Mortality and implant survival with simultaneous and staged bilateral total hip arthroplasty: Experience from the Australian Orthopaedic Association National Joint Replacement Registry.

Abstract

Background Total hip arthroplasty (THA) is an effective procedure for relieving pain and restoring function in osteoarthritis. A significant proportion of patients have severe disease bilaterally. Consensus regarding safety and selection of patients for simultaneous bilateral THA, or the optimal timing for staged THA has not been reached. The aim of this study is to compare rates, causes of revision and 30-day mortality between simultaneous and staged bilateral THA using data from the Australian Orthopaedic National Joint Replacement Registry (AOANJRR). Methods Data for 12,359 bilateral THA procedures was collected from September, 1999 to December, 2017. Rates and causes of revision and 30-day mortality were obtained for simultaneous bilateral and staged procedures with intervals of 1 day-6 weeks, 6 weeks-3 months and 3 months-6 months. Yearly cumulative percent revision (CPR) or survival (CPS) with 95% confidence intervals calculated by the Kaplan-Meier method and adjusted hazard ratios were used for comparisons. Results Thirty-day mortality is lower in patients who have bilateral procedures within 6 months, regardless of timing, than those who have unilateral procedures (0.06% vs 0.18%). Staged bilateral THA had a significantly lower mortality than simultaneous bilateral THA (OR 0.175, 95% CI 0.04-0.78, p=0.022). When separate time intervals were compared, no significant differences were seen. Bilateral 6wk-3mths has a higher rate of revision from 1.5y-2yrs compared to same day bilaterals (HR=2.39, 95% CI 1.12, 5.09, p=0.024). There were no other significant differences in the rate of revision between groups. The most common reasons for revision were fracture, loosening and infection. Simultaneous bilateral procedures have a significantly higher rate of revision for fracture compared to staging 3-6 months (HR=1.96 (1.27, 3.03), p=0.002). Conclusion This study demonstrates that bilateral THA has a low mortality rate regardless of time interval between procedures. Simultaneous and staged bilateral THA have similar rates of revision.