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Journal of Bone and Joint Surgery - British Volume, Vol 89-B, Issue 3,
301-305.
doi: 10.1302/0301-620X.89B3.18520 Copyright © 2007 by British Editorial Society of Bone and Joint Surgery Transplacental transfer of cobalt and chromium in patients with metal-on-metal hip arthroplastyA CONTROLLED STUDYH. Ziaee, BSc(Hons), Biomedical Scientist1; J. Daniel, FRCS, Director of Research, Staff Orthopaedic Surgeon1; A. K. Datta, MD, MRCOG, Specialist Registrar2; S. Blunt, MD, FRCOG, Consultant Obstetrician2; and D. J. W. McMinn, FRCS, Consultant Orthopaedic Surgeon1
1 The McMinn Centre, 25, Highfield Road, Birmingham, B15 3DP, UK. Correspondence should be sent to Mr J. Daniel; e-mail: josephdaniel{at}mcminncentre.co.uk
Metal-on-metal bearings are being increasingly used in young patients. The potential adverse effects of systemic metal ion elevation are the subject of ongoing investigation. The purpose of this study was to investigate whether cobalt and chromium ions cross the placenta of pregnant women with a metal-on-metal hip resurfacing and reach the developing fetus. Whole blood levels were estimated using high-resolution inductively-coupled plasma mass spectrometry. Our findings showed that cobalt and chromium are able to cross the placenta in the study patients with metal-on-metal hip resurfacings and in control subjects without any metal implants. In the study group the mean concentrations of cobalt and chromium in the maternal blood were 1.39 µg/l (0.55 to 2.55) and 1.28 µg/l (0.52 to 2.39), respectively. The mean umbilical cord blood concentrations of cobalt and chromium were comparatively lower, at 0.839 µg/l (0.42 to 1.75) and 0.378 µg/l (0.14 to 1.03), respectively, and this difference was significant with respect to chromium (p < 0.05). In the control group, the mean concentrations of cobalt and chromium in the maternal blood were 0.341 µg/l (0.18 to 0.54) and 0.199 µg/l (0.12 to 0.33), and in the umbilical cord blood they were 0.336 µg/l (0.17 to 0.5) and 0.194 µg/l (0.11 to 0.56), respectively. The differences between the maternal and umbilical cord blood levels in the controls were marginal, and not statistically significant (p > 0.05). The mean cord blood level of cobalt in the study patients was significantly greater than that in the control group (p < 0.01). Although the mean umbilical cord blood chromium level was nearly twice as high in the study patients (0.378 µg/l) as in the controls (0.1934 µg/l), this difference was not statistically significant. (p > 0.05) The transplacental transfer rate was in excess of 95% in the controls for both metals, but only 29% for chromium and 60% for cobalt in study patients, suggesting that the placenta exerts a modulatory effect on the rate of metal ion transfer. This article has been cited by other articles:
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