An accurate 3D reconstruction of the hip is mandatory to enhance clinical outcomes and to help increasing the implants life expectancy. These goals may be difficult to achieve in some patients with outlier anatomy. Custom stem technology is a reliable solution to treat degenerated hip patients having such an atypical hip anatomy. In our practice 12% of patients require a custom stem to achieve an accurate reconstruction of their proximal femur anatomy. Performing 3D planning for all osteoarthritic hip patients and checking intraoperative anatomical parameters are key steps to anticipate the surgical difficulties, select the appropriate implants, and restore normal hip biomechanics.