Fig. 4.
a The linear wear contour for Disc Only and Disc + FSU at 1,3,5,7 and 10 million cycles as per ISO18192 (Flexion/Extension (Flex/Ext) of ±7.5°, lateral bending (LB) of ±6°, and axial rotation (AR) of ±4° and a compressive-follower load of 50–150 N). Wear contours clearly indicate the circumferential wear pattern for the Disc only test case, while an uneven, one-sided wear pattern is shown for the Disc + FSU test case. Black denotes maximum wear, while orange or red means minimal wear. In the inset, FV1 stands for magnitude of linear wear (mm). b Cumulative volumetric wear (mm3) at the end of each million cycles for Disc only and Disc + FSU model as per ISO18192 (Flexion/Extension (Flex/Ext)) of ±7.5°; lateral bending (LB) of ±6°, axial rotation (AR) of ±4° and a compressive-follower load of 50–150 N)