A randomized controlled trial evaluating the efficacy of combined dexamethasone and dexmedetomidine as adjuvants to ropivacaine in adductor canal block for postoperative analgesia in total knee arthroplasty.

BACKGROUND AND AIMS: This prospective, randomized, double-blind controlled trial investigated whether adding perineural dexamethasone and dexmedetomidine to ropivacaine in adductor canal block (ACB) improves postoperative analgesia compared to using only perineural dexamethasone with ropivacaine in patients undergoing total knee arthroplasty (TKA).

MATERIAL AND

METHODS

Fifty-eight patients undergoing TKA received ultrasound-guided ACB (30 mL of 0.5% ropivacaine). They were randomly assigned to receive either perineural dexamethasone (4 mg) or a combination of perineural dexamethasone (4 mg) and dexmedetomidine (50 mcg), with 29 participants in each group. A blinded observer assessed the primary outcome: morphine consumption in the first 24 postoperative hours. Secondary outcomes included total 48-hour morphine consumption, postoperative pain scores (NRS) at rest and during movement, quadriceps muscle strength, timed up and go (TUG) test time, Ramsay sedation score, and incidence of nausea, vomiting, hypotension, bradycardia, and desaturation.

RESULTS

The dexamethasone-dexmedetomidine group showed significantly lower 24-hour (14.38 ± 5.68 mg vs. 8.55 ± 4.37 mg, P = 0.0001) and 48-hour (20.96 ± 7.09 mg vs. 12.06 ± 6.11 mg, P = 0.00001) morphine consumption compared to the dexamethasone-only group. Pain scores at rest and with movement were also lower in the combination group during the first 12 postoperative hours. No significant between-group differences were observed in other secondary outcome measures (quadriceps strength, TUG time, sedation score, and complication rates). No serious adverse events were reported in either group.

CONCLUSION

The study suggests that adding dexamethasone and dexmedetomidine to ropivacaine for ACB may significantly improve postoperative pain relief in TKA patients without causing harmful side effects.