Congenital deformities of the hand are very common and are often corrected in early childhood to avoid affecting the mental development of the child. Of course, there are also residuals that are corrected after adulthood, as the deformed fingers have adapted to the new life and formed stereotypes in the brain, making surgical correction quite difficult. Fortunately, the thick bones of adult finger deformities provide a lot of convenience for the osteotomy and fixation of corrective surgery. This article shows a case of correction of compound thumb deformity, female, 33 years old, with congenital polydactyly of the right thumb, usually with more than one finger on the radial side. On examination, two fingers were superfluous on the distal side of the first metacarpal bone of the right hand, with two interphalangeal joints on the radial side and an obvious ulnar deformity on the ulnar side, and both superfluous fingers were inflexible. The radial finger had three phalanges and the ulnar one had two phalanges, but the base of the last phalanges was ulnarly deformed. The decision to keep the ulnar side was made considering several factors: its length and phalanges are similar to normal anatomy and preserve the tiger’s mouth perfectly. If the radial side finger is chosen, it may lead to a deep tiger’s mouth, an oversized tiger’s mouth, and an overlong thumb. The difficulty was how to deal with the metacarpophalangeal joint of the ulnar side of the finger and how to deal with the ulnar deviation of the terminal segment. The final result was very satisfactory. Figure 1 Pre-operative metacarpal appearance Figure 2 Pre-operative dorsal appearance Figure 3 Pre-operative X-ray Figure 4 Post-operative dorsal view Figure 5 Post-operative metacarpal view Figure 6 Contralateral palm Figure 7 Contralateral figure 8 Post-operative X-ray