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

Background and purpose — The safety aspects of bilateral simul- taneous 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 2012 a, b). All re-admissions within 90 days were identified and mortality rates and time until death were recorded. Transfusion rates and num- bers of transfusions were also recorded. Logistic regression analy- sis 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 cardio- pulmonary 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.