Conversion of failed proximal femoral nail antirotation to uncemented or cemented femoral component fixation: a multicentre retrospective study with a median 10-year follow-up.

Background: Conversion of a failed proximal femoral nail antirotation (PFNA) to a total hip arthroplasty (THA) is becoming increasingly universal. However, consensus has not been reached regarding which device (uncemented or hybrid THA) to use. The aim of this retrospective study was to compare the clinical outcomes of the conversion of failed PFNAs to uncemented versus hybrid THAs in the elderly population.

Methods: Consecutive elderly patients with prior failed PFNAs treated with uncemented or hybrid THA from January 2008 to December 2019 were retrospectively identified from two medical centres. The primary outcome was implant survival after THA revision; secondary outcomes were the functional outcomes assessed using the Harris Hip Score (HHS) and the incidence of key THA-related complications.

Results: A total of 236 patients (uncemented THA, n = 116; hybrid THA, n = 120) were eligible for this study. Kaplan-Meier survival curves demonstrated that the 10-year cumulative survival rates were 0.801 (95% confidence interval [CI], 0.783-0.852) in the uncemented THA group versus 0.925 (95% CI, 0.861-0.964) in the hybrid THA group (hazard ratio [HR] 0.36 [95% CI 0.24-0.56], p = 0.004). From the 72nd month after the revision to the last follow-up, functional outcomes differed considerably between cohorts (each p < 0.05), and the rate of key THA-related complications was comparable between cohorts (p = 0.004).

Conclusion: For elderly patients with prior failed PFNAs who experienced uncemented or hybrid THA, hybrid THA revision may provide a clinically significant improvement over uncemented THA revision with regard to implant survival, functional outcomes, and THA-related complications compared to uncemented THA revision.