Congenital thumb trigger, or finger flexor tenosynovitis, in children is a narrow tenosynovitis, which is not uncommon in clinical practice and is not difficult to diagnose. Treatment is often delayed because of under-recognition and missed diagnosis. The disease is a bundling of the tendon at the joint where the palm and finger are attached during alternating movements of flexion and extension of the thumb. In children, this can affect the development and function of the affected finger. According to its pathology, this disease can be divided into 3 types: 1. Type I: thumb interphalangeal joint flexion less than 30°, interphalangeal joint flexion and extension are somewhat impaired, but still able to actively flex and extend. No nodules can be felt on the palmar side of the metacarpophalangeal joint hyperextension; 2. Type II: thumb interphalangeal joint flexion is greater than 30°, interphalangeal joint flexion and extension is significantly impaired, the interphalangeal joint can be flexed after passive straightening of the interphalangeal joint, and smaller nodules can be molded on the palmar side of the metacarpophalangeal joint hyperextension; 3. Type III: thumb interphalangeal joint flexion is greater than 30°, the interphalangeal joint cannot be actively flexed and extended, and the interphalangeal joint cannot be flexed after passive straightening of the interphalangeal joint, and the metacarpophalangeal joint hyperextension Large nodules can be molded on the palmar side, and the diameter of the thickened tendon is more than 1.5 times the normal diameter. The medical community has different views on the etiology and treatment of the disease. Most scholars believe that the disease should be treated surgically as soon as it is diagnosed, and that non-surgical treatment is not effective. Moreover, the long-term flexion of the interphalangeal joint causes compensatory hyperextension of the metacarpophalangeal joint, which may affect the development of the thumb and form a vicious circle due to repeated rubbing. Our opinion is that type I cases can be treated with massage physiotherapy, passive extension and flexion of the interphalangeal joint, and after 6-8 weeks of treatment, if it is not effective, early surgery should be performed to remove part of the thickened and narrowed tendon sheath. For type II and type III cases, surgery should be performed promptly. In general, partial resection of the narrow tendon sheath can be performed; in some cases, in addition to partial resection of the tendon sheath, tendinoplasty must be performed. For reference only, it is necessary to go to a regular hospital for consultation.