title: Oxidation of Second Generation Sequentially Irradiated and Annealed Highly Cross-Linked X3™ Polyethylene Tibial Bearings.
abstract: Since the first use of ultra-high-molecular-weight polyethylene as a bearing material, research and development efforts have sought to improve wear resistance, increase longevity and lessen the potential for debris mediated adverse tissue responses. A series of second generation sequentially cross-linked and annealed tibial bearings were analysed after several bearings sent for routine retrieval analysis showed oxidative degradation including subsurface whitening, cracking and gross material loss. Evaluation incorporated visual and white banding assessment, mechanical testing and spectroscopy analysis. Whilst visual observation and white banding assessment confirmed oxidative changes, a decrease in mechanical properties and increasing ketone oxidation index as a function of time in vivo suggest time dependent oxidative degradation. Clinically relevant degradation of the sequentially cross-linked and annealed tibial bearings was observed.
authors.affiliation: Centre for Implant Technology and Retrieval Analysis, Department of Medical Engineering and Physics, Royal Perth Hospital, Perth, WA, Australia.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Kop
authors.affiliation: Centre for Implant Technology and Retrieval Analysis, Department of Medical Engineering and Physics, Royal Perth Hospital, Perth, WA, Australia.
authors.forename: Moreica B
authors.initials: MB
authors.lastname: Pabbruwe
authors.affiliation: Centre for Implant Technology and Retrieval Analysis, Department of Medical Engineering and Physics, Royal Perth Hospital, Perth, WA, Australia.
authors.forename: Catherine
authors.initials: C
authors.lastname: Keogh
authors.affiliation: Centre for Implant Technology and Retrieval Analysis, Department of Medical Engineering and Physics, Royal Perth Hospital, Perth, WA, Australia.
authors.forename: Eric
authors.initials: E
authors.lastname: Swarts
mesh_terms: D000368:Aged; D003432:Cross-Linking Reagents / Q000737:chemistry; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D010100:Oxygen / Q000737:chemistry; D011095:Polyethylenes / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical; D013977:Tibia / Q000601:surgery*
chemical_list: D003432:Cross-Linking Reagents; D011095:Polyethylenes; D011108:Polymers; C111601:ultra-high molecular weight polyethylene; D010100:Oxygen
keywords: FTIR; arthroplasty; mechanical testing; oxidation; polyethylene (UHMWPE); retrieval