Chao Ching-Kong, Chen You-Lin, Lin Jinn
Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan.
Department of Orthopedic Surgery, National Taiwan University Hospital, Taipei, Taiwan.
Bone Joint Res. 2020 Oct 10;9(10):645-652. doi: 10.1302/2046-3758.910.BJR-2019-0237.R2. eCollection 2020 Oct.
To determine whether half-threaded screw holes in a new titanium locking plate design can substantially decrease the notch effects of the threads and increase the plate fatigue life.
Three types (I to III) of titanium locking plates were fabricated to simulate plates used in the femur, tibia, and forearm. Two copies of each were fabricated using full- and half-threaded screw holes (called A and B, respectively). The mechanical strengths of the plates were evaluated according to the American Society for Testing and Materials (ASTM) F382-14, and the screw stability was assessed by measuring the screw removal torque and bending strength.
The B plates had fatigue lives 11- to 16-times higher than those of the A plates. Before cyclic loading, the screw removal torques were all higher than the insertion torques. However, after cyclic loading, the removal torques were similar to or slightly lower than the insertion torques (0% to 17.3%), although those of the B plates were higher than those of the A plates for all except the type III plates (101%, 109.8%, and 93.8% for types I, II, and III, respectively). The bending strengths of the screws were not significantly different between the A and B plates for any of the types.
Removing half of the threads from the screw holes markedly increased the fatigue life of the locking plates while preserving the tightness of the screw heads and the bending strength of the locking screws. However, future work is necessary to determine the relationship between the notch sensitivity properties and titanium plate design.Cite this article: 2020;9(10):645-652.
确定一种新型钛锁定钢板设计中的半螺纹螺孔是否能显著降低螺纹的切口效应并提高钢板的疲劳寿命。
制作三种类型（I至III）的钛锁定钢板以模拟用于股骨、胫骨和前臂的钢板。每种类型制作两份，分别采用全螺纹和半螺纹螺孔（分别称为A和B）。根据美国材料与试验协会（ASTM）F382 - 14评估钢板的机械强度，并通过测量螺钉拆除扭矩和弯曲强度来评估螺钉稳定性。
B型钢板的疲劳寿命比A型钢板高11至16倍。在循环加载之前，螺钉拆除扭矩均高于插入扭矩。然而，在循环加载之后，拆除扭矩与插入扭矩相似或略低（0%至17.3%），尽管除III型钢板外，B型钢板的拆除扭矩均高于A型钢板（I型、II型和III型分别为101%、109.8%和93.8%）。对于任何类型，A、B型钢板螺钉的弯曲强度均无显著差异。
去除螺孔一半的螺纹可显著提高锁定钢板的疲劳寿命，同时保持螺钉头部的紧固性和锁定螺钉的弯曲强度。然而，有必要开展进一步研究以确定切口敏感性特性与钛钢板设计之间的关系。引用本文：2020;9(10):645 - 652。
