Advances in the processing, sterilization, and crosslinking of ultra-high molecular weight polyethylene for total joint arthroplasty.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/jor.1100170203

Development of an extremely wear-resistant ultra high molecular weight polyethylene for total hip replacements.

Lubrication and wear of ultra-high molecular weight polyethylene in total joint replacements

Ultra-high molecular weight polyethylene (UHMWPE) is the most common bearing material in total joint arthroplasty due to its unique combination of superior mechanical properties and wear resistance over other polymers. A great deal of research in recent decades has focused on further improving its performances, in order to provide durable implants in young and active patients. From “historical”, gamma-air sterilized polyethylenes, to the so-called first and second generation of highly crosslinked materials, a variety of different formulations have progressively appeared in the market. This paper reviews the structure–properties relationship of these materials, with a particular emphasis on the in vitro and in vivo wear performances, through an analysis of the existing literature.

/pdf/ultra-high-molecular-weight-polyethylene-influence-of-the-3v7f7qhgba.pdf

Ultra-High Molecular Weight Polyethylene: Influence of the Chemical, Physical and Mechanical Properties on the Wear Behavior. A Review

Deformation, yielding, fracture and fatigue behavior of conventional and highly cross-linked ultra high molecular weight polyethylene

Orientation softening in the deformation and wear of ultra-high molecular weight polyethylene

Linear reciprocating pin-on-plate-type wear testing has been a standard technique for the screening of orthopaedic implant materials since the early 1980s. This investigation compares a wear screening technique based on linear motion with a modern hip joint simulator based on multi-axial motion. Two groups of differently sterilized UHMWPE samples were tested. The first group of samples was sterilized by ethylene oxide (EtO) gas that caused no structural changes in the UHMWPE. The second group of samples was sterilized in nitrogen by gamma-irradiation and then subjected to a stabilization treatment that resulted in a significant level of crosslinking in the UHMWPE. When tested on the linear reciprocating wear machine, the EtO sterilized specimens (non-crosslinked linear polyethylene) showed an approximately 30% lower wear rate than the gamma-irradiated and stabilized specimens (crosslinked polyethylene). When tested on the hip simulator, the EtO sterilized specimens exhibited two to three times higher wear rates than the gamma irradiated and stabilized specimens. The ranking of wear resistance obtained with the hip simulator was strikingly different than that obtained with the linear reciprocating wear machine. This study indicates that screening wear machines based on linear motion do not correlate with multi-axial joint simulators and may produce misleading results in the prediction of clinical wear performance of UHMWPE bearing materials.

M. Sokol

Papers

Orientation softening in the deformation and wear of ultra-high molecular weight polyethylene

The significance of nonlinear motion in the wear screening of orthopaedic implant materials