Stenosing tenosynovitis of the long and flexor thumb tendon is a chronic aseptic inflammation of the tendon sheath caused by mechanical abrasion, which is clinically common in adults. Due to the lack of adequate understanding of this disease, pediatric thumb flexor stenosing tenosynovitis is often misdiagnosed and underdiagnosed, delaying treatment and affecting the development and function of the affected finger. Clinical manifestations: Usually the child is seen by parents who find the interphalangeal joint of the thumb is flexed and cannot be passively extended, with or without thumb extension popping and pain, physical examination: the interphalangeal joint of the thumb is in flexion, and active and passive dorsal extension are not possible, painless nodules can be palpated or not palpated on the palmar side of the metacarpophalangeal joint of the thumb, unilateral or bilateral onset, other diagnoses should be excluded such as extension tendon rupture, congenital karabiner thumb, extensor tendon deficiency, joint contracture or spasm, etc. Etiology and pathology: The tendinitis of the flexor tendons of the fingers is usually found in the finger flexor tendons corresponding to the head of the palm, at the beginning of the fibrous sheath canal, where the thickening of the annular fibers is called the annular ligament, which constitutes a relatively narrow fibrous canal with the head of the palm, and long-term forceful holding activities lead to the repeated extrusion of the tendon sheath by hard objects and the head of the palm, gradually forming an annular stenosis. This is a common cause in adults, but children do not have a history of long-term repetitive injury, which is different from the common cause in adults. In children, when the palm of the hand is landed, the first metacarpal head and the ground squeeze the thumb flexor tendon and its tendon sheath, causing a transient injury to the tendon and tendon sheath. If the affected finger does not have reasonable functional exercise, adhesions will easily occur and aggravate the dysfunction of the affected finger, thus causing stenosing tenosynovitis. The cause of congenital stenosing tenosynovitis in children with thumb flexor tendon is mostly due to abnormalities in the shape of the thumb flexor tendon during the fetal period, hypertrophy of the seed bone or hypertrophy of the ligament, and kozozozozo is believed to be the cause of congenital thickening of the transparent deformation of the flexor tendon sheath and disturbance of the collagen fiber arrangement. Treatment: In traumatic pediatric thumb flexor tendon stenosis tendinitis, early passive extension and flexion functional exercise of the affected finger, local hot compresses should be performed to prevent the occurrence of tenosynovitis, traumatic pediatric thumb flexor tendon stenosis tendinitis conservative treatment is ineffective or congenital thumb flexor tendon stenosis tendinitis children should promptly choose surgery, and surgery should be early rather than late, once the diagnosis should be surgical treatment, long-term interphalangeal joint maintenance flexion position The surgical plan is to make a transverse incision of about 1 cm at the palmar aspect of the metacarpophalangeal joint of the thumb, cut the skin, separate the subcutaneous tissue longitudinally and bluntly, open the vascular nerves on both sides, reveal the stenosis of the tendon sheath, find the stenosis of the tendon sheath, cut the tendon sheath from one side with a small sharp knife, then use small scissors to reduce the sides and lateral wall of the stenosis of the tendon sheath, cut the A1 carriage, and see that the long flexor tendon of the thumb has The enlarged Notta’s node is not required to be removed, as the enlargement will gradually disappear after loosening the A1 sliding carriage.