Objective To investigate the degradation and mechanical property of fixation devices of magnesium alloy.Methods Twelve rabbits were divided into two groups, with 6 in each group.Ulnae fracture models were estab-lished in the experimental group, which then were fixed with ZK60 magnesium alloy.The control group served as healthy control without setting ulnae fracture models.After 16 weeks, ulnae fracture healing were tested by strength measurement, and corrosion rate of magnesium alloy was calculated through MicroCT.Results Three-point bending strength measure-ment showed that the mechanical loads between two groups were not statistically different (P>0.05).After 8 weeks, Mi-croCT showed that the corrosion rate of the screws was ( 0.40 ±0.04 ) mm/year, and the corrosion behavior of screw heads was faster than that of the screw shafts.The corrosion rate of bone plates was (0.55 ±0.02) mm/year.Conclusion The internal fixation of magnesium alloy is an ideal system for orthopaedics, which does not affect bone formation and fa-cilitates fracture healing.%目的：探讨镁合金内固定物的降解与力学强度。方法将12只兔子分为实验组和对照组，每组6只。实验组建立尺骨骨折模型，然后使用镁合金（ ZK60）内固定系统进行固定；对照组不建立模型，仅作正常对照。术后16周采用实验应力分析手段测试尺骨的生物力学特性，通过MicroCT测算镁合金的腐蚀率。结果三点弯曲力学实验结果显示，两组力学载荷差异无统计学意义（P＞0.05）；MicroCT测算结果显示，术后8周螺钉的腐蚀率为（0.40±0.04）mm／年，但螺帽比螺杆腐蚀快，接骨板的腐蚀率为（0.55±0.02）mm／年。结论镁合金可作为一种理想的新型内固定材料应用，且对成骨无不良影响，并可促进骨增殖。
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