High Complication Rates Following Revision of Aseptic Metal-on-Metal Hips to Dual Mobility Bearings

Background: Patients with metal-on-metal (MoM) bearings continue to experience complications requiring revision total hip arthroplasty (rTHA). Revision to dual mobility (DM) bearings is often debated given a persistent metal-metal interface. We sought to report on the outcomes of rTHA from MoM to DM constructs. Methods: Patients who underwent rTHAs from 2010 to 2024 were retrospectively reviewed. Only patients with MoM constructs undergoing revision to DM were included. Demographic and perioperative data were collected, in addition to complications and survivorship free of rerevision. Results: Thirty-two hips in 28 patients underwent rTHA to DM constructs. The mean time from MoM THA to rTHA was 9.4 years. All rTHAs were indicated for pain and concerning serum metal ion levels. Findings at the time of rTHA included fluid collections in 68.7% (n = 22) of cases, taper corrosion in 43.7% (n = 14), and acetabular component loosening in 18.75% (n = 6). Mean preoperative cobalt and chromium levels were 13.6 ug/L and 10.5 ug/L, respectively. The rerevision rate was 31.25% (n = 10 hips) at a mean follow-up of 6 years. The most common reasons for rerevision were dislocation (n = 4, 12.5%), followed by acetabular loosening and periprosthetic joint infection (PJI) (n = 3 each, 9.38%). At most recent follow-up, serum metal ions had decreased to mean cobalt of 0.98 ug/L and chromium of 5.15 ug/L. Conclusions: Revision surgery of MoM THA is associated with high complication rates. Serum cobalt and chromium ions can be expected to steadily decline after revision to DM despite the metallic interface. Level of Evidence: IV; retrospective case series.