Study To Improve The Accuracy Of Prediction About The Suitable Size Of Cementless Femoral Prosthesis In The Preoperative Planning

Background and objectiveOne of the most important failures of THR is aseptic loosening of the femoral prosthesis Researches have shown good fit and fill of the femoral component in the medullary canal are of much importance to reduce micromotion and subsidence,especially for the cementless femoral prosthesis.Prediction of the suitable size of the femoral component is an important task in the preoperative planning of THR.Templating method is now widely applied to predict the suitable femoral prosthesis in the preoperative planning of THR. However, there are several factors that affect the accuracy of templating method.The anatomy of femoral medullary canal is fundamental to influence the matching of implant with femoral canal.So the prediction of the suitable size of femoral prosthesis should involve the anatomic features of femoral medullary canal.The isthmus is an important anatomical structure of the proximal femoral medullary canal,which apparently affects the implantation of femoral prosthesis.The good fit and fill of the femoral component depend on its close contact with the endosteal surface of medullary canal,which is critical to provide vital stability of stem .The shape of isthmus also plays an important role in the determination of the suitable size of femoral prosthesis. Therefore,the dimension of isthmus is closely related to prediction and selection of the suitable size of femoral prosthesis in THR.The purpose of this study is to observe the factors which probably influence the accuracy of templating method to predict the suitable femoral prosthesis in the preoperative planning of THR. We aslo study the relationship between the dimension of femoral isthmus and femoral prosthesis in THR. Then the suitable size of femoral prosthesis is predicted depending on the dimension of isthmus;and we also evaluate the accuracy of isthmus...