Hemiarthroplasty Conversion: A Comparison to Primary and Revision Total Hip Arthroplasty

BackgroundArthroplasty is the standard of care for elderly patients with displaced femoral neck fractures, with viable options including hemiarthroplasty (HA) and total hip arthroplasty (THA). With time, HA may need to be converted to THA, but it is unclear whether this is more similar to primary or revision THA. We compare complication and revision rates between these groups within 90 days and 2 years postoperatively.MethodsWe retrospectively reviewed 3 cohorts of patients treated at our institution: primary, conversion, and revision THA. Outcomes studied included intraoperative data, postoperative complications, and revision rates. We analyzed the groups using both parametric (analysis of variance test) and nonparametric (chi-squared test) statistics.ResultsOperative time between primary THA (108.0 minutes), conversion HA (147.9 minutes), and revision THA (160.1 minutes) cohorts differed significantly (P = .011). Estimated blood loss was also different between primary THA (386 mL), conversion HA (587 mL), and revision THA cohorts (529 mL) (P = .011). At 2 years, major complication rates between primary THA (6.2%), conversion HA (11.7%), and revision THA (26.7%) cohorts also differed significantly (P = .003), as was the revision rate in the primary THA (4.6%), conversion HA (10.0%), and revision THA (18.3%) cohorts (P = .043).ConclusionThis is the first study to compare short-term and midterm complications between primary, conversion, and revision THA. We observed conversion HA had similar operative time and estimated blood loss to revision THA, which was significantly higher than primary THA. However, we found that conversion HA more closely resembled primary THA with respect to perioperative complications rates.