Preoperative weight-adjusted dexamethasone in total knee arthroplasty: Optimizing analgesic efficacy and safety

Background: Total knee arthroplasty (TKA) is frequently associated with moderate to severe postoperative pain. Dexamethasone (DEX) is widely used as part of multimodal analgesia, although the optimal dose remains uncertain. This study compared the analgesic efficacy of a weight-adjusted intermediate DEX dose (0.3 mg/kg) with a fixed 8 mg dose. Methods: In this retrospective cohort study, 577 patients undergoing primary TKA between January 2021 and December 2024 received either 0.3 mg/kg DEX (n = 305) or a fixed 8 mg dose (n = 272) preoperatively. Pain was assessed using a numerical rating scale (NRS, 0–10 points) and the number of 5 mg oxycodone rescue doses at 24 and 48 hours postoperatively. C-reactive protein (CRP) and blood glucose were measured at 24 hours. Multivariate analyses evaluated the association of age, sex, and DEX dose with pain outcomes. Results: Patients receiving 0.3 mg/kg DEX reported significantly lower pain scores than those receiving 8 mg, with mean differences of 1.13 NRS points at 24 hours and 1.17 points at 48 hours (p < 0.001). Oxycodone rescue use was reduced at both time points (p < 0.001). Older age and male sex were independently associated with lower pain scores. CRP levels at 24 hours were lower in the weight-adjusted group, whereas postoperative glucose levels were higher (both p < 0.05). Length of stay did not differ significantly between groups. Conclusion: A preoperative, weight-adjusted dexamethasone dose of 0.3 mg/kg provides superior early postoperative analgesia compared with a fixed 8 mg dose after TKA, reducing pain scores and opioid requirements during the first 48 hours.