A tibial prosthesis can include a bearing component and a tibial tray. The bearing component can include at least one concave articulating surface, a distal surface opposite said concave articulating surface, and a notch formed in said distal surface. The notch can define a longitudinal axis, the longitudinal axis defining an offset axis angle relative to the sagittal plane. The offset axis angle can range from greater than zero degrees to about 90 degrees. The tibial tray can include a support surface capable of supporting said bearing component, the support surface having a lateral edge and a medial edge opposite said lateral edge. The tibial tray can further include a boss having a longitudinal axis, the longitudinal axis angled with respect to the sagittal plane. The boss can be lockingly engageable with said notch along said offset axis angle to lock said tibial tray to said bearing component.
