Background: Open surgical trigger finger release has limited success and the risk of complications; however, percutaneous techniques offer a successful alternative. There is limited understanding of the success of percutaneous trigger finger release. Objective: To prospectively evaluate the functional outcomes of patients with Green classification Grade 2 to 4 trigger finger treated with an ultrasound-guided microinvasive trigger finger release using a special 18-gauge needle with a blade at the tip. Design: Prospective, case-series study. Setting: This study took place at an academic institution by one sports medicine physician (R.E.C.) with subspecialty training and certification in musculoskeletal ultrasound. Patients: Sixty patients (79 cases) met criteria and agreed to participate in this study; 19 patients had multiple fingers treated. Average patient age was 62.8 years (SD 10.2). Average trigger finger severity diagnosis was Grade 3. Interventions: Patients were treated with an ultrasound-guided microinvasive trigger finger release using a special 18-gauge needle with a blade at the tip. Main Outcome Measurements: Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH), numerical rating scale (NRS), and Nirschl scores were captured preprocedure, at various time points, and at final follow-up. Changes between preprocedure and final follow-up were analyzed by paired t test (p <.05). Differences were also analyzed between finger, grade level, and gender by repeated measures analyses of variance (p <.05). Results: No adverse events were documented perioperatively or postoperatively. Average follow-up time was 18.4 months (SD 4.6). At final follow-up, 100% of patients reported no recurrence of catching/locking, 97% had complete resolution of symptoms and significant improvement in QuickDASH scores, and 99% required no further treatment. All measurements showed a decrease in pain and symptoms over time. The improvements in QuickDASH score, NRS, and Nirschl scale and the resolution of mechanical symptoms were all statistically significant. Conclusions: Ultrasound-guided release using the 18-gauge needle with a blade provides significant functional improvement and full resolution of mechanical symptoms with minimal adverse events.