Complications following bilateral simultaneous versus staged total knee arthroplasty in the Japanese population: a propensity-matched case-control study

Although bilateral simultaneous total knee arthroplasty (BSTKA) is an effective treatment for bilateral knee osteoarthritis, safety concerns and lack of precise patient selection criteria persist. This study aimed to determine the differences in perioperative parameters and complication rates between BSTKA and staged TKA in the Japanese population. We retrospectively reviewed 531 patients who underwent BSTKA or staged TKA between 2012 and 2021. Propensity score matching, performed on a 1:1 nearest neighbor basis for age, BMI, diagnosis, ASA score, and age-adjusted Charlson Comorbidity Index, yielded matched cohorts of 94 patients (188 knees) for each group. Outcome measures included operative time, perioperative blood loss, length of hospital stay, and nonmechanical complications after surgery. The BSTKA group had a shorter median operative time and hospital stay (111 min and 16 days) than the staged TKA group (159 min and 33 days) (p < 0.001). Overall complication rates were higher in the BSTKA group than in the staged TKA group (26% vs. 13%, p = 0.026), with anemia requiring transfusion being the most common. Cardiovascular complications were more frequent in the BSTKA group (4.3% vs. 0%, p = 0.043). These findings emphasize the importance of careful patient selection and risk assessment when considering BSTKA.