When I first read this description, I had already guessed that it might be a floating bunion, so I asked the parents to send me a picture of their child, and as expected, it was indeed a floating bunion. Floating bunions make up a relatively small percentage of hand and foot deformities, and are not as common as syndactyly, which is why many parents don’t know what to do when they encounter them. The most typical feature of a floating thumb is that it lacks a metacarpal bone and is connected to the palm of the hand by a loose dermatome, making the thumb floating and very fragile. The first step is to reconstruct the metacarpal bone to give it a better shape and preserve the five fingers. Currently, there are two types of metacarpal bone reconstruction, metatarsal bone reconstruction and hemimetacarpal bone graft reconstruction. Metatarsal reconstruction takes the metatarsal bone of the foot and reconstructs the first metacarpal bone from it. Since the foot is a weight-bearing area, taking the bone here will have some impact and there is a certain chance of bone resorption and necrosis, so many parents will have some concerns about this. Semi-metacarpal bone grafting is a technique to reconstruct the first metacarpal bone from the second metacarpal bone, which has a lower risk of bone resorption and necrosis, and because the surgery does not involve other parts of the body, the post-operative care is relatively simple. Semi-metacarpal bone graft reconstruction surgery is divided into two phases. After reconstructing the metacarpal bone, the first phase of the surgery will be done to establish the function of the thumb, and after the two phases of the surgery, the thumb will be able to achieve the effect of both form and function.