Our thumb, like other fingers, has a tendon sheath canal on the outside of the flexor tendon that facilitates the pulling of the tendon and the flexion and extension of the finger. The difference is that there are two seed bones at the opening of the tendon sheath canal in the thumb. In some infants, the seed bones are too large and interfere with the development of the opening of the tendon sheath canal. If the opening of the tendon sheath is relatively slow, it can cause compression of the tendon and cause unfavorable flexion and extension of the thumb. This is called congenital stenosing tenosynovitis of the thumb. It is often seen in infants around one week of age who have unfavorable flexion and extension of the thumb or are unable to straighten it in flexion. It can get progressively worse. It is generally accepted that if the thumb can be straightened and flexed by local massage, the stenosis of the tendon sheath opening is not very severe. In some children, it may improve or heal with massage. However, if the thumb is flexed and still cannot be straightened by massage, it means that the stenosis of the opening of the tendon sheath canal is serious. Because of the rapid development of children, if not corrected in time, it will affect the development of bones and joints and tendons. So the performance is treated in time. The general treatment method is surgery. The surgery is not very difficult, just make a small incision and cut open the narrow tendon sheath opening to release it. However, the child is too small to cooperate, so general anesthesia is usually required. Our hospital has been treating adults with stenosing tenosynovitis for more than 20 years and children with congenital stenosing tenosynovitis of the thumb for nearly 10 years, with hundreds of cases of experience. We believe that needle knife relaxation is practical and feasible. However, there are some conditions that need to be noted with needle knife treatment. Although the treatment is painless after local anesthesia, if the child is very uncooperative, the treatment cannot proceed. Second, the needle knife release may not be as complete as the surgical release, (most cases can be solved in one go), and the release can be done again after a period of time. Thirdly, in some cases, the child recovered well at that time, but after a year or two, the finger movement problem appeared again. This is because with the increase of age, the child’s bone grows thicker and the tendon thickens, but the opening of the tendon sheath still cannot be enlarged accordingly. It can be loosened again. This is not a common occurrence. It is also a problem that may be encountered with open surgery.