Patent ID: 8808388

Claim:
A tibial insert, comprising: a base; a post extending from the base along a longitudinal axis, the post having a medial surface, a lateral surface, and a height along the longitudinal axis, the medial surface having a medial section, and the lateral surface having a lateral section oriented substantially parallel to the medial section, the medial section and the lateral section each having a width in a substantially anterior-posterior direction that is sufficient to enable varus/valgus constraint over a flexion/extension range from extension to about 90 to 120 degrees of flexion when the tibial insert is mated with a femoral component defining an opening for receiving the post between substantially parallel walls, the opening providing a clearance of 0.005 inches to 0.030 inches between the post and the substantially parallel inner walls when the post is received in the opening, the medial section and the lateral section each extending such that, along at least half of the height of the post, the width of the medial section and width of the lateral section in the substantially anterior-posterior direction at a given axial position along the longitudinal axis are between one sixth and two thirds of a largest width of the post in the substantially anterior-posterior direction at that axial position.