The maximum stem-cortical bone contact plays a dominant role in the long-term fixation of the prosthesis; narrowing stem-cortical bone space and the bony ingrowths reduces the reaction to debris due to wear, the particle flows caused by the wear debris, the bone resorption, and the growth of pseudomembrane.1-4 We realized that the endosteal contour varies significantly from person to person.5,6 Thus, only one common designed prosthesis is not sufficient to achieve a high degree of accuracy in terms of modelling the proximal femur, therefore computer-assisted reconstruction of a three-dimensional canal model of the femur is a very promising way to produce custom hip stem prostheses.7-9