Predicting UHMWPE wear: evidence for rapid decline in wear rates following a change in sliding direction

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Description/Abstract

Extending the service life of total joint replacements by improving the wear resistance of UHMWPE remains a priority that is driven by the demands of a more active patient [1]. Extensive experimental testing has shown that wear rates depend on the details of the wear path: Unidirectional paths produce minimal wear while those with direction change produce high wear [2-4]. This implies that a linear wear path that undergoes a sudden change in direction will generate a high wear rate immediately following that direction change and then will transition to a near zero wear rate with continued sliding. To the authors’ knowledge, this variation in wear rate with sliding distance after a change in sliding direction has not been explored experimentally. The goal of this study was to investigate the incremental wear as the sliding distance is increased between step-changes in sliding direction. We hypothesized that small increases in sliding distance after a direction change would produce additional wear while no additional wear would be produced at longer sliding distances sufficient to reestablish ‘unidirectional’ sliding.