Serologic and radiographic outcome of total hip arthroplasty with CoCr modular neck at mid-term follow-up

Purpose: The aim of this study is a radiographic evaluation and to determine serologic values of chromium and cobalt in the blood and urine of patients who have been implanted with a Stryker® ABG II Modular Neck and see if there is correlation with the features of prosthesis and patients. Methods: The study involves the collection of data from patients operated on for total hip model with the ABG II Modular Neck with a minimum follow-up of 1 year. Results: We evaluated 22 patients who underwent implantation of a hip prosthesis with modular neck in CoCr. Of these, the average Cr in the blood was 0.63 μgL−1 (range 0.1–2.15 μgL−1), the average of Co in the blood was 3.50 μgL−1 (range 0.62–7.78 μgL−1), the average Cr in the urine was 1.24 μgL−1 (range 0.48–2.21 μgL−1), and the average Co in urine was 14.22 μgL−1 (range 3.3–31.2 μgL−1). None of these patients had undergone revision surgery. Conclusions: Our study seems to indicate that the restoration of offset and age are correlated with the release of metal ions, although the correlation is weak and needs better methodological studies and a greater number of patients to confirm this hypothesis. Study type: Case series Level of Evidence 4. © 2016, Istituto Ortopedico Rizzoli.