Reevaluating Pain Perception in Staged Bilateral Total Knee Arthroplasty: A 72-Hour Postoperative Analysis

Background Total knee arthroplasty (TKA) is a well-established treatment for end-stage knee osteoarthritis (OA) that significantly alleviates pain and improves joint function. In staged bilateral TKA, previous studies suggest that patients may experience greater pain in the second knee; however, the evidence and underlying mechanisms remain inconsistent and unclear. This study re-evaluated pain perception during the initial 72 h following staged bilateral TKA and examines factors influencing postoperative pain levels, including opioid consumption and the interval between surgeries. Methods This retrospective analysis included 175 patients who underwent staged bilateral TKA between 2015 and 2020. Pain was assessed using a verbal numerical rating scale (VNRS) every 4 h for 72 h postoperatively. A linear mixed-effect model compared pain levels between the first and second surgeries, adjusting for time, opioid consumption, nerve block type, femorotibial angle, and osteoarthritis severity. A subgroup analysis was conducted based on the interval between surgeries (< 6 months, 6–12 months, and > 12 months). Results The mean interval between the surgeries was 12.34 months. Analysis revealed no significant difference in pain levels between the first and second TKAs (β = -0.070, p  = 0.198). However, pain significantly decreased over time (β = -0.076 per 4-hour interval, p  < 0.001), and femoral nerve block was associated with reduced pain (β = -0.335, p  < 0.001). Sensitivity analysis indicated a slight reduction in pain during the second surgery ( p  = 0.041). Subgroup analysis showed no significant differences in pain trajectories across the surgical intervals. Conclusions Pain following second-stage TKA was not significantly higher and was slightly lower than that following first-stage TKA. Additionally, the interval between surgeries did not appear to significantly influence pain outcomes. These findings suggest flexibility in scheduling the second procedure without concern for increased pain and provide valuable insights for optimizing pain management in staged bilateral TKA.