Purpose: This study was conducted to evaluate the effectiveness of the low level laser on the fracturehealing of the guinea pig femurs.
Materials and methods: This study was performed on 36 guinea pigs (17 in the experimental group and 19 in the control group. After anesthesia of the guinea pigs, the shaft of femur was fractured with Gigli saw under aseptic conditions, and then the intramedullary nailing of K-wire was performed. The application of low level laser on the fracture sites in the experimental group began 2 days after the operation under anesthesia, for 30 minutes every 2 days. The laser we used was a CW-type microchip laser with output wave length of 890 nm and intensity of 13 mWatts, measuring up to 4.68 J/cm3 per each application. In order to compare the femur fracture healing process of both groups; gross findings, simple radiologic findings, and histologic findings of fracture site stability were evaluated. The simple radiologic and histologic findings were assessed by the scoring system invented by Zorlu and his colleagues. The statistical evaluation was done by using repetitive measured ANOVA test.
Results: In both experimental and control groups, the gross findings progressed favorably. Although the improvement in radiologic findings were found in both groups with the passage of time, the experimental group showed a greater rate of callus formation with statistical significance (p<0.01) compared to the control group. The result of histological findings showed that an increase of osteoblastic proliferation was also greater in the experimental group (p<0.01).
Conclusion: In this study, the low level laser was revealed to be effective on acceleration of femur fracture healing in guinea pigs.