Comparison of Safety Profile of Bilateral Simultaneous Versus Staggered Total Knee Arthroplasty: A Prospective Randomized Controlled Trial.

BACKGROUND

Bilateral total knee arthroplasty (TKA) can be performed using simultaneous, staggered, or staged approaches. While simultaneous TKA minimizes hospitalization and anesthesia exposure, it is associated with increased perioperative risks. The staggered approach, involving two procedures within the same hospitalization, is proposed as a middle ground, but remains underexplored. This study aimed to compare the safety profiles of simultaneous and staggered bilateral TKA in terms of complication rates, transfusion requirements, and hospital stay.

METHODS

This single-center, prospective, parallel-arm randomized controlled trial included patients who had bilateral knee osteoarthritis undergoing either simultaneous or staggered bilateral TKA. Eligible participants were randomized into two groups: simultaneous TKA (both knees replaced under one anesthesia) and staggered TKA (second knee replaced after 72 hours within the same hospitalization). Primary outcomes included intraoperative, perioperative, and 90-day complications. The secondary outcomes comprised blood transfusion requirements and hospital lengths of stay.

RESULTS

A total of 150 patients (75 per cohort) were eligible for final analysis. No significant differences were found between both cohorts in adverse intraoperative events, surgical site infections, or 90-day complications. However, the staggered TKA group had significantly higher blood transfusion rates (64 versus 10.6%, P < 0.001) and greater mean blood loss (535 versus 298 mL, P < 0.05). The hospital stay was significantly longer in the staggered cohort (7.4 versus 3.5 days, P < 0.001). Penalized logistic regression analyses demonstrated that age and Charlson Comorbidity Index were the strongest predictors of complications, though neither reached statistical significance (P > 0.05).

CONCLUSIONS

Both simultaneous and staggered bilateral TKA are safe when patient selection is optimized. While complication rates are comparable, staggered TKA results in higher transfusion requirements and prolonged hospitalization. The decision between these approaches should be individualized based on patient-specific risk factors, resource availability, and institutional protocols. The trial was prospectively registered with the national trial registry (CTRI/2023/03/051,141).