title: Intermediate-term trends in serum levels of metal ions after hip resurfacing arthroplasty.
abstract: BACKGROUND
  The potential risks associated with hip resurfacing arthroplasty (HRA) are controversial and underestimated. The aim of this study was to explore intermediate-term trends for the levels of cobalt (Co), chromium (Cr), and molybdenum (Mo) ions after HRA.
  
  
  METHODS
  Forty patients who underwent HRA from October 2005 to December 2010 were recruited to this study. The serum levels of metal ions were examined preoperatively and 3, 12, 24, and 60 months after surgery. Trends and differences in levels of metal ions with respect to sex, operated side, and body mass index (BMI) were analyzed.
  
  
  RESULTS
  There were no significant differences in levels of Cr, Co, and Mo at each time point with respect to sex, operated side, and BMI (p > 0.05). The postoperative levels of Cr, Co, and Mo ions were significantly higher than the preoperative levels across sex, operated side, and BMI groups. Postoperative levels of Cr, Co, and Mo peaked at 12, 24, and 60 months, respectively. Cr levels peaked earlier (at 12 months) in the overweight (BMI ≥25 kg/m(2)) group compared to the normal-weight group (BMI <25 kg/m(2)), Co levels (at 12 months) peaked in women compared to men, and Mo levels (at 3 months) peaked in the bilateral HRA group compared to the unilateral HRA group.
  
  
  CONCLUSIONS
  Serum levels of Cr, Co, and Mo increased significantly after HRA. Cr levels peaked earlier in the overweight patients, Co levels peaked in women, and Mo levels peaked in patients who underwent bilateral HRA. However, there were no significant differences with respect to sex, operated side, and BMI.
authors.affiliation: Department of Orthopedics, Tianjin The First Center Hospital, 24 Fukang Rd., Nankai District, Tianjin, 300192, China. jiangwenxue@medmail.com.cn.
authors.forename: Wenxue
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Department of Orthopedics, Tianjin The First Center Hospital, 24 Fukang Rd., Nankai District, Tianjin, 300192, China. jiamu010@sina.com.
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Wan
authors.affiliation: Department of Orthopedics, Tianjin Hospital, 406 Jiefang South Road, Hexi District, Tianjin, 300210, China. mohuang009@163.com.
authors.forename: Peng
authors.initials: P
authors.lastname: Cui
authors.affiliation: Department of Epidemiology, Tianjin Neurological Institute, 154 Anshan Rd, Heping District, Tianjin, 300052, China. xjn0906@gmail.com.
authors.forename: Xianjia
authors.initials: X
authors.lastname: Ning
mesh_terms: D000328:Adult; D019644:Arthroplasty, Replacement, Hip / Q000639:trends*; D015415:Biomarkers / Q000097:blood; D002857:Chromium / Q000097:blood; D003035:Cobalt / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000639:trends*; D006801:Humans; D007477:Ions; D008297:Male; D008670:Metals / Q000097:blood*; D008875:Middle Aged; D008982:Molybdenum / Q000097:blood; D011182:Postoperative Care / Q000639:trends*
chemical_list: D015415:Biomarkers; D007477:Ions; D008670:Metals; D002857:Chromium; D003035:Cobalt; D008982:Molybdenum