Li Yong-jiang, Zhang Mei-chao, Liu Min, Cai Chun-yuan
Zhongguo Gu Shang. 2015 Feb;28(2):162-7.
To study mechanical affect of knee joint of reasonable positioning of femoral tunnel during knee posterior cruciate ligament (PCL) double-bundle reconstruction and graft fixation after reconstruction by virtual reality interactive technology and evaluate the biomechanical response of knee after reconstruction by finite element analysis.
Knee specimens from five fresh frozen cadavers were used. Computer simulations and biomechanical experiments were used in this study. Experiments on flexion and extension movements of the knee joint were performed on specimens of fresh human knee joint. Laser three dimensional scanning was used to record and calculate the indexes of movements. Three-dimensional models of knee joint bone structure were then reconstructed on computer with the experimental data. Simulations of flexion and extension movements were carried out on the models to show the spatial positions of femur and tibia and label the attachment sites of PCL. Ten test points in the anterior,posterior, proximal, distal at the femoral attachment area of anterior and lateral bundle (ALB) and postoperior medial bundle (PMB) were selected and the central points of tibial en attachment areat anchored. The distance btween each two points of two article surface was calculated and contacted by software of Geomagic. Model was import software Ansys, adopting the tetrahedron unit a finite element model of complex tibial and femoral was set up to simulat human walking in one leg,on this condition the the joint surface force of model under weight impact load were analyzed.
The three-dimensional models could demonstrate the spatial positions of the bone structure of the knee in different flexions and extensions. The models could be used to measure the spatial distance between 2 points on the femoral and tibial planes by software Geomagic. There was significantly difference among the length changes of anterolateral bundle and posteromedial bundle at every fixed point with different flexion angles (P<0.05), so the fixed angle with different points. The length changes of anterior lateral bundle's A2, A1 and posterior medial bundle's B3, B1 points were (1.35±0.19) mm, (5.41±1.22) mm, (1.95±0.04) mm and (5.23±2.21) mm, respectively. The A2 and B3 points' length changes were the less, and that of the Al and B1 points were the more. It had no significant difference between the length changes of anterior lanteral bundle's A2 and A3 point (P=0.913>0.05). All of the maximal length changes of anterior lateral bundle's A2, A3 and postterior medial bundle's B3 points were less than 2 mm.
The models of knee joint were builded through computer technology and it can be measure the lenth of cruciate ligament with software Geomagic exactly. The femoral tunnel for the PCL double-bundle reconstruction should be located as follows: ALB at the middle point of upper edge of femoral attachment site (proximal point),while PMB at the middle point of femoral attachment site (proximal point). This model provides a satisfactory method for the evaluation of the biomechanical response of knee after cruciate ligament reconstruction.
通过虚拟现实交互技术研究膝关节后交叉韧带（PCL）双束重建术中股骨隧道合理定位及重建后移植物固定对膝关节力学的影响，并通过有限元分析评估重建后膝关节的生物力学响应。
使用5具新鲜冷冻尸体的膝关节标本。本研究采用计算机模拟和生物力学实验。对新鲜人膝关节标本进行膝关节屈伸运动实验。采用激光三维扫描记录并计算运动指标。然后利用实验数据在计算机上重建膝关节骨结构的三维模型。在模型上进行屈伸运动模拟，以显示股骨和胫骨的空间位置并标记PCL的附着点。在前外侧束（ALB）和后内侧束（PMB）股骨附着区的前后、近端、远端选择10个测试点，并固定胫骨附着区的中心点。通过Geomagic软件计算并连接两个平面上各两点之间的距离。将模型导入Ansys软件，采用四面体单元建立复杂胫骨和股骨的有限元模型，模拟人体单腿行走，在此条件下分析模型在体重冲击载荷下的关节面力。
三维模型可以展示膝关节在不同屈伸状态下骨结构的空间位置。该模型可通过Geomagic软件测量股骨和胫骨平面上两点之间的空间距离。在不同屈曲角度下，各固定点处前外侧束和后内侧束的长度变化存在显著差异（P<0.05），因此固定角度不同。前外侧束的A2、A1点和后内侧束的B3、B1点的长度变化分别为（1.35±0.19）mm、（5.41±1.22）mm、（1.95±0.04）mm和（5.23±2.21）mm。A2和B3点的长度变化较小，A1和B1点的长度变化较大。前外侧束的A2和A3点的长度变化差异无统计学意义（P=0.913>0.05）。前外侧束的A2、A3点和后内侧束的B3点的最大长度变化均小于2mm。
通过计算机技术构建膝关节模型，利用Geomagic软件可准确测量交叉韧带长度。PCL双束重建的股骨隧道应如下定位：ALB位于股骨附着点上缘中点（近端点），而PMB位于股骨附着点中点（近端点）。该模型为评估交叉韧带重建后膝关节的生物力学响应提供了一种满意的方法。
