Digital speckle measurement of the displacement under internal fixation for fracture of femoral shaft / 中国组织工程研究

ABSTRACT

BACKGROUND: The biomechanical features of the plate internal fixation for the fractures are commonly analyzed utilizing direct contact and low accuracy sensor. However, it has some limitations such as direct contact and low accuracy. The digital speckle method used in the biomechanics of fractures is more accurate to analyze the characteristics of the screw breakage.OBJECTIVE: To measure the displacement of screws under different tensile force conditions after the internal fixation surgery of compression plate for adult thighbone using digital speckle method. METHODS: A total of six femur samples from adults were used to prepare model of midshaft humerus fractures. Each of two ends of fractured samples was fixed with five screws, and the pull test was conducted under the load of 200 and 300 N by electronic versatile machine to measure the displacement of the screws under 10 conditions. RESULTS AND CONCLUSION: The displacement distance of the screw was significantly longer under 300 N loading force compared with 200 N (P < 0.01). Except screws 1 and 10, 2 and 9, 3 and 8, 4 and 7, and 5 and 6, there were significant differences in the displacement between any two screws (P < 0.05). Results showed that the displacement of the screws increased with increasing pulling force, and the displacement near the fracture line significantly changed with pulling force.