Three-dimensional element analysis of swan-like memory compressive connector for treating fractures and nonunion of humerus / 第二军医大学学报

ABSTRACT

Objective:To study the biomechanical basis of swan like memory compressive connector (SMC) for treating fractures and nonunions, and the facilitating effects of dynamic memorial stress of SMC for bone healing. Methods:By computer emulation and three dimensional (3D) finite element analysis, the biomechanical behavior of humeral type connector for fixing humerus was emulated and analyzed. The finite element model of humeral type connector was divided into 3 487 units. The number of nodes was 5 397. The element was a unit with 20 nodes, 4 faces. The finite element model of humerus was divided into 5 783 units, the number of nodes was 9 863. And the finite element was a 3D unit with 10 nodes, 4 faces.Results:When the connector fixated humerus, it came in for tension stress in its inner surface, and compressing stress in its outer surface. The maximum first structural major stress of metamorphosed compressive part was 224.5 MPa and -34 MPa, far less than its utmost stress and fatigue limit. The initiative memorial bone holding force for maintaining axial stability was 125.05 N, and the longitudinal initiative memorial compression force was 196 N. The stress distribution in fixed humerus was even, the stress in most nodes was positive stress. Conclusion:The SMC has good anti fatigue and reuse characters. The dynamic memorial compressive stress field is good for the stability of fixation and enhancement of bone healing.