股骨单隧道内分叉双束纤维重建后交叉韧带的实验研究

AN EXPERIMENTAL STUDY OF SPLIT-DOUBLE-BUNDLE POSTERIOR CRUCIATE LIGAMENT RECONSTRUCTION IN SINGLE FEMORAL TUNNEL

目的在人膝关节标本上行股骨单隧道分叉双束纤维重建后交叉韧带(posterior cruciate ligament,PCL),探讨其术式的优缺点。方法应用力学试验机对14侧捐赠新鲜冷冻人膝关节标本进行生物力学测试,男12侧,女2侧;年龄20～31岁。标本股骨段长20cm,胫骨段长20cm。首先测量PCL完整时胫骨后移距离和交叉韧带的应变(完整组,n=14);然后切断PCL(切断组,n=14),测量胫骨受力时的后移距离后,再将标本随机分为两组:单束重建组(n=7)和分叉双束重建组(n=7),分别测量屈膝0、30、60、90和120°5个角度时胫骨后移距离和移植韧带的应变。结果胫骨受到100N后向力量,完整组在不同屈膝角度下,胫骨向后移位1.97±0.29～2.60±0.23mm,前外束和后内束纤维交替紧张松弛。切断组膝关节明显松弛,胫骨向后移位达11.27±1.06～14.94±0.67mm,与完整组比较差异有统计学意义(P<0.05);单束纤维重建组,在不同屈膝角度下胫骨向后移位1.99±0.19～2.72±0.38mm,移植韧带持续紧张。双束纤维重建组在不同屈膝角度下胫骨向后移位2.27±0.32～3.05±0.44mm,移植的双束纤维交替紧张,协同作用。组内比较:双束重建组在不同屈膝角度时胫骨向后位移差异无统计学意义(P>0.05),而单束重建组在屈膝90°时与屈膝30、60和120°时相比,胫骨后移增大,差异有统计学意义(P<0.05)。结论股骨单隧道内分叉双束纤维重建PCL术在各屈膝角度均能有效防止胫骨后移,股骨单隧道单束重建术屈膝90°时后移较其他角度时增大。分叉双束重建PCL的两束纤维束交替紧张,生物力学特征更接近于正常PCL。

Objective To compare the single femoral tunnel split-double-bundle posterior cruciate ligament （PCL） reconstruction with the single-bundle PCL reconstruction and to discuss the advantages of the modified reconstruction method. Methods Fourteen donated fresh-frozen human knee specimens were biomechanically tested, which included knee specimens from 12 males and 2 females, and their ages ranged from 20 to 31 years. The specimen length of the femur and the tibia was 20 cm. The tibial posterior translation and the PCL strains were first measured when PCL was in an intact state （the intact group, n=14）. Then, PCL was cut （the cut group, n=14）. The posterior translation was measured when a posterior load was applied. After that, the specimens were randomly divided into two groups： the single-bundle group （n=7） and the double-bundle group （n=7）. When the posterior load was applied to the tibia, the bundle strain and the tibial posterior translation were measured with the knees flexed at 0, 30, 60, 90 and 120°, respectively. Results While a 100 N posterior force was applied, the posterior tibial displacement of the intact PCL knee ranged from 1.97±0.29 mm to 2.60±0.23 mm at the different knee flexion angles. In the PCL-cut state, the tibial displacement increased significantly from 11.27±1.06 mm to 14.94±0.67 mm （P（0.05）. After the singlebundle reconstruction, the posterior tibial translation ranged from 1.99±0.19 mm to 2.72±0. 38 mm at the different knee flexion angles. In the split-double-bundle reconstruction, the posterior tibial translations ranged from 2.27±0.32 mm to 3.05±0.44 mm. The graft of the single-bundle reconstruction was tensioned from 0° to 120°, and the tibial displacement increased significantly at 90° compared with that at the other angles （P〈0.05）. In the double-bundle reconstruction, the anterolateral bundle and the posteromedial bundle were tensioned in a reciprocal fashion, and the tibial displacement had no significant difference at the five kinds of the flexion angles. Conclusion The single femoral tunnel split-double-bundle PCL reconstruction can restore the posterior tibial displacement at different flexion angles, and the tibial displacement in the single-bundle PCL reconstruction knee can be increased when the knee flexion is at 90°. In the double-bundle reconstruction, the graft can be tensioned in a reciprocal fashion and the biomechanical features can be nearer to those of the normal PCL bundles.