Repeat-dose dexamethasone to prevent pain relapse after total knee arthroplasty in high-pain-response patients: A randomised, double-blind, placebo-controlled superiority trial

BACKGROUND Peri-operative glucocorticoids reduce pain after total knee arthroplasty, with evidence suggesting potential benefits of increased dosing in specific patient groups. However, the impact of repeat-dose glucocorticoids has not been studied in high-pain-response patients receiving pre-operative high-dose glucocorticoids. OBJECTIVE To investigate the effect on pain of an oral dose of dexamethasone after total knee arthroplasty in selected high-pain-response patients who had received a pre-operative high dose of intravenous dexamethasone (1 mg kg^-1). DESIGN Randomised, double-blind, placebo-controlled superiority study. SETTING A multicentre study conducted at two major arthroplasty centres in Denmark from November 2021 to March 2024. PATIENTS One hundred and ten patients undergoing total knee arthroplasty who had received multimodal analgesia including pre-operative intravenous dexamethasone 1 mg kg^-1. Selection criteria included a Pain Catastrophising Scale score greater than 20 and moderate-to-severe pain (VAS >30) during walking 24 h postoperatively. INTERVENTION Patients were randomised to either oral dexamethasone 24 mg or placebo on postoperative day 1. MAIN OUTCOME MEASURES The primary outcome was the proportion of patients experiencing moderate-to-severe pain during walking at 48 h postoperatively. Secondary outcomes included pain scores at various time points within 1 week postoperatively, rescue analgesics, quality of sleep, length of hospital stay and morbidity with follow-up at 30 days. RESULTS At 48 h postoperatively, 65% of patients in the dexamethasone group and 79% in the placebo group reported moderate-to-severe pain during walking: odds ratio 0.48 [95% confidence interval (CI), 0.20 to 1.16]; P ¼ 0.100. The mean ± SD Visual Analogue Scale (VAS) at 48 h during walking was 43 ± 21 in the dexamethasone group and 51 ± 22 in the placebo group (P ¼ 0.051). There were no differences between the groups regarding secondary pain outcomes or the use of rescue analgesics. CONCLUSION The administration of a high oral dose of dexamethasone following an initial pre-operative dose of 1 mg kg^-1 intravenously in selected high-pain-response patients had no effect on postoperative pain following total knee arthroplasty.