Fixed-bearing knee prosthesis having interchangeable components

A fixed-bearing knee prosthesis, comprising:

• a femoral component having a medial condyle surface and a lateral condyle surface,
• a bearing having (i) a medial bearing surface configured to articulate with the medial condyle surface of the femoral component, and (ii) a lateral bearing surface configured to articulate with the lateral condyle surface of the femoral component, and
• a tibial tray secured to the bearing, the tibial tray having a platform with a fixation member extending downwardly from a lower surface thereof, the platform having (i) a posterior buttress extending along a posterior section of a perimeter of the platform and extending upwardly from an upper surface of the platform, 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,
• wherein the posterior buttress is generally Y-shaped and has (i) a first arm extending along a posterior edge of the platform and having a first undercut defined therein, (ii) a second arm extending along the posterior edge of the platform in a direction away from the first arm and having a second undercut defined therein, and (iii) a third arm extending anteriorly away from the first arm and the second arm,
• wherein the anterior buttress has (i) a first arm extending along an anterior edge of the platform, (ii) a second arm extending along the anterior edge of the platform in a direction away from the first arm of the anterior buttress, and (iii) an undercut defined therein, and
• wherein (i) an imaginary line extends along a posterior-most edge of the first arm of the anterior buttress and a posterior-most edge of the second arm of the anterior buttress, and (ii) the imaginary line defines a curve having a constant radius.

A fixed-bearing knee prosthesis, comprising:

• a femoral component having a medial condyle surface and a lateral condyle surface,
• 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
• a plurality of bearings configured to be separately secured to the tibial tray, wherein each of the plurality of bearings has (i) a width that is different from at least some of the other of the plurality of 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 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 (v) an anterior locking tab arranged to be received in the undercut defined in the anterior buttress.