Background and aim: Knee osteoarthritis (OA) is one of the most common synovial joint diseases (i.e. weight bearing joints) of the human body. This problem probably is more common in Iranian society that is used to sit on the floor and carpet. Following knee OA, patients complain of pain, inflammation, decrease of range of motion and muscle weakness. Therefore, they can not independently do their activity of daily living (ADL). Consequently, the side effects of physical incapability may render to psychological problems and this in respect do affect on their quality of life.Various treatments such as pharmalogical, surgical and physiotherapy have been recommended at different stages of OA by specialist. In the present study, the effect of physical therapy agents (considering the point that physiotherapy has no or negligible side effects) have been studied on OA. 

Materials and methods: 40 patients participated in this study the patients were refereed by orthopedic surgeon to the physiotherapy clinic of the Faculty of Rehabilitation. University ethical committee approved the procedures. Patients were randomly divided in two groups and physiotherapy treatments were applied as following:

Group I.  Low Level Laser Therapy, heat, exercise.

Group II. Placebo (i.e. inactive Laser), heat, exercise.

Results: The result of current study shows that both methods of physical therapy were quiet efficient on 7 variables that measured in this study (p< 0.05).  However, the result of this study showed that in laser group, pain and speed of gait were more effectively influenced (p< 0.000 and p<0.048 respectively) in comparison with routine physiotherapy. Consequently, patients can fairly independently do their activity of daily living and this in respect may reduce the psychological side effects of illness.