This site summarizes standards activities for UHMWPE at the American Society for Testing and Materials International, Inc. (ASTM International) and the International Organization for Standardization (ISO). Historically, UHMWPE standards have been fragmented into ASTM and ISO documents. However, because many of the UHMWPE experts have been attending ASTM meetings and quickly developing new standards, the ISO documents for medical grade UHMWPE have fallen behind the times, due largely to their much longer (typically 5-year) ISO renewal cycle. In the latest revision of the ISO UHMWPE standards (currently underway), the working drafts under review convert the parts of ISO 5834 into "umbrella" documents that refer to key sections of existing (and more advanced) ASTM standards. Those interested in the state-of-the-art testing and material standards of medical grade UHMWPE are encouraged to participate in the activities of ASTM International, which convenes twice per year.
-S.M. Kurtz, August 15, 2009
CURRENT ASTM INTERNATIONAL STANDARDS FOR MEDICAL GRADE UHMWPE
ASTM D4020 - 05 Standard Specification for Ultra-High-Molecular-Weight Polyethylene Molding and Extrusion Materials
This specification provides for the determination of the dilute solution viscosity and Izod impact strength of UHMW-PE. Those polyethylenes with a relative viscosity of greater of 1.44 at a solution concentration of 0.02% in decalin are considered UHMW-PE resins.
ASTM F648 - 07e1 Standard Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated Form for Surgical Implants
This specification defines material characteristics for UHMW-PE used for the application of surgical implants. The standard is written in two parts: powder and fabricated form, the latter used for the fabricated device. The specification does not apply to packaging and sterilization of the final product.
ASTM F2003 - 02(2008) Standard Practice for Accelerated Aging of Ultra-High Molecular Weight Polyethylene after Gamma Irradiation in Air
This guide outlines the 5 atmospheres of pure oxygen, 70°C procedure for accelerated aging to evaluate the oxidative stability of UHMWPE. This procedure was initially validated based on certain components that were gamma irradiated in air and subsequently shelf-aged in air. However, the procedures do not replicate natural aging of UHMWPE irradiated in an inert environment, nor do they replicate the degradation patterns associated with in vivo oxidation. Notwithstanding these limitations, ASTM F2003 is widely used in the orthopedic community to evaluate the oxidative stability of highly crosslinked and stabilized UHMWPE biomaterials.
ASTM F2102 - 06e1 Standard Guide for Evaluating the Extent of Oxidation in Ultra-High-Molecular-Weight Polyethylene Fabricated Forms Intended for Surgical Implants
This guide outlines a procedure for quantifying the oxidation of UHMWPE using Fourier Transform Infrared Spectroscopy. The standard definition of an oxidation index for UHMWPE is provided in this standard.
ASTM F2183 - 02(2008) Standard Test Method for Small Punch Testing of Ultra-High Molecular Weight Polyethylene Used in Surgical Implants
This standard describes a method for evaluating the mechanical behavior of UHMWPE using miniature disk specimens 0.5 mm in thickness and 6.4 mm in diameter. Because of the miniature specimen size, it is useful for testing fabricated components as well as retrieved implants after revision surgery.
ASTM F2214 - 02(2008) Standard Test Method for In Situ Determination of Network Parameters of Crosslinked Ultra High Molecular Weight Polyethylene (UHMWPE)
This standard describes the methodology for measuring the swell ratio of highly crosslinked UHMWPE, which can be used to calculate the crosslink density.
ASTM F2381 - 04 Standard Test Method for Evaluating Trans-Vinylene Yield in Irradiated Ultra-High-Molecular-Weight Polyethylene Fabricated Forms Intended for Surgical Implants by Infrared Spectroscopy
This guide outlines a procedure for quantifying the trans-vinylene content of UHMWPE using Fourier Transform Infrared Spectroscopy. The standard definition of a trans-vinyline index for UHMWPE is provided in this standard.
ASTM F2565 - 06 Standard Guide for Extensively Irradiation-Crosslinked Ultra-High Molecular Weight Polyethylene Fabricated Forms for Surgical Implant Applications
This guidance document outlines the recommended test methods for characterizing highly crosslinked UHMWPE materials. This standard pertains to the material properties of fabricated forms, and does not discuss performance standards for devices. Such guidance is provided in ASTM F2695, discussed below.
ASTM F2625 - 07 Standard Test Method for Measurement of Enthalpy of Fusion, Percent Crystallinity, and Melting Point of Ultra-High-Molecular Weight Polyethylene by Means of Differential Scanning Calorimetry
This test method outlines a standard procedure for performing DSC measurements on UHMWPE.
ASTM F2695 - 07 Standard Specification for Ultra-High Molecular Weight Polyethylene Powder Blended With Alpha-Tocopherol (Vitamin E) and Fabricated Forms for Surgical Implant Applications
This material specification covers UHMWPE blended with Vitamin E; methods for doping UHMWPE with Vitamin E after consolidation or crosslinking do not fall within the scope of this standard.
ASTM F2759 - 09 Standard Guide for Assessment of the Ultra High Molecular Weight Polyethylene (UHMWPE) Used in Orthopedic and Spinal Devices
This guidance document outlines the recommended test methods for characterizing conventional, Vitamin E-blended, and/or highly crosslinked UHMWPE orthopedic and spinal devices. This test method was developed at the request of AdvaMed to assist orthopedic and spinal device manufacturers in the development and regulatory process.
CURRENT ISO STANDARDS FOR MEDICAL GRADE UHMWPE
ISO 11542.1/.2 Plastics - Ultra-high-molecular weight polyethylene (PE-UHMW) moulding and extrusion materials - Part 1: Designation system and basis for specifications / Part 2: Preparation of test specimens and determination of properties
These specifications establish a designation system, test specimen preparation methods and testing methods for polyethylenes with a MFR (melt flow rate) of less than 0.1 g/10 min. measured at 190 °C and 21.6 kg load. The designation is based primarily on the following parameters: density, viscosity number and elongational stress.
ISO 5834.1/.2 - Implants for surgery - Ultra-high molecular weight polyethylene - Part 1: Powder form/Part 2: Moulded forms
These specifications provide the requirements and corresponding test methods for powder and molded forms of UHMW-PE used in the manufacture of surgical implants. This standard is essentially an ISO adaptation of ASTM F648. A revision of Part 1 is currently underway to convert this ISO standard into an "umbrella" document referring explicitly to ASTM F648.
ISO 5834.3 - Implants for surgery - Ultra-high molecular weight polyethylene - Part 3: Accelerated Aging Methods
This standard is currently an "umbrella" document that explicitly refers to the ASTM method for accelerated aging described in ASTM F2003.
ISO 5834.4 - Implants for surgery - Ultra-high molecular weight polyethylene - Part 4: Oxidation Index Measurement Method
This standard is essentially an ISO adaptation of ASTM F2102. A revision of this standard is currently underway to convert this ISO standard into an "umbrella" document referring explicitly to ASTM F2102.
ISO 5834.5 - Implants for surgery - Ultra-high molecular weight polyethylene - Part 5: Morphology Assessment Method
This standard is essentially an ISO adaptation of Annex 2 for ASTM F648. A revision of this standard is currently underway to convert this ISO standard into an "umbrella" document referring explicitly to ASTM F648.