人工關節置換手術，至今已發展數十年的時間，在產學界也對此投入了相當多的人力及物力，無論是手術前人工關節之設計、製造或手術中的影像導引技術，都漸漸發展成型，但手術後於人體內之情形為何，卻較少人針對此探討。本研究則利用現今於臨床上已普遍使用的數位X光片，並配合電腦影像處理以及幾何投影特徵之特性，來發展一程式平台，以預測置換率最高之人工膝關節術後的空間對位關係。 本研究初步先拍攝兩張夾角固定之數位X光片，並利用影像處理之方式，擷取出影像之邊界，並將其向量化，進而得到二維影像中可以代表三維空間的特徵資訊，有點對點間的距離、邊界斜率等，最後利用SolidWorks的環境，將既有的人工膝關節模型進行空間的定位，最後產生其股骨與脛骨之對位情形，便可由此得到較精確的定位資訊，使醫護人員除了憑藉經驗來判斷此關節置入體內後之磨耗或對位之外，還有較明確的資訊可供參考，除此之外，也可供人工關節設計者作為未來人工膝關節設計之評估機制。 The artificial joint arthroplasty, has already developed the time in decades so far, the academics and the industries have invested quite a lot of manpower and material resources, no matter the design or the manufacture of artificial joint in pre-operation, and planning and navigation system for surgery are developed gradually. But in post-operation, there are a few number of studies have been research it. The purpose of this study is using the digital fluoroscopy with computer image processing methods and characteristics of geometrical projection to develop a program which can predict the relationship of space of the total knee arthroplasty in post-operation. The first step of this study is shooting two digital fluoroscopy with regular angle and using the image processing methods to detect the edge of image and then vectorizing it. After that we can get the two-dimensional image which can represent the characteristic information of three-dimensional. These information including the vertex,the distance of two points, and the slope of the edge. At last, we position the CAD model of artificial knee replacement with the above information by using SolidWorks, and we will know the relationship of space between the femur part and the tibia part. Base on the process before, we can obtain more precisely information of position of the knee replacement in human’s body. This information can provide doctors to judge the wearing and the position after this joint puts into the body. In addition, this program can also be a new assessment mechanism for the joint replacement designer in the future.