title: Chemistry-driven structural alterations in short-term retrieved ceramic-on-metal hip implants: Evidence for in vivo incompatibility between ceramic and metal counterparts.
abstract: Ceramic-on-metal (CoM) hip implants were reported to experience lower wear rates in vitro as compared to metal-on-metal (MoM) bearings, thus hinting metal-ion release at lower levels in vivo. In this article, we show a spectroscopic study of two short-term retrieval cases of zirconia-toughened alumina (ZTA) femoral heads belonging to CoM hip prostheses, which instead showed poor wear performances in vivo. Metal contamination and abnormally high fractions of tetragonal-to-monoclinic (t→m) polymorphic transformation of the zirconia phase could be found on both ZTA heads, which contrasted with the optimistic predictions of in vitro experiments. At the molecular scale, incorporation of metal ions into the ceramic lattices could be recognized as due to frictionally assisted phenomena occurring at the ceramic surface. Driven by abnormal friction, diffusion of metal ions induced lattice shrinkage in the zirconia phases, while residual stress fields became stored at the surface of the femoral head. Diffusional alterations destabilized the chemistry of the ceramic surface and resulted in an abnormal increase in t→m phase transformation in vivo. Frictionally driven metal transfer to the ceramic lattice thus hinders the in vivo performance of CoM prostheses. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1469-1480, 2017.
authors.affiliation: Department of Medical Engineering for Treatment of Bone and Joint Disorders, Osaka University, Suita, Osaka, 565-0854, Japan.
authors.forename: Wenliang
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Ceramic Physics Laboratory, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, Kyoto, 606-8585, Japan.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pezzotti
authors.affiliation: Ceramic Physics Laboratory, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, Kyoto, 606-8585, Japan.
authors.forename: Marco
authors.initials: M
authors.lastname: Boffelli
authors.affiliation: PMK Hip & Knee Surgery, Department of Orthopedics, Phramongkutklao Hospital and College of Medicine, Bangkok, 10330, Thailand.
authors.forename: Thanainit
authors.initials: T
authors.lastname: Chotanaphuti
authors.affiliation: PMK Hip & Knee Surgery, Department of Orthopedics, Phramongkutklao Hospital and College of Medicine, Bangkok, 10330, Thailand.
authors.forename: Saradej
authors.initials: S
authors.lastname: Khuangsirikul
authors.affiliation: Department of Medical Engineering for Treatment of Bone and Joint Disorders, Osaka University, Suita, Osaka, 565-0854, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sugano
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D019544:Equipment Failure Analysis; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008875:Middle Aged; D011475:Prosthesis Failure; D015040:Zirconium / Q000737:chemistry*
chemical_list: D015040:Zirconium; D000535:Aluminum; C028541:zirconium oxide
keywords: alumina zirconia composite; ceramic-on-metal bearings; hip replacement prosthesis; metal ion; surface analysis