A tibial insert (10) for use in knee arthroplasty, comprises a platform (12) including an upper bearing surface (14), and a keel (16) extending downwardly from the platform. The insert includes (i) a first downwardly-extending surface (15), (ii) a second downwardly-extending surface (17), and (iii) a rounded, distal surface (13) defining a continuous radius connecting the first and second downwardly-extending surfaces.
