Patent ID: 8328874

Claim:
A mobile tibial assembly comprising: a tibial tray configured to be coupled to a surgically-prepared surface of a proximal end of a tibia, the tibial tray including (i) a platform having a curved upper surface, the curved upper surface having a first substantially straight edge that defines an anterior end of a generally wedge-shaped opening in the curved upper surface and a second substantially straight edge that defines a posterior end of the wedge-shaped opening, the first substantially straight edge being shorter than the second substantially straight edge such that the anterior end of the wedge-shaped opening is narrower than the posterior end of the wedge-shaped opening, (ii) an anchor extending downwardly from a bottom surface of the platform, and (iii) a cavity extending downwardly from the generally wedge-shaped opening formed in the upper surface of the platform of the tibial tray into the anchor; and a unicompartmental tibial insert including (i) a platform having an upper bearing surface and a curved bottom surface configured to contact the curved upper surface of the platform of the tibial tray and (ii) and a stem extending downwardly from the curved bottom surface of the platform of the unicompartmental tibial insert through the generally wedge-shaped opening in the upper surface of the platform of the tibial tray, the stem being received within the cavity of the tibial tray such that a bottom surface of the stem of the unicompartmental tibial insert is positioned below a bottom surface of the platform of the tibial tray.