Patent ID: 8480752

Claim:
A tibial bearing comprising: a platform having a medial bearing surface, a lateral bearing surface, and an anterior rim; and a spine extending upwardly from the platform between the medial bearing surface and the lateral bearing surface, the spine including a posterior cam surface, a medial sidewall, and a lateral sidewall, wherein the spine has a length when viewed in the transverse plane that is defined by a first line segment extending from a medial-lateral center point of the posterior cam surface of the spine to a medial-lateral center point of the anterior rim of the platform, wherein the spine has (i) a first width when the tibial bearing is viewed in the transverse plane that is defined by a second line segment orthogonal to and bisecting the first line segment, the second line segment extending from the medial sidewall to the lateral sidewall of the spine and (ii) a second width when the tibial bearing is viewed in the transverse plane that is defined by a third line segment orthogonal to the first line segment and crossing the first line segment at a point on the first line segment posterior to the second line segment, the third line segment extending from the medial sidewall to the lateral sidewall of the spine, wherein the first width is greater than the second width, and the posterior cam surface of the spine is convex such that when the tibial bearing is viewed in the transverse plane the posterior cam surface bows outwardly posteriorly to define a convex superior edge and a convex inferior edge, and wherein the platform has a centerline axis defined in the anterior-posterior direction when viewed in the transverse plane, and the spine has a longitudinal axis defined along its length, wherein an angle is defined between the longitudinal axis of the spine and the centerline axis of the platform, when viewed in the transverse plane, and said angle is greater than about five degrees.