The effect of low-level LASER on pain improvement and function in patients affected anterior knee pain

Backgroun and Anterior knee pain is a common problem among adults and young people. This study aimed to investigate the effects of low-level LASER on improvement of knee pain and function in patients with anterior knee pain. This double-blind, randomized clinical trial was carried out in Zahedan University of Medical Sciences, in 2008. In this study, thirty patients were randomly divided into experimental (N=15) and control groups (N=15). In the experimental group, beside the exercise, a low-level Ga-As LASER was applied with a 100 mW average power, wavelength 905 nm and 8 J/cm2 dosages for 3 minutes duration. In the control group, sham LASER was used. A 16 session treatment program (during 4 weeks, 4 sessions per weeks) was performed for both groups. Before and after the intervention, we measured the pain level through visual analog scale (VAS) and the function by Knee and Osteoarthritis Outcome Score (KOOS) and range of knee flexion by goniometry. Paired and Independent t-tests were used for data analysis. The knee pain decreased from 6.06±2.6 to 2.7±2.6 in the experimental group (P<0.001) and from 6.4±1.9 to 3.4±1.4 in the control group (P=0.003). KOOS score was decreased from 87.2±29.8 to 48.4±24.1 in the experimental group and from 94.8±20.9 to 61.7±15.3 in the control group (P<0.001). Level of pain was significantly decreased in the experimental group compared to the control group (P=0.012). The results showed that exercise therapy with or without LASER can reduce pain and cause better knee function and expansion of the ranges of knee flexion. However; LASER is more effective in decreasing anterior knee pain.