Zhao Mingxin, Guo Yuan, Wang Changjiang, Zhang Xushu, Ji Binping, Zhang Kai, He Dongdong
College of Biomedical Engineering, Taiyuan University of Technology, Jinzhong, Shanxi 030600, P. R. China.
University of Sussex, Brighton, BN1 9RH, UK.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2022 Aug 25;39(4):660-671. doi: 10.7507/1001-5515.202202007.
In unicompartmental replacement surgery, there are a wide variety of commercially available unicompartmental prostheses, and the consistency of the contact surface between the common liner and the femoral prosthesis could impact the stress distribution in the knee after replacement in different ways. Medial tibial plateau fracture and liner dislocation are two common forms of failure after unicompartmental replacement. One of the reasons is the mismatch in the mounting position of the unicompartmental prosthesis in the knee joint, which may lead to failure. Therefore, this paper focuses on the influence of the shape of the contact surface between the liner and the femoral prosthesis and the mounting position of the unicompartmental prosthesis on the stress distribution in the knee joint after replacement. Firstly, a finite element model of the normal human knee joint was established, and the validity of the model was verified by both stress and displacement. Secondly, two different shapes of padded knee prosthesis models (type A and type B) were developed to simulate and analyze the stress distribution in the knee joint under single-leg stance with five internal or external rotation mounting positions of the two pads. The results showed that under a 1 kN axial load, the peak contact pressure of the liner, the peak ACL equivalent force, and the peak contact pressure of the lateral meniscus were smaller for type A than for type B. The liner displacement, peak contact pressure of the liner, peak tibial equivalent force, and peak ACL equivalent force were the smallest for type A at 3° of internal rotation in all five internal or external rotation mounting positions. For unicompartmental replacement, it is recommended that the choice of type A or type B liner for prosthetic internal rotation up to 6° should be combined with other factors of the patient for comprehensive analysis. In conclusion, the results of this paper may reduce the risk of liner dislocation and medial tibial plateau fracture after unicompartmental replacement, providing a biomechanical reference for unicompartmental prosthesis design.
在单髁置换手术中，市场上有各种各样的单髁假体，普通衬垫与股骨假体之间接触面的一致性可能会以不同方式影响置换后膝关节的应力分布。胫骨内侧平台骨折和衬垫脱位是单髁置换后两种常见的失败形式。其中一个原因是单髁假体在膝关节中的安装位置不匹配，这可能导致失败。因此，本文重点研究衬垫与股骨假体之间接触面的形状以及单髁假体的安装位置对置换后膝关节应力分布的影响。首先，建立了正常人体膝关节的有限元模型，并通过应力和位移验证了模型的有效性。其次，开发了两种不同形状的带衬垫膝关节假体模型（A型和B型），以模拟和分析在单腿站立时，两种衬垫的五个内旋或外旋安装位置下膝关节的应力分布。结果表明，在1 kN轴向载荷下，A型衬垫的峰值接触压力、前交叉韧带等效峰值力和外侧半月板的峰值接触压力均小于B型。在所有五个内旋或外旋安装位置中，A型衬垫在3°内旋时的衬垫位移、峰值接触压力、胫骨等效峰值力和前交叉韧带等效峰值力最小。对于单髁置换，建议在假体向内旋转角度达6°时选择A型或B型衬垫应结合患者的其他因素进行综合分析。总之，本文的结果可能会降低单髁置换后衬垫脱位和胫骨内侧平台骨折的风险，为单髁假体设计提供生物力学参考。
