Effect of Low- Power Helium-Neon Laser Irradiation of Healing of Incisized Medial Collateral Ligament of Knee in Rars

Purpose: The aim of the present study is to investigate the effects of LPL on healing of incisized medial collateral ligament (MCL) of knee of rats. Materialsand Methods:MCL of right hind limb of 30 rats were transversly incisied. LPL (Helium- Neon, Continuose, output 10mW) were exposed (10 mJ/cm2 and 1.2 J/cm2) daily to group 1& II (experimental groups) respectively. In control group MCL were incisized, but they werent received LPL. In normal group, there wasnt any intervention. At day12 and day 21 Femur- MCL- Tibia of experimental groups, control group, and normal group were extracted. Biomechanical tests is: tensile strength (N/mm2) and working up to tensile strength (Nmm) and elastic modulus (N/mm2)were performed. Then, data were analysed by ANOVA method. Results: Tensile strength of no 2 experimental group (11.48±1.48) at day 12 had significant difference (P=0.000)comparring with to control group (7.55±0.37) and of no one experimental group (8.92±1.32) and of normal group (21.77±27). Working up to Tensile strength of normal group at day 12 (P=0.000)and day 21(p=0.005)were higher than other groups. Conclusion: Low- power laser (1.2 J/cm2) treated inisized MCLof rats increased tensiIe strength comparing with control but it was lower than normal. There wasnt any positive effect of LPL related to other biomechanical parameters. Further investigations are recommended.