Finite element analysis of the treatment of middle clavicle fracture with wing plate internal fixation

Objective: To investigate the mechanical properties of a new type of biplane locking plate with wings in the treatment of middle clavicle fractures. Methods: Based on the CT data of a healthy adult male volunteer's clavicle, a three-dimensional finite element model of the middle clavicle fracture was constructed by digital three-dimensional reconstruction technology, and the two kinds of fixation methods of single-plane locking plate (SP) and wing plate (WP) were simulated. Four load cases of axial compression, axial torsion, cantilever bending and pull-out were used to analyze the models. Results: ①Under axial compression, axial torsion, cantilever bending and pull-out conditions, compared with SP, the stiffness phase of WP increased by 1.47％, 5.82％, 1.51％ and 3.96％ respectively, and the strain energy decreased by 1.50％, 5.39％, 1.48％ and 3.49％ respectively. ②The stress distribution characteristics of WP under various load conditions were similar to SP, and the high stress area was located around the screw hole of the steel plate above the fracture gap; ③Under the pull-out condition of WP, the peak value of screw hole surface stress was greatly reduced compared with SP, especially in the screw hole on both sides of the wing screws, which had higher resistance to pull out. Conclusion: The load-bearing mode of WP under various load conditions is similar to that of SP, and the stability is slightly higher than that of SP and in terms of pull-out resistance, WP has more obvious advantages. The biplane locking plate with wings is expected to be a more ideal choice for patients with comminuted fracture of the middle clavicle or with osteoporosis.