人工髖關節表面置換術股骨頸骨折預防之研究

Evaluation for the causes of a femoral neck fracture in hip resurfacing arthroplasty –A finite element study

陳首豪(Shou-Hao CHen)

指導教授 ： 黎文龍

國立臺北科技大學/機電學院/製造科技研究所/碩士(2012年)

摘要

由於現今工業技術發達使人工髖關節有了重大的突破，目前發展出表面置換型人工髖關節，不同於過去全人工髖關節所消耗不必要人體骨本，其手術範圍小復原性快已經成為現今醫療趨勢，如今有許多國外的研究以及臨床案例進行研究，應用在表面置換術人工髖關節已是成熟的技術。
雖然表面置換型人工髖關節擁有符合未來醫學發展趨勢，而且也可以讓病患從全人工髖關節置換術有另外新的選擇，但是表面置換型人工髖關節的臨床案例依然有失敗的可能性，從文獻中在植入物無菌鬆脫和股骨頸骨折之失敗案例原因，得知植入角在表面置換型人工髖關節中扮演重要的角色。
從過去文獻研究得知，植入角外翻對整體表面置換行人工髖關節系統為有利方向，但是目前相關對於植入角的研究只限於二維平面的考量，因此本研究擬進一步考慮股骨的前傾角對於全人工髖關節表面置換影響，更配合植入角外翻角度得到最佳的植入角方位進行有限元素分析科學驗證，提供未來臨床醫師手術之參考。
從本研究結果得知手術外翻方向進行植入，並不會立即對於股骨頸斷裂產生威脅，但是各項模擬組合在植入物的根部位置有應力集中現象，這可能造成股骨產生應力遮蔽效應而使置換手術失敗，不同骨質的改變，則會影響到最大應力發生位置，若皮質骨與鬆質骨差異過大，會使得股骨頸部應力值上升則可能產生斷裂的風險，這證明因骨壞死使得楊氏系數下降是有可能造成股骨頸骨折原因，最後適當的前傾角與股骨頸部剖面有關，選擇植入的前傾角之前必須對股骨頸部剖面做評估，另外外翻角度超過15度更可能讓手術失敗，本研究建議植入角在外翻角度適合5度和10度之間。

關鍵字

表面置換型人工髖關節 ； 股骨頸骨折 ； 有限元素分析

並列摘要

With advancements in industrial technologies, resurfacing artificial hip has developed, unlike total hip in the past consumed by unnecessary human bone, the extent of surgery has become a small recovery faster by the medical trend, significant research effort has been devoted to total hip resurfacing arthroplasty and clinical trials have been performed in many countries. Thus, the technology is already mature.

The increased use of total hip resurfacing arthroplasty is consistent with current trends in medical science. It provides patients with an alternative to total hip arthroplasty. However, clinical trials suggest there are still some issues with total hip resurfacing arthroplasty. Our study analyzes the factors that causes cause failures in the implants, resulting in aseptic loosening and femoral neck fractures. Total hip resurfacing arthroplasty technology is very important for biomechanics, and the implant angle is especially significant.

Previous research studies suggest that the implant valgus angle is significant for the overall effectiveness of the total surface replacement artificial hip joint system. Previous studies on implant angles are limited to the 2-D plane, resulting in discrepancies compared to actual surgical conditions. This study also considers the importance of the anteversion angle of the femoral bone in total surface-replacement hip resurfacing arthroplasty. Based on the implant valgus angle, the best implant angle is obtained. Finite element analysis is performed on the location data for scientific verification. This analysis will serve as a reference for clinical surgeons during surgeries.

The results of this study suggest that the valgus of an implant does not lead to increased risk of femoral neck fractures. Simulations showed the effect of stress concentration at the bottom of the implant. This may reduce the femoral stress shielding effect, causing failure of the hip replacement. Changes in the nature of different bone will affect the position of maximum stress. When cortical bone and cancellous bone is too large difference, would make the increase in femoral neck stress to fracture risk. This proves that it is possible to cause osteonecrosis will be decline young's modulus of femoral neck fracture. The anteversion angle is associated with femoral neck section. Choose implant anteversion angle must be to know femoral neck section. In addition, if the valgus angle is greater than 15 degrees, the joint may fail during operation. Thus, we suggest that the suitable valgus angle for the implant is between 5 and 10 degrees.

並列關鍵字

hip resurfacing arthroplasty ； femoral neck fractures ； finite element analysis

參考文獻

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