In Silico Approach in Estimating Wear and Failure of Dual Mobility Implants With Large Cup and Liner Thickness Under Different Cup Inclination Angles for Routine Gait Activities

Dual mobility helps in improving the range of motion and also reduces the revision of implants compared with standard implants. The present study focuses on analyzing the wear of implants using global model finite element approach in estimating wear of dual mobility implants under regular gait activities for steep cup inclinations. The gait activities considered are normal walking, sitting down or getting up, and stairs up and down. The cup inclination angles considered are [Formula: see text], [Formula: see text], and [Formula: see text]. The large value of cup and outer shell thickness is considered for simulation purposes, since the model is simulated for secondary sliding to predict wear under wide range of motion for 2 million cycles. The cobalt–chromium (Co–Cr) alloy femur head with ultra-high molecular weight polyethylene (UHMWPE) acetabular cup backed by Co–Cr alloy liner is considered for the current study. Primary contact pressure is found to be lower for cup inclination angle of [Formula: see text], and maximum primary contact pressure is reported for cup inclination of [Formula: see text], but the difference is quite minimal. Larger cup size and liner thickness effectively reduced the contact pressure for steeper cup inclinations, even under the possibility of edge loading conditions. The linear wear depth of UHMWPE is found to be lower for cup inclination of [Formula: see text], followed by [Formula: see text], and maximum for [Formula: see text]. This clearly indicates that large cup thickness comparatively reduced contact stress, as it plays major role in increasing wear depth. No change in volumetric wear was observed for all gait activities, and maximum volumetric wear was observed for sitting down or getting up gait activity due to wide range of articulation of the joint. Archard’s wear equation is used to obtain both linear and volumetric wear. Stairs-down gait activity exhibited least volumetric wear. For all steep cup inclination angles, von Mises stress of UHMWPE is well within the yield stress limit. This study clearly shows that large cup and liner thickness help in improving longevity of implants in contrast to implants having smaller cup and liner thickness.