Polydactyly is a common congenital deformity for which surgical removal is the only solution. Most parents think that surgery is only for aesthetic purposes. It is true that improving the appearance of the hand is one of the purposes of surgery, because the deformity of the hand can cause many children to have low self-esteem; however, the more important purpose of surgery is to restore the function of the hand, especially the thumb polydactyly. Because the function of the thumb accounts for 50% of the entire hand, if the thumb loses its function, many movements of the hand cannot be completed. But no matter what the purpose is, parents always have the same questions and concerns about the surgery: How is it done? Is it risky? Will it look exactly like a normal finger after surgery? Today, we will help the families of the affected children to do their homework. Is there a big incision for polydactyly surgery? The size of the incision is determined by the type of polydactyly and the diameter of the extra finger root (Figure 1). However, even in the simplest types, the incision is not too small. Generally, the incision is about one centimeter in diameter, and the incision looks longer when it becomes linear after suturing. Many parents wonder why the stitches are bent after surgery, how not to stitch more beautiful? In fact, experienced doctors will try to avoid making a straight incision during surgery. First of all, after the multiple fingers are cut off, the skin on the hand is missing, so if you want to close the wound, you have to “rip” the skin on both sides, and in this case, you can’t use intradermal sutures (cosmetic stitches); and if you use a straight incision to close the wound, it will be more likely to have scar contracture, and the fingers will bend to one side along the suture line. Therefore, doctors usually use C-shaped, S-shaped or forward and reverse U-shaped incisions, so that the chances of scar contracture are much smaller. Once a scar contracture occurs, a scar release implant surgery is required, which cannot be solved by massage, plasters and scar removal medications. How does surgery straighten a bent finger? Simple soft tissue polydactyly, in common parlance, means that the extra finger is a piece of “flesh” with no bones and no tendons. For this type, it is sufficient to cut off the polydactyly and no other corrections are needed. If the polydactyly contains finger bones, tendons, etc., which are connected to normal finger bones or joints, in this case, in addition to removing the polydactyly, functional reconstruction of the finger, such as the displacement of tendons and reconstruction of ligaments (Figure 2), is required to ensure that the finger returns to its normal position and does not affect its function. For more serious deformities of the polydactyly, such as the metacarpophalangeal joint (the joint between the palm and the fingers) has been bent, osteotomy of the metacarpal bone is also done to correct the bend. In addition, if the child has curvature of the interphalangeal joints, osteotomies of the phalanges can be done at the age of 3 or older. As shown in Figure 3, the middle phalanx of the finger is bent, and a wedge-shaped osteotomy is done to straighten the phalanx and restore the joint to its proper position; the osteotomy does not completely cut off the phalanx, but retains the bone cortex on the bent side so that the phalanx looks like a fold; then a kerf pin is inserted through the phalangeal joint for fixation, and the finger is straightened and rotation of the osteotomy site is prevented. The reason for waiting until after 3 years of age to perform the osteotomy is that the finger bones are very thin and it is difficult to do wedge osteotomy in children who are too young; moreover, when fixation is performed, the Kirschner pin passes through the too thin bones and damages the joint surface. Another important reason is that children have a great potential for growth and development, and surgery is done at the age of 1 to cut off the extra finger, and after surgery, massage and braces are used to promote the growth of the preserved finger, which will grow straighter and straighter, and many children can end up without osteotomy orthopedic surgery. Can I have a normal finger after surgery for polydactyly? Regardless of the type of polydactyly, it is difficult to say whether the affected finger will be identical to the normal finger in terms of length, thickness and function after surgery. If the affected finger is very different from a normal finger before surgery, it will still look different even after surgery. However, overall, the removal of the extra finger is definitely beneficial to the appearance and function of the hand, which is why children should have surgery around the age of one. Just like a small tree growing two branches, breaking off one of the bad branches when the tree is relatively small, the remaining one will grow stronger and straighter. Functionally, normal hand function can usually be restored after surgery. Even if some children have a particularly complex polydactyly with some residual cosmetic and functional deficits, there is no problem in meeting normal living standards.