Outcomes and survivorship after conversion of failed hip hemiarthroplasty to total hip arthroplasty

Background: Arthroplasty is the treatment of choice for elderly patients with displaced femoral neck fractures. When compared to total hip arthroplasty (THA), higher revision rates have been reported for hemiarthroplasty (HA). Conversion of failed HA to THA can be complex, especially in the elderly population at risk for revision surgery complications. We report a single institution's experience with conversion of failed HA to THA at mid-term follow-up. Methods: We identified patients converted from failed HA to THA from 2006 to 2016. Clinical data including indication for index and conversion surgery, maintenance or revision of femoral component during conversion, operative time, estimated blood loss, postoperative complications, and need for revision surgery were collected. Descriptive statistics were analysed in SPSS. Results: The cohort included 21 men and 39 women (mean age of 74.5 years). The mean follow-up after conversion HA to THA was 2.8 years. During conversion surgery, the femoral component was revised in 75.0% and retained in 25.0% of cases. After conversion HA to THA, the rate of major complications and re-revision at 2 years was 11.7% and 10.0%, respectively. Femoral revision versus retention did not affect complication rates (11.1% vs. 6.7%; p = 0.31) or re-revision rates (8.9% vs. 13.3%; p = 1.0). Conclusions: In this high-risk population, mid-term follow-up demonstrated tolerable complication and re-revision rates, the majority of which were for instability. We observed high rates of femoral component revision during conversion THA, although this did not increase the likelihood of postoperative complications or need for future surgery.