Morbidity and mortality after bilateral simultaneous total knee arthroplasty in a fast-track setting.

Background and purpose - The safety aspects of bilateral simultaneous total knee arthroplasty (BSTKA) are still debated. In this retrospective single-center study, we investigated early morbidity and mortality following BSTKA in a modern fast-track setting. We also identified risk factors for re-admission within 90 days and for a length of stay (LOS) of more than 5 days. Patients and methods - 284 patients were selected to receive BSTKA at our institution from 2008 through 2014 in a well-described, standardized fast-track setup (Husted 2012a, b). All re-admissions within 90 days were identified and mortality rates and time until death were recorded. Transfusion rates and numbers of transfusions were also recorded. Logistic regression analysis was used to identify risk factors for re-admission within 90 days, and also for a LOS of more than 5 days. Results - 90-day mortality was 0%. 10% of the patients were re-admitted within 90 days. Median time to re-admission was 18 (3-75) days. 153 patients (54%) received postoperative blood transfusions. An ASA score of 3 was identified as an independent risk factor for re-admission within 90 days (OR = 5, 95% CI: 1.3-19) and for LOS of > 5 days (OR = 6, 95% CI: 1.6-21). Higher BMI was a weak risk factor for re-admission within 90 days. Interpretation - BSTKA in selected patients without cardiopulmonary disease in a fast-track setting appears to be safe with respect to early postoperative morbidity and mortality. Surgeons should be aware that patients with an ASA score of 3 have an increased risk of re-admission and a prolonged length of stay, while patients with higher BMI have an increased risk of re-admission following BSTKA.