Safety of Single-Stage Bilateral Versus Unilateral Anterior Total Hip Arthroplasty A Propensity-Matched Cohort Study

Background: Limited data exist on patient safety after single-stage bilateral and unilateral total hip arthroplasty (THA) through the anterior approach (AA). Therefore, the aim of this study was to compare length of stay (LOS), operative time, 90-day adverse events, 90-day readmission rate, and 1-year revision rate after single-stage bilateral and unilateral THA in matched patients. Methods: This was a retrospective matched cohort study of prospectively collected data from 2008 to 2018 of a single-surgeon practice. We used the built-in propensity score matching formula in SPSS software and matched bilateral and unilateral patient groups on the relevant covariates of age, sex, and body mass index. This resulted in 60 patients undergoing bilateral THA and 60 patients undergoing unilateral THA. Results: The average LOS was 4.7 days (interquartile range [IQR], 3 to 5 days; range, 2 to 21 days) after bilateral THA and 3.0 days (IQR, 2 to 4 days; range, 1 to 13 days) after unilateral THA (p < 0.001). The mean operative time was 140 minutes for bilateral THA and 69 minutes for unilateral THA (p < 0.001). The adverse event rate was 6.7% after bilateral THA and 5.0% after unilateral THA (p = 0.660). The 90-day readmission rate was 3.3% after bilateral THA and 5.0% after unilateral THA (p = 0.321), which also accounted for all of the revisions within the first year. Conclusions: When considering single-stage versus staged bilateral AA total hip replacement, patients can expect the same clinical outcome. Because the operative time is longer with bilateral THA, the main advantages are that the patient avoids a second anesthesia session and has an overall shorter recovery time.