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Chemistry‐driven structural alterations in short‐term retrieved ceramic‐on‐metal hip implants: Evidence for in vivo incompatibility between ceramic and metal counterparts
Author(s) -
Zhu Wenliang,
Pezzotti Giuseppe,
Boffelli Marco,
Chotanaphuti Thanainit,
Khuangsirikul Saradej,
Sugano Nobuhiko
Publication year - 2017
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.33689
Subject(s) - ceramic , cubic zirconia , in vivo , materials science , tetragonal crystal system , metal , monoclinic crystal system , composite material , chemistry , metallurgy , crystallography , crystal structure , microbiology and biotechnology , biology
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.