Xiao Yang, Liang Zhaoxin, Shen Shiwen, Liu Fei, Hu Hai, Chen Bin
Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.
The First Clinical College of Southern Medical University, Guangzhou, China.
J Exp Orthop. 2023 Oct 28;10(1):108. doi: 10.1186/s40634-023-00677-x.
Flattened femoral tunnels were recently applied in anatomical single-bundle anterior cruciate ligament (ACL) reconstruction. Little is known about the biomechanical effect of such changes during knee flexion. The aim of the present simulation study was to assess the effect of altered ACL direct insertion coverage on the biomechanics of the graft and bone tunnel.
Five finite element (FE) models, including a round femoral tunnel and four progressively flattened rounded rectangular femoral tunnels, were established to represent the ACL reconstructions. In vivo knee kinematics data obtained from the validated dual fluoroscopic imaging techniques controlled the FE models to simulate lunge motions. The maximal principal stress of the graft and the volume of equivalent strain within 1000-3000 microstrain (V) of the cancellous bone were subsequently calculated at 0°, 30°, 60° and 90° of knee flexion.
A lower stress state on the graft and a more beneficial strain state on the cancellous bone were observed when the femoral tunnel better covered the ACL direct insertion. The average maximal principal stress of each model were 3.93 ± 0.60 MPa, 3.82 ± 0.54 MPa, 3.43 ± 0.44 MPa, 3.45 ± 0.44 MPa and 3.05 ± 0.43 MPa, respectively. The average V of the cancellous bone of each model were 179.06 ± 89.62 mm, 221.40 ± 129.83 mm, 247.57 ± 157.78 mm, 282.74 ± 178.51 mm and 295.71 ± 162.59 mm, respectively. Both the stress and strain values exhibited two peaks during the flexion simulation. The highest value occurred at 30° of flexion, and the second highest value occurred at 90° of flexion.
Increased ACL direct insertion coverage provided more positive biomechanical effects after anatomical single-bundle ACL reconstruction during knee flexion.
扁平股骨隧道最近被应用于解剖单束前交叉韧带（ACL）重建。关于膝关节屈曲过程中这种改变的生物力学效应知之甚少。本模拟研究的目的是评估ACL直接插入覆盖范围改变对移植物和骨隧道生物力学的影响。
建立五个有限元（FE）模型，包括一个圆形股骨隧道和四个逐渐变平的圆角矩形股骨隧道，以代表ACL重建。从经过验证的双荧光透视成像技术获得的体内膝关节运动学数据控制FE模型以模拟弓步动作。随后在膝关节屈曲0°、30°、60°和90°时计算移植物的最大主应力和松质骨在1000 - 3000微应变（V）范围内的等效应变体积。
当股骨隧道更好地覆盖ACL直接插入时，观察到移植物上的应力状态较低，松质骨上的应变状态更有利。每个模型的平均最大主应力分别为3.93±0.60 MPa、3.82±0.54 MPa、3.43±0.44 MPa、3.45±0.44 MPa和3.05±0.43 MPa。每个模型的松质骨平均V分别为179.06±89.62 mm、221.40±129.83 mm、247.57±157.78 mm、282.74±178.51 mm和295.71±162.59 mm。在屈曲模拟过程中，应力和应变值均出现两个峰值。最高值出现在屈曲30°时，第二高值出现在屈曲90°时。
在解剖单束ACL重建后，增加ACL直接插入覆盖范围在膝关节屈曲过程中提供了更积极的生物力学效应。
