Topper for a pocket sprung mattress with a memory foam section.

I bought a pocket sprung mattress with a memory foam layer from a reputable supplier 4 years ago when I bought my new king sized bed.
Recently my wife and I noted that the top layer was showing some indentations on my side of the bed.
As the mattress can't be turned over like normal without loosing the memory foam advantages, would it be possible to overcome our problem by adding a new topper on either side.