1.Tianjin Key Laboratory of Integrated Design and On-line Monitoring for Light Industry Food Machinery and Equipment,School of Mechanical Engineering,Tianjin University of Science and Technology;2.Institute of Medical Science,Tianjin Naton Institute of Medical Technology
目的 探究锁定螺钉的头部角度以及锁定次数对钉板系统力学性能的影响,为临床手术过程医生选用适当锁定螺钉和把控锁定次数提供理论依据。方法 选用具有不同头部角度的锁定螺钉与同种接骨板配合,并进行不同次数的锁定,通过悬臂弯曲试验,比较各组试件力学性能的差异性。结果 头部角度不同的锁定螺钉与锁定加压接骨板配合之后的失效载荷与抗弯刚度存在显著性差异(P<0.05),锁紧程度最佳的钉板系统的力学性能最优；钉板配合进行3次锁定与进行1次锁定之间显著性差异不明显(P>0.05)；不同头部角度的锁定螺钉在不同锁定次数情况下的螺钉失效形式存在差异,锁定螺钉失效形式与其头部角度以及锁定次数正相关。结论 头部角度不同的锁定螺钉与锁定加压接骨板配合后力学性能的差异性不容忽视,医生在临床过程中选用锁紧程度最佳的锁定螺钉与锁定加压接骨板,并选用合适扭矩的限力扳手酌情进行多次锁定,避免螺钉松动影响患者康复。
Objective To investigate the effects of head angle and locking times of locking screws on mechanical properties of the screw-plate system,it provides a theoretical basis for doctors to select locking screws and master the locking times in the course of operation. Methods Selecting locking screws with slight head angle difference and matching with locking compression plates in the case of different locking times,cantilever bending method was used to compare the mechanical properties of each group. Results There are significant differences in failure load and bending stiffness between locking compression plate and locking screw with slight head angle difference(p<0.05),The mechanical properties of the screw-plate system with the best locking degree are the best;There was no significant difference between three times locking and one time locking(p>0.05);The failure modes of locking screw with different head angles and different locking times are different,so the failure mode of locking screw is related to its head angle and locking times. Conclusions The difference of mechanical properties between locking screw with small head angle difference and locking compression plate can not be neglected,It is suggested that doctors should choose locking screw and locking compression plate with the best locking degree in clinical process,and choose the right torque wrench to lock properly many times,these are all designed to prevent the screw loosening affecting patients’ recovery.