Sixty patients with stenosing tenosynovitis of the flexor pollicis longus were randomized to receive ultrasound-guided needle knife release (n=20), traditional conservative treatment (n=20), or open surgery (n=20). The primary outcome of interest was Quinnell grade of triggering severity. Secondary outcomes of interest included pain intensity (VAS), patient satisfaction, grip and pinch strength, DASH score, and complication rates. Outcomes were assessed at baseline, 1 week, 1 month, and 3 months. Overall, the results of the study revealed that ultrasound-guided needle knife release significantly improved triggering severity and pain, and had higher patient satisfaction compared to conservative treatment, with outcomes similar to open surgery. These findings suggest that ultrasound-guided needle knife release is a safe, effective, and minimally invasive alternative for patients with moderate to severe trigger thumb.