A tibial implant system has an ultra-high molecular weight polyethylene tibial insert which can engage with either one of two tibial trays through differing means of engagement. The tibial insert includes a locking wire and locking tab disposed along an anterior surface and a locking recess disposed along a posterior surface. A first polymeric tibial tray includes a bead along an anterior wall and an undercut area along a posterior wall. A second metallic tibial tray includes a plurality of barbs along an anterior wall and an undercut area along a posterior wall.