Congenital floating thumb, also known as floating thumb, is a thumb that is floating and non-functional due to partial or total absence of the first metacarpal bone. It is characterized by hypoplasia of the thumb. A congenital floating thumb is a congenital deformity of the hand in which the thumb is hypoplastic, often making the thumb slightly smaller or very small than the healthy side and softer at the root, lacking the bony joints attached to the hand and having only a few dermatomes or soft tissues. Treatment of congenital floating thumb is usually surgical. There are usually two methods of reconstruction: metatarsal reconstruction or hemimetacarpal graft reconstruction. Metatarsal reconstruction, in which the metatarsal bones of the foot are intercepted for transplantation. Hemimetacarpal bone graft reconstruction involves taking a portion of bone from the second metacarpal bone of the hand to reconstruct the first metacarpal bone. Patients with congenital floating thumb should go to the hospital for treatment as soon as possible. After treatment and rehabilitation exercises, the function and appearance of the thumb will be greatly improved.