Bi-unicompartmental knee arthroplasty （Bi-UKA） is an effective surgical approach for select knee osteoarthritis （KOA） patients，significantly improving knee function and quality of life. However，Bi-UKA was once regarded as a middle-groud or supplementary option to total knee arthroplasty （TKA）. In recent years，the clinical value and application prospects of Bi-UKA have once again become a focus of research. Increasing evidence suggests that Bi-UKA，by balancing anatomical structure preservation with more natural postoperative kinematic recovery，may offer a novel strategy for the stepwise treatment of KOA. This paper aims to review recent advances concerning the fundamental concepts，current development，clinical outcomes，patient selection，and future trends of Bi-UKA，and discusses its role and challenges in the context of stepwise treatment for KOA，aiming to provide a reference for clinical application.