Comparative Outcomes of Bilateral Versus Unilateral Total Knee Arthroplasty: A Big Data Analysis

Background: Bilateral total knee arthroplasty (B-TKA) is a surgical option for patients with bilateral osteoarthritis, offering potential efficiency and cost advantages but with increased perioperative risk. Methods: We conducted a retrospective analysis of 2,299,979 elective TKA cases from the Nationwide Inpatient Sample (2016-2019). Propensity score matching (PSM) was used to compare 83,980 B-TKA patients with matched unilateral TKA (U-TKA) patients. Outcomes included in-hospital mortality, complications, length of stay, and hospital charges. Results: B-TKA patients had higher rates of complications such as deep vein thrombosis (OR 1.798) and pulmonary embolism (OR 1.883), longer hospital stays (3.03 vs. 2.49 days), and higher charges (USD 83,639 vs. USD 59,215; all p < 0.001). Conclusions: Although B-TKA is associated with increased perioperative risk, it may offer logistical and economic advantages in well-selected patients. These findings support the need for risk stratification in surgical decision-making.