28-第一跖跗关节骨折脱位三种内固定对骨面应力传导变化的生物力学研究 二院 余霄.doc

第一跖跗关节骨折脱位三种内固定对骨面应力传导变化的生物力学研究 余 霄1，俞光荣2，庞清江1，伊力哈木·托合提3 [摘要]目的: 测量第一跖跗关节骨折脱位三种内固定对骨面应力传导变化，为选择内固定提供参考。方法: 取6具新鲜足标本，制成第一跖跗关节骨折脱位模型，依次进行3.5mm全螺纹皮质骨螺钉，1/4管型钢板及加压骑缝钉固定。经加载600N后，通过电阻应变片法测量第一跖骨基底及内侧楔骨的应变。另选取健康男性志愿者1名，经有限元建模软件建立第一跖跗关节骨折脱位模型，并依次模拟螺钉、钢板、骑缝钉固定，模拟600N加载，观察内固定上的应力分布。结果：第一跖跗关节骨折脱位分别进行螺钉，钢板及骑缝钉固定后，第一跖骨基底及内侧楔骨的应力都将减小；其中，钢板与螺钉固定后的应力较骑缝钉固定后的应力更小，差异有统计学意义（P＜0.05）。而有限元分析显示，螺钉固定应力最集中，并在中部表现出较高的应力；而钢板和骑缝钉应力则较为分散，最高应力也较螺钉小。结论：第一跖跗关节骨折脱位会引起中前足应力传导障碍。从应力传导角度看，钢板或螺钉固定比骑缝钉更能表现出较明显的应力遮挡效应，有利于骨折脱位的早期愈合，但螺钉由于应力较为集中，负重前要及时去除。 [关键词] 跖跗关节，骨折脱位，内固定，应力，生物力学 The Stress Conduction changes of the First Tarsometatarsal Joint Fracture-Dislocation Fixation by Three Different Internal Implants: A Biomechanical Study [Abstract]: Objectives: To measure the changes of stress conduction on the first tarsometatarsal joint fracture-dislocation by three different implants to provide reference in selecting implants. Methods: Six fresh foot specimens were made into the models of the first tarsometatarsal joint fracture-dislocation, which were fixated with 3.5 mm cortical screw, 1/4 tubular plate and compressive staple in turn. After 600N loading, the strain at the base of the first metatarsal and the medial cuneiform was measured by the resistance strain gauge. In addition, one healthy male volunteer was recruited and the first tarsometatarsal joint fracture-dislocation model was established by the finite element software. The fixation of screw, plate and staple were simulated under the 600N loading to observe the stress distribution of implants. Results: After the fixation of the first tarsometatarsal joint fracture-dislocation by screw, plate and staple respectively, the stress was reduced at the base of the first metatarsal and the medial cuneiform, among which the stress by plate and screw become smaller than by staple and the difference was statistically significant(P＜0.05).The finite element analysis demonstrated that the stress of screw fixation was the most centralized and