Aim: This study aimed to use high-frequency ultrasound guidance to compare the efficacy of percutaneous release combined with intra-tendon sheath injection (PR-ITSI) and percutaneous release only (PR-ONLY) in the treatment of adult trigger finger (TF) patients. Materials and methods: A total of 48 patients were randomly divided into PR-ITSI group and PR-ONLY group. The thickness of the A1 pulley was measured prior to surgery and 1-year after surgery. Visual Analogue Scale (VAS) score and Patient Global Impression of Improvement (PGI-I) scale score of affected fingers were evaluated at 1 day, 1 month, and 1 year after surgery. Results: The overall difference of VAS score between the two groups after treatment was statistically significant (p<0.001), while the VAS scores gradually decreased in both groups at different time-points after treatment. The VAS scores in the PR-ITSI group at 1 day and 1 month after surgery were 1.475 and 0.904 (p<0.001), respectively, which were lower than those in the PR-ONLY group. Different treatment methods had no effect on the VAS score at 1 year after surgery (p=0.055). The thickness of the A1 pulley at 1 year after surgery was lower than that before surgery (p<0.001), whereas there was no significant difference in A1 pulley thickness between the two groups (p=0.095). The rate of PGI-I scale improvement by one grade at 1 day, 1 month, and 1 year after surgery in the PR-ITSI group was 15.322 times (95%CI: 4.466-52.573, p<0.001), 14.807 times (95%CI: 2.931-74.799, p=0.001), and 15.557 times (95%CI: 1.119-216.307, p=0.041), respectively, than that in the PR-ONLY group. Conclusion: Ultrasound-guided PR-ITSI is superior to PR-ONLY in the VAS score and PGI-I scale for adult TF patients. [ABSTRACT FROM AUTHOR]