两种前交叉韧带胫骨止点撕脱骨折固定的生物力学比较

Biomechanical comparison of two fixations for tibial avulsion fractures of anterior cruciate ligaments

[目的]探讨前交叉韧带(ACL)胫骨止点撕脱骨折两种内固定的生物力学特性,为临床提供良好的理论依据。[方法]12具猪膝关节新鲜标本,制备ACL胫骨撕脱骨折模型,按照随机数字表法分2组,每组各6具膝关节。缝线组采用缝线结合外排锚钉固定,双排组采用锚钉双排桥式固定。生物力学测试机上进行测试,记录最终失效荷载、屈服载荷、位移、刚度。[结果]除缝线组1例失效,其余对象都通过了50~250 N载荷,1000周期循环测试,位移缝线组为(4.19±1.31)mm,双排组为(1.94±0.31)mm,差异有统计学意义(P<0.05)。之后,轴向加载损毁试验,最终失效荷载缝线组为(612.60±121.59)N,双排组为(580.19±119.79)N,差异无统计学意义(P>0.05)。屈服载荷缝线组为(343.09±208.07)N,双排组为(278.01±196.39)N,差异无统计学意义(P>0.05)。刚度:缝线组(17.93±7.72)N/mm,双排组(48.34±9.57)N/mm,差异有统计学意义(P<0.05)。[结论]两种内固定方式都具有良好生物力学特性,均提供可靠内固定,在生物力学上无明显差异。在循环加载环境下,双排固定提供了更少的位移。相比抗拔能力,双排固定更强。

[Objective]To investigate the biomechanical properties of 2 different internal fixations for tibial avulsion frac ture of anterior cruciate ligament(ACL)and provide a theoretical basis for clinical practice.[Methods]A total of 12 fresh speci mens of pig knee joints were used in the study.After models of tibial avulsion fractures of ACL were created,the fracture was fixed by sutures and the outer row anchor in 6 sample(the suture group),while by anchor and double-row bridge in the other 6 samples(the double-row group)according to the random number table method.After that,the samples were tested on a biome chanical machine to record the maximal failure load,yield load,displacement and stiffness of the samples.[Results]Except 1 sample in the suture group failed in cyclic loading test,all the samples tolerated the cyclic loading of 50~250 N for 1000 cycles successfully,associated with displacement of(4.19±1.31)mm in the suture group,while(1.94±0.31)mm in the the double-row group,which proved statistically significant(P<0.05).In term of the axial loading to failure test subsequently,the maximal fail ure strength was of(612.60±121.59)in the suture group,whereas(580.19±119.79)N in the double-row group without a statisti cal significance between the two groups(P>0.05),the yield load was of(343.09±208.07)N in the suture group,while(278.01±196.39)N in the double-row group without a statistical significance between them(P>0.05),however,the stiffness proved of(17.93±7.72)N/mm in the suture group,whereas(48.34±9.57)N/mm in the double-row group,which was statistically signifi cant between the two group(P<0.05).[Conclusion]Both the fixation methods provide good biomechanical properties and reliable internal fixation strength without significant dif ferences in biomechanics.By comparison,the double row fixation provides less displacement under cyclic loading con ditions,with better anti-pull capacity.