The present study explores the hypothesis that polyethylene compo

The present study explores the hypothesis that polyethylene components sterilized in a low-oxygen environment undergo similar in SIS3 ic50 vivo oxidative mechanisms as inserts sterilized in air. In addition, the potential influence of the different sterilization processes on the wear performance of the polyethylene components was examined.

Methods: An analysis of oxidation, wear, and surface damage was performed for forty-eight acetabular liners and 123 tibial inserts. The mean implantation time was 12.3 +/- 3.7 years for

thirty-one acetabular liners that had been gamma sterilized in air and 4.0 +/- 2.5 years for the seventeen acetabular liners that had been gamma sterilized in inert gas. The mean implantation time was 11.0 +/- 3.2 years for the twenty-six tibial inserts that had been sterilized in air and 2.8 +/- 2.2 years for the ninety-seven tibial inserts that had been gamma sterilized in inert gas. Oxidation and hydroperoxide levels were characterized in loaded and unloaded regions of the inserts.

Results: Measurable oxidation and oxidation potential were observed in all cohorts. The oxidation and hydroperoxide levels were regional. Surfaces with access to body fluids were more heavily oxidized than

protected bearing surfaces were. This variation appeared to be greater in historical (gamma-in-air-sterilized) components. Regarding wear performance, historical and conventional acetabular liners showed similar wear penetration rates, whereas selleck chemicals a low incidence of delamination was confirmed for the conventional tibial inserts in the first decade of implantation.

Conclusions: The present study explores the impact of industry-wide changes in sterilization practices BV-6 for polyethylene. We found lower oxidation and oxidation potential in the conventional acetabular liners and tibial inserts that had been gamma sterilized in inert gas as compared with the historical

components that had been gamma sterilized in air. However, we also found strong evidence that conventional components undergo mechanisms of in vivo oxidation similar to those observed following gamma irradiation in air. In addition, gamma sterilization in inert gas did not provide polyethylene with a significant improvement in terms of wear resistance as compared with gamma sterilization in air, except for a lower incidence of delamination in the first decade of implantation for tibial inserts.”
“Objective: To determine the prevalence and outcome of higher order multiple (HOM) pregnancies in Lagos, Nigeria.

Methods: The mode of delivery, gestational age, pregnancy and neonatal outcome of babies delivered from HOM pregnancies were reviewed retrospectively from the labor ward and theater registers, neonatal unit admission records and medical notes in a tertiary referral centre from April 2009 to March 2012.

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