Revision rate of large head diameter metal-on-metal total hip arthroplasty: long-term results.

BACKGROUND

To assess the long-term outcomes (minimum 10 years) of total hip arthroplasty (THA) using a large head diameter metal-on-metal (MoM) acetabular prosthesis.

METHODS

In total, 108 primary THAs (98 patients) were performed using a Cormet MoM acetabular prosthesis. Clinical hip function, radiographic evaluation and revision rate were evaluated.

RESULTS

Of the 98 patients, 15 (16 hips) followed up for < 10 years were excluded. Among the remaining 92 hips (83 patients), 35 (38.0%) had pseudotumors (PTs) detected by MRI at an average of 5.0 years after the initial THA. On radiographic evaluation, osteolysis (OL) was noted in 10 hips (10.8%) on the cup side and six hips (6.5%) on the stem side. Loosening was observed in six hips (6.5%) on the cup side, whereas no loosening was noted on the stem side. Twenty-three hips (22 patients) were switched to metal-on-polyethylene articulation between 1.2 and 14.7 years (mean: 6.3 years) postoperatively due to pain, swelling, infection, and/or implant failure. In this analysis, cup failure (OL, loosening, or both) was the highest in patients with revision surgery compared to those with PTs but not revision surgery and those without PTs.

CONCLUSIONS

The prevalence of PTs was 38.0%, and that of revision surgery was 25%. Some cases required revisions even after 10 years following surgery. We advise against its continued use and recommend regular clinical surveillance, such as MRI, to detect adverse reactions to metal debris and periprosthetic joint infection early.