A tibial implant includes a baseplate having a proximally facing surface surrounded at least in part by a proximally extending wall. The wall has a ramp surface extending from the wall towards the baseplate proximally facing baseplate surface and a bore located distally of the ramp. A polyethylene bearing insert is mounted on the baseplate and has a distally facing surface engaging the proximally facing surface of the baseplate. The distally facing bearing insert surface has a recess and the insert has a side surface with a passageway extending from the recess through the insert side surface. A spring detent is mounted in the bearing insert recess and has a moveable pin biased outwardly of the bearing insert side surface and into the bore of the baseplate.
