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Friday, October 8, 2010, 8:00-8:30Session A10: Bearings and TribologyMetal Ion Levels and Associated Chromosome Aberrations in Metal-on-Metal Total Hip Arthroplasties*Baljinder Dhinsa - Royal National Orthopaedic Hospital - Stanmore, United KingdomKieran Gallagher - Royal National Orthopaedic Hospital - Stanmore, United KingdomZuhair Nawaz - Royal National Orthopaedic Hospital - Stanmore, United KingdomBen Spiegelberg - Royal National Orthopaedic Hospital - Stanmore, United KingdomSam Hanna - Royal National Orthopaedic Hospital - Stanmore, United KingdomStephen Tai - Royal National Orthopaedic Hospital - Stanmore, United KingdomRob Pollock - Royal National Orthopaedic Hospital - London, UKRichard Carrington - Royal National Orthopaedic Hospital - London, UKSteve Cannon - Royal National Orthopaedic Hospital - London, UKTim Briggs - . - London, UK*Email: bsd14@hotmail.comThe aim of this study is to investigate whether Metal-on-Metal (MoM) implants result in morechromosome aberrations and increased blood metal ions post-operatively when compared toMetal-on-Polyethylene (MoP) implants.Metal-on-metal arthroplasties are being inserted in increasing numbers of younger patients dueto the increased durability and reduced requirement for revision in these implants. Recentstudies have raised many concerns over possible genotoxicity of MoM implants.This is a prospective study of patients who have undergone elective total hip replacement, theywere selected and then randomised into two groups. Group A received a MoP implant andgroup B received a MoM implant. Patients are reviewed pre-operatively (control group), at 3months, 6 months, 1 year and 2 years post-operatively. On each occasion blood tests are takento quantify metal ion levels (chromium, cobalt, titanium, nickel and vanadium) using HR-ICPMS method and chromosome aberrations in T lymphocytes using 24 colour fluorescent insitu hybridisation (FISH).53 patients have been recruited to date. 24 of whom had MoP prosthesis and 29 a MoM. 37 ofthese have had their one year follow-up with blood analysis and 14 have had 2 year follow up.Cobalt and chromium concentration increased during the first 6 months in both MoM and MoPgroups, in the MoM group the chromium levels were twice that of MoP group and 12x that ofthe preoperative samples. Chromosome aberrations occurred in both groups. At 6 months boththe MoM and MoP groups showed increase frequency of aneuploidy aberrations with furtherincreases after one year. Structural damage in the form of translocations occurred in the MoMgroup after one year, but not in the MoP group, by two years there was a profound increase intranslocationsPreliminary results of this study show that the levels of chromium and cobalt are significantlyhigher in the MoM group compared to the MoP group. This corresponds to increases inchromosome aberrations in the groups with increases in structural chromosome damage aftertwo years.file:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]