Paragraph Number

147

Referring to FIG. 28F, the medial ramp 2838 and the gradient it creates along the medial articulation surface 2820 towards the medial low point 2828 and may cause a translation or movement of the medial condyle 2802 greater than a translation or movement of the lateral condyle 2803, as the knee and assembly 2800 range from 0 degrees of flexion, or extension, to 90 degrees of flexion. The medial condyle 2802 may move down the medial ramp 2838 such that the medial dwell point 2835 migrates anteriorly and outwardly toward the medial perimeter 2826 as the degree of flexion increases. The lateral condyle 2803 may remain in generally the same location near the lateral low point 2831 so the lateral dwell point 2836 may remain in generally the same location. In certain embodiments, the lateral condyle 2803 may also migrate as the knee moves into flexion, so that the lateral dwell point 2836 migrates posteriorly and outwardly concurrently as the medial dwell point 2835 migrates anteriorly and outwardly. The asymmetric translation of the medial dwell point 2835 and lateral dwell point 2836 may create a tibiofemoral rotation between extension and flexion. Such tibiofemoral rotation is desired behavior for a healthy knee joint and may be referred to as Screw home Mechanism (SHM) of a knee joint caused, at least in part, by the difference in size of the medial condyle and lateral condyle of the distal femur.

Added by DJM 1 2022