Abstract
Introduction. The usage of metal-metal bearings in young patients has rekindled the debate about the potential adverse effects of mutagenecity on offspring born to them. This question could be answered in part if it was known whether metal ions are transferred to the developing foetus. One recent study seems to suggest that such transfer does not occur [Brodner et al, J Arthroplasty2004; 19 Suppl(3) p102–107]. Unfortunately the instrument used there was not sensitive enough (5 out of 6 analyses were below the limit of detection), leaving the question of transplacental metal ion transfer unanswered. The present study uses a more powerful analytic technique.
Methods. After informed consent, whole blood specimens were obtained at the time of delivery from five patients who had undergone a Birmingham Hip Resurfacing and from their babies’ umbilical cords. High resolution plasma mass spectrometry (HRICPMS) was used for analysis.
Results. Cobalt and chromium ions have been detected in all the specimens obtained so far. The cord blood cobalt levels were lower than the mothers blood levels in all the specimens. A similar relationship was found in all but one individual chromium measurement. The mean (±95% CI) of the two groups are shown in figure 1.
Discussion and Conclusion. The present study shows that with the use of whole blood specimens rather than serum; and the use of a better analytic method than previously used in the only other study on the topic, metal ions can be detected in all specimens of patients with metal-metal devices and in the cord blood of babies born to them.
There is sufficient evidence in this study to prove that metal ions do cross the placenta. There is therefore a continuing need for vigilance on the possible effects on the offspring born to patients with metal-metal devices.
Correspondence should be addressed to The Secretary, BHS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
