目的 接骨螺钉是骨科中常用的内固定植入物之一，由于长期植入人体，因此在临床使用前需要对其进行力学安全性评价。旋动性能是医用接骨螺钉的最主要力学指标，对于旋动性能建立科学的计算模型对接骨螺钉的研发与临床应用具有重要意义。方法 本文针对自攻型接骨螺钉分析了其在旋入过程中的三个主要阶段，对螺纹形成阶段的扭矩与扭转角进行力学建模与模拟计算；同时根据ASTM F543-17（YY/T 1506-2016）标准的要求，对来自三个厂家的规格均为φ2.9×12的接骨螺钉在不同等级聚氨酯实验块上开展螺钉体外旋入实验，将实验结果与计算结果进行比较分析。结果 理论模型所得旋入扭矩值与实验测得值相吻合，两者最大旋入扭矩值偏差值分别为0.005N·m和0.012N·m，小于实验测得扭矩的10%，在可接受的误差范围内。结论 所开发的接骨螺钉旋动力学计算模型能够模拟并预测研发与临床应用中的旋动扭矩，结合体外扭动实验，能够为接骨螺钉的研发与设计提供一种有效的途径。 关键词：医用接骨螺钉；旋入扭矩；力学模型
Objective Bone screws are one of the most widely used internal fixation implants in orthopedics. As they have to be implanted into human body for a long time during treatment, it is essential to evaluate their mechanical safety before clinical use. Insertion torque is the most important mechanical index of medical bone screws, therefore to establish a scientific calculation model of the torque is of great significance for the development and clinical application of bone screws. Method This paper builds the mechanical calculation model for the screw forming stage with simulation carried out in computer according to the three stages of the screw insertion process for the self-tapping screw. Meanwhile, we perform the insertional experiments of screws with specification of φ2.9×12 from three manufactures on polyurethane test blocks of different grades according to ASTM F543-17(YY/T 1506-2016), and the results are compared with the calculated ones. Results The deviations between the insertion torque predicted by the model and the value measured in the experiments are 0.005N·m and 0.012N·m within the acceptable error range, which are less than 10% of the average value of the experimentally measured ones. Conclusion The mechanical calculation model can be used to simulate and predict the insertion torque of medical bone screws in research and development or clinical use, and its combination with invitro mechanical experiments can be helpful in developing and designing bone screws.