OBJECTIVE: To evaluate the efficacy and safety of the drug by observing the effects of transdermal scopolamine（ TDS） on the incidence of nausea and vomiting

improvement of visual analogue scale（ VAS） and the first time of postoperative activity out of bed after total knee arthroplasty. METHODS: A total of 97 patients with total knee arthroplasty in department of knee joint of Xi’an Honghui Hospital from Jun. 2019 to Sept. 2021 were extracted to be divided into the study group（ TDS

n = 49） and the control group（ placebo

n = 48） via the random number table. In both groups

patches were applied behind the patients’ ear 4 h before surgery

and kept for 72 h. All patients were anesthetized with general anesthesia + femoral nerve block

and preoperative education

surgical operation

postoperative rehabilitation

and multi-mode analgesia were performed by the same group of clinicians. The occurrence of nausea and vomiting in from 4 to 24 h

from 24 to 48 h

from 48 to 72 h and 72 h after surgery

improvement of VAS score and the first time of postoperative activity out of bed was recorded and counted by independent observers. RESULTS: The incidence of PONV in the study group was 0. 261 9 times of that in the control group（ 95% CI = 0. 105-0. 654

P = 0. 004）. The VAS scores of nausea and vomiting were statistically different between the study group and the control group from 4 to 24 h

from 24 to 48 h and from 48 to 72 h after surgery（ P <0. 05）

and the study group was lower than the control group. In terms of the first time of postoperative activity out of bed

62. 50%（ 30 cases） of patients in the control group and 85. 71%（ 42 cases） of patients in the study group could take exercise on the first day after operation

the proportion of patients in the study group was significantly higher than that in the control group

with statistically significant differences（ χ~2= 6. 83

P = 0. 009）. There was no significant difference in the incidence of adverse dru reactions between two groups（ P > 0. 05）. CONCLUSIONS: TDS has the positive effects on reducing the incidence of nausea and vomiting after total knee arthroplasty

avoiding the hepatic intestinal first pass effect and stimulation of the gastrointestinal tract during oral administration

prolonging the duration of drug action

being more convenient for administration and discontinuation of drug administration

and having less adverse drug reactions and higher safety.