Optimal timing in staged bilateral total knee arthroplasty: A retrospective analysis of complications and functional outcomes

Abstract

Aim: To investigate the association between inter-stage timing and postoperative complications, hospital readmissions, and functional outcomes in staged bilateral TKA.

Methods: A retrospective analysis was performed on 815 staged bilateral TKA cases between March 2019 and April 2024. Patients were stratified into four groups based on inter-stage intervals: 3 weeks–90 days, 91–180 days, 181 days–1 year, and >1 year. Demographic data, complication rates, unplanned readmissions, length of hospital stay, and functional outcomes, as Knee Osteoarthritis Outcomes Score for Joint Replacement (KOOS JR) and the Lower Extremity Activity Scale (LEAS), were analyzed.

Results: A total of 645 patients (1,290 knees) met inclusion criteria. The 91–180 days group demonstrated the lowest complication rate (1.8%), significantly lower than the 3 weeks–90 days group (13.1%; p<0.001). Functional outcomes were superior in the 91–180 days group, with higher KOOS JR (p=0.035) and LEAS scores (p=0.002). Although hospital stay and readmissions were lower in this group, differences in readmission rates were not statistically significant.

Conclusion: Early reoperation within 90 days carries a substantially elevated complication risk. Our data strongly suggest that scheduling the second TKA between 91 and 180 days offers the most favorable balance of safety and functional recovery. These findings address a critical gap in surgical planning for bilateral TKA and warrant further validation through prospective multicenter trials.