Background: Pain after total knee arthroplasty (TKA) affects postoperative recovery and patient satisfaction. The analgesic benefits of corticosteroids have not been well studied. We, therefore, investigated the analgesic effects of intravenous (IV) dexamethasone (DEX) in patients undergoing a TKA.

Methods: This was a randomized, double-blind, placebo-controlled trial of 0.15 mg/kg of IV DEX vs saline placebo in unilateral TKA. Fifty patients/arm were recruited. Primary outcomes were pain level, determined by a visual analog scale, and the amount of morphine consumption (mg) ≤48 hours post-TKA. Secondary outcomes were rates of nausea and vomiting, C-reactive protein concentrations, and functional outcomes.

Results: The DEX group had a significantly lower mean visual analog scale score both at rest and during motion at 12, 15, 18, and 21 hours (P < .05). At 21 hours, the mean difference (Δ) in pain at rest was -11 points (95% confidence interval [CI], -21 to -2 points; P = .02) while the mean difference in pain during motion was -15 points (95% CI, -25 to -5 points; P = .004). The DEX group also had lower rates of nausea and vomiting: 29/50 (58%) vs 42/50 (84%) (P = .008) and lower mean C-reactive protein level: 89 vs 167, Δ = -78 mg/L (95% CI, -100 to -58 mg/L, P < .0001). There were no significant differences in mean morphine consumption by 48 hours, modified Western Ontario and McMaster University Osteoarthritis Index scores, and range of motion of the knee at 3-month follow-up (P > .05).

Conclusion: IV DEX relieves postoperative pain between 12 to 21 hours after TKA and may be a useful adjunct for controlling pain in patients undergoing TKA.