Lo LWT, Suh J, Chen JY, et al. - This study was sought to distinguish perioperative factors correlated with increased early postoperative pain and investigate the effects of the acute postoperative day (POD) 1 and 2 pain on outcomes at 6 months and 2 years post-total knee arthroplasty (TKA). This retrospective cohort study enrolled a total of 1,041 unilateral TKA patients. Individuals were classified into minor (Visual Analogue Scale: Visual Analogue Scale (VAS) < 5) and major (VAS ≥ 5) pain groups based on postoperative day (POD)1/2 VAS scores. Individuals were evaluated preoperatively, at 6 months and 2 years using Knee Society Knee (KSKS) and Function Scores, Oxford Knee Score, SF-36 Physical and Mental Component Score, expectation, and satisfaction scores. Researchers applied multiple logistic regression to distinguish predictors of ‘major pain’. According to the findings, individuals should be counseled about risk factors of postoperative pain to manage pre-operative expectations of surgery. Using multimodal pain protocols, patients should be managed adequately to improve subsequent functional outcomes while avoiding unnecessary opioid use.