Adverse Tissue Reactions and Metal Ion Behavior After Small‐Head Metasul Hip Arthroplasty: A Long‐Term Follow‐Up Study

Abstract

Objective To investigate the long‐term survivorship, incidence of adverse reactions to metal debris (ARMD), and metal ion behavior in patients who underwent small‐head Metasul metal‐on‐metal (MoM) total hip arthroplasty (THA). Methods Between February 1998 and September 2003, a retrospective study was performed on 43 consecutive patients (43 hips) who underwent unilateral cementless Metasul MoM THAs at our institution. Of them, 35 patients (nine males and 26 females) who were available for follow‐up more than 15 years after THA were enrolled in this study and underwent metal artifact reduction sequence magnetic resonance imaging (MARS‐MRI) to identify ARMD. The mean age at surgery of the patients was 59.7 years old (range, 31–83). Clinical and radiographic outcomes were evaluated retrospectively. Clinical examinations were conducted using the Harris Hip Score (HHS). Serum cobalt (Co) and chromium (Cr) ion levels and Co/Cr ratio were assessed at different postoperative periods of 11 years postoperatively. Conclusion Our results suggest that increased Cr ion levels and decreased Co/Cr ratio may be signs of ARMD in patients who underwent small‐head Metasul MoM THA.

Keywords

• Adverse reactions to metal debris
• Metal ion levels
• Metal‐on‐metal
• Metasul
• Small head