Three dimensional finite element simulation of humerus fracture caused by indirect force / 中国矫形外科杂志

ABSTRACT

[Objective]To simulate the biomechanics mechanism and environment of humeral fracture caused by indirect impact force for the purpose of biomechanics understanding and treatment of such fracture.[Method]Based on the data source, which was high-resolution anatomic slice images from approximal clavicle to distal humerus, 1 mm thickness and totally 380 layers, the geometric model of total shoulder joint was established according to the orderpoint, line,area, and further meshed to set up the three dimension finite element model of shoulder, fracture sites and instantaneous stress and strain of humerus were simulated and analyzed under the condition which longitudinal impact force was loaded on the humerus based on the 12 functional positions of shoulder(abduction 30?、 45?、 60?、 90?, and simultaneous neutrality, internal rotation 45?,external rotation 45?).[Result]According to the humeral shaft load-strain curve in different functional positions of shoulder, linear relation was found when load changed from 0 N to 250 N, after which non-linear come out, and even load was removed , bone was deformed eternally. With the rise in load amount, the increase in stress was detected. When abduction degree changed from 90? to 30?, the strain of humerus, both the lateral and the medial increased gradually,and increase in internal rotation 45?and external rotation 45? was more significant than that in neutrality. Meanwhile, stress difference could be seen between the lateral and the medial , and medial was larger than the lateral. Increase in stress in rotation positions was quicker and more than that in other functional positions.[Conclusion]Based on 4 abduction degrees (30?, 45?, 60?, 90?) and 3 rotation degrees(neutrality, internal rotation 45?,external rotation 45?) ,the three dimensional finite element shoulder could simulate precisely stress, strain, general trend of fracture line, three dimension images of bone failure. Three dimension finite element simulation and analysis of shoulder is a valuable mechanical method for research on biomechanics theory related to humerus fracture.