises, LLLT (active laser) Control group (N=40): Therapeutic exercises, LLLT‐placebo (inactive laser) CONDITION: Gonarthrosis ; M17 M00‐M99 PRIMARY OUTCOME: Pain intensity on the knee, assessed by a 10‐cm visual analog scale (VAS), at baseline and post‐intervention (right after treatment and at 12 and 24‐week follow‐up period) SECONDARY OUTCOME: Pain, stiffness and physical function, assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire ‐ global scale ; ; ; ; Perceived global change after intervention, assessed by a 15‐point scale (‐7 to +7) of global rating of change Physical function, assessed by performance‐based tests ‐ 30s Chair Stand Test, 40m Fast‐paced Walk Test, and Stair Climb Test Quality of life, assessed by the SF‐36 questionnaire ; INCLUSION CRITERIA: Present OA diagnosis at least in one knee compartment (tibiofemoral and/or patellofemoral); present grade 2 or 3 in the radiographic examination of OA; present a minimum pain intensity of 4 cm in the visual analogue scale (total of 10 cm) at the most affected knee