A trial system for an implantable joint replacement includes an articular insert having an insert body and an insert post captive to the insert body. The insert post is translatable relative to the insert body while remaining captive to the insert body. An aperture on the insert body forms a path, which may be arcuate, along which the insert post can translate. An axis of rotation about which the insert post translates passes through the insert body, and may be medially offset from the center of the body. A flexible element may connect the insert post to the insert body. In one method of use, the trial system is engaged with a femoral component and a tibial component during a prosthetic total knee joint implantation procedure to determine selection of an implantable articular insert which provides knee joint articulation closely matching the articulation of a natural knee.