人工踝關節置換術是用於治療足踝相關疾病的手術，然而目前對於全人工踝關節置換術主要的評估方式來自於臨床結果。雖然先前研究開發的骨植入物模型提供可參考生物力學，但它們的數值模型可能過於簡單化。因此本研究的目的是建立更完整下肢模型，並透過有限元素法探討不同足踝姿勢時全人工踝關節置換術的生物力學。
本研究依序完成完整足踝模型之建構、踝關節置換假體模型之建構與植入踝關節假體至足踝模型中，接著使用ANSYS Workbench進行模擬，本研究使用不同類型的人工踝關節假體，並且各款式擁有不同脛骨元件設計包括：平面、彎曲與傾斜，針對五種不同足踝姿勢包括：正常站立、外翻、內翻、足屈與背屈，探討穩定度、脛骨應力、距骨應力、脛骨元件應力、內襯元件應力與距骨元件應力，詳細的探討植入物與骨骼應力。
本研究結果顯示不同的姿勢確實對於植入物有一定程度的影響，多方考量不同姿勢有助於更全面評估不同人工踝關節假體的設計優勢，內翻與外翻確實對於特定類型的人工踝關節假體有相當的風險存在，使用平面設計的脛骨元件對於脛骨應力與脛骨元件應力有較好的表現，然而內襯元件的應力為最重要的參考指標。本研究的結果能夠直接提供骨科臨床醫生相關建議，幫助他們了解全人工踝關節置換術之生物力學性能。

Total ankle replacement surgery has been used to treat ankle joint disorders. However, the biomechanical performances of total ankle prostheses were mainly evaluated according to the outcomes of clinical applications. Although the bone-implant constructs developed by the previous studies could provide referable biomechanical outcomes, their numerical models may be oversimplified. Thus, the purpose of this study was to evaluate the biomechanical performances of the ankle joint designs with different ankle postures using finite element methods.
Three-dimensional finite element models of human lower extremity were developed using ANSYS Workbench 17. Different designs of the total ankle replacement prostheses (flat, curved, and tilted designs) under five types of ankle postures (standing, eversion, inversion, dorsiflexion, and plantarflexion) were evaluated.
The results showed that the ankle postures played an important role on the effects of the bone-implant construct stability, the bone stress, and the implant stress. The ankle joint with an eversion or inversion posture would deteriorate the biomechanical performances of the total ankle replacement prostheses. The outcomes of the present study could directly provide the surgical suggestion to orthopedic surgeons and help them to understand the biomechanics of total ankle replacement.

[1]J. M. Michael, A. Golshani, S. Gargac, and T. Goswami, “Biomechanics of the ankle joint and clinical outcomes of total ankle replacement,” J Mech Behav Biomed Mater, vol. 1, no. 4, pp. 276-94, Oct, 2008.
[2]M. K. Steven, “Applications of UHMWPE in total ankle replacements Chapyer 11,” pp. 153-169, 2015.
[3]C. W. Reb, J. E. McAlister, C. F. Hyer, and G. C. Berlet, “Posterior ankle structure injury during total ankle replacement,” J Foot Ankle Surg, vol. 55, no. 5, pp. 931-4, Sep-Oct, 2016.
[4]Y. R. Kerkhoff, N. M. Kosse, and J. W. Louwerens, “Short term results of the mobility total ankle system: clinical and radiographic outcome,” Foot Ankle Surg, vol. 22, no. 3, pp. 152-7, Sep, 2016.
[5]T. S. Roukis, and M. A. Prissel, “Reverse evans peroneus brevis medial ankle stabilization for balancing valgus ankle contracture during total ankle replacement,” J Foot Ankle Surg, vol. 53, no. 4, pp. 497-502, Jul-Aug, 2014.
[6]M. A. Baldwin, C. W. Clary, C. K. Fitzpatrick, J. S. Deacy, L. P. Maletsky, and P. J. Rullkoetter, “Dynamic finite element knee simulation for evaluation of knee replacement mechanics,” J Biomech, vol. 45, no. 3, pp. 474-83, Feb 02, 2012.
[7]M. Maestro, and B. Ferre, “Anatomie fonctionnelle du pied et de la cheville de l’adulte,” Revue du Rhumatisme Monographies, vol. 81, no. 2, pp. 61-70, 2014.
[8]A. Leardini, J. J. O’Connor, and S. Giannini, “Biomechanics of the natural, arthritic, and replaced human ankle joint,” J Foot Ankle Surg, vol. 7, no. 8, 2014.
[9]B. Reggiani, A. Leardini, F. Corazza, and M. Taylor, “Finite element analysis of a total ankle replacement during the stance phase of gait,” J Biomech, vol. 39, no. 8, pp. 1435-43, 2006.
[10]J. T. M. Cheung, G. de Vrles, and B. M. Nigg, “Biomechanical effects of midfoot fusion - a finite element Study,” J Biomech, vol. 40, pp. S326, 2007.
[11]J. T. Cheung, and M. Zhang, “Parametric design of pressure-relieving foot orthosis using statistics-based finite element method,” Med Eng Phys, vol. 30, no. 3, pp. 269-77, Apr, 2008.
[12]J. P. Halloran, M. Ackermann, A. Erdemir, and A. J. van den Bogert, “Concurrent musculoskeletal dynamics and finite element analysis predicts altered gait patterns to reduce foot tissue loading,” J Biomech, vol. 43, no. 14, pp. 2810-5, Oct 19, 2010.
[13]T. Ingrassia, L. Nalbone, V. Nigrelli, D. Tumino, and V. Ricotta, “Finite element analysis of two total knee joint prostheses,” International Journal on Interactive Design and Manufacturing (IJIDeM), vol. 7, no. 2, pp. 91-101, 2012.
[14]L. Zach, S. Konvickova, and P. Ruzicka, “Finite element analysis of the lower extrtemity - hinge knee behavior under dynamic load,” 2013.
[15]Mustafa Ozen , Onur Sayman , and Hasan Havitcloglu “Modeling and stress analyses of a normal foot-ankle and a prosthetic foot-ankle complex,” Acta Bioeng Biomech, vol. 15, no. 3, 2013.
[16]B. Jay Elliot, D. Gundapaneni, and T. Goswami, “Finite element analysis of stress and wear characterization in total ankle replacements,” J Mech Behav Biomed Mater, vol. 34, pp. 134-45, Jun, 2014.
[17]J. Guo, L. Wang, Z. Mo, W. Chen, and Y. Fan, “Biomechanical behavior of valgus foot in children with cerebral palsy: A comparative study,” J Biomech, vol. 48, no. 12, pp. 3170-7, Sep 18, 2015.
[18]H. Vo, B. Tuvel, B. Nguyen, and T. Le, “Determination of the neutral axis in total ankle replacement,” Ifmbe Proc, vol. 46, pp. 121-124, 2015.
[19]D. Wai-Chi Wong, Y. Wang, M. Zhang, and A. Kam-Lun Leung, “Functional restoration and risk of non-union of the first metatarsocuneiform arthrodesis for hallux valgus: A finite element approach,” J Biomech, vol. 48, no. 12, pp. 3142-8, Sep 18, 2015.
[20]Y. Wang, Z. Li, D. W. Wong, and M. Zhang, “Effects of ankle arthrodesis on biomechanical performance of the entire foot,” PLoS One, vol. 10, no. 7, pp. e0134340, 2015.
[21]C. S. Yuan, W. Chen, C. Chen, G. H. Yang, C. Hu, and K. L. Tang, “Effects on subtalar joint stress distribution after cannulated screw insertion at different positions and directions,” J Foot Ankle Surg, vol. 54, no. 5, pp. 920-6, Sep-Oct, 2015.
[22]R. T. Anderson, D. J. Pacaccio, C. M. Yakacki, and R. D. Carpenter, “Finite element analysis of a pseudoelastic compression-generating intramedullary ankle arthrodesis nail,” J Mech Behav Biomed Mater, vol. 62, pp. 83-92, Sep, 2016.
[23]J. Yu, D. W. Wong, H. Zhang, Z. P. Luo, and M. Zhang, “The influence of high-heeled shoes on strain and tension force of the anterior talofibular ligament and plantar fascia during balanced standing and walking,” Med Eng Phys, vol. 38, no. 10, pp. 1152-6, Oct, 2016.
[24]Z. J. Zhu, Y. Zhu, J. F. Liu, Y. P. Wang, G. Chen, and X. Y. Xu, “Posterolateral ankle ligament injuries affect ankle stability: a finite element study,” BMC Musculoskelet Disord, vol. 17, pp. 96, Feb 24, 2016.
[25]V. Filardi, and D. Milardi, “Experimental strain analysis on the entire bony leg compared with FE analysis,” J Orthop, vol. 14, no. 1, pp. 115-122, Mar, 2017.
[26]F. Lintz, T. Barton, M. Millet, W. J. Harries, S. Hepple, and I. G. Winson, “Ground reaction force calcaneal offset: a new measurement of hindfoot alignment,” Foot Ankle Surg, vol. 18, no. 1, pp. 9-14, Mar, 2012.
[27]A. P. Silva, D. D. Chagas, M. L. Cavaliere, S. Pinto, J. S. de Oliveira Barbosa, and L. A. Batista, “Kinematic analysis of subtalar eversion during gait in women with fibromyalgia,” Foot (Edinb), vol. 28, pp. 42-46, Aug, 2016.
[28]G. M. Monaghan, W. H. Hsu, C. L. Lewis, E. Saltzman, J. Hamill, and K. G. Holt, “Forefoot angle at initial contact determines the amplitude of forefoot and rearfoot eversion during running,” Clin Biomech (Bristol, Avon), vol. 29, no. 8, pp. 936-42, Sep, 2014.
[29]R. Wang, and E. M. Gutierrez-Farewik, “The effect of subtalar inversion/eversion on the dynamic function of the tibialis anterior, soleus, and gastrocnemius during the stance phase of gait,” Gait Posture, vol. 34, no. 1, pp. 29-35, May, 2011.
[30]R. Kakkar, and M. S. Siddique, “Stresses in the ankle joint and total ankle replacement design,” Foot Ankle Surg, vol. 17, no. 2, pp. 58-63, Jun, 2011.
[31]K. D. Button, F. Wei, and R. C. Haut, “Unlocking the talus by eversion limits medial ankle injury risk during external rotation,” J Biomech, vol. 48, no. 13, pp. 3724-7, Oct 15, 2015.
[32]C. W. Imhauser, S. Siegler, J. K. Udupa, and J. R. Toy, “Subject-specific models of the hindfoot reveal a relationship between morphology and passive mechanical properties,” J Biomech, vol. 41, no. 6, pp. 1341-9, 2008.
[33]L. Zach, L. Kuncicka, P. Ruzicka, and R. Kocich, “Design, analysis and verification of a knee joint oncological prosthesis finite element model,” Comput Biol Med, vol. 54, pp. 53-60, Nov, 2014.
[34] G. Valente, L. Pitto, E. Schileo, S. Piroddi, A. Leardini, M. Manfrini, and F. Taddei, “Relationship between bone adaptation and in-vivo mechanical stimulus in biological reconstructions after bone tumor: A biomechanical modeling analysis,” Clin Biomech (Bristol, Avon), vol. 42, pp. 99-107, Feb, 2017.
[35]P. K. Thain, G. T. Hughes, and A. C. Mitchell, “The effect of repetitive ankle perturbations on muscle reaction time and muscle activity,” J Electromyogr Kinesiol, vol. 30, pp. 184-90, Oct, 2016.