The perigee of an orbit originating from a collision cannot be higher than the collision point and is very likely to be lower. Apogee could be higher, but it wo

The perigee of an orbit originating from a collision cannot be higher than the collision point and is very likely to be lower. Apogee could be higher, but it won't be for most of the debris. And even if it is, the low perigee will still cause the orbit to decay. And as Gwypaas points out, the pieces will in general decay faster than the whole satellite would due to higher surface area to mass ratio.