Abstract
Introduction
The observation of elevated heavy metal ions in arthroplasty patients in association with complications has led to concern on the part of patients and surgeons. The aim of this study was to determine the levels of cobalt chromium ions in three compartments, the joint fluid, plasma, and CSF.
Method
Patients were divided into 3 groups:
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239 without any implant(M132F108)
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50 having a supplementary implant, with a well performing contralateral THR.
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– 16 large head MoM arthroplasty (Birmingham modular M7F9)
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– 44 a Birmingham resurfacing(M39F5)
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6 revisions of MoM bearings(M3F3)
Blood and CSF specimens were harvested at the time of induction of anaesthesia. Joint fluid was aspirated before the surgical incision was made under sterile conditions. Cobalt was assayed using an Agilent7500ce inductively coupled plasma mass spectrometer. Chromium was assayed with a graphite furnace atomic absorption spectrometer (Varian240zlGFAAS). Bivariate correlations were used to determine similarities between group
Results
All results are in nanomoles/litre.
Primary group.
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Blood: Co4.62±3.86; Cr6.10+I-4.17.
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CSF: Co2.43±3.44; Cr4.82±3.24
Supplementary group:
THR
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Blood: Co37.3±62.96; Cr29.2±45.2
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CSF: Co3.7±2.6;Cr7.4±4.9
BHR
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Blood: Co35.2+I-48.8; Cr66.5+I-1 01.03.
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CSF: Co4.7±11.6;Cr6.6-'-I-4.1
Revision Group
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Joint Fluid: Co5184.5±4662.9; Cr4452.7 ±3302.9.
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Blood: Col 07.5+1–77.6, Cr127.5±90.2.
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CSF: Co6.3±3.0, Cr8.3+I-6.2.
Comparing with total hip with resurfacing patients, cobalt levels were not significantly different, but chromium levels were higher in resurfacing patients. The CSF levels, however, were not significantly different in the two groups. The CSF chromium level in all circumstances was higher than the cobalt. In patients with well functioning prostheses the blood ion levels were some 50% to 100% higher than patients without prostheses. While cobalt was higher in the joint fluid and the blood measurements, chromium was higher in the CSF. CSF measurements in the three groups of patients with pre-existing implant either well functioning or not, were not significantly different. The blood levels obtained are consistent with that described as reference values” for cobalt and chromium provided in pathology reports. On that basis, we believe that the CSF levels in the samples tested are an accurate representation of the levels.
Conslusion
Blood sample chromium levels were higher than cobalt levels with the exception of total hip replacements. In spite of high levels and joint fluid, and less than 5% of the ion level was found in the blood. Of the blood level, less than 15% of was reflected in the CSF
