The evolution of modern total knee arthroplasty (TKA) began over 50 years ago. Seeking alternatives for arthrodesis and fascial arthroplasty for the treatment of knee arthritis, surgeons and engineers were developing various implants such as the Polycentric, the ICLH, and the Freeman Swanson prostheses. In 1970, the Duocondylar Prosthesis was designed as a modification of the Polycentric Knee Prosthesis. Further refinements lead to the Duopatellar Prosthesis that was designed by Insall and Walker. This implant was the precursor of the Total Condylar Prosthesis that was a cruciate sacrificing design with a conforming articular surface, an anterior femoral flange and a dome shaped patellar component. While first implanted in 1974, this prothesis was the first real modern TKA design that became the foundation for future implants. With the growing number of implants and surgical experience, there was debate about the utility of posterior cruciate ligament (PCL) retention. By 1978, Insall and Burstein introduced the Insall Burstein posterior stabilized knee prothesis. This innovative design substituted the PCL with a spine- cam mechanism that provided greater stability with better kinematics and range of motion. Over time, there became two camps of knee arthroplasty surgeons, those who retained the PCL and those who preferred PCL substitution. While this debate continued, further refinements in implants designs continued with more shapes and sizes to better accommodate the individual anatomy, along with improvements accommodate higher range of motion and normal knee kinematics. To reduce the stresses and possible polyethylene wear, mobile bearing designs with a more conforming articulation were introduced. The mobile bearing designs reduced the kinematic conflict of a conforming surface by decoupling the flexion-extension and rotation with a rotating tibial platform. More recently, there has been a move toward more guided motion knee designs with the medial pivot and medial congruent prosthesis, that provide rollback and motion based upon the differential conformity of the articular surface. These newer designs have features that accommodate both sacrificing or retention of the PCL. With the vast number of current implant designs on the international market, it is apparent that there is an effort, realistic or not, to find the “holy grail” and provide patients with a durable knee prothesis that will restore normal function without residual symptoms.