title: TEM observation of seven retrieved total knee joints made of Co-Cr-Mo and Ti-Al-V alloys.
abstract: We demonstrate that a myriad of fine particles produced by the abrasion of both cobalt-chromium-molybdenum (Co-Cr-Mo) and titanium-aluminum-vanadium (Ti-Al-V) alloys accumulate in the synovial cells next to surgical implants made from these alloys. The metallic particles were of various sizes, and were observed within the lysosomes. Energy dispersive X-ray spectroscopy studies revealed that the fine spherical particles consisted solely of Cr, and that other larger particles were composed of the Co-Cr-Mo alloy. We measured the size of the metallic particles using the public domain NIH image program, and found that most of the fine spherical particles were 10-15 nm in diameter (n=1000). Eighty percent of the large particles were 30-35 nm in length and 20-25 nm in width (n=300). In addition, EDS examination clarified that all of the fine particles of the Ti-Al-V alloy were composed of that alloy. For this alloy, when discounting the larger particles, the fine metal deposits were 20-25 nm in length and 10-15 nm in width (n=1000). From these findings, we conclude that the Co-Cr-Mo alloy is easily corroded and that Co is released from the cells. In contrast, the Ti-Al-V alloy is very stable and does not corrode, although the Ti-Al-V alloy does produce particles that are smaller than those produced by the Co-Cr-Mo alloy.
authors.affiliation: Instrumental Analysis Research Center, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
authors.forename: Shizuko
authors.initials: S
authors.lastname: Ichinose
authors.forename: Takeshi
authors.initials: T
authors.lastname: Muneta
authors.forename: Hideki
authors.initials: H
authors.lastname: Aoki
authors.forename: Motoki
authors.initials: M
authors.lastname: Tagami
mesh_terms: D000368:Aged; D000497:Alloys; D019544:Equipment Failure Analysis; D005260:Female; D005547:Foreign Bodies / Q000473:pathology*; D006801:Humans; D007719:Knee Joint / Q000473:pathology* / Q000601:surgery; D007720:Knee Prosthesis; D008247:Lysosomes / Q000648:ultrastructure; D008854:Microscopy, Electron; D008875:Middle Aged; D011475:Prosthesis Failure; D013583:Synovial Membrane / Q000648:ultrastructure*; D014025:Titanium; D014800:Vitallium
chemical_list: D000497:Alloys; D014800:Vitallium; C031462:titanium alloy (TiAl6V4); D014025:Titanium