Complications Associated With Same-Day Bilateral Total Knee Arthroplasties

Same-day bilateral total knee arthroplasties (SBTKAs) are associated with shorter rehabilitation and lower cost. However, controversy surrounding the safety of SBTKAs exists. Recent studies are lacking to determine whether patient selection has brought SBTKA in line with unilateral total knee arthroplasty (UTKA). Therefore, the authors evaluated and compared patient characteristics, hospital characteristics, and inpatient course between UTKA and SBTKA from 2009 to 2016. The National Inpatient Sample was queried from 2009 to 2016 for UTKA and SBTKA patients. Of the 5,329,466 patients identified, 5,084,328 (95.4%) patients received UTKAs and 245,138 (4.6%) patients underwent SBTKAs. Incidence, rate, patient and hospital characteristics, health status, length of stay (LOS), discharge disposition, hospital charges, hospital costs, and complications were analyzed and statistically compared. The incidence (-1.4%) and rate (15.8%) of SBTKAs decreased (both P<.001). The SBTKA cohort had more patients who were younger, male, White, obese, healthier, and using private insurance (P<.001 for all). The SBTKA cohort had longer LOS, a higher proportion of discharges to skilled nursing facilities, higher cost and charges, and more complications, including deep venous thromboses/pulmonary emboli (DVT/PE) and transfusions (P<.001 for all). Conversely, SBTKA was associated with fewer myocardial infarctions (P<.001). Although improved from previous literature, SBTKA is still associated with longer LOS, higher cost and charges, and more complications, including DVT/PE and transfusions, although with a lower rate of myocardial infarction. However, studies are needed to determine whether the risk of 1 SBTKA outweighs the cumulative risk of staged UTKAs. [Orthopedics. 2021;44(3):e407-e413.].