采用不同缝线及缝合位点缝合内侧半月板后根部损伤的生物力学研究

Biomechanical study on different high-strength sutures and suture site for repairing posterior root tear of the medial meniscus

目的:比较不同高强度缝线及不同缝合位点缝合固定内侧半月板后根部损伤的生物力学特性。方法:取新鲜猪(雌性,月龄5~9个月,平均7个月)膝关节内侧半月板标本48个,采用Mason-Allen缝合方法建立实验模型。根据缝合位点不同随机分为红区固定组、红-白区固定组,每组24例。再根据固定材料不同将每组随机分为3个亚组,每组8例,分别采用Ethibond缝线、Ultrabraid缝线、FiberWire缝线固定。采用万能电磁力学试验机,先给予1000次的循环载荷后行拔出试验,直至拔出失败;测量并计算标本最大失败载荷、失效载荷、拔出刚度及循环位移。结果:所有标本顺利完成生物力学测试。Ethibond缝线组失败模式均为缝线断裂。Ultrabraid缝线组失败模式:6例为缝线断裂,均属红区固定组;10例为缝线拔出,其中2例属红区固定组,8例属红-白区固定组。FiberWire缝线组失败模式均为缝线拔出。生物力学结果:(1)在缝线强度比较方面,最大失败载荷、失效载荷及拔出刚度:Ethibond缝线组<Ultrabraid缝线组<FiberWire缝线组,组间比较差异有统计学意义(P<0.05);100、500、1000次循环位移:Ethibond缝线组>Ultrabraid缝线组>FiberWire缝线组,组间比较差异有统计学意义(P<0.05);表明FiberWire缝线强度最优,Ultrabraid缝线次之,Ethibond缝线最差。(2)在缝合位点比较方面,最大失败载荷、失效载荷及拔出刚度:红区固定组>红-白区固定组,组间比较差异有统计学意义(P<0.05);100、500、1000次循环位移:红区固定组<红-白区固定组,组间差异有统计学意义(P<0.05),表明红区缝合强度优于红-白区缝合。结论:Mason-Allen缝合方法可有效固定内侧半月板后根部损伤并满足术后早期部分负重要求。术中采用FiberWire缝线并将缝合位点置于红区可获得更好的固定效果,有利于半月板愈合及功能恢复。

Objective:To compare biomechanical characteristic of different high-strength sutures and suture sites for repairing posterior root tear of the medial meniscus with modified Mason-Allen technique.Methods:Forty-eight specimen of medial meniscus of knee joint from fresh porcine(female,aged from 5 to 9 months with an average of 7 months)were chosen and established experimental model.The samples were divided into red zone fixation group and red-white zone fixation group according to suture sites,24 in each group;and then were randomly divided into 3 subgroups which 8 in each group,and fixed with Ethibond suture,Ultrabraid suture and FiberWire suture,respectively.Biomechanical tests were performed on universal electromagnetic and mechanical testing machine.Each specimen was underwent 1000 cyclic tests on the first time,then pull-out test until failure.The maximum failure load,yield load,stiffness and displacement were analyzed.Results:All specimen were successfully completed biomechanical tests.The failure mode of Ethibond group was caused by suture fracture;6 cases of Ultrabraid suture group was caused by suture fracture which belong to red zone fixation group,10 cases were caused by suture pull-out,which 2 cases belong to red zone fixation group,8 cases belong to red-white zone fixation group;8 cases of FiberWire group was caused by suture pull-out.Biomechanical test showed that:(1)In terms of suture strength,comparison of the maximum failure load,yield load and stiffness showed that Ethibond suture group<Ultrabraid suture group<FiberWire suture group,and had statistical differences among groups(P<0.05);comparison of cyclic displacement at 100,500 and 1000 cycles showed that Ethibond suture group>Ultrabraid suture group>FiberWire suture group,and had statistical differences among groups(P<0.05);the results showed the suture strength in Ethibond was the best,Ultrabraid suture took the second place,and FiberWire suture was the worst.(2)As for different suture sites,comparison of the maximum failure load,yield load and stiffness showed that red zone fixation group>red-white region fixation group,and had statistical difference between two groups(P<0.05);comparison of cyclic displacement at 100,500 and 1000 cycles showed that red zone fixation group<red-white zone fixation group,and had statistical difference between two groups(P<0.05);the results showed that suture strength in red zone fixation group was better than that of red-white zone fixation group.Conclusion:Mason-Allen suture could effectively fix posterior root tear of the medial meniscus and meet needs of early partial weight bearing after surgery.Suturing with Fiberwire in red zone is stronger and better for the meniscus healing and rehabilitation.