IRCT201502224549N8 IRCT 2015-05-19 Vice chancellor for research,Semnan University of Medical Sciences The effect of laser therapy on knee Osteoarthritis treatment The effect of low and high power laser therapy on pain,disability and range of motion in patients with knee osteoarthritis: a comparative clinical trial study 2015-04-19 anticipated 50 Complete https://irct.ir/trial/4857 interventional Randomization: Randomized, Blinding: Not blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Other design features: Sampling is convenience and the volunteers are randomly allocated to three groups by lottery. 2 Osteoarthritis of the knee joint. Intervention 1: In the low power laser group the treatment that applied is 1 MHZ continuous mode Ultrasound with duration of 5 MIN and intensity of 1 W.CM2, TENS current with frequency of 100 HZ and pulse duration of 0.05 MS and the time of treatment of 15 MIN. Hot pack, SLR in supine position and Gal-AL-AS diode laser device with a power output of 30 MW and a wavelength of 830 NM will be used. Intervention 2: In the placebo laser group the treatment that applied is 1 MHZ continuous mode Ultrasound with duration of 5 MIN and intensity of 1 W.CM2, TENS current with frequency of 100 HZ and pulse duration of 0.05 MS and the time of treatment of 15 MIN. Hot pack, SLR in supine position and A same laser device will be used while turned off the laser device. Intervention 3: In the high power laser group the treatment that applied is 1 MHZ continuous mode Ultrasound with duration of 5 MIN and intensity of 1 W.CM2, TENS current with frequency of 100 HZ and pulse duration of 0.05 MS and the time of treatment of 15 min. Hot pack, SLR in supine position and A Gal-AL-AS diode laser device with a power output of 3.2 W and a wavelength of 910 NM will be used.