A fixed-bearing knee prosthesis system includes a femoral component having a medial condyle surface and a lateral condyle surface. The system also includes a tibial tray having a platform with a fixation member extending downwardly from a lower surface thereof, the platform having (i) a generally Y-shaped posterior buttress extending upwardly from an upper surface of the platform and having a pair of arms extending along a posterior section of a perimeter of the platform, each of the pair of arms having an undercut defined therein, and (ii) an anterior buttress extending along an anterior section of the perimeter of the platform and extending upwardly from the upper surface of the platform, the anterior buttress being discontiguous with the posterior buttress and having an undercut defined therein, and (iii) an elongated bore having a superior end that opens into an upper surface of the posterior buttress. The system also includes a plurality of revision bearings configured to be separately secured to the tibial tray, wherein each of the plurality of revision bearings has (i) a width that is different from at least some of the other of the plurality of revision bearings, (ii) an upper surface having a medial bearing surface configured to articulate with the medial condyle surface of the femoral component and a lateral bearing surface configured to articulate with the lateral condyle surface of the femoral component, (iii) a lower surface having a posterior recess defined therein to receive the posterior buttress and an anterior recess defined therein to receive the anterior buttress, (iv) a reinforcing pin extending out of the posterior recess, (v) a pair of posterior locking tabs arranged to be respectively received in the undercuts defined in each of the pair of arms of the posterior buttress, and (vi) an anterior locking tab arranged to be received in the undercut defined in the anterior buttress. Also included in the system is a plurality of primary bearings con
