TY - JOUR
T1 - A new finding on the in-vivo crevice corrosion damage in a CoCrMo hip implant
AU - Hashemi Oskouei, Reza
AU - Barati, Mohammad
AU - Farhoudi, Hamidreza
AU - Taylor, Mark
AU - Solomon, Lucian
PY - 2017/10/1
Y1 - 2017/10/1
N2 - A detailed investigation was performed to characterize the fretting wear and corrosion damage to the neck component of a CoCrMo stem from a metal-on-polyethylene implant retrieved after 99 months. The stem was a low-carbon (0.07 wt%) wrought Co-28Cr-6Mo alloy with no secondary carbide phases in the matrix (γ-phase). The original design of the neck surface contained an intentionally fabricated knurled profile with a valley-to-peak range of approximately 11 μm. Roughness measurements indicated that the tip of the knurled profile was significantly damaged, especially in the distal medial region of the neck, with up to a 22% reduction in the mean peak-to-valley height (Ra) compared to the original profile. As a new finding, the channels between the peaks of the profile created an additional crevice site in the presence of stagnant body fluid within the head-neck taper junction. These channels were observed to contain the most severe corroded areas and surface oxide layers with micro-cracks. SEM/EDS, XRD and XPS evaluations identified the formation of Cr2O3 as a corrosion product. Also, decobaltification was found to occur in these corroded areas. The findings of this work indicate the important role of the knurled profile in inducing additional crevice corrosion.
AB - A detailed investigation was performed to characterize the fretting wear and corrosion damage to the neck component of a CoCrMo stem from a metal-on-polyethylene implant retrieved after 99 months. The stem was a low-carbon (0.07 wt%) wrought Co-28Cr-6Mo alloy with no secondary carbide phases in the matrix (γ-phase). The original design of the neck surface contained an intentionally fabricated knurled profile with a valley-to-peak range of approximately 11 μm. Roughness measurements indicated that the tip of the knurled profile was significantly damaged, especially in the distal medial region of the neck, with up to a 22% reduction in the mean peak-to-valley height (Ra) compared to the original profile. As a new finding, the channels between the peaks of the profile created an additional crevice site in the presence of stagnant body fluid within the head-neck taper junction. These channels were observed to contain the most severe corroded areas and surface oxide layers with micro-cracks. SEM/EDS, XRD and XPS evaluations identified the formation of Cr2O3 as a corrosion product. Also, decobaltification was found to occur in these corroded areas. The findings of this work indicate the important role of the knurled profile in inducing additional crevice corrosion.
KW - Chromium oxide
KW - CoCrMo alloy
KW - Crevice corrosion
KW - Fretting wear
KW - Orthopaedic implants
KW - X-ray photoelectron spectroscopy
UR - https://doi.org/10.1016/j.msec.2017.05.086
UR - http://www.scopus.com/inward/record.url?scp=85019400971&partnerID=8YFLogxK
U2 - 10.1016/j.msec.2017.05.086
DO - 10.1016/j.msec.2017.05.086
M3 - Article
VL - 79
SP - 390
EP - 398
JO - MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS
JF - MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS
SN - 0928-4931
ER -