Biomechanical study of swan-like memory compressive connector for treating fractures and nonunions of humerus
XU Shuo Gui 1, ZHANG Chun Cai 1, SU Jia Can 1, ZENG Wei Ming 2, GU Shao De 2, FANG Ru Hua 2, ZHANG Lin Chun 2 (1. Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai 200433, China; Laboratory of Photome
Objective:To study the biomechanical basis of swan like memory compressive connector (SMC) for treating fractures and nonunions of humerus. Methods:The study was performed by electrometric, two and three dimensional (3D) photoelasticity techniques. By gauging and multiple time standardization, load strain curve was got, then the dynamic memory force of SMC was calculated. The dynamically compressive force of swan neck compressive part was calculated by 2D photoelasticity. By precision moulding, the epoxy resin 3D photoelasticity humeral model was established, then it was fixated by SMC, meanwhile, an epoxy resin cirque was used to share the continuously memorial compress. The 3D stress distribution of humeral model was got, and 6 space component stress of the inspected node was divided by Leize polarizing microscope. Results:The continuously memory force of SMC was 110.35 N. The longitudinal dynamical compressive memory force was 163.88 N. 3D photoelasticity method showed that the swan neck compressive part of SMC, swan body connecting part of SMC and swan wing holding part of SMC were in consistent with each other, memorably holding bone, 3D fixation style was formed, and overall stress distribution was produced.. Conclusion:The stress field produced by 3D memory fixation of SMC is good for the treatment of fractures and nonunions. Early function exercises are allowed, and the fracture healing is prompted.