Just because a child’s thumb is connected to the palm of the hand by a single skin tube does not mean that the finger is completely useless, and parents should not give up easily. This condition, also known as floating thumb, is a complex form of congenital thumb dysplasia. Although the root of the thumb is only a skin tube on the surface, it actually contains blood vessels and nerves and can be treated actively to preserve the five fingers. There are two main treatment options for floating thumb: metatarsal reconstruction and hemi-metacarpal bone grafting. Metatarsal reconstruction refers to the reconstruction of the first metacarpal by taking a portion of the metatarsal bone from the foot, which has a certain chance of bone resorption and necrosis. After the surgery, the baby’s foot cannot bear weight for three months and the postoperative care is tedious. The most important thing is that there will be more or less permanent damage to the foot, which is why some parents do not accept the surgery, after all, the child’s hand already has a problem, and it is difficult to accept another foot. We have been researching and exploring this problem, so we have a second surgical option to preserve the five fingers – hemi-metacarpal bone grafting, which is currently the most advanced surgical method for floating thumb treatment. The hemi-metacarpal bone graft refers to the reconstruction of the first metacarpal bone by taking part of the bone from the baby’s second metacarpal bone, which is operated only on the baby’s hand and the chance of bone resorption and necrosis is greatly reduced. What’s more, the baby can have the surgery at six months, and after the surgery, the baby can start active exercise.