Quantifying the effect of resin type and sterilization method on the degradation of ultrahigh molecular weight polyethylene after 4 years of real-time shelf aging
✍ Scribed by Willie, Bettina M. ;Ashrafi, Shadi ;Alajbegovic, Sanjin ;Burnett, Trever ;Bloebaum, Roy D.
- Book ID
- 102294309
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 257 KB
- Volume
- 69A
- Category
- Article
- ISSN
- 0021-9304
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✦ Synopsis
Abstract
Alternative sterilization methods including ethylene oxide, gas plasma, and gamma‐radiation in an inert environment were implemented in the late 1990s, to limit oxidative degradation of ultrahigh molecular weight polyethylene (PE). There was also a simultaneous transition to PE resins that did not contain calcium stearate. Shelf storage duration of PE inserts following gamma‐irradiation in air has been correlated to poor clinical performance and increased wear. This study aimed to determine how sterilization method and resin type influenced degradation of PE after 4 years of real‐time shelf aging. It was hypothesized that gamma‐irradiation and stearate containing resins would incur significantly more degradation than nonradiated, stearate‐free resins. Gamma‐irradiated PE samples in air and nitrogen had a significantly increased density and oxidation index, compared to nonirradiated PE after 4 years of shelf aging. Alternative sterilization methods such as ethylene oxide and gas plasma appeared to have significantly less oxidation regardless of PE resin type. A partial correlation demonstrated that density and oxidation index were not correlated (r^2^ = 0.079) when examining the influence of sterilization method. The data supported that after 4 years of real‐time shelf aging, the type of sterilization method had a larger influence on PE degradation than resin type. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 477–489, 2004