The application of low-dose dexamethasone in total knee arthroplasty: finding out the best route and dosage schedule

The use of dexamethasone as additive to multimodal analgesic regimen in total knee arthroplasty has been well established, but the most suitable route, effectiveness, safety and dose schedule of low-dose dexamethasone is not known.

We conducted a prospective, randomized, double-blinded trial to investigate and compare the analgesic and antiemetic effects and safety of low-dose (8 mg) dexamethasone introduced as periarticular injection or intravenous (as a single dose or in two divided doses of 4 mg separated by 24 h) in unilateral total knee arthroplasty patients.

The single dose intravenous administration as well as the periarticular administration of dexamethasone had similar mean visual analogue scores which were significantly lower than divided dose group at 24 and 48 h postoperatively. The rate of postoperative nausea and vomiting was lowest among single intravenous dose group and highest among interval dose group at 24 h, while no difference was noted at 48 h. No significant differences were noted in terms of knee flexion angle at 48 h and modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score at 6 weeks.

Single low-dose intravenous dexamethasone is the most appropriate dose which can safely be given to TKA patients and is only moderately associated with rise in blood sugar not causing any significant complication. Alternatively, periarticular infiltration of low-dose dexamethasone can produce equivalent analgesic effect as SDIV in first 24 h without causing significant blood sugar rise and wound complications, but its antiemetic effect remains subtle. Therefore, it is recommended to further study the combination of intraoperative periarticular and postoperative intravenous dexamethasone for their possible additive effect.