Despite its theoretical advantages in terms of less invasive surgery, bi-unicompartmental knee replacement still represents a controversial knee reconstructive procedure. Many orthopaedic surgeons are skeptical about this demanding procedure despite the possibility of maximally preserving anatomy, with benefits for functional aspects such as gait, muscle activity and proprioception. Presently, no results of bi-unicompartmental knee replacement have been reported in the literature, even if several surgeons use it in selected cases. We present a retrospective analysis of our experience with this implant at a minimum follow-up of 36 months. At the latest follow-up, the mean Knee Society score was 80.58, the mean functional score was 83.5 and the mean postoperative GIUM score was 78. No implant has been revised and all patients are satisfied with the outcome. We consider bi-unicompartmental knee replacement to be a reasonable, less invasive option for the treatment of knee arthritis in selected cases.