title: Oxidation and other property changes of retrieved sequentially annealed UHMWPE acetabular and tibial bearings.
abstract: This investigation analyzed retrieved sequentially crosslinked and annealed (SXL) ultra-high molecular weight polyethylene bearings to determine whether the material is chemically stable in vivo. A series of retrieved tibial and acetabular components were analyzed for changes in ketone oxidation, crosslink density, and free radical concentration. Oxidation was observed to increase with in vivo duration, and the rate of oxidation in tibial inserts was significantly greater than in acetabular liners. SXL acetabular bearings oxidized at a rate comparable to gamma-sterilized liners, while SXL tibial inserts oxidized at a significantly faster rate than their gamma-sterilized counterparts. A significant decrease in crosslink density with increased mean ketone oxidation index was observed, suggesting that in vivo oxidation may be causing material degradation. Furthermore, a subsurface whitened damage region was also found in a subset of the bearings, indicating the possibility of a clinically relevant decrease in mechanical properties of these components.
authors: Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, 03755.
authors: Steven D
authors: SD
authors: Reinitz
authors: Barbara H
authors: BH
authors: Currier
authors: Douglas W
authors: DW
authors: Van Citters
authors: Rayna A
authors: RA
authors: Levine
authors: John P
authors: JP
authors: Collier
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D020878:Device Removal; D019544:Equipment Failure Analysis; D005609:Free Radicals / Q000032:analysis; D005720:Gamma Rays; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D007659:Ketones / Q000032:analysis; D007720:Knee Prosthesis / Q000009:adverse effects; D008422:Materials Testing; D010084:Oxidation-Reduction; D011095:Polyethylenes / Q000737:chemistry* / Q000528:radiation effects; D016459:Prosthesis-Related Infections; D012189:Retrospective Studies; D017550:Spectroscopy, Fourier Transform Infrared; D013242:Sterilization; D013499:Surface Properties; D013977:Tibia / Q000601:surgery*; D013997:Time Factors
chemical_list: D005609:Free Radicals; D007659:Ketones; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene
keywords: FTIR; arthroplasty; implant retrieval; oxidation; polyethylene (UHMWPE)