迦瑪骨釘與動態髖骨螺絲，廣泛應用於治療股骨近端骨折，但臨床治療過程中時常會伴隨內固定器失效，失效模式有骨螺絲、骨釘破壞或骨螺絲鬆脫等現像，若發生失效必定需進行二次手術，但如此病患必需受二次傷害，因此內固定器的穩定性就非常之重要。
本研究是針對遲滯螺絲進行多目標最佳化，目標函數是拉出強度與彎曲強度，但從文獻中發現這兩個目標函數對設計參數是很極端的，因此本文先利用SolidWorks進行模型的設計，在依目前市售新型鎖定式骨髓內釘(雙螺絲骨釘)中的遲滯螺絲參數定義設計範圍，使用田口方法L25直交表規劃模擬參數，模擬的部份是使用市售有限元素分析軟體ANSYS Workbench，在彎曲模型以最大張應力最為目標值;拉出模型以總反作用力為目標值，再以變異數分析將最大張應力轉為望小;總反作用力轉為望大，進行各因子貢獻度比較，其後將兩組數據建立類神經網路模型，並且各加入十組測試組，以達到網路模型之收斂後，將網路模型加入遺傳演算法進行多目標最佳化，找出能同時保有最大張應力與總反作用力模型參數。
本研究結果顯示，針對彎曲強度，圓錐起始位置與螺絲內徑為最重要之參數，拉出強度為螺絲內徑、近端弧角半徑和節距為最重要之參數，兩種目標函數在類神經網路模型中學習組與測試組誤差相當的小(5%以內)，並且能有效的預測有限元素結果，加入遺傳演算法後最佳化權重值落於0.5~0.55之間，參數為圓椎起始位置為0mm、內徑值為3.3mm、近端弧角半徑為0.22mm、節距為3.12至3.3mm、 近端弧角半角為5°、螺牙厚度為0.17至0.2mm，並且可以同時保有90%以上的強度。

Gamma nail and dynamic hip screw have been widely used in the treatment of proximal femoral fractures. However, these internal fixation devices may fail, including breaking and loosening of the lag screws, during the treatment and cause severe problems after an operation. To design these kinds of device the stability of the structure is very important. Therefore, the multi-objective optimization of lag screws has been studied in this research by considering two objective function, bending and pullout strength, which contradict each other.
In this study, SolidWork 2008 and ANSYS Workbench 11 were used to create the 3D models and simulate the Finite Element Analysis which are based on clinical conditions. All of important parameters and ranges of each factor were designed from literature reviews and commercial devices, respectively. Taguchi method and L25 orthogonal array were used to represent full factorial experiment of 6 parameters with 5 levels and then the contribution of each design factor was calculated by using ANOVA. 25 data from L25 orthogonal array and 10 additional data were used to be learning set and testing set in Artificial Neural Network (ANN) for both objective functions. Then Genetic Algorithm (GA) was applied to obtain the multi-objective optimal design of the lag screws.
The results of this study showed that the most important factors for bending strength was initial position of the conical angle (IP) and inner diameter (ID). For pullout strength, the inner diameter (ID), proximal root radius (PRR), and pitch (Pi) were the most important parameters. In the ANN models, Mean Absolute Error (MAE) in the learning and testing group of two objective functions were smaller than 5%. In the GA part, an optimum weight was 0.5 to 0.55. The optimal values were 0 mm for the IP, 3.3 mm for the ID, 0.22 mm for the PRR, 3.12 to 3.3 mm for the PI, 5° for Proximal Half Angle (PHA) and 0.17 to 0.2 mm for Thread Width (TW).
From this study, ANN was an effective tool which could be used to predict the results of the Finite Element Models. The optimum lag screw had a high performance for both the bending and pullout strength, over than 90% of the high value.

[1]楊榮森, "臨床骨折學，合記圖書出版社，台北," (1998)
[2]R. C. Haynes, R. G. Poll, A. W. Miles, and R. B. Weston, "An experimental study of the failure modes of the Gamma Locking Nail and AO Dynamic Hip Screw under static loading: a cadaveric study," Medical Engineering & Physics, vol. 19, pp. 446-453, (1997)
[3]A. D. Bridle Sh Fau - Patel, M. Patel Ad Fau - Bircher, P. T. Bircher M Fau - Calvert, and P. T. Calvert, "Fixation of intertrochanteric fractures of the femur,"
[4]林晉, "鎖定式骨髓內釘之基礎科學與臨床應用，合記出版社，台北市," (2004)
[5]游祥明、宋晏仁、古宏海、傅毓秀、林光華, "解剖學," 杏出版股份有限公司，台北, (2005)
[6]F. H. Netter, "Atlas of Human Anatomy 2nd," Icon Learning Systems, (2000)
[7]周建基, "股骨近心端治療之有限元素分析," 台灣科技大學機械工程系碩士論文, ((2004))
[8]張裕長, "應用類神經網路與遺傳演算法於雙螺絲骨釘中遲滯螺絲之最佳化設計，國立台灣科技大學機械工程系碩士論文，2009,"
[9]J. Lin, "Encouraging Results of Treating Femoral Trochanteric Fractures With Specially Designed Double-Screw Nails," The Journal of Trauma: Injury, Infection, and Critical Care, vol. 63, pp. 866-874, (2007)
[10]J. D. Spivak Jm Fau - Zuckerman, F. J. Zuckerman Jd Fau - Kummer, V. H. Kummer Fj Fau - Frankel, and V. H. Frankel, "Fatigue failure of the sliding screw in hip fracture fixation: a report of three cases,"
[11]P. Q. Chen, S. J. Lin, S. S. Wu, and H. So, "Mechanical performance of the new posterior spinal implant: effect of materials, connecting plate, and pedicle screw design," Spine (Phila Pa 1976), vol. 28, pp. 881-6; discussion 887, (2003)
[12]C. K. Chao, C. C. Hsu, J. L. Wang, and J. Lin, "Increasing bending strength of tibial locking screws: mechanical tests and finite element analyses," Clin Biomech (Bristol, Avon), vol. 22, pp. 59-66, (2007)
[13]C. K. Chao, C. C. Hsu, J. L. Wang, and J. Lin, "Increasing bending strength and pullout strength in conical pedicle screws: biomechanical tests and finite element analyses," J Spinal Disord Tech, vol. 21, pp. 130-8, (2008)
[14]G. K. Kouvidis, M. B. Sommers, P. V. Giannoudis, P. G. Katonis, and M. Bottlang, "Comparison of migration behavior between single and dual lag screw implants for intertrochanteric fracture fixation," Journal of Orthopaedic Surgery and Research, vol. 4, p. 16, (2009)
[15]B. B. Abshire, R. F. McLain, A. Valdevit, and H. E. Kambic, "Characteristics of pullout failure in conical and cylindrical pedicle screws after full insertion and back-out," Spine J, vol. 1, pp. 408-14, (2001)
[16]C.-C. Hsu, C.-K. Chao, J.-L. Wang, S.-M. Hou, Y.-T. Tsai, and J. Lin, "Increase of pullout strength of spinal pedicle screws with conical core: Biomechanical tests and finite element analyses," Journal of Orthopaedic Research, vol. 23, pp. 788-794, (2005)
[17]K. Panneerselvam, S. Aravindan, and A. Noorul Haq, "Hybrid of ANN with genetic algorithm for optimization of frictional vibration joining process of plastics," The International Journal of Advanced Manufacturing Technology, vol. 42, pp. 669-677, (2008)
[18]C. C. Hsu, C. K. Chao, J. L. Wang, and J. Lin, "Multiobjective optimization of tibial locking screw design using a genetic algorithm: Evaluation of mechanical performance," J Orthop Res, vol. 24, pp. 908-16, (2006)
[19]C.-K. Chao, J. Lin, S. T. Putra, and C.-C. Hsu, "A Neurogenetic Approach to a Multiobjective Design Optimization of Spinal Pedicle Screws," Journal of Biomechanical Engineering, vol. 132, p. 091006, (2010)
[20]賴育良, "ansys電腦輔助工程分析，儒林圖書有限公司，台北市," (1997)
[21]張季娜, "田口式品質工程導論，中華民國品質學會，台北市," (2003)
[22]王進德編著, "類神經網路與模糊控制理論入門與應用，全華科技圖書股份有限公司," (2007)
[23]張傑富, "腰椎椎弓足螺絲之多目標最佳化設計：有限元素分析與生物力學測試," 國立台灣科技大學機械工程系碩士論文, (2010)
[24]林昇甫、徐永吉, "遺傳演算法及其應用 Advanced design of experiments，五南圖書出版股份有限公司，臺北市," (2009)
[25]S.-J. Chen Pq Fau - Lin, S.-S. Lin Sj Fau - Wu, H. Wu Ss Fau - So, and H. So, "Mechanical performance of the new posterior spinal implant: effect of materials, connecting plate, and pedicle screw design,"
[26]J. Lin and S. M. Hou, "Bending strength and holding power of a prototype tibial locking screw," Clin Orthop Relat Res, pp. 232-9, (2002)
[27]徐慶琪, "骨螺絲之結構設計與生物力學分析," 國立台灣科技大學機械工程研究所博士論文, (2005)

[1]楊榮森, "臨床骨折學，合記圖書出版社，台北," (1998)
[2]R. C. Haynes, R. G. Poll, A. W. Miles, and R. B. Weston, "An experimental study of the failure modes of the Gamma Locking Nail and AO Dynamic Hip Screw under static loading: a cadaveric study," Medical Engineering & Physics, vol. 19, pp. 446-453, (1997)
[3]A. D. Bridle Sh Fau - Patel, M. Patel Ad Fau - Bircher, P. T. Bircher M Fau - Calvert, and P. T. Calvert, "Fixation of intertrochanteric fractures of the femur,"
[4]林晉, "鎖定式骨髓內釘之基礎科學與臨床應用，合記出版社，台北市," (2004)
[5]游祥明、宋晏仁、古宏海、傅毓秀、林光華, "解剖學," 杏出版股份有限公司，台北, (2005)
[6]F. H. Netter, "Atlas of Human Anatomy 2nd," Icon Learning Systems, (2000)
[7]周建基, "股骨近心端治療之有限元素分析," 台灣科技大學機械工程系碩士論文, ((2004))
[8]張裕長, "應用類神經網路與遺傳演算法於雙螺絲骨釘中遲滯螺絲之最佳化設計，國立台灣科技大學機械工程系碩士論文，2009,"
[9]J. Lin, "Encouraging Results of Treating Femoral Trochanteric Fractures With Specially Designed Double-Screw Nails," The Journal of Trauma: Injury, Infection, and Critical Care, vol. 63, pp. 866-874, (2007)
[10]J. D. Spivak Jm Fau - Zuckerman, F. J. Zuckerman Jd Fau - Kummer, V. H. Kummer Fj Fau - Frankel, and V. H. Frankel, "Fatigue failure of the sliding screw in hip fracture fixation: a report of three cases,"
[11]P. Q. Chen, S. J. Lin, S. S. Wu, and H. So, "Mechanical performance of the new posterior spinal implant: effect of materials, connecting plate, and pedicle screw design," Spine (Phila Pa 1976), vol. 28, pp. 881-6; discussion 887, (2003)
[12]C. K. Chao, C. C. Hsu, J. L. Wang, and J. Lin, "Increasing bending strength of tibial locking screws: mechanical tests and finite element analyses," Clin Biomech (Bristol, Avon), vol. 22, pp. 59-66, (2007)
[13]C. K. Chao, C. C. Hsu, J. L. Wang, and J. Lin, "Increasing bending strength and pullout strength in conical pedicle screws: biomechanical tests and finite element analyses," J Spinal Disord Tech, vol. 21, pp. 130-8, (2008)
[14]G. K. Kouvidis, M. B. Sommers, P. V. Giannoudis, P. G. Katonis, and M. Bottlang, "Comparison of migration behavior between single and dual lag screw implants for intertrochanteric fracture fixation," Journal of Orthopaedic Surgery and Research, vol. 4, p. 16, (2009)
[15]B. B. Abshire, R. F. McLain, A. Valdevit, and H. E. Kambic, "Characteristics of pullout failure in conical and cylindrical pedicle screws after full insertion and back-out," Spine J, vol. 1, pp. 408-14, (2001)
[16]C.-C. Hsu, C.-K. Chao, J.-L. Wang, S.-M. Hou, Y.-T. Tsai, and J. Lin, "Increase of pullout strength of spinal pedicle screws with conical core: Biomechanical tests and finite element analyses," Journal of Orthopaedic Research, vol. 23, pp. 788-794, (2005)
[17]K. Panneerselvam, S. Aravindan, and A. Noorul Haq, "Hybrid of ANN with genetic algorithm for optimization of frictional vibration joining process of plastics," The International Journal of Advanced Manufacturing Technology, vol. 42, pp. 669-677, (2008)
[18]C. C. Hsu, C. K. Chao, J. L. Wang, and J. Lin, "Multiobjective optimization of tibial locking screw design using a genetic algorithm: Evaluation of mechanical performance," J Orthop Res, vol. 24, pp. 908-16, (2006)
[19]C.-K. Chao, J. Lin, S. T. Putra, and C.-C. Hsu, "A Neurogenetic Approach to a Multiobjective Design Optimization of Spinal Pedicle Screws," Journal of Biomechanical Engineering, vol. 132, p. 091006, (2010)
[20]賴育良, "ansys電腦輔助工程分析，儒林圖書有限公司，台北市," (1997)
[21]張季娜, "田口式品質工程導論，中華民國品質學會，台北市," (2003)
[22]王進德編著, "類神經網路與模糊控制理論入門與應用，全華科技圖書股份有限公司," (2007)
[23]張傑富, "腰椎椎弓足螺絲之多目標最佳化設計：有限元素分析與生物力學測試," 國立台灣科技大學機械工程系碩士論文, (2010)
[24]林昇甫、徐永吉, "遺傳演算法及其應用 Advanced design of experiments，五南圖書出版股份有限公司，臺北市," (2009)
[25]S.-J. Chen Pq Fau - Lin, S.-S. Lin Sj Fau - Wu, H. Wu Ss Fau - So, and H. So, "Mechanical performance of the new posterior spinal implant: effect of materials, connecting plate, and pedicle screw design,"
[26]J. Lin and S. M. Hou, "Bending strength and holding power of a prototype tibial locking screw," Clin Orthop Relat Res, pp. 232-9, (2002)
[27]徐慶琪, "骨螺絲之結構設計與生物力學分析," 國立台灣科技大學機械工程研究所博士論文, (2005)