Floating thumb, also known as floating thumb, is a type IV thumb dysplasia that is clinically manifested by the absence of the metacarpal bone and only a single pituitary attached to the palm of the hand, which looks very fragile. Such a thumb is definitely not able to do anything and can cause great inconvenience to the child later in life if not intervened by surgery. Although the floating thumb looks very fragile, it can be preserved. I use the hemi-metacarpal bone graft reconstruction technique, which means that I take part of the bone from the second metacarpal of the baby’s affected hand to reconstruct the first metacarpal, so that the thumb has a better appearance first, and then reconstruct the function of the thumb, so that the appearance and function of the thumb are both available. After a period of scientific functional exercise, the baby can use the thumb to do things such as hold a pen and write, or to hold large objects with strength. We generally recommend that babies undergo surgery between the ages of 6 months and 1 year, because this is the time when correction will allow the thumb to build up its function more smoothly and provide advantages in terms of appearance and functional recovery.