Life Sciences & Biomedicine Orthopedics Science & Technology Surgery
Gas sterilization (eg, ethylene oxide [EtO] and gas plasma) was introduced for polyethylene to reduce oxidation due to free radicals occurring during radiation sterilization. Recently, oxidation has been observed in polyethylenes with undetectable levels of free radicals, which were expected to be oxidatively stable. It is unclear whether in vivo oxidation will occur in unirradiated inserts sterilized with EtO.
We collected 20 EtO-sterilized tibial inserts at revision surgeries. We assessed oxidative using Fourier transform infrared spectroscopy and mechanical properties using the small punch test. Surface damage was assessed using damage scoring techniques and micro-CT.
Oxidation indexes were low and uniform between the regions. The subtle changes did not affect the mechanical properties of the polymer. The dominant surface damage modes included burnishing, abrasion, and third-body wear. There was no evidence of delamination in the retrievals.
The retrieved EtO-sterilized UHMWPE retrievals remained stable with respect to both oxidative and mechanical properties for up to 10 years in vivo. We did observe slight measurable amounts of oxidation in the inserts; however, it was far below levels that would be expected to compromise the strength of the polymer.
Due to the stable oxidative and mechanical properties, EtO-sterilized tibial components appear to be an effective alternative to gamma-sterilized inserts, at least in short-term implantations.
In Vivo Oxidation and Surface Damage in Retrieved Ethylene Oxide-sterilized Total Knee Arthroplasties
Creators
Daniel MacDonald - Exponent (United States)
Josa Hanzlik - Drexel University
Peter Sharkey - Rothman Institute
Javad Parvizi - Rothman Institute
Steven M. Kurtz - Exponent (United States)
Publication Details
Clinical orthopaedics and related research, v 470(7), pp 1826-1833
Publisher
Lippincott Williams & Wilkins
Number of pages
8
Grant note
StelKast, Inc (McMurray, PA, USA)
StelKast, Inc.
NIAMS R01 AR47904 / NIH; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA
Zimmer, Inc (Warsaw, IN, USA)
Stryker Orthopaedics, Inc (Mahwah, NJ, USA)
Resource Type
Journal article
Language
English
Academic Unit
School of Biomedical Engineering, Science, and Health Systems
Web of Science ID
WOS:000305211800004
Scopus ID
2-s2.0-84864278762
Other Identifier
991019169641204721
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