New Update (Nov. 18, 2002): Symposium Presentations and Abstracts are Now Available for Viewing in HTML Format Below.

Sponsored by ASTM Committee F04 on Medical and Surgical Materials and Devices

Symposium Co-Chairmen

About the Symposium

The symposium is devoted to highly crosslinked and thermally treated UHMWPE. Wear of the UHMWPE has been linked to osteolysis and late loosening of joint replacements. Improvement in the wear resistance of the UHMWPE by radiation crosslinking is expected to reduce the late onset of osteolysis and thus extend the longevity of contemporary joint replacements.

After irradiation, UHMWPE materials may be thermally processed, either by annealing or remelting. Thermal processing improves the oxidation resistance of the polymer, as well as modifiying the crystallinity, and hence mechanical behavior. By combining radiation crosslinking and thermal processing, researchers have greatly increased the complexity of the polymer, when compared with conventional UHMWPE.

Developing new standards for this diverse family of implant materials is a challenging, but urgently needed, task. Thus far, standardization activities have focused on the development of new assessment methods, such as the swell ratio technique for characterizing crosslink density. The first goal of this symposium is to develop consensus for future standards activities related to crosslinked UHMWPE. The second main objective is to highlight the current state-of-the-art in laboratory and clinical assessment of crosslinked UHMWPE.

Symposium Schedule

Tuesday, November 5, 2002

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Introduction and Welcoming Remarks   S. M. Kurtz

Session I - Quantifying Clinical Response (J. Martell, Moderator)

Validation of a Deconvolution Technique for Quantifying Short-Term Wear in a Conventional and Highly Crosslinked Acetabular Components   S. M. Kurtz   Comparison of Cross-Linked and Conventional UHMWPE Wear Debris   M. A. Wimmer   Wear Debris Generation in Joint Simulator Testing of Crosslinked UHMWPE   S. Jani   Morphology of Wear Debris from Non-crosslinked, Gamma-Air Sterilized (Crosslinked) and Gamma-Crosslinked-Remelted Low-Wear Polyethylenes   H. McKellop   Evaluation of Accuracy and Precision of two Radiographic Regimes for use with the Martell Computer Assisted Method of Measuring Acetabular Wear   C. R. Bragdon

Session II - Short-Term Retrievals (R. Gsell, Moderator)

Wear Surfaces of Highly Crosslinked Components   C. Rieker   Surface Analysis of Early Retrieved Acetabular Polyethylene Liners: A Comparison of Conventional and Highly Crosslinked Polyethylenes   O. K. Muratoglu   Retrieval Analysis Of Cross-linked Acetabular Bearings   J. P. Collier

Session III – Crosslinked PE in Knees: Is It Safe? (J. Martell, Moderator)

Improved Resistance to Wear, Delamination and Posterior Loading of Electron Beam Irradiated, Melt-annealed, Highly Crosslinked UHMWPE Knee Inserts   J. Q. Yao   The Effect of Crosslinking UHMWPE on In Vitro Wear Rates of Fixed and Mobile Bearing Knees   D. McNulty   The Wear of Crosslinked UHMWPE in the Presence of Abrasive Particles: Hip and Knee Simulator Studies   M. P. Laurent   The Sensitivity of Crosslinked UHMWPE to Abrasive Wear: Hips vs. Knees   V. Good   Multiaxial Fatigue Behavior of Oxidized and Unoxidized Conventional UHMWPE   M. Villarraga   The Reduced Fracture Toughness that Accompanies Elevated Cross-Linking of Polyethylene is not associated with an Increase in Pitting and Delamination Type Wear   S. A. Maher   Wear & Functional Fatigue Simulation of Crosslinked UHMWPE   Aiguo Wang

Wednesday, November 6, 2002

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Session IV - Mechanical Properties (S. Kurtz, Moderator)

The Effect of Aging on Mechanical Properties of Melt-Annealed Highly Cross-Linked UHMWPE   S. K. Bhrambri   The Flow Ratio Effect on Oriented, Crosslinked UHMWPE   R. King   Quantifying Low Wear Rates in Ultra High Molecular Weight Polyethylene Orthopaedic Implants   Paul Ostic   The effect of specimen thickness on the mechanical behavior of UHMWPE characterized by the small punch test   M. Herr

Session V - In-Vitro Testing (S. Kurtz, Moderator)

The Effects of Raw Material, Irradiation Dose, and Irradiation Source on Crosslinking of UHMWPE   K. W. Greer     Characterization of the Wear Performance of Crosslinked UHMWPE and Relationship to Molding Procedures   K. R. St. John   Influence of the irradiation dose on the properties of crosslinked UHMWPE   N. Abt   The Development of a Third Body Wear Model   C. R. Bragdon   Elevated Crosslinking Alone Does Not Explain Polyethylene Wear Resistance   B. D. Furman

Symposium Concludes

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