异体前十字韧带移植重建兔后十字韧带的生物力学研究

The biomechanical research on posterior cruciate ligament reconstruction with anterior cruciate ligament allograft in rabbits

目的探讨以兔异体前十字韧带为移植物解剖重建后十字韧带的生物力学变化。方法在研究正常兔前、后十字韧带解剖学和生物力学特性的基础上,用异体前十字韧带移植物解剖重建后十字韧带。应用无菌取材、新鲜冰冻技术制备异体骨-前十字韧带-骨移植物,-80℃保存14d以上待用。24只成年新西兰大白兔,随机选取其一侧后腿作为实验组,重建后十字韧带,对侧为对照组。分别于术后6、12、26、52周取材,测定股骨-移植物-胫骨的几何学特点、断裂部位、结构力学特性和材料力学特性。结果移植物平均长度在52周时为对照组正常后十字韧带的101%(P=0.90),平均横截面积为142%;强度在术后52周时为对照组正常后十字韧带的83%,最大拉长量为72%,刚度为92%;最大应力在术后52周时为对照组正常后十字韧带的58%,最大应变为72%,弹性模量为65%。断裂部位均位于移植物体部。移植物的几何学特点、结构力学特性和材料力学特性均有逐渐接近对照组正常后十字韧带的趋势。结论相同材料力学特性的移植物重建后十字韧带后生物力学特性转归良好,移植物的相同材料力学特性是影响后十字韧带重建效果的重要因素。

Objective To determine the biomechanicat properties of anterior cruciate ligament allograft reconstructing posterior cruciate ligament in rabbits. Methods Based on the study of anatomy and biomechanics of normal rabbit cruciate ligaments, anterior cruciate ligament allografts were employed to reconstruct the posterior cruciate ligament in rabbits, The sterilized fresh-frozen allograft of bone-anterior cruciate ligament-bone were prepared and reserved for more than 14 days under -80℃, Twenty-four skeletally matured New Zealand white rabbits underwent a posterior cruciate ligament reconstruction on one knee randomly, the opposite knee was served as the paired control, Rabbits were sacrificed at 6, 12, 26 and 52 weeks respectively. Evaluations of the reconstructions and contralateral controls included the geometric, structural and material properties and rupture site. Results The mean length of the grafts at 52 weeks was 101% of the control （P=0.90）, the cross-sectional area was 142%; the maximum load at 52 weeks was 83% of the control, the maximum elongation was 72%, the stiffness was 92%; the maximum stress at 52 weeks was 58% of the control, the maximum strain was 72%, and the modulds was 65%; the rupture site was all at the body part of the graft. The geometric, structural and material properties of the graft were gradually similar to those of the normal posterior cruciate ligament with the elapse of the time. Conclusion The biomeehanical prop- erpies of graft with similar material properties to normal posterior cruciate ligament following posterior cruci- ate ligament reconstruction in rabbits was favourable, The similar material properties of graft to normal posterior cruciate ligament play the very important roles in the posterior cruciate ligament reconstruction.