Bunion dysplasia refers to the absence of any anatomical structure of the thumb to varying degrees, and its clinical manifestations are diverse, according to the degree of abnormality of the thumb’s anatomical structure and the appearance of the thumb can be categorized into five types, and the floating bunion belongs to the type Ⅳ of bunion dysplasia. So, is the thumb dysplasia a floating bunion or not? If the X-ray shows that the metacarpal bone is still present, then we can assume that it is a milder form of type I bunion dysplasia, which does not require treatment. If the X-ray shows that the metacarpal bone is missing, then we can assume that it is a floating thumb, which requires surgery to correct, and the earlier the surgery, the better. Why do we emphasize the timing of surgery? Because our thumb function is usually established around 6 months to 1 year of age. If the child cannot use his thumb at this time, he will use his index and middle fingers to pinch things, and over time, the index finger will rotate in the direction of the middle finger causing a certain degree of deformity, which is not good for the child. Therefore, we recommend that the surgery should be done at around 6 months to 1 year of age, so that the thumb function can be established more smoothly.