Research On Individualized Modeling Of Artificial Femoral Head Prosthesis

Femoral head necrosis is a universal disease in the world now. In the middle and late period of femoral head necrosis, the femoral head becomes serious collapse and deformation. The patient’s necrotic femoral head only can be replaced by artificial femoral head prosthesis. Femoral head is a weight-bearing joint of the body. Different persons have the individual difference. Therefore, designing a kind of precise and reasonable individualized femoral head prosthesis model is becoming a difficulty in CAM and CAD.The femoral head prosthesis model determines the matching quality between femoral head and acetabulum. If the size and the shape of femoral head is unreasonable, the femoral head prosthesis will cause loosening and dislocation. The patients have to accept the second repair surgery. Meanwhile, it can reduce the lifespan of the femoral head prosthesis. All the doctors use the femoral head prosthesis model by standardized design and mass production. However, this kind of the model can’t meet the individual requirements of the patients.The paper proposes a method for individualized modeling of femoral head in order to build the individualized femoral head prosthesis model. Firstly, the CT images are preprocessed by the denoising and enhancement method with Contourlet transformation based on the characteristics of the CT images. Secondly, the acetabulum is segmented by a new improved segmentation algorithm. The2D sampling and an improved3D sampling algorithms are proposed in order to obtain the data on the acetabulm lunate surface for curve fitting. In addition, the sampled data points are refined. Finally, the femoral head prosthesis is fitted by an improved fitting method of the ellipsoid femoral head prosthesis because of the special anatomical characteristics of the acetabulum. A new improved MC algorithm is proposed to achieve the3D reconstruction of the femoral head and acetabulum and facilitate the diagnosis of the lesions for the doctors. The experiments indicate that the improved ellipsoid model of femoral head prosthesis can match with the acetabulum well. It can provide theoretical parameters for the patients to customize the femoral head prosthesis. It’s also useful for the navigation and simulation of orthopedic surgery.