A unicompartmental knee prosthesis for implantation in a knee joint betweena femoral condyle and a corresponding tibia plateau is provided including a generallyelliptical body having opposed femoral and tibial face, the body having an anteriorend and a posterior end. A keel is provided on the tibial face having a generallyanterior-posterior orientation, the keel having an anterior end and a posteriorend, where the keel posterior end includes a distal posterior portion that extendsfarther toward the body posterior end compared with a proximal posterior portionof the keel posterior end.
