title: A comparative microstructural study of vitamin-E blended and infused highly crosslinked UHMWPE for total knee arthroplasty.
abstract: The impact of adding antioxidant vitamin-E (α-tocopherol) to the microstructure of ultrahigh molecular weight polyethylene (UHMWPE) for total knee arthroplasty has been studied in detail by means of Raman microprobe spectroscopy. Three tibial insert samples prepared by different manufacturing methods were investigated, as follows: (A) a sample manufactured without blending with vitamin E which did not receive any irradiation dose after consolidation but underwent final sterilization in ethylene oxide (EtO); (B) a sample blended with 0.3 wt% of α-tocopherol, an isomer of vitamin E, and manufactured as sample (A); and, (C) a sample in which vitamin E was diffused after being irradiated with 100 kGy dose of γ-ray. Clear microstructural differences were observed in terms of phase contents (i.e., amorphous, crystalline, and intermediate phase fraction), molecular orientation, and the degree of anisotropy between the investigated tibial plates. Vitamin E in the starting resin promoted chain mobility leading to reorganization of the molecular chains. The spectroscopic characterizations helps to rationalize the complex effect of vitamin-E on the UHMWPE microstructure and gives useful information on how significantly any single step of the manufacturing procedures might affect the mechanical properties of the final orthopedic component.
authors.affiliation: Ceramic Physics Laboratory and Research Institute for Nanoscience, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, 606-8585 Kyoto, Japan.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Puppulin
authors.affiliation: Piezotech Japan, Ltd. Sakyo-ku, Ichijouji, Mukaihatacho 4, 606-8126 Kyoto, Japan.
authors.forename: Andrea
authors.initials: A
authors.lastname: Leto
authors.affiliation: Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, Tsu City 514-8507, Mie, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hasegawa
authors.affiliation: Ceramic Physics Laboratory and Research Institute for Nanoscience, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, 606-8585 Kyoto, Japan. Electronic address: pezzotti@kit.ac.jp.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pezzotti
mesh_terms: D016880:Anisotropy; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001672:Biocompatible Materials / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D003460:Crystallization; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008968:Molecular Conformation; D009985:Orthopedics; D020959:Polyethylene / Q000737:chemistry; D011095:Polyethylenes / Q000737:chemistry*; D013053:Spectrophotometry; D013059:Spectrum Analysis, Raman; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013977:Tibia / Q000473:pathology; D014810:Vitamin E / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene; D014810:Vitamin E; D020959:Polyethylene
keywords: Annealing; Irradiation; Knee replacement; Microstructure; Raman spectroscopy; Remelting; UHMWPE; Vitamin-E