Sample size
postoperative pain, pain
PASS 15.0 (NCSS, Inc., USA) was used to calculate the sample size required for the study. Considering that there are few studies on the correlation between TXA and postoperative pain in the previous literature, the results of the pilot experiment were used for calculation. The results of the preliminary experiment showed that the average pain scores of the topical group were 3.41, 2.83 and 2.56 at 3 days after surgery, the mean pain score of the intravenous group was 3.79, 2.88 and 2.76 at 3 days after surgery. Using a two-tailed test with α = 0.05 and β = 0.2, a total of 140 patients were recruited. To allow for a potential drop-out of 15%, we enrolled 161 patients.