Unicompartmental knee arthroplasty (UKA) is a bone conserving and ligament-sparing procedure that reliably restores normal knee kinematics and function for arthritis limited either to the medial or the lateral compartment of the knee. Although there is enough evidence to demonstrate that the UKA offers good mediumto long-termsuccess given the correct patient selection, prosthesis design, and implantation technique, there are several reports to suggest inferior survival rates in comparison with the total knee arthroplasty (TKA). Furthermore, it is a specialized procedure which works well in the hands of the experienced operator and therefore different authors’ tend to draw different conclusions based on the same evidence, and as a result, there is great variability in the usage of the UKA. The aimof this current concept’s review is to present to the readers the history of the UKA especially with reference to implant design, discuss current controversies, and outline the future perspectives of this novel procedure.