Ren S, Shi H J, Zhang J H, Liu Z L, Shao J Y, Zhu J X, Hu X Q, Huang H S, Ao Y F
Department of Sports Medicine, Peking University Third Hospital; Institute of Sports Medicine of Peking University; Beijing Key Laboratory of Sports Injuries, Beijing 100191, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2021 Oct 18;53(5):865-870. doi: 10.19723/j.issn.1671-167X.2021.05.009.
To explore the stress distribution characteristics of the graft after anterior cruciate ligament (ACL) reconstruction, so as to provide theoretical reference for the surgical plan of ACL reconstruction.
Based on 3D MRI and CT images, finite element models of the uninjured knee joint and knee joint after ACL reconstruction were established in this study. The uninjured knee model included femur, tibia, fibula, medial collateral ligament, lateral collateral ligament, ACL and posterior cruciate ligament. The ACL reconstruction knee model included femur, tibia, fibula, medial collateral ligament, lateral collateral ligament, ACL graft and posterior cruciate ligament. Linear elastic material properties were used for both the uninjured and ACL reconstruction models. The elastic modulus of bone tissue was set as 17 GPa and Poisson' s ratio was 0.36. The material properties of ligament tissue and graft were set as elastic modulus 390 MPa and Poisson's ratio 0.4. The femur was fixed as the boundary condition, and the tibia anterior tension of 134 N was applied as the loading condition. The stress states of the ACL of the intact joint and the ACL graft after reconstruction were solved and analyzed, including tension, pressure, shear force and von Mises stress.
The maximum compressive stress (6.34 MPa), von Mises stress (5.9 MPa) and shear stress (1.83 MPa) of the reconstructed ACL graft were all at the anterior femoral end. It was consistent with the position of maximum compressive stress (8.77 MPa), von Mises stress (8.88 MPa) and shear stress (3.44 MPa) in the ACL of the intact knee joint. The maximum tensile stress of the graft also appeared at the femoral end, but at the posterior side, which was consistent with the position of the maximum tensile stress of ACL of the uninjured knee joint. More-over, the maximum tensile stress of the graft was only 0.88 MPa, which was less than 2.56 MPa of ACL of the uninjured knee joint.
The maximum compressive stress, von Mises stress and shear stress of the ACL graft are located in the anterior femoral end, and the maximum tensile stress is located in the posterior femoral end, which is consistent with the position of the maximum tensile stress of the ACL of the uninjured knee joint. The anterior part of ACL and the graft bore higher stresses than the posterior part, which is consistent with the biomechanical characteristics of ACL.
探讨前交叉韧带（ACL）重建术后移植物的应力分布特征，为ACL重建手术方案提供理论参考。
本研究基于三维磁共振成像（3D MRI）和计算机断层扫描（CT）图像，建立了未受伤膝关节及ACL重建术后膝关节的有限元模型。未受伤膝关节模型包括股骨、胫骨、腓骨、内侧副韧带、外侧副韧带、ACL和后交叉韧带。ACL重建膝关节模型包括股骨、胫骨、腓骨、内侧副韧带、外侧副韧带、ACL移植物和后交叉韧带。未受伤模型和ACL重建模型均采用线弹性材料属性。骨组织的弹性模量设定为17吉帕（GPa），泊松比为0.36。韧带组织和移植物的材料属性设定为弹性模量390兆帕（MPa），泊松比为0.4。将股骨固定作为边界条件，施加134牛（N）的胫骨前张力作为加载条件。求解并分析完整关节的ACL及重建后ACL移植物的应力状态，包括拉力、压力、剪切力和冯·米塞斯应力（von Mises应力）。
重建的ACL移植物的最大压应力（6.34兆帕）﹑冯·米塞斯应力（5.9兆帕）和剪应力（1.83兆帕）均位于股骨前端。这与完整膝关节的ACL中最大压应力（8.77兆帕）、冯·米塞斯应力（8.88兆帕）和剪应力（3.44兆帕）的位置一致。移植物的最大拉应力也出现在股骨端，但位于后侧，这与未受伤膝关节的ACL最大拉应力位置一致。此外，移植物的最大拉应力仅为0.88兆帕，小于未受伤膝关节的ACL的2.56兆帕。
ACL移植物的最大压应力、冯·米塞斯应力和剪应力位于股骨前端，最大拉应力位于股骨后端，这与未受伤膝关节的ACL最大拉应力位置一致。ACL及其移植物的前部比后部承受更高的应力，这与ACL的生物力学特征一致。
