Abstract: BACKGROUND: Total knee arthroplasty is an effective treatment for end-stage knee osteoarthritis, but some patients will experience severe knee pain in early postoperative period. How to reduce postoperative knee pain is an important issue for clinicians.
OBJECTIVE: To investigate the effect of adjuvant dexamethasone combined with furosemide on early pain and swelling after unilateral total knee arthroplasty. 
METHODS: Ninety-two patients who underwent primary unilateral knee arthroplasty due to knee osteoarthritis in the Northern Jiangsu People’s Hospital from June to December 2020 were retrospectively analyzed. The patients in the treatment group (n=46) were given intravenous infusion of dexamethasone 10 mg + 100 mL normal saline on the first day of surgery and after surgery, and intravenous injection of furosemide 20 mg on the second to fourth days after surgery. The patients in the control group (n=46) were given intraoperative intravenous infusion of dexamethasone 10 mg + 100 mL normal saline, and intravenous injection of the same amount of normal saline on the second to fourth days after surgery. Postoperative knee visual analogue scale score, knee range of motion, knee HSS score, and the affected limb circumference were assessed. The incidence of postoperative adverse reactions was recorded. 
RESULTS AND CONCLUSION: (1) The visual analogue scale scores at 2, 3, 4 and 5 days after surgery in the treatment group were lower than those in the control group in resting state (P < 0.05), and the visual analogue scale scores at 2, 3, 4 and 5 days after surgery in the treatment group were lower than those in the control group in the moving state (P < 0.05). (2) The range of motion of knee joint in the treatment group was higher than that in the control group at 2, 3 and 5 days after operation (P < 0.05). The knee HSS score at 2, 3 and 5 days after operation was higher in the treatment group than that of the control group 
(P < 0.05). The lower limb circumference of the treatment group at 2, 3 and 5 days after surgery was significantly decreased compared with the control group (P < 0.05). (3) There was no significant difference in the incidence of adverse reactions such as hypokalemia, nausea and vomiting, dizziness, constipation, delirium, and lower limb venous thrombosis between the two groups after surgery (P > 0.05). (4) Adjuvant application of dexamethasone combined with postoperative use of furosemide can effectively reduce postoperative swelling and early pain of the affected limb, improve postoperative joint activity of the knee joint, and effectively promote the early rehabilitation after total knee arthroplasty.

Key words: total knee arthroplasty, furosemide, dexamethasone, swelling, pain, knee osteoarthritis