后交叉韧带单束重建术股骨隧道角度与内侧副韧带损伤的相关性分析

Correlation analysis of femoral tunnel angle and medial collateral ligament injury in posterior cruciate ligament single-bundle reconstruction

目的探讨后交叉韧带重建术(posterior cruciate ligament reconstruction,PCLR)中,股骨隧道在股骨内侧髁的开口是否会造成内侧副韧带(medial collateral ligament,MCL)医源性损伤,并估计股骨隧道放置的安全角度。方法使用13具甲醛浸泡人体膝关节标本,捐赠者男8例,女5例;年龄49~71岁,平均61岁。仔细解剖每个膝关节标本股骨内侧区,明确MCL在股骨内侧走行与附着的区域,并沿此区域前缘作1条标记线,通过这条标记线将股骨内侧髁分割为MCL覆盖区和无MCL分布的相对安全区域。然后将膝关节标本的后交叉韧带(posterior cruciate ligament,PCL)切断以暴露PCL股骨附着区,在120°屈曲角度固定的膝关节标本上,模拟PCL单束重建术中股骨隧道制备,采用由内向外技术从膝关节内部的PCL股骨足迹处向股骨内侧方向进行股骨隧道钻孔,并通过轴面和冠状面两平面角度组合的方式实现不同方向股骨隧道的创建。选取15种角度组合[0°/30°、0°/45°、0°/60°、15°/30°、15°/45°、15°/60°、30°/30°、30°/45°、30°/60°、45°/30°、45°/45°、45°/60°、60°/30°、60°/45°和60°/60°(轴面/冠状面)],验证股骨隧道放置角度是否为损伤MCL的危险因素,并通过检验各角度组合产生的股骨隧道开口点与MCL前缘标记线的最短距离是否存在差异来估计股骨隧道放置的安全角度。结果在PCLR中创建股骨隧道时,存在MCL被股骨隧道出口损伤的风险,发生率为0~100%,当轴平面钻孔角度为0°和15°时,MCL损伤发生率高达69.23%~100%。并且股骨隧道放置角度不同,其MCL损伤发生率差异有统计学意义(χ^(2)=148.195,P<0.001)。通过组间比较发现,以45°/45°、45°/60°、60°/30°、60°/45°和60°/60°(轴面/冠状面)这5个角度组合创建的股骨隧道,其隧道出口点与标记线最短距离与0°/45°、0°/60°、15°/45°、15°/60°和30°/30°(轴面/冠状面)比较差异有统计学意义(P<0.05);进一步比较最短距离的中位数发现,这5个角度组合的股骨隧道出口点更远离标记线及其后方的MCL。结论在PCLR中股骨隧道的创建会造成MCL医源性损伤,且损伤风险受隧道角度影响,推荐以45°/45°、45°/60°、60°/30°、60°/45°和60°/60°(轴面/冠状面)角度组合创建股骨隧道,以降低MCL的医源性损伤风险。

Objective To investigate whether the outlet of the femoral tunnel will cause iatrogenic injury to the medial collateral ligament(MCL)during posterior cruciate ligament reconstruction(PCLR)and estimate the safe angle of femoral tunnel placement.Methods Thirteen formaldehyde-soaked human knee joint specimens were used,8 from men and 5 from women;the donors’age ranged from 49 to 71 years,with an average of 61 years.First,the medial part of the femur was carefully dissected to clearly expose the region of the MCL course and attachment on the femoral medial aspect and to outline the anterior margin of the region with a marked line.The marked line divided the medial femoral condyle into an area with an MCL course and a bare bone area which is regarded relatively safe for no MCL course.Then,the posterior cruciate ligament(PCL)was cut to identify the femoral attachment of the PCL.After the knee joint was fixed at a 120°flexion angle,the process of femoral tunnel preparation for the PCL single-bundle reconstruction was simulated.The inside-out technique was used to drill the femoral tunnel from the PCL femoral footprint inside the knee joint with an orientation to exit the medial condyle of the femur,and the combination angle of the two planes,the axial plane and the coronal plane,was adapted to the process of drilling femoral tunnels at different orientations.The following 15 angle combinations were used in the study:0°/30°,0°/45°,0°/60°,15°/30°,15°/45°,15°/60°,30°/30°,30°/45°,30°/60°,45°/30°,45°/45°,45°/60°,60°/30°,60°/45°,60°/60°(axial/coronal).The positional relationship between the femoral tunnel outlet on the femoral medial condyle and the marked line was used to verify whether the tunnel drilling angle was a risk factor for MCL injury or not,and whether the shortest distance between the femoral exit center and the marked line was affected by the various angle combinations.Furthermore,the safe orientation of the femoral tunnel placement would estimated.Results When creating the femoral tunnel for PCLR,there was a risk of damage to the MCL caused by the tunnel outlet,and the incidence was from 0 to 100%;when the drilling angle of the axial plane was 0°and 15°,the incidence of MCL damage was from 69.23%to 100%.There was a significant difference in the incidence of MCL damage among femoral tunnels of 15 angle combinations(χ~2=148.195,P<0.001).By comparison between groups,it was found that when drilling femoral tunnels at 5 combinations of 45°/45°,45°/60°,60°/30°,60°/45°,and 60°/60°(axial/coronal),the shortest distances between the tunnel exit and the marked line were significantly different than 0°/45°,0°/60°,15°/45°,15°/60°,and 30°/30°(axial/coronal)(P<0.05).Additionally,after comparing the median of the shortest distance with other groups,the outlets generated by these 5 angles were farther from the marked line and the posterior MCL.Conclusion The creation of the femoral tunnel in PCLR can cause iatrogenic MCL injury,and the risk is affected by the tunnel angle.To reduce the risk of iatrogenic injury,angle combinations of 45°/45°,45°/60°,60°/30°,60°/45°,and 60°/60°(axial/coronal)are recommended for preparing the femoral tunnel in PCLR.