Hand surgery is when a doctor helps fix problems with your hands or wrists. For example, if you cut yourself and need stitches, a doctor can do hand surgery to give you stitches and help the area heal. If you have a broken bone in your hand, they can help put the pieces back together and help it heal. Hand surgery might also involve repairing nerves or tendons if they have been damaged. A doctor might even replace parts of your hand if they are not working properly.