This child had a syndactyly with short fingers, the index finger was particularly underdeveloped, and the first web was not open. During the operation, all the fingers had to be separated, because the earlier the fingers were separated, the better the tendency of the fingers to grow and develop independently. The follow up is very obvious, the fingers were short at the beginning, but after separation, they grew very fast and functioned well, and the thumb function was fully realized. At the beginning, we were worried about lengthening, but in this child’s postoperative period, lengthening was no longer needed, and although the shape was still lacking, we focused mainly on function. If we do lengthening, the child is in pain and the parents have to spend a lot of time cooperating, so when lengthening is not necessary, my advice is not to do lengthening, and only consider lengthening if the function is really affected.