Evaluating the Optimal Timing Between Staged Bilateral Total Knee Arthroplasties for Improved Clinical Outcomes.

BACKGROUND

Simultaneous bilateral total knee arthroplasty (BTKA) is avoided due to higher perioperative risk, favoring staged procedures. This study evaluated how the interval between staged TKAs affects patient-reported outcome measures (PROMs) and compared complications between the first and second procedures.

METHODS

We retrospectively reviewed patients undergoing primary, elective, staged, BTKAs at a high-volume academic center between 2011 and 2024. Intra- and perioperative data and complications were compared between the surgeries. Patients were stratified by interval: less than three months ("extremely short waiters"), three to six months, six to nine months, nine to 12 months, one to two years, two to five years, and greater than five years. The PROMs were compared across these groups. A total of 4,210 patients underwent 8,420 staged, BTKAs at a mean 21.4-month interval. The most common intervals were six to nine months (27.4%) and nine to 12 months (21.1%).

RESULTS

Patients were more likely to return to the emergency department (22 versus 16, P = 0.030) and be readmitted (48 versus 26, P = 0.113) after the second surgery, primarily due to infection. Revision rates did not differ. "Extremely short waiters" had the greatest improvement in Patient-Reported Outcomes Measurements Information System Pain Intensity and interference scores nine months after the second TKA (change 13.4 and 15.1, P < 0.001). At three months following the second surgery, those who waited three to six months had the largest Knee Injury and Osteoarthritis Outcome Score for Joint Replacement score improvement (change 23.7, P = 0.004). At one year after the second surgery, "extremely short waiters" again showed the greatest reduction in Patient-Reported Outcomes Measurements Information System Pain Intensity (change 10.5, P = 0.007) and Interference (change 11.3, P < 0.001).

CONCLUSIONS

The interval between surgeries significantly impacted PROMs, with shorter intervals associated with better pain relief and functional recovery. Surgical timing should be tailored to individual patient goals and recovery trajectories.