Updated Oxidation Index Test Method Published by ASTM
ASTM has now published F2381-06, "Standard Guide for Evaluating the Extent of Oxidation in Ultra-High-Molecular-Weight Polyethylene Fabricated Forms Intended for Surgical Implants." This updated method has incorporated additional details regarding the limits of integration for the carbonyl region of the FTIR spectrum. The standard is currently available to download from the ASTM website. At the May 2006 ASTM meeting, ongoing development of the standard was discussed to include protocols for measuring oxidation in retrieved components.
Conference on Degradation, Stabilization, and Crosslinking of UHMWPE
Orthopedic surgeons and researchers at the University of Turin, Italy, will be convening a new, one-day symposium about UHMWPE on Friday, March 18, 2005. The meeting will be held at the Museo dell'Automobile "Carlo Biscaretti di Medicina del Lavoro Ruffia", Corso Unità d'Italia, 40 - Torino. The meeting, directed primarily towards clinicians and researchers, is being organized (in part) to discuss advances in the stabilization of polyethylene using Vitamin E. Click here to download the meeting agenda. For further details, please visit the conference website or contact Prof. Luigi Costa.
Trans-Vinylene FTIR Test Method Published by ASTM
ASTM has now published F2381-04, "Standard Test Method for Evaluating the Trans-Vinylene Yield in Irradiated Ultra-High Molecular Weight Polyethylene." This new method can be used to infer the dose of radiation used to crosslink UHMWPE. The standard is currently available to download from the ASTM website. At the November 2004 meeting in Washington DC, further clarifications on the round robin protocol were made. The purpose of the round robin will be to quantify the repeatability and reproducibility of this new test method.
ISO Publishes Resin, Oxidation Index, and Morphology Standards
At the September 2004 ISO TC 150 Meeting in Vancouver, Canada, it was announced that several parts of the ISO standards related to UHMWPE had now advanced to the publication stage. The resin standard (ISO 5834 Part 1), oxidation index (Part 4), and morphology index (Part 5) test methods are all expected to be published by ISO this fall. Parts 1 and Parts 5 of ISO 5834 are similar to ASTM Standard F648, whereas the oxidation index standard (Part 4) is the same method as ASTM F2102.
Accelerated Aging Test Method and Consolidated Form Specification Now Final Draft ISO Standards
The ISO accelerated aging standard (5834 Part 3) and the updated specification for consolidated forms (Part 2) will be circulated this fall as final draft ISO standards (FDIS). The ISO aging standard is the same method as ASTM F2003, whereas the consolidated form standard (Part 2) is similar to ASTM F648.
Trans-Vinylene FTIR Test Method Approved at ASTM
In April 2004, ASTM approved F2381-04, "Standard Test Method for Evaluating the Trans-Vinylene Yield in Irradiated Ultra-High Molecular Weight Polyethylene." This new method can be used to infer the dose of radiation used to crosslink UHMWPE. The standard will be available for download from the ASTM website (www.astm.org) in the near future. A round robin has been initiated to quantify the repeatability and reproducibility of this new test method.
Resin, Aging, and Morphology Test Methods Passed as Draft International Standards
During the latest ballot, the ISO TC 150 elevated parts 1, 3, and 5 of ISO 5834 to the status of "Draft International Standards (DIS)." These parts of the ISO standard pertain to medical grade UHMWPE resin, accelerated aging, and morphology index. The draft ISO standards are expected to be finalized in 2004. Parts 1 and 5 of the ISO 5834 standard incorporate the specification and morphology test methods contained in ASTM F648. The accelerated aging ISO document (Part 3 of ISO 5834) incorporates the test method from ASTM F2003.
Miniature Specimen Izod Round Robin
The UHMWPE task force for ASTM F648 is conducting a round robin to evaluate miniature specimens that can be used with 1" diameter rod stock. The existing standard IZOD impact specimen is too large to be used under such circumstances. Starting in May 2003, seven centers agreed to participate in the testing of miniature and standard-sized IZOD specimens fabricated from Type 1, Type 2, and Type 3 resin. As of the November 2003 ASTM meeting in Tampa, all of the participating centers had completed testing. Analysis of the round robin results is anticipated by the next ASTM meeting in March 2004.
Oxidation Index Method Passed as Draft International Standard
During September 2003, at the ISO TC 150 meeting in Izmir, Turkey, the oxidation index standard was elevated to the status of "Draft International Standard (DIS)." The standard will be designated ISO 5834-4, "Ultra-high molecular weight polyethylene. Part 4: Procedure for Measuring the Extent of Oxidation in UHMWPE." The draft ISO standard will be finalized in 2004. This standard incorporates the oxidation index method described in ASTM F2102.
Morphology Index Round Robin Completed
The task forces for medical grade UHMWPE at ASTM (F648) and ISO (5834-5) embarked last year on a round robin to evaluate the repeatability and reproducibility of a standard method for quantifying the morphology index of UHMWPE. The morphology index method is currently part of ASTM F648-00, and is being considered for adoption into ISO 5834-5. Six centers participated in this international study, which was completed in May 2003. The results for the round robin testing are summarized in the PDF report, which is available here for download.