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

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 (0.3mg/kg) with a fixed 8mg dose.

In this retrospective cohort study, 577 patients undergoing primary TKA between January 2021 and December 2024 received either 0.3mg/kg DEX (n=305) or a fixed 8mg dose (n=272) preoperatively. Pain was assessed using a numerical rating scale (NRS, 0-10 points) and the number of 5mg oxycodone rescue doses at 24 and 48h postoperatively. C-reactive protein (CRP) and blood glucose were measured at 24h. Multivariate analyses evaluated the association of age, sex, and DEX dose with pain outcomes.

Patients receiving 0.3mg/kg DEX reported significantly lower pain scores than those receiving 8mg, with mean differences of 1.13 NRS points at 24h and 1.17 points at 48h (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 24h 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.

A preoperative, weight-adjusted dexamethasone dose of 0.3mg/kg provides superior early postoperative analgesia compared with a fixed 8mg dose after TKA, reducing pain scores and opioid requirements during the first 48h.