Risk factors affecting the onset of adverse reaction to metal debris after metal-on-metal total hip arthroplasty with a focus on serum metal ion concentrations

Abstract

Objective: This study was performed to investigate risk factors affecting the onset of adverse reaction to metal debris (ARMD) after metal-on-metal total hip arthroplasty (THA). Methods: Of the patients who underwent metal-on-metal THA as a primary surgery from January 2007 to August 2011, we included 48 patients in whom the serum metal ion concentrations were measured postoperatively. For these patients, we examined the relationship of the serum cobalt ion concentration with sex, age, Japanese Orthopaedic Association (JOA) hip score as a preoperative clinical evaluation parameter, body mass index (BMI), femoral head diameter, cup abduction angle, height of cup positioning, and magnetic resonance imaging (MRI) findings. Results: No correlation was observed between the serum cobalt ion concentration and age, sex, preoperative JOA hip score, femoral head diameter, cup abduction angle, height of the cup, or MRI findings. Patients with a BMI of >23 kg/m2 had significantly higher serum cobalt ion concentrations. Conclusions: We found that a BMI of >23 kg/m2 is a risk factor for a high serum cobalt ion concentration. We believe that postoperative periodic measurement of the serum cobalt ion concentration in such patients will help to accurately diagnose ARMD and determine treatment strategies.

Keywords

• metal-on-metal tha
• adverse reaction to metal debris (armd)
• serum metal ion concentration