后交叉韧带重建中不同角度胫骨隧道的生物力学研究

Biomechanical research of different tibia tunnel in posterior cruciate ligament reconstruction

目的评价后交叉韧带重建中不同角度胫骨隧道对移植物生物力学性能的影响。方法应用18具人体跟腱作为移植物重建后交叉韧带,分别建立与胫骨平台呈30°、40°、50°3组不同夹角的胫骨隧道,在胫骨隧道出口边缘与移植物之间放置压敏片计算压强值及试验前后隧道出口面积变化来评估磨损作用的大小、"锐角效应"的影响以及移植物循环载荷能力。结果胫骨隧道与胫骨平台夹角50°时压强最小、隧道出口面积扩大最小。夹角减小压强增大、隧道出口面积的扩大增大,"锐角效应"增加,导致循环载荷能力下降。结论增加胫骨隧道与胫骨平台的夹角,可以降低隧道出口处的压强,减少移植物磨损,增加疲劳力学性能。

Objective To perform a biomechanical study for evaluation of the failure rates of PCL grafts which reconstructed with 3 different angles of tibia tunnels in cadaveric knees. Methods Eighteen cases of Achilles tendons were used to reconstruct the posterior cruciate ligament on the cadaveric tibia. According to different angles between the tunnels and the tibial platforms, the spices were divided into 3 groups： A （30 degrees）, B （40 degrees）, C （50 degrees）. Cyclic load tests were conducted to evaluate the failure rates of the PCL grafts. The area of tibia tunnels and pressures on tibia tunnels were measured before and after cyclic load tests. Resulls The angle between tibia tunnel and tihial platform had the positive correlation with the graft failure strength. Group C had the minimum pressures on the tibia tunnels, the minimum changes of the measures of area of tibial tunnels, and the biggest failure strength. Conclusion Increasing the angel of the tunnel and the tibial platform could reduce the ＂killer turn＂ effect with advantage of graft failure strength.