VAS scores showed a significant improvement in the active laser group compared with the placebo laser group at 6 weeks post intervention [ mean difference -1.3 , 95 % confidence interval ( CI ) of the difference -2.4 to -0.3 ; P = 0.014 ] and 6 months post intervention ( mean difference -1.8 , 95 % CI of the difference -3.0 to -0.7 ; P = 0.003 ) using the independent samples test .