科技進步與醫療技術的提升使高齡人口急速增加，現代人生活習慣改變及婦女停經後等因素，使得骨疏鬆症已高居全球第二大的流行病學。骨鬆後造成骨折之危險性會大幅提高，根據2000年國際骨質疏鬆協會(IOF)研究指出：全球有900萬人因骨質疏鬆造成骨折傷害，其中160萬人為髖部骨折，170萬人為前臂骨折，而140萬人為椎體骨折。動態式髖部骨釘常用來治療近端股骨骨折，對於骨質良好之穩定骨折具有較佳的治療效果；但對於不穩定骨折型態，骨骼外型結構破裂成許多小碎塊，力量會概括由延遲骨釘承受，使延遲骨釘鎖固於股骨內部的交界處產生應力集中的現象，讓術後失敗機率增加。目前臨床所使用的K-pin植入導引器械因其功能性不足，再植入過程中讓臨床醫師與病患長時間暴露在高劑量的輻射環境之下，且使得手術時間增加，因而提高了手術的風險。因此本研究利用有限元素模擬分析DHS應用於股骨轉子間骨折之生物力學，並設計新型導引輔助器械，幫助臨床醫師將 K-pin旋至股骨內適當之位置，以輔助植入動態式髖部骨釘，減少術後產生 cut-out的結果。特定目標為： (1)探討不同角度DHS與不同TAD植入位置對於DHS治療正常股骨與骨鬆股骨之轉子間穩定骨折的力學效應 (2) 探討不同角度的DHS與不同TAD植入位置對於DHS治療骨鬆及轉子間不穩定骨折(A2.1)之力學效應(3)設計與發展輔助DHS手術植入K-pin之新型導引器械。

本研究利用CT影像重建股骨模型，接著根據AO轉子間穩定及不穩定骨折分類建構股骨轉子間骨折模型，並將股骨骨折模型與DHS模型相互結合後匯入有限元素軟體內，給予適當之邊界條件與材料參數，以探討不同DHS角度與不同TAD植入位置對於DHS固定股骨之轉子間骨折之力學效應。此外為輔助延遲骨釘植入股骨內適當之位置，因此本研究研發一套新型導引輔助器械，根據臨床上的功能性需求，於器械上加入導引鋼條與可選擇式K-pin植入套筒之設計，利用CAD來建構器械各構件之三維模型，爾後利用不銹鋼製作新型導引輔助器械之雛型。
本研究結果顯示：(1) 由文獻得知發生骨鬆後股骨頭內部海綿骨降伏強度會大幅下降50%，但根據本研究分析結果發現骨鬆股骨組別之股骨頭內部海綿骨最大應力只略小於正常股骨組別，因此在相同受力條件下發生骨鬆後股骨頭海綿骨被破壞的機率較高；(2) 使用135°DHS且延遲骨釘植入位置正中時，對於固定正常股骨與骨鬆股骨之轉子間穩定骨折具有較佳的力學特性；(3) 利用DHS固定骨鬆股骨之A2.1轉子間不穩定骨折時，會於破碎之小轉子上產生最大位移，且因受到髂腰肌之拉扯故使得小轉子往上方靠股骨內側產生翻轉；(4) 新型導引器械雛型經測試校正後，確實可達到導引K-pin之功能性。

研究方向建議：(1) 建立不同解剖尺寸之股骨模型，以進一步探討不同解剖外型之股骨轉子間骨折利用DHS固定之力學效應；(2) 建立更多臨床上常見之近端股骨骨折模型，利用有限元素方法探討DHS固定近端股骨骨折型態之力學效應，以歸納出各種近端股骨骨折情形下DHS適合之植入角度與延遲骨釘植入位置；(3) 利用傳統導引器械與本研究設計之新型導引輔助器械模擬臨床手術植入K-pin過程，比較X光使用量與手術植入時間，以驗證新型導引輔助器械於臨床使用之可行性。

The advance of Medical technology rapidly increases the population of elderly people, adding the changing of modern lifestyle and women in postmenopausal makes osteoporosis the second largest epidemic in the world.The risk of bone fracture significantly increases after having osteoporosis. According to the 2000 IOF study, there are 900 million people worldwide having fracture due to osteoporosis. Within them, 1.6 million have hip fracture, 1.7 million have forearm fracture and 140 million people have vertebral fractures. Dynamic hip bone screw is used to treat proximal femoral fractures, it has good therapeutic effect on stable fractures; but in unstable fracture type, where bone structure breakes into many small pieces, the lag screw will undertake more force, therefore increase the internal stress concentration in the junction of lag screw locking the femur, resulting in high failure probability.The K-pin guiding device currently used in clinical implantation lacks functionality, resulting in the exposure to high doses of radiation on clinicians and patients in the implant process, making the operation time increase, thus increasing the risk of surgery.This study uses finite element analysis to simulate the biomechanics of DHS fixation on pertrochanteric fractures and design new guidance instrument to help clinicians guide K-pin to an appropriate location to support Dynamic hip implants bone screw reduce postoperative produce cut-out results. Specific objectives are: (1) investigate the mechanical effects of the normal and the osteoporotic bone on stable pertrochanteric fractures with variant angle of the DHS and tip apex distance(TAD)，(2) investigate the mechanical effects of the osteoporotic unstable pertrochanteric fracture type A2.1 with variant angle of the DHS and tip apex distance(TAD)，(3) design and develope new guidance instrument to assist DHS surgery implant K-pin .

This reaserch reconstruct the femur model from CT image, then builde the stable and unstable intertrochanteric fracture model according to AO intertrochanteric fracture classification. Then combine femur fracture model with the DHS model. After importing the models into finite element software, we give the appropriate boundary conditions and material parameters to investigate the mechanical effects with variant angle of the DHS and TAD for DHS fixation intertrochanteric fractures. In addition to finding the appropriate locations for supporting lag screw implant, this study developed a new guidance instrument according to the clinical-functional requirements. Design guiding steel bar and the selective K-pin implant tube on new guidance instrument, using CAD construct three-dimensional model of the various components of the new guidance instrument, and production the prototype of new guidance instrument by stainless steel。

The results showes: (1) From the document reviewed, we know the yield strength of femoral head’s sponge bone after osteoporosis will be substantially decreased by 50%, but according to the results found that the osteoporotic femoral head’s sponge bone’s maximum stress is only slightly less than the normal femoral group, so the force conditions in the same place of the osteoporotic femoral head’s sponge bone should have a higher probability of destroyed ; (2) 135 ° DHS and the lag screw implanted in the middle position has a better stability and mechanical properties for fixed normal intertrochanteric stable fractures and osteoporotic intertrochanteric stable fractures; (3) Useing DHS fixation on the osteoporotic intertrochanteric stable fractures type A2.1 will generate the maximum displacement and crushing the lesser trochanter. Because it is pulled by the iliopsoas muscle, it flips up to the side by the medial femoral of the lesser trochanter; (4)After testeing and calibration, the prototype of the new guidance instrument can indeed achieve the function of guiding K-pin.

Research proposals: (1) Reconstruct different dimension models of femur to further explore the mechanical effects of intertrochanteric fractures using DHS fixation ; (2)Reconstruct more fracture models of common clinical proximal femoral fracture and investigat the mechanical effects of DHS fixation of proximal femur fracture by finite element method to incorporate appropriate angle for the DHS and TAD variety of proximal femur fracture cases; (3) Compare the traditional guidance instruments and new guidance instrument using simulated surgical course to implant K-pin. Compared by the use of X-ray and implant time, to verify the feasibility in clinical use of new guidance instrument.

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