Vanadium release in whole blood, serum and urine of patients implanted with a titanium alloy hip prosthesis

Abstract

Introduction. Vanadium (V) is a minor constituent of the Titanium–Aluminum–Vanadium (TiAlV) alloy currently used in cementless hip prostheses. Present study aimed at verifying the correlation of vanadium levels among different matrices and assessing reference levels of the ion in a population of patients wearing a well-functioning hip prosthesis. Methods. Vanadium was measured using Inductive Coupled Plasma Mass Spectrometry (ICP-MS) in whole blood, serum and urine of 129 patients implanted with a TiAlV-alloy hip prosthesis. Results. The values in the serum were above the upper limit of the reference values in 42% of patients (29% in urine and 13% in whole blood). A good correlation among matrices was observed (p < 0.001). The cohort of patients (N = 32) complaining of pain or in which a loosening or damage to the prosthesis was assessed showed a significantly higher excretion of vanadium in urine as compared with the remaining asymptomatic patients (p = 0.001). The 95th percentile distribution of vanadium in the cohort of patients with a well-functioning prosthesis was 0.3 μg/L in whole blood, 0.5 μg/L in serum and 2.8 μg/L in urine, higher that in the unexposed population, especially for urine. Conclusions. The presence of a prosthesis, even though well-functioning, may cause a possible release of vanadium into the blood and a significant urinary excretion. The reference values of vanadium of the asymptomatic patients with titanium alloy hip prostheses supplied information regarding the background exposure level of the ions and their lower and upper limits.

Keywords:

• titanium alloy
• cementless hip prosthesis
• vanadium
• blood
• urine
• serum

Acknowledgment

The study had a partial grant from the Italian Ministry of Health, Research project ‘Pending failure of hip prosthesis with hard to hard bearings’.

The contribution of Dr. Marilina Amabile who collected the data of the patients, and of the nursing personnel of the departments and polyclinics who carried out the collection of the samples is gratefully acknowledged.

Declaration of interest

The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper.