Abstract
Introduction: Metal-on-metal arthroplasties are being used for their increased durability and reduced requirement for revision. Previous data reports that metal-on-metal bearing surfaces release three times more cobolt and chromium ions than metal-on-polyethelene hip replacements. Data also suggests that these metal ions can cause DNA damage.
Method: A prospective study of patients (aged 60–80), meeting exclusion criteria were selected and randomised to metal-on-metal or metal-on-polyethylene articulation. Patients were reviewed preoperatively (control model) and at 3 months, 6 months and one year postoperatively. On each occasion blood tests were taken to quantify metal ion levels (chromium, cobalt, nickel, vanadium and titanium) and chromosome aberrations in T lymphocytes using 24 colour fluorescent in situ hybridization (FISH).
Results: The number of chromosome aberrations increased with time; in particular there was a statistically significant increase in aneuploidy after one year, there was also an increase in chromosome translocations. There was a similar increase in blood concentration of metal ions over this same time period which proved significant. Higher levels of metal ions were seen in the metal-on-metal group when compared with the metal-on-polyethylene.
Conclusion: This study has highlighted the effects of metal ions on chromosome replication in particular causing aneuploidy aberrations. This provides evidence of the short-term effects of metal-on-metal arthroplasty but further research needs to be undertaken to assess long-term risk and also the risk associated to other cell lines.
Correspondence should be addressed to BHS c/o BOA, at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London, WC2A 3PE, England.
