Total Hip Arthroplasty Using Dual Mobility Cups for Failed Hip Fracture Fixation.

Backgroud: Conversion to total hip arthroplasty (THA) is the most common treatment for older patients following failed hip fracture fixation. However, the dislocation rate after conversion THA is higher than that after primary THA for arthritis. Recent studies have reported that a dual-mobility (DM) cup has a lower dislocation rate than fixed-bearing (FB) THA. This study aimed to assess the outcomes of conversion THA using a DM cup for failed hip fracture fixation.

Methods: Between April 2015 and June 2021, 116 patients underwent conversion THA for failed hip fracture fixation at a tertiary hospital. Among them, 83 and 33 cases using the FB and DM cups, respectively, were included in the study. The following outcomes were assessed and compared between the 2 groups: reoperation, dislocation, intraprosthetic dissociation (IPD), periprosthetic fracture, deep joint infection, and modified Harris hip score (mHHS).

Results: There were no significant differences between the FB and DM groups in terms of radiological outcomes, reoperation, IPD, periprosthetic fracture, deep joint infection, or mHHS. In particular, there was no statistically significant difference in the dislocation rate between the FB and DM groups (6.02% and 3.03%, respectively; p = 0.673).

Conclusions: The dislocation rate in the DM group was lower than that in the FB group, with a relative risk of 0.50, although this difference did not reach statistical significance. These findings suggest that DM implants may be potentially beneficial options in such cases; however, further research is required to confirm this trend.