Patent ID: 8740984

Claim:
An orthopedic prosthesis comprising: a tibial base comprising an upper surface, a medial side, a lateral side, an anterior side, a posterior side, a peripheral edge including an anterior portion and a posterior portion, and a first locking structure provided on the upper surface, the medial side and the lateral side being defined by a medial-lateral midline and the anterior side and the posterior side being defined by an anterior-posterior midline, the first locking structure including a first shoulder along the posterior portion of the peripheral edge, the first shoulder projecting upwardly from the upper surface and defining a first undercut structure, a second shoulder is provided along the anterior portion of the peripheral edge, the second shoulder defining a second undercut structure; and a unitary tibial insert comprising a medial bearing surface and a lateral bearing surface and a bottom surface, a second locking structure provided on the bottom surface, wherein the first and second locking structures are configured for engaging each other and the first locking structure guides the tibial insert along an engagement direction vector when the tibial insert is inserted into the tibial base towards the posterior side, the engagement direction vector being angled away from the medial-lateral midline of the tibial base towards the medial side of the tibial base by a predetermine angle, the second undercut configured to receive a lip of the tibial insert for locking the tibial insert to the tibial base when the tibial insert is fully seated.