Total knee arthroplasty with total hip arthroplasty nowadays represents around 90% of the entire joint reconstruction market. They are required mainly as a result of osteoarthritis. Knee prosthesis can be implanted following two main philosophies: mechanical alignment and kinematic alignment. The mechanical alignment consists in implanting the knee prosthesis so that the interface between bone and prosthesis is perpendicular to the tibial axis. Since each component is perpendicular to the mechanical axis, this allows, once the load is applied, to have a load distribution in which the compression component prevails. Nevertheless, the components of the human knee do not lie perpendicular to each other.