股骨遠端骨折是常見的臨床病例之一，常發生在高衝擊之情形以及骨質疏鬆患者身上。對於股骨骨折之手術治療，其通常利用鎖定式骨板(Locking compression plate)以加強股骨骨折的機械穩定性。在先前研究已經分析螺釘在鎖定式骨板的固定穩定性，其主要討論的參數為骨釘數量和骨釘位置。儘管如此，大部分的研究使用了簡化的股骨數值模型，此無法較真實的考量人體下肢之生物力學。
本研究中，模型建立為完整下肢之有限元素模型，主要探討不同治療策略之術後結果，以及在步態週期期間之生物力學情形。在這項研究中，下肢模型包括：骨盆、股骨、髕骨、脛骨、腓骨和足踝，同時皮質骨與鬆質骨有考慮在整體模型內。下肢模型與骨板骨螺絲之建立為使用SolidWorks 2015繪製，然後導入到分析軟體ANSYS Workbench 19.2。在分析步態週期的四個階段設定為：初始接觸(Initial contact)、足平時期（Foot flat）、站立中期（Mid-stance）和腳跟離地（Heel off）。在治療策略方面，螺釘被分為11種的鎖定方式和位置。利用有限元素分析探討股骨骨折在不同鎖定式骨板之治療策略，以及四種步態動作之生物力學影響，並且探討其骨折處位移量、骨板應力值、骨釘應力值與股骨應力結果。
透過有限元素分析之研究結果，可發現當骨板的工作長度增加時，骨板與骨螺絲之最大應力增加，以及股骨骨折位移量增加，然而，股骨之最大應力會減少。由結果也可觀察施打14根螺絲釘的治療策略有更好的固定穩定度。然而，對於患者的最佳固定策略的決定，此仍需藉由臨床醫師的經驗和臨床情況來判斷。本研究可利用有限元素模擬之結果，提供臨床醫師在骨科生物力學觀點的資訊與治療策略建議。

Distal femoral fracture is the most common cause in both elderly people with weak bones and younger people with high energy injuries. Locking compression plate (LCP) is a surgery used to improve the fixation stability and treatment of distal femoral fractures. Previous studies have analyzed the number and location of locking screws as the main factors affecting the reliability of the LCP. However, most researches used a simplified femoral numerical model that could not truly analyze the biomechanical effects of the implants to investigate the effect of the number and location of the screws. In the present study, a finite element (FE) model of the lower limb was developed to investigate the biomechanical efficiency of various LCP fixation strategies in femoral fractures during the gait cycle.
The completed lower limb model in this study included pelvis, femur, patella, tibia, fibula, and foot. Cortical bone and cancellous bone were considered to simulate the actual condition of the human body. The completed lower limb models, locking screws, and plates were generated by SolidWorks and then imported into ANSYS Workbench 19.2. Four phases of the gait cycle were considered: initial contact (IC), foot flat (FF), mid-stance (MS), and heel off (HO) phases. In terms of the fixation strategy, the screw placement was divided into eleven types. The FE study was conducted to investigate the influence of the number and location of locking screws under four postures. The findings were reported by measuring the displacement of fractures and the maximum stress on the plate, locking screws, and the bones.
Among the FE models in four postures found that the maximum stress of both locking plates and the screws decreased when the working length of the plate increased. On the other hand, the maximum stress of both locking plates and the screws decreased when the working length of the plate increased. The results suggest that the implementation of 14 screws have higher fixation efficiency. However, the best fixation technique for the patient depends on the experience of the orthopedic surgeon and in the case of personal injury. This research could provide helpful information for the simulation of the model and a better strategy for the treatment of distal femoral fractures.

[1] J.V. Inacio, A. Malige, J.T. Schroeder, C.O. Nwachuku, H.L. Dailey, "Mechanical characterization of bone quality in distal femur fractures using pre-operative computed tomography scans", Clin Biomech (Bristol, Avon), 67 (2019) 20-26.

[2] S.C. Wu, C.S. Rau, S.C.H. Kuo, P.C. Chien, C.H. Hsieh, "The influence of ageing on the incidence and site of trauma femoral fractures: a cross-sectional analysis", BMC Musculoskelet Disord, 20 (2019) 1-9.

[3] M.S. Coon, B.J. Best, "Distal Femur Fractures", StatPearls Publishing, Treasure Island (FL), 2019.

[4] A.M. Khan, Q.O. Tang, D. Spicer, "The Epidemiology of Adult Distal Femoral Shaft Fractures in a Central London Major Trauma Centre Over Five Years", Open Orthop J, 11 (2017) 1277-1291.

[5] M. Hadhoud, Y. Hannout, A.E.-H. Abd El-Hamid Rageh, "Treatment of distal femoral fractures in adults using the less invasive stabilization system", Menoufia Medical Journal, 30 (2017) 434-441.

[6] L. Cristofolini, E. Schileo, M. Juszczyk, F. Taddei, S. Martelli, M. Viceconti, "Mechanical testing of bones: the positive synergy of finite-element models and in vitro experiments", Philos Trans A Math Phys Eng Sci, 368 (2010) 2725-2763.

[7] Y. Luo, S. Ahmed, W.D. Leslie, "Automation of a DXA-based finite element tool for clinical assessment of hip fracture risk", Comput Methods Programs Biomed, 155 (2018) 75-83.

[8] M. Douglas M. Anderson, P. Patricia D. Novak, M. Jefferson Keith, M. Michelle A. Elliott, "Dorland's Illustrated Medical Dictionary", USA, 2009.

[9] D. Mariam Chowdhry, P. Thomas R Gest, "Hip Joint Anatomy", in, American Academy of Pain Medicine, 2017.

[10] B. Chhajer, "Knee Pain: Anatomy of Knee", (2006) 10–11.

[11] M.D. Burgess, F. Lui, "Anatomy, Bony Pelvis and Lower Limb, p Bones", in: StatPearls, StatPearls Publishing, Treasure Island (FL), 2020, pp. 1-7.

[12] A.M. Wobser, Z. Adkins, R.W. Wobser, "Anatomy, Abdomen and Pelvis, Bones (Ilium, Ischium, and Pubis)", in: StatPearls, StatPearls Publishing, Treasure Island (FL), 2020, pp. 1-12.

[13] K.L. Moore, "Clinically Oriented Anatomy", Williams & Wilkins, 1992.

[14] A.R. Manral, N. Gariya, K.C. Nithin Kumar, "Material optimization for femur bone implants based on vibration analysis", Materials Today: Proceedings, (2020).

[15] A. Dhanopia, M. Bhargava, "Finite Element Analysis of Human Fractured Femur Bone Implantation with PMMA Thermoplastic Prosthetic Plate", Procedia Engineering, 173 (2017) 1658-1665.

[16] K.L. Hsu, W.L. Chang, C.Y. Yang, M.L. Yeh, C.W. Chang, "Factors affecting the outcomes of modified tension band wiring techniques in transverse patellar fractures", Injury, 48 (2017) 2800-2806.

[17] Q.D. Yin, J.B. Wang, S.J. Gu, Y.W. Wu, Y.J. Rui, "Clinical observation of C3-type patellar fractures treated by operation methods with or without a turned-over patella", Injury, 50 (2019) 966-972.

[18] F. Vatankhahan, M. Mahmoudi, M. Salehi, "Resistance analysis of Tibia bone on upper, midell and terminal sections by compressive strength testing and FEM", 2016.

[19] D.B.K. Sinha, D.R. Prasad, "Morphometric study of upper end of tibia in Bihar region and its clinical implication in knee Arthroplasty", International Journal of Medical and Health Research, 4 (2018) 120-122.

[20] T.D. White, P.A. Folkens, "Chapter 15 - LEG: FEMUR, PATELLA, TIBIA, & FIBULA", in: T.D. White, P.A. Folkens (Eds.) The Human Bone Manual, Academic Press, San Diego, 2005, pp. 255-286.

[21] E.J.C. Dawe, J. Davis, "(vi) Anatomy and biomechanics of the foot and ankle", Orthopaedics and Trauma, 25 (2011) 279-286.

[22] A. Das, J. Baruah, D. Bhuyan, "Review on the Anatomy and Biomechanics of the Foot-Ankle Complex", Asian Journal of Convergence in Technology 4(2018).

[23] K.H. Park, C.W. Oh, I.H. Park, J.W. Kim, J.H. Lee, H.J. Kim, "Additional fixation of medial plate over the unstable lateral locked plating of distal femur fractures: A biomechanical study", Injury, 50 (2019) 1593-1598.

[24] L.M. Lucinda, B.J. Vieira, T.T. Oliveira, R.C. Sa, V.M. Peters, J.E. Reis, M.O. Guerra, "Evidences of osteoporosis improvement in Wistar rats treated with Ginkgo biloba extract: a histomorphometric study of mandible and femur", Fitoterapia, 81 (2010) 982-987.

[25] M. Marco, E. Giner, J.R. Caeiro-Rey, M.H. Miguelez, R. LarrainzarGarijo, "Numerical modelling of hip fracture patterns in human femur", Comput Methods Programs Biomed, 173 (2019) 67-75.

[26] H. Shigeishi, K. Ohta, M. Takechi, "Risk factors for postoperative complications following oral surgery", J Appl Oral Sci, 23 (2015) 419-423.

[27] E.G. Meinberg, J. Agel, C.S. Roberts, M.D. Karam, J.F. Kellam, "Fracture and Dislocation Classification Compendium-2018", J Orthop Trauma, 32 Suppl 1 (2018) 1-170.

[28] M. Marco, M. Rodriguez-Millan, C. Santiuste, E. Giner, M. Henar Miguelez, "A review on recent advances in numerical modelling of bone cutting", J Mech Behav Biomed Mater, 44 (2015) 179-201.

[29] S. Nayak, D.L. Edwards, A.A. Saleh, S.L. Greenspan, "Performance of risk assessment instruments for predicting osteoporotic fracture risk: a systematic review", Osteoporos Int, 25 (2014) 23-49.

[30] E.G. Meinberg, J. Agel, C.S. Roberts, M.D. Karam, J.F. Kellam, "Femur", J Orthop Trauma, 32 Suppl 1 (2018) 33-44.

[31] M. Ehlinger, G. Ducrot, P. Adam, F. Bonnomet, "Distal femur fractures. Surgical techniques and a review of the literature", Orthop Traumatol Surg Res, 99 (2013) 353-360.

[32] L. Bedes, P. Bonnevialle, M. Ehlinger, R. Bertin, E. Vandenbusch, G. Pietu, SoFcot, "External fixation of distal femoral fractures in adults' multicentre retrospective study of 43 patients", Orthop Traumatol Surg Res, 100 (2014) 867-872.

[33] M. Zlowodzki, J.S. Prakash, N.K. Aggarwal, "External fixation of complex femoral shaft fractures", Int Orthop, 31 (2007) 409-413.

[34] G. Toro, G. Calabrò, A. Toro, A. de Sire, G. Iolascon, "Locking plate fixation of distal femoral fractures is a challenging technique: a retrospective review", Clin Cases Miner Bone Metab, 12 (2015) 55-58.

[35] N.M. Willems, G.E. Langenbach, V. Everts, A. Zentner, "The microstructural and biomechanical development of the condylar bone: a review", Eur J Orthod, 36 (2014) 479-485.

[36] G.I. Im, S.R. Shin, "Treatment of femoral shaft fractures with a titanium intramedullary nail", Clin Orthop Relat Res, (2002) 223-229.

[37] J. Letechipia, A. Alessi, G. Rodríguez, J. Asbun, "Design and preliminary testing of an active intramedullary nail", Rev Invest Clin, 66 Suppl 1 (2014) 70-78.

[38] C.E. Henderson, L.L. Kuhl, D.C. Fitzpatrick, J.L. Marsh, "Locking plates for distal femur fractures: is there a problem with fracture healing?", J Orthop Trauma, 25 Suppl 1 (2011) 8-14.

[39] J.Q. Wang, Z.X. Chen, W.J. Guo, Y.M. Zhao, L. Peng, "Comparison of plate and intramedullary nail fixation of extra-articular tibial fractures: A retrospective study exploring hidden blood loss", Injury, 50 (2019) 546-550.

[40] H.A. Vallier, "Current Evidence: Plate Versus Intramedullary Nail for Fixation of Distal Tibia Fractures in 2016", J Orthop Trauma, 30 Suppl 4 (2016) 2-6.

[41] H.A. Vallier, B.A. Cureton, B.M. Patterson, "Factors Influencing Functional Outcomes After Distal Tibia Shaft Fractures", Journal of Orthopaedic Trauma, 26 (2012) 178-183.

[42] C. Sommer, E. Gautier, M. Muller, D.L. Helfet, M. Wagner, "First clinical results of the Locking Compression Plate (LCP)", Injury, 34 Suppl 2 (2003) 43-54.

[43] D.L. Miller, T. Goswami, "A review of locking compression plate biomechanics and their advantages as internal fixators in fracture healing", Clin Biomech (Bristol, Avon), 22 (2007) 1049-1062.

[44] C.N. Cornell, O. Ayalon, "Evidence for success with locking plates for fragility fractures", HSS J, 7 (2011) 164-169.

[45] R.M. Greiwe, M.T. Archdeacon, "Locking plate technology: current concepts", J Knee Surg, 20 (2007) 50-55.

[46] Z.O. Abu-Faraj, G.F. Harris, P.A. Smith, S. Hassani, "Human gait and Clinical Movement Analysis", in: Wiley Encyclopedia of Electrical and Electronics Engineering, 2015, pp. 1-34.

[47] R. Baker, "Gait analysis methods in rehabilitation", Journal of NeuroEngineering and Rehabilitation, 3 (2006) 1-10.

[48] G. Khalid, "Kinematic analysis of human gait cycle", Nahrain University, College of Engineering Journal, 16 (2014) 208-222.

[49] K. Shah, M. Solan, E. Dawe, "The gait cycle and its variations with disease and injury", Orthopaedics and Trauma, 34 (2020) 153-160.

[50] M.A. Laribi, S. Zeghloul, "Chapter 4 - Human lower limb operation tracking via motion capture systems", in: M. Ceccarelli, G. Carbone (Eds.) Design and Operation of Human Locomotion Systems, Academic Press, 2020, pp. 83-107.

[51] A. Kharb, V. Saini, Y. Jain, S. Dhiman, M. Tech, Scholar, "A review of gait cycle and its parameters", IJCEM Int J Comput Eng Manag, 13 (2011) 78-83.

[52] K.L. Hoffmeier, G.O. Hofmann, T. Muckley, "Choosing a proper working length can improve the lifespan of locked plates. A biomechanical study", Clin Biomech (Bristol, Avon), 26 (2011) 405-409.

[53] S.H. Chen, M.C. Chiang, C.H. Hung, S.C. Lin, H.W. Chang, "Finite element comparison of retrograde intramedullary nailing and locking plate fixation with/without an intramedullary allograft for distal femur fracture following total knee arthroplasty", Knee, 21 (2014) 224-231.

[54] C.H. Lee, K.S. Shih, C.C. Hsu, T. Cho, "Simulation-based particle swarm optimization and mechanical validation of screw position and number for the fixation stability of a femoral locking compression plate", Med Eng Phys, 36 (2014) 57-64.

[55] A. Bonnefoy-Mazure, S. Armand, "Normal gait", in: F. Canavese, J. Deslandes (Eds.) Orthopedic Management of Children with Cerebral Palsy, 2015, pp. 199-214.

[56] J. Nourisa, A. Baseri, L. Sudak, G. Rouhi, "The effects of bone screw configurations on the interfragmentary movement in a long bone fixed by a limited contact locking compression plate", Journal of biomedical science and engineering, (2015) 1-11.

[57] J.C. Bel, "Pitfalls and limits of locking plates", Orthop Traumatol Surg Res, 105 (2019) 103-109.

[58] J. Coquim, J. Clemenzi, M. Salahi, A. Sherif, P. Tavakkoli Avval, S. Shah, E.H. Schemitsch, Z.S. Bagheri, H. Bougherara, R. Zdero, "Biomechanical Analysis Using FEA and Experiments of Metal Plate and Bone Strut Repair of a Femur Midshaft Segmental Defect", BioMed Research International, 2018 (2018) 1-11.

[59] S. Mohajerzadeh, K. Farhangdoost, P. Zamani, K. Kolasangiani, "Experimental Investigation on Fatigue Evaluation of Orthopaedic Locking Compression Plate", Advanced Design and Manufacturing Technology, 11 (2018) 47-52.

[60] Y.Y. Chen, "Fixation Strategies of a Locking Compression Plate For the Treatment of Distal Femoral Fracture Using a Complete Lower Extremity Model with Various Gait Postures", in: Applied Sciences, National Taiwan University of Science and Technology, 2019, pp.78.

[61] G. Osterhoff, E.F. Morgan, S.J. Shefelbine, L. Karim, L.M. McNamara, P. Augat, "Bone mechanical properties and changes with osteoporosis", Injury, 47 Suppl 2 (2016) 11-20.

[62] A. Ramos, J.A. Simões, "Tetrahedral versus hexahedral finite elements in numerical modelling of the proximal femur", Medical Engineering & Physics, 28 (2006) 916-924.

[63] L.W. Marks, T.N. Gardner, "The use of strain energy as a convergence criterion in the finite element modelling of bone and the effect of model geometry on stress convergence", Journal of Biomedical Engineering, 15 (1993) 474-476.

[64] A. Fryzowicz, M. Murawa, J. Kabaciński, A. Rzepnicka, L. Dworak, "Reference values of spatiotemporal parameters, joint angles, ground reaction forces, and plantar pressure distribution during normal gait in young women", Acta of bioengineering and biomechanics / Wroclaw University of Technology, 20 (2018) 49-57.

[65] K. Stoffel, U. Dieter, G. Stachowiak, A. Gachter, M.S. Kuster, "Biomechanical testing of the LCP-how can stability in locked internal fixators be controlled?", Injury, 34 (2003) 11-19.