High-dose dexamethasone in low pain responders undergoing total knee arthroplasty: a randomised double-blind trial.

Background: Postoperative pain after total knee arthroplasty (TKA) is a continuing problem despite optimised multimodal analgesia. Previous studies have shown preoperative glucocorticoids to reduce postoperative pain, but knowledge about specific doses and effects in specific patient groups is lacking.

Methods: A two-centre, double-blind, two-arm study comparing preoperative dexamethasone (1 mg kgvs 0.3 mg kg i.v.) on postoperative pain in 160 planned TKA subjects with low preoperative pain catastrophising and no opioid use. Subjects received multimodal analgesia with paracetamol, cyclooxygenase-2 inhibitors, local anaesthetic infiltration analgesia, and rescue opioids. The primary outcome was percentage of subjects experiencing moderate to severe pain (visual analogue scale >30 mm) upon ambulation at 24 h. Secondary outcomes included pain scores, postoperative inflammation (C-reactive protein), opioid and antiemetics use, and 'Quality of Recovery-15' and 'Opioid-Related Symptom Distress Scale', length of stay, readmissions, and complications up to Day 90.

Results: A total of 157 subjects (80 vs 77) were included. No difference was found between groups in the incidence of subjects experiencing visual analogue scale >30 on ambulation 24 h after surgery (56% vs 53%, relative risk =1.07, confidence interval: 0.8-1.4, P=0.65). No differences in other pain outcomes or use of rescue opioids and antiemetics, in Quality of Recovery-15 and Opioid-Related Symptom Distress Scale, length of stay, readmissions, or complications. C-reactive protein values were comparable at 24 h (13 [6-25] mg Lvs 16 [9-38] mg L, P = 0.07), but lower at 48 h (26 [9-52] mg Lvs 50 [30-72] mg L, P<0.01) in the high-dose group.

Conclusion: Use of 1 mg kgvs 0.3 mg kg i.v. dexamethasone in low pain responders after TKA did not improve early postoperative pain or other outcomes in contrast to benefits in a high pain responder population.

Clinical Trial Registration: NCT03758170 (first registration 29-11-2018).