兔保留与切除残迹前交叉韧带重建生物力学的比较

目的比较兔保留与切除残迹前交叉韧带（ACL）重建的生物力学差异，探讨保留残迹的意义。方法新西兰兔10只，体重（2．66±0．32）kg。切断双侧ACL，右侧股骨与胫骨端各保留残迹2mm，左侧完全切除两端残迹。切取跟腱制备移植物，对应ACL印迹解剖位分别建立胫骨与股骨隧道，重建双侧ACL。于术后8周，行单轴拉力测试。SPSS19．0软件进行数据统计。结果术后8周，保留残迹组的最大载荷（t=2．931，P〈0．05）、屈服载荷（t=2．680，P〈0．05）、刚度（t=5．411，P〈0．05）明显高于切除残迹组，两组之间差异均有统计学意义；保留残迹组拉伸长度显著低于切除残迹组，两组差异有统计学意义（t=-3．872，P〈0．05）。两组损毁模式不同，保留残迹组多表现为移植物关节内断裂，而切除残迹组多表现为移植物自骨隧道拔出。Fisher精确检验表明两组的样本损毁模式有统计学差异（P〈0．05）。结论保留残迹ACL重建的生物力学特征优于切除残迹ACL重建，提示临床采用保留残迹技术重建ACL有可能促进移植物腱-骨愈合和“韧带化”，从而改进治疗效果。

Biomechanical comparison of anterior cruciate ligament reconstruction in rabbits

Objective To explore the significance of remnant preservation in anterior cruciate ligament （ACL） reconstruction by comparison of biomechanical differences between remnant preservation and remnant resection in rabbit models. Methods 10 New Zealand rabbits, whose weight were （2. 66±0. 32） kg in average, were used in this study. The tendon grafts harvested from Achilles tendon were prepared for ACL reconstruction. As ACL was cut off in bilateral knees of the animal, the remnant was preserved 2 mm on both tibial and femoral ends in the right knee （ remnant preservation, RP group） , in contrast, while the remnant was removed completely in the left knee （remnant resection, RR group）. The tibial and femoral tunnels were created on the anatomic ACL footprints, then the ACL was reconstructed with the tendon graft. Eight weeks after operation, uniaxial tensile test was performed. The data were analyzed by paired student＇s t test and Fisher＇s exact test by SPSS 19.0 software. Results Eight weeks after operation, the ultimate failure load（t = 2. 931, P 〈 0. 05）, yield load（t = 2. 680, P 〈 0. 05） and stiffness（t =5. 411, P 〈0. 05）were much higher in the RP group than those in the RR group. However, the elongation of failure was much less in the RP group than it in the RR group （t = - 3. 872, P 〈 0. 05）. All of these differences were statistically significant. The failure types were different in these two groups. In the RP group the graft failures were mostly intra - articular, whereas in the RR group, the grafts were mostly pulled out from the bone tunnels. Fisher＇s exact test showed significant difference between the two groups in failure mode （P 〈 0. 05）. Conclusions Biomechanical properties in the remnant - preservation group are superior to the remnant - resection group in this ACL reconstruction model. It implies that remnant preservation in clinical ACL reconstruction might enhance the tendon -bone healing and ＂ligamentization＂ process, which would improve clinical outcome.