踝关节3.5mm全螺纹空心无头加压螺钉取出困难原因分析

目的:探讨踝关节3.5mm全螺纹空心无头加压螺钉取出困难的原因。方法:选取2019年4—12月行踝关节内固定(包括3.5mm全螺纹空心无头加压螺钉)取出术患者的病例资料进行分析。统计患者的人数、性别、年龄,及使用3.5mm全螺纹空心无头加压螺钉的数量、材料、使用部位、留置时间。按照是否发生螺钉取出困难,将患者分为螺钉正常取出组和螺钉取出困难组,对螺钉取出困难的原因进行统计分析。结果:符合要求的患者共31例,涉及87枚3.5mm全螺纹空心无头加压螺钉,均为国内同一厂家生产的TC4钛合金螺钉。螺钉正常取出组26例(77枚螺钉),螺钉取出困难组5例(10枚螺钉),螺钉取出困难发生率为11.49%。螺钉正常取出组男13例、女13例,螺钉取出困难组男2例、女3例;2组患者的性别比较,差异无统计学意义(χ²=0.000,P=1.000)。2组患者年龄比较,差异无统计学意义[(49.80±11.72)岁,(43.60±12.09)岁,t=1.044,P=0.305]。螺钉取出困难组患者的螺钉留置时间比螺钉正常取出组长[(14.78±3.08)个月,(16.10±1.14)个月,t=2.550,P=0.016]。螺钉正常取出组螺钉应用于外踝33枚、内踝39枚、后踝5枚,螺钉取出困难组螺钉应用于外踝1枚、内踝4枚、后踝5枚;2组患者的螺钉应用部位比较,差异有统计学意义(P=0.001);螺钉取出困难组中螺钉应用于后踝(50%)和内踝(9.3%)的比例更高。结论:踝关节骨折应用3.5mm全螺纹空心无头加压螺钉固定,后期发生螺钉取出困难的风险较高;螺钉留置时间过长及固定后踝或内踝骨折更易发生螺钉取出困难。

Cause analysis of difficulty in removal of 3.5-mm diameter full-thread hollow headless compression screws used for treatment of ankle fractures

Objective:To explore the causes of difficulty in removal of 3.5-mm diameter full-thread hollow headless compression screws(HCSs)used for treatment of ankle fractures.Methods:The medical records of patients who received ankle internal fixation removal surgery from April 2019 to December 2019 were selected out.In the surgery, the 3.5-mm diameter full-thread hollow HCSs were used.The information, including quantity, gender, age of patients and quantity, material, location, indwelling time of 3.5-mm diameter full-thread hollow HCSs, were extracted from the medical records and were analyzed.The patients were divided into normal removal group and difficult removal group according to whether the screws were difficult to remove, and the causes of difficulty in screw removal were statistically analyzed.Results:Thirty-one patients(87 3.5-mm diameter full-thread hollow TC4 titanium alloy HCSs produced by the same domestic manufacturer)were enrolled in the study, 26 cases(77 screws)in normal removal group and 5 cases(10 screws)in difficult removal group.The incidence rate of difficulty in screw removal was 11.49%.The patients consisted of 13 males and 13 females in normal removal group and the patients consisted of 2 males and 3 females in difficult removal group.There was no statistical difference in age and constituent ratio of gender between the 2 groups(49.80±11.72 vs 43.60±12.09 years, t=1.044,P=0.305;χ2=0.000,P=1.000).The indwelling time of HCSs was longer in difficult removal group compared to normal removal group(14.78±3.08 vs 16.10±1.14 months, t=2.550,P=0.016).The screws were applied to lateral malleolus(33),medial malleolus(39)and posterior malleolus(5)in normal removal group and the screws were applied to lateral malleolus(1),medial malleolus(4)and posterior malleolus(5)in difficult removal group.There was statistical difference in location of screws between the 2 groups(P=0.001).The proportions of screws applied to the posterior malleolus(50%)and medial malleolus(9.3%)were higher in difficult removal group compared to normal removal group.Conclusion:Internal fixation with 3.5-mm diameter full-thread hollow HCSs for treatment of ankle fracture has a high risk of subsequent difficulty in removal of HCSs.Overlong indwelling time of HCSs and applying HCSs to posterior malleolus and medial malleolus would increase the difficulty in removal of HCSs.