Biomechanics Research Laboratory, School of Mechanical & Materials Engineering, Indian Institute of Technology Mandi, Kamand, Mandi, 175075, Himachal Pradesh, India.
Biomechanics Research Laboratory, School of Mechanical & Materials Engineering, Indian Institute of Technology Mandi, Kamand, Mandi, 175075, Himachal Pradesh, India.
Comput Biol Med. 2024 Jul;177:108645. doi: 10.1016/j.compbiomed.2024.108645. Epub 2024 May 22.
Tibial implants with functionally graded material (FGM) for total ankle replacement (TAR) can provide stiffness similar to the host tibia bone. The FGM implants with low stiffness reduce stress shielding but may increase implant-bone micromotion. A trade-off between stress shielding and implant-bone micromotion is required if FGMs are to substitute traditionally used Ti and CoCr metal implants. The FGM properties such as material gradation law and volume fraction index may influence the performance of FGM implants. Along with the FGM properties, the design of FGM implants may also have a role to play. The objective of this study was to examine FGM tibial implants for TAR, by comparing implant materials, FGM properties, and implant designs. For this purpose, finite element analysis (FEA) was conducted on 3D FE models of the intact and the implanted tibia bone. The tibial implants were composed of CoCr and Ti, besides them, the FGM of Ti and HA was developed. The FGM implants were modelled using exponential, power, and sigmoid laws. Additionally, for power and sigmoid laws, different volume fraction indices were taken. The effect of implant design was observed by using keel type and stem type TAR fixation designs. The results indicated that FGM implants are better than traditional metal implants. The power law is most suitable for developing FGM implants because it reduces stress shielding. For both power law and sigmoid law, low values of the volume fraction index are preferrable. Therefore, FGM implant developed using power law with 0.1 vol fraction index is ideal with the lowest stress shielding and marginally increased implant-bone micromotion. FGM implants are more useful for keel type fixation design than stem type design. To conclude, with FGMs the major complication of stress shielding can be solved and the longevity and durability of TAR implants can be enhanced.
胫骨植入物采用功能梯度材料（FGM）进行全踝关节置换术（TAR）可以提供与宿主胫骨相似的刚度。低刚度的 FGM 植入物可减少应力遮挡，但可能会增加植入物-骨微动。如果 FGM 要替代传统使用的钛和 CoCr 金属植入物，则需要在应力屏蔽和植入物-骨微动之间进行权衡。FGM 特性（如材料梯度规律和体积分数指数）可能会影响 FGM 植入物的性能。除了 FGM 特性外，FGM 植入物的设计也可能起到一定作用。本研究的目的是通过比较植入物材料、FGM 特性和植入物设计，来研究 FGM 胫骨植入物在 TAR 中的应用。为此，对完整和植入胫骨骨的 3D FE 模型进行了有限元分析（FEA）。胫骨植入物由 CoCr 和 Ti 组成，此外还开发了 Ti 和 HA 的 FGM。使用指数、幂和 S 型规律对 FGM 植入物进行建模。此外，对于幂和 S 型规律，采用了不同的体积分数指数。通过使用龙骨式和干骨式 TAR 固定设计来观察植入物设计的效果。结果表明，FGM 植入物优于传统金属植入物。幂律最适合开发 FGM 植入物，因为它可以减少应力屏蔽。对于幂律和 S 型规律，体积分数指数的低值是优选的。因此，使用幂律和 0.1 体积分数指数开发的 FGM 植入物是理想的，具有最低的应力屏蔽和略微增加的植入物-骨微动。FGM 植入物对于龙骨式固定设计比干骨式设计更有用。总之，使用 FGM 可以解决应力屏蔽的主要并发症，并提高 TAR 植入物的耐久性和耐用性。
