Half a century ago, Michael Freeman introduced the concept of right-angled femoral and tibial bone cuts in total knee arthroplasty (TKA)- mechanical alignment (MA). A little later, John Insall, raised the importance of balancing the resulting medial-lateral and flexion-extension joint gaps. MA technique, subsequently, became the gold standard in total knee arthroplasty. The MA technique can be defined as “systematic”, in that all patients are implanted in a standardised fashion, without considering the individual native knee anatomy and physiological soft tissue laxities. This non-physiological implantation was thought to be biomechanically-friendly, aiming to reduce the knee adduction moment and thus the risk of unbalanced prosthetic joint load. This rationale made sense at a time when polyethylene quality, cementation technique and instrumentation were rudimentary. Over the decades that followed, multiple implant designs were developed, the quality of the polyethylene improved, the precision of implantation of components enhanced through advanced instrumentation and technological assistance (e.g. computational, robotics), and the implant fixation optimised. MA surgical technique was refined to reduce residual knee instability linked to modification of joint gaps: using soft tissue release algorithms with measured resection technique or the gap-balancing technique.