后交叉韧带重建中股骨侧复合固定技术的生物力学研究

目的探讨股骨侧＂锐角效应＂及复合固定技术对后交叉韧带重建术后移植物的影响。方法50例猪膝关节,随机分为5组,以猪的屈趾肌腱作为移植重建后交叉韧带。移植物固定方法分别采用：EndoButton、可吸收界面螺钉（螺钉分别固定在移植物前上方及后下方）、复合固定（EndoButton联合小号界面螺钉）且螺钉固定在移植物后下方。在移植物与骨道边缘之间放置压敏片,并对其施以352N的负荷作用来测定其与骨道边缘之间压强。然后再对各移植物施以屈服负荷,记录各组压强值及屈服负荷。结果各组间的压强值以及屈服负荷间的差异有统计学意义（P〈0.01）。其中,复合固定组压强值（3.28±0.22）Mpa低于其他各组,但是屈服负荷（470±55）N大于其他各组。并且,螺钉固定在后下方压强值（3.22±0.13）Mpa明显小于前上方固定（3.49±0.27）Mpa。结论应用复合固定技术重建后交叉韧带,可以减小＂锐角效应＂,并且复合固定技术固定强度大于单纯皮质外固定及单纯界面螺钉固定。

Biomechanical study on the "critical corner" of femur in posterior cruciate ligament reconstruction with combine fixation

Objective To explore the ＂critical corner＂ of femur and moreover, to evaluated the combine fixation in posterior cruciate ligament reconstruction. Methods 50 porcine knees were divided into 5 groups, randomly. Using the porcine flexor digitorum tendon as graft reconstructed posterior cruciate ligament. The methods of graft fixation were： extracortical fixation, biodegradable interference screw fixation （the fixation location of interference screw was front-upward and rear-inferior）, combine fixation （EndoButton combined small biodegradable interference screw） with the fixation location of interference screw being rear-inferior. Press-sensitive slice was put between the ligament graft and the bone tunnel edge for evaluating the pressure between the ligament graft and bone tunnel edge. The load abute 352 N was applied to the specimen for calculative pressure. Then the yield load was applied to the specimen for the biomechanical data. Results There was difference （P0.01） in pressure and yield load of all groups. The pressure of combine fixation was the smallest （3.28±0.22）Mpa] of all the reconstruction groups, and the yield load was the largest （470±55）N]. The pressure of rear-inferior interference screw fixation （3.22±0.13）Mpa] was smaller than the front-upward interference screw fixation （3.49±0.27）Mpa]. Conclusions That the ＂critical corner＂ existing in femur can be reduced by combine fixation technique. Furthermore, the combine fixation provids superior fixation for graft than extracortical fixation and interference screw fixation.