Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran.
Faculty of Medical Sciences, Islamic Azad University of Tehran, Tehran, Iran.
Int J Numer Method Biomed Eng. 2021 Sep;37(9):e3514. doi: 10.1002/cnm.3514. Epub 2021 Aug 3.
Total ankle replacement (TAR) and subtalar joint (STJ) fusion, are popular treatments for ankle osteoarthritis (OA). Short endurance limits the former, and movement disability comes with the latter. It is hypothesized here that fusion of the STJ can improve the longevity of the TAR prosthesis. In this study, a fresh human cadaver's ankle joint underwent TAR surgery, and strain patterns in the vicinity of prosthesis were recorded after the application of axial compressive load on tibia, resembling stance phase of the gait. Then, STJ of the same sample fused (FTAR), and a similar test procedure was pursued. The obtained strains in the FTAR were smaller than those of the TAR (p < .01). Finite element models of the tested samples were also made, and validated by experimental strains. The validated FE models were then employed to find stress distribution on the tibial plateau and prosthesis compartments. FTAR demonstrated more regular stress profiles in bone-prosthesis interface. Also, maximum von Mises stress in the talar component of the FTAR is approximately half of that in the TAR (8 and 15 MPa, respectively). Based on the results of this study, having a more symmetric load distribution on the prosthesis after STJ fusion, longevity of the TAR may likely increase.
全踝关节置换术（TAR）和距下关节（STJ）融合术是治疗踝关节骨关节炎（OA）的常用方法。前者的耐力较短，后者则会导致运动障碍。这里假设 STJ 融合可以提高 TAR 假体的使用寿命。在这项研究中，对一个新鲜的人体踝关节进行了 TAR 手术，然后在胫骨上施加轴向压缩载荷，类似于步态的站立阶段，记录假体附近的应变模式。然后，对同一样本进行 STJ 融合（FTAR），并进行类似的测试程序。FTAR 的获得的应变小于 TAR 的应变（p<.01）。还对测试样本进行了有限元模型制作，并通过实验应变进行了验证。然后使用经过验证的 FE 模型来查找胫骨平台和假体隔间上的应力分布。FTAR 在骨-假体界面上显示出更规则的应力分布。此外，FTAR 中距骨部件的最大 von Mises 应力约为 TAR 的一半（分别为 8 和 15 MPa）。基于这项研究的结果，在 STJ 融合后，假体上的负载分布更加对称，TAR 的使用寿命可能会延长。
