Not anything that Collier hasn't been saying for years (In vivo oxidation in retrieved highly crosslinked tibial inserts http://www.ncbi.nlm.nih.gov/pubmed/22997097) but there have been 2 articles accepted to JOA that confirm via retrievals. 1) Kop Alan M., Pabbruwe Moreica B., Keogh Catherine, Swarts Eric, Oxidation of second generation sequentially irradiated and annealed highly cross-linked X3 polyethylene tibial bearings, Journal of Arthroplasty (2015), doi: 10.1016/j.arth.2015.04.027 "In doing so, it is proposed that the X3 material may not be oxidatively stable as a function of time in vivo. The exact role of applied load, the in vivo environment and its effect on oxidation however remains to be fully understood. Even so, oxidation has resulted in pitting and substantial material loss as well as subsurface white banding and cracking a common finding for older (pre 2000) polyethylene retrievals. In summary, oxidation should be closely monitored with clinicians monitoring long term patient outcomes and researchers scrutinising sequentially irradiated and annealed UHMWPE retrievals. Caution with regard to this material may be warranted; is history repeating?" 2) Rowell Shannon L., Reyes Christopher R., Malchau Henrik, Muratoglu Orhun K., In vivo oxidative stability changes of highly cross-linked polyethylene bearings: An ex vivo investigation, Journal of Arthroplasty (2015), doi: 10.1016/j.arth.2015.05.006 "Oxidation behavior differed between sequentially irradiated and annealed retrievals and their irradiated and melted counterparts in both extent and location, with the former showing more advanced oxidation and oxidation located in both loaded and unloaded regions. The most likely cause of the more advanced oxidative degradation in sequentially irradiated and annealed components is the presence of free radicals" "Sequentially irradiated and annealed components appeared to be more prone to both in vivo oxidation and overall destabilizing effects of in vivo factors, consistent with historic materials containing residual free radicals"