Interchangeable neck failures of bi-modular femoral stems in primary total hip arthroplasty cannot be predicted from serum trace element analysis.

Abstract

Revision of a well-fixed stem due to unexpected modular neck fracture is a catastrophe for the patient and a challenge for the surgeon. This study aimed to test the possibility of predicting interchangeable neck fracture from serum levels of the stem/neck alloy-consisting metals. Nineteen patients at high risk for interchangeable neck fracture were randomly selected out of a cohort of 680 bimodular stems made from Ti6Al4V alloy. Serum levels of titanium, aluminium and vanadium were determined. Nine age- and gender-matched patients were used as controls. Mean serum levels of Ti were 6.04 ± 2.52μg/L, of Al 3.89 ± 1.68μg/L and of V 0.07 ± 0.04μg/L in the high-risk group, and 8.22 ± 4.74μg/L, 4.99 ± 3.98μg/L and 0.27 ± 0.44μg/L in the low-risk group, respectively. No statistically significant differences were found between the groups. Interchangeable neck fracture of bimodular femoral stems cannot be predicted from serum trace element analysis.