Kinetically Critical Sites of Femoral Head Roughening for Wear Rate Acceleration in Total Hip Arthroplasty

Polyethylene wear acceleration from (scratching) damage to the femoral head is a recognized hazard from constructs prone to generate third-body debris, but the phenomenon is nebulous and therefore often is subordinated to more direct and immediate considerations. To help delineate tangible quantitative relationships between counterface roughening and accelerated polyethylene wear, an experimentally validated sliding-distance-coupled finite element model of total hip replacement wear was adapted to incorporate regions of localized femoral head roughening. This computational formulation was used systematically to identify the sites on the femoral head for which a given severity of local roughening (parameterized in terms of roughening patch size and tribologic wear coefficient) was most consequential in terms of elevated polyethylene wear. Two such sites, of nominally comparable kinetic importance, were consistently evident throughout a wide range of roughening severities. These critical sites were located quasi-superiorly near the sagittal midline of the head, one slightly anterior and one slightly posterior of the coronal midline.