A unicompartmental knee prosthesis for implantation in a knee joint between afemoral condyle and a correspondingtibia plateau is provided including a generally elliptical body having opposedfemoral and tibial face, the body having an anteriorend and a posterior end. A keel is provided on the tibial face having agenerally anterior-posterior orientation, the keel having ananterior end and a posterior end, where the keel posterior end includes adistal posterior portion that extends farther toward the bodyposterior end compared with a proximal posterior portion of the keel posteriorend.
