Reconstruction of Patient Specific Models of Femur for Surgery of Avascular Necrosis of Femoral Head

We developed a new reverse engineering based method for the reconstruction of patient specific models of femoral head for surgery of ANFH. Three dimensional models were reconstructed from the 3D CT dataset and approximated with 3D fitting algorithms based on reverse engineering. In this paper, a strategy of classifying femur from hip joint CT datasets based on Active Shape Model was introduced, a curvature based reduction method was applied to reduce the noise or redundancy points in the point cloud of femur and a surface reconstruction method from point cloud was analyzed too. In order to regain the spherical surface of collapsing femoral head, a fitting algorithm, which is the optimal least squares spherical approximation to a 3D point cloud was used. Comparing the fitting models with their original shapes by overlapping them, we found that only part regions have little deviation. The results show that the fitting models and their original models are matching strictly.