Differences in functional recovery after unilateral versus bilateral total knee arthroplasty.

Background: Understanding functional changes between unilateral and simultaneous bilateral total knee arthroplasty (TKA) patients remains limited. The purpose of this study was to investigate the differences in recovery times between unilateral and bilateral TKA.

Methods: We retrospectively recruited patients who met the eligibility criteria. All patients engaged in a standard rehabilitation program and completed both self-reported questionnaires and performance-based physical function tests preoperatively, at 6 and 12 weeks postoperatively.

Results: A total of 838 patients were included in this study. Those who underwent bilateral TKA (n = 281) were younger than those opting for unilateral TKA (n = 557), with no significant differences in baseline health status observed between the two groups. Both groups showed continuous improvements in pain, function, and performance-based physical functions from preoperatively to 12 weeks postoperatively. Notably, stiffness did not significantly improve from the preoperative to 6 weeks postoperatively and the stair-climbing test (SCT) showed delayed recovery, with deterioration at 6 weeks but subsequent improvement at 12 weeks in bilateral TKA group. Similarly, the recovery rate in the 6-min walking test (6MWT) was initially slow for the bilateral TKA group during the first 6 weeks, but later accelerated. Significant interactions between time and group were observed in the timed-up-and-go test, 6MWT, and SCT.

Conclusion: Patients who underwent bilateral TKA showed distinct recovery patterns, suggesting the need for tailored rehabilitation approaches compared those who underwent unilateral surgery. These findings underscore the need to provide patients with information about potential differences in recovery patterns based on their chosen surgical approach prior to surgery.