I wouldn't bother having your son put under to have the nail sewen back on because it won't 'take'. Once the nail plate has been ripped from the nail bed, the only thing they can do is to leave it alone and let it heal on its own. If it is ripped all the way back to the matrix, they can numb the finger and cut off the lifted portion. Once the nail bed has been ripped up, the nail palte that emerges from the matrix will not usually grow attached past the point of the tear. The reason? The nail grows forward on the nail be dupon a series of rails and grooves much like a train rides forward on its tracks. The rails are on the surface of the nail bed and the grooves are on the underside of the nail plate. When the 'rails' are ripped up, there is nothing left for the nail plate to ride forward on. As long as the matrix was not compromised, it will continue to produce nail plate cells, although he will probably have a very short nail on that finger for the rest of his life. It will grow in attached to the point of the tear, but probably not past that point.

In all honesty, I think you will be wasting your money and putting your child under anesthetic for no viable reason.