Association of preoperative anxiety with acute postoperative pain after total knee arthroplasty

Objective: Preoperative anxiety may influence postoperative pain perception and analgesic requirements. This study aimed to investigate the association between preoperative anxiety and acute postoperative pain during the first 24 hours following primary total knee arthroplasty.Methods: This prospective observational cohort study included 100 adults undergoing elective primary total knee arthroplasty under spinal anesthesia. Preoperative anxiety was assessed using the Amsterdam Preoperative Anxiety and Information Scale (APAIS). Postoperative pain intensity was evaluated using the Numerical Rating Scale (NRS) at 1, 6, 12 and 24 hours. All patients received a standardized multimodal analgesic regimen and intravenous tramadol was administered as rescue analgesia when NRS scores were ≥ 4. Associations between preoperative anxiety and postoperative pain were evaluated using correlation and multivariable regression analyses.Results: The median APAIS anxiety score was 10.0 (IQR 5.0–15.0). Higher preoperative anxiety was significantly associated with higher postoperative pain scores at all evaluated time points during the first 24 hours (all adjusted p < 0.001). In multivariable analysis, preoperative anxiety remained independently associated with higher pain intensity at 24 hours after adjustment for age, sex and preoperative pain. Higher preoperative anxiety was also associated with greater cumulative rescue tramadol consumption during the first 24 postoperative hours.Conclusion: Higher preoperative anxiety was associated with greater acute postoperative pain and greater cumulative rescue tramadol consumption after total knee arthroplasty. Preoperative anxiety screening may help identify patients at risk of more intense early postoperative pain and support individualized perioperative pain management strategies.