Good question. Best I can come up with is Joseph D Keyser of the 120th New York Infantry, (who fought at Gettysburg on Day 2 at the Peach Orchard) and who later testified against Henry Wirz.
I have no idea what happened to his feet
Edit - Not a bad try. Keyser did testify against Wirz and he did belong to the 120th NY, which did fight on the second day at Gettysburg.
However, the records of the 120th NY indicate that he was a hospital steward, not a private. And, as you indicated, there is no record of anything unusual happening with his feet.
Hoosier