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The UHMWPE Lexicon is the online reference for ultra-high molecular weight polyethylene used in total joint replacements. The additional goals for this website are to provide an overview of state-of-the-art research in several key polyethylene related problems of clinical significance and to encourage hypothesis driven polyethylene research.
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2009 Society for Biomaterials Tutorial: Advances in UHMWPE
This SFB tutorial reviews historical, conventional and highly crosslinked polyethylene used in total hip and knee replacement. We begin with an overview of the basic science concepts and terminology related to polyethylene and the two main thermal processing techniques with 1st generation materials, which involve either annealing or remelting the polymer after irradiative crosslinking. The second part of the review is a summary of key findings and concepts from the peer-reviewed literature on the subject of vitamin E stabilization of UHMWPE. 2nd generation highly crosslinked UHWMPE and future directions in UHMWPE research are also briefly reviewed.
Mechanical Properties, Oxidation, and Clinical Performance of Retrieved Highly Crosslinked Crossfire Liners after Intermediate-Term Implantation
Researchers from Drexel University have evaluated 60 Crossfire liners implanted after an average of 2.9 years (range: 0.01 – 8.0 years) for reasons unrelated to wear or mechanical performance of the polyethylene. Elevated oxidation was measured on the rim that correlated with implantation time. Rim surface damage, however, was observed in only 3/60 (5%) cases. Retrieval analysis of the three rim-damaged liners did not reveal an association between surface damage and the reasons for revision.
PhD Dissertation: Static and Cyclic Behavior of Crosslinked UHMWPE in the Presence of Mild Stress Risers
This Ph.D. Dissertation by Michael Sobieraj from the Case Western Reserve University describes the static and fatigue behavior of annealed and remelted highly crosslinked UHMWPE under smooth and notched conditions. Crosslinked formulations of GUR 1050 were investigated. Monotonic stress-strain behavior in the presence of a notch was examined using a custom developed video based system, under physiologically relevant conditions. The fatigue behavior was also investigated using a total life approach to fatigue.
2009 ORS Poster: Evaluation of Sub-Micron PE Wear Debris by Enhanced Polarized Light Microscopy
Major limiting factors for polarized imaging (and most optical systems) of wear debris is a lack of automation for capturing entire tissue sections in both brightfield and polarized modes, and the diffraction (Rayleigh) limit which limits imaging of small particles (e.g. <1 μm). The purpose of this study was to adapt a new elliptically polarized light imaging system (EPLIS) to in situ analysis of PE particles. The EPLIS system uses novel 3-D deconvolution to achieve “superresolution” allowing particles smaller than 1 μm to be analyzed. Validation of particles sizes were made by comparing with environmental scanning electron microscope (ESEM) images of the same particles.
2009 ORS Poster: Histomorphologic Characteristics of Periprosthetic Tissue from Crosslinked PE Hip Implants
The objective of this study was to evaluate the histomorphologic changes of periprosthetic tissue in relationship to areas of the tissue with PE wear debris. To accomplish this objective, a duel image analysis was done on H&E stained sections to determine histomorphologic changes
and inflammation by brightfield microscopy, and to evaluate PE debris size and distribution by polarized light microscopy. The hypothesis was that the size and volume of wear debris, and thus the histomorphologic changes in the tissue, would be more extensive for patients with historical gamma-air sterilized PE components as compared to the newer gamma-inert sterilized, highly crosslinked PE components.
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The Second Edition:UHMWPE Biomaterials Handbook
 The 2nd Edition of the UHMWPE Biomaterials Handbook, edited by Steven M. Kurtz, Ph.D., is currently in press and will be published in April 2009. The expanded Handbook will include 35 chapters and over 15 contributors, expanding upon the history, properties, and clinical performance of biomaterials used for joint replacement. The new edition contains dedicated chapters to remelted and annealed highly crosslinked UHMWPE, Vitamin E stabilization, composite biomaterials, high pressure crystallization, as well as chapters covering advances in characterization, such as hip and knee simulator testing, radiographic wear measurement, biological response of wear debris, and fatigue and fracture behavior. The book can be ordered via the Amazon website
or downloaded as an ebook. A preview of the ebook is also available.
Spine Technology Handbook
 A new frontier for surgical grade UHMWPE is in the field of spine implants. The Spine Technology Handbook, edited by Steven M. Kurtz, Ph.D., and Avram A. Edidin, Ph.D., is published by Elsevier Academic Press. The 16 chapters of the Spine Technology Handbook (560 pp.) describe the bioengineering principles, biomaterials, and designs of implants used in the treatment of spine disorders. Major technologies reviewed include devices used for fusion (screws, plates, rods, and cages), disc repair and augmentation, total disc replacement, and vertebral body repair and augmentation. An excerpt from Chapter 11, which discusses the use of UHMWPE in disc replacement, can be found here. Copies of the book can now be ordered through Amazon and Academic Press.
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Call for Papers for the 4th UHMWPE International Meeting in Torino, Italy
We are pleased to announce that the 4th UHMWPE International Meeting Update will be convened by the University of Torino, Italy, for September 16-18, 2009. As in previous years, the meeting will include two main parts: one basic research module, open for papers and oriented to gather cutting-edge research on UHMWPE; and a second part oriented to clinical aspects and discussion. Abstract submission for oral and poster presentations is now open (Deadline: June 1, 2009).
The conference will be focused on the following themes: (1) Oxidation of UHMWPE; (2) Stabilization of UHMWPE; (3) Crosslinking of UHMWPE; (4) Mechanical properties of UHMWPE; (4) UHMWPE debris; and (5) Alternative materials and alternative bearings. Selected papers from this meeting will be published as a Symposium in Clinical Orthopaedics and Related Research. Additional details about the conference can now be found at the conference website. If you are interested in submitting an abstract to this conference, please contact Professor Luigi Costa at Prof. Luigi Costa.
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New Standard Guide for UHMWPE Implant Components Published by ASTM International
ASTM International has recently published ASTM F2759 - 09, Standard Guide for Assessment of the Ultra High Molecular Weight Polyethylene (UHMWPE) Used in Orthopedic and Spinal Devices. The scope of this standard includes conventional and highly crosslinked UHMWPE, with and without Vitamin E. This standard provides guidance for UHMWPE testing to manufacturers of hip, knee, upper extremity, and spinal implants. The intent of this standard is to provide the basis for a future FDA guidance document for UHMWPE.
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