Unacceptable biodegradation of polyethylene in vivo

Characterization of ultrahigh molecular weight polyethylene irradiated with ?-rays and electron beams to high doses

“…This may be due to formation of a double bond and oxidation, as very often observed for irradiated polymers. 25 Indeed, also in the case of UHMWPE, IR spectra exhibited carbonyl and double bond formation upon irradiation with ␥-rays in air, as shown in Figure 11. The IR peaks at 1725 and 980 cm Ϫ1 were assigned to CAO and CAC formation, respectively, while the peak at 1375 cm Ϫ1 was used as an internal standard.…”

Hysteretic Heating During Cyclic Loading of Medical Grade Ultra High Molecular Weight Polyethylene (UHMWPE)

“…Longterm degeneration in UHMWPE is known to alter the properties drastically and to fulfil the Arrhenius correlation, according to which the chemical reaction rate, in this case oxidation, increases with temperature. [32,33] In all fatigue studies known to the authors, UHMWPE wear and oxidation processes in artificial joints do not take into account temperature rise due to hysteretic heating. Although it is known that flow in the material initiates stress concentrations and therefore provokes a local temperature peak, we considered a temperature increase in the flawless material.…”

Prevention of Biofilm Associated Infections and Degradation of Polymeric Materials Used in Biomedical Applications

“…These failures may appear together or separately depending on the application, however, it is typical that the orthopaedic implants undergo mechanical friction which is associated with motion under pressure. Although UHMWPE is a superior material for joint purposes, some studies have reported high degree of mechanical degradation on hip and knee implants (Brach del Prever et al, 1996, Heisel et al, 2004, Kabo et al, 1993. It was also determined that the wear, friction and oxidative properties are better for crosslinked UMPWE than the conventional one (Heisel et al, 2004, Heisel et al, 2005, MarkutKohl et al, 2009) and that during the mechanical wear, oxidative degradation of the polyethylene may occur.…”