Gender difference in metal ion levels following metal-on-metal resurfacing hip arthroplasty

Abstract

Objective To study the effect of gender on the serum ion levels of Co, Cr and Mo in the patients who have undergone metal-on-metal resurfacing hip arthroplasty. Methods Enrolled in the present study were 24 patients with fracture of uni-lateral femoral head who were injured from November 2008 to March 2013 in traffic accidents. There were 12 men, with an average age of 54.7±5.9 years, including 5 cases of type 31-C1 and 7 cases of 31-C2. There were also 12 women, with an average age of 53.9±5.8 years, including 6 cases of type 31-C1 and 6 cases of 31-C2. All the patients received metal-on-metal resurfacing hip arthroplasty. The ion levels of Co, Cr and Mo in the serum of the patients were measured by electrochemical trace element determination at 3, 6, 9 and 12 months after surgery for comparison between the male and female groups. Results The ion concentrations of Co and Cr in both groups significantly increased and then decreased after reaching the peak at 6 months post-surgery. In the male group at 3, 6, 9 and 12 months after surgery, the Co levels were respectively 1.37±0.50 μg/L, 2.51±0.78 μg/L, 1.99±0.46 μg/L and 1, 26±0.60 μg/L and the Cr levels were respectively 0.98±0.18 μg/L, 1.39±0.44 μg/L, 1.12±0.21 μg/L and 0.74±0.15 μg/L. In the female group at 3, 6, 9 and 12 months after surgery, the Co levels were respectively 1.23±0.59 μg/L, 2.17±0.82 μg/L, 1.79±0.43μg/L and 1.23±0.11 μg/L and the Cr levels were respectively 0.90±0.20 μg/L, 1.19±0.31 μg/L, 1.03±0.20 μg/L and 0.74±0.17 μg/L. There was no significant change in the ion concentration of Mo in either male or female groups after surgery. No significant differences were found in the ion levels of Go, Cr or Mo after surgery between the 2 groups (P > 0.05) except that the Cr ion level in the male patients was significantly higher than that in the female patients at 9 months after surgery (P <0.05). Conclusion No significant differences can be found in the ion levels of Co, Cr or Mo after surgery between males and females except that the Cr ion level in the male patients may be significantly higher than that in the female patients at 9 months after surgery. Key words: Arthroplasty, Replacement, hip; Sex factors; Serum; Metals, heavy; Ions