While there is not a coolsculpting applicator designed to treat the lower legs, the cool mini or cool petite applicator can often be used to target small deposits of fat around the knees.
Yes, Coolsculpting can be effective for those areas as can SculpSure. As we like to say, "If you can squeeze it, we can freeze it". However, that is in reference to fat. If the areas have a significant amount of sagging skin, you may want to combine your body contouring treatment with a skin tightening treatment such as Ultherapy.