Development of computational wear prediction on total ankle replacement

Abstract

The computational wear simulation has been widely used to predict wear generated on hip and knee implant but studies related to wear analysis of the ankle are limited. The purpose of this study is to develop finite element analysis on total ankle replacement (TAR) wear prediction. Three-dimensional (3D) models of a right ankle TAR have been created to represent Bologna-Oxford (BOX) TAR model. The model consist of three components; tibial, bearing and talar representing their physiological functions. The joint reaction force profile at ankle joint has applied 25 discrete instants during stance phase of a gait cycle. It is to determine the distribution of contact stress on meniscal bearing surfaces contact with talar component. The sliding distance was obtained from predominate motions of plantar/dorsi flexion. Parametric studies to reduce wear have been conducted to optimize the design of polyethylene joint. The parameters involved are the thickness of the meniscal bearing, the radius of curvature between talar and bearing component, the width and length of meniscal bearing. The value of linear wear depth is 0.01614 mm per million cycles which is in agreement with other studies (0.0081 – 0.0339 mm per million cycles). The relative difference is 9%. The value of volumetric wear after five million cycles is 30.5 mm3 which is in agreement with other studies (16 – 66 mm3). The relative difference is 12%. The best dimension to use for the thickness, radius of curvature, width and length of meniscal bearing are 6 mm, 30 mm, 30 mm and 22 mm, respectively.