Is Oxinium Losing Its Luster?: Commentary on an article by Christopher J. Vertullo, MBBS, FRACS(Orth), FAOrthA, et al.: "Twelve-Year Outcomes of an Oxinium Total Knee Replacement Compared with the Same Cobalt-Chromium Design. An Analysis of 17,577 Prostheses from the Australian Orthopaedic Association National Joint Replacement Registry"