Dear Mr. Olofsson, you may also wish to look at the information M. Giscand mentioned at this site: https://www.napoleon.org/histoire-des-2-empires/articles/les-blessures-de-napoleon/
This little article discusses the controversy around exactly which surgeon initially tended N's wound outside of Regensburg/Ratisbonne/Ratisbon.

The mention of a wound at Wagram comes from Las Cases and the "Mémorial de Sainte–Hélène" (tome 2, p. 118 of the 1828 edition: https://books.google.com/books?id=Uo9x3CEqUegC&pg=PA116&dq=%22Las+cases%22+M%C3%A9morial+%22la+botte,+le+bas+et+la+peau+de+la+jambe+gauche%22&hl=en&sa=X&ved=2ahUKEwj6y_X449_kAhUFU98KHa5xDuwQ6AEwCXoECAIQAg#v=onepage&q=%22Las%20cases%22%20M%C3%A9morial%20%22la%20botte%2C%20le%20bas%20et%20la%20peau%20de%20la%20jambe%20gauche%22&f=false).

However, as there is no other mention of N's wounding at Wagram, one must suspect that Las Cases misremembered or misrecorded what he heard from N in December 1815 on that little island. N spent a long part of 6 July (the Battle of Wagram) at the hinge of his line, more/less in a crossfire that knocked down any number of officers around him (Bessières, for instance, being among the wounded). When a round took off a staff officer's plume or shako, N even joked that it was well the officer was not taller. Savary, who accompanied him, was fearful that N would indeed be wounded or killed in this vulnerable position "un égout à boulets...je m'attendais à chaque instant à le voir tomber" (from the 1828 edition of his memoirs, vol. IV, p. 174). Although he was visible to any number of soldiers (French and German alike) and many, many memoirs and contemporary reports describe his role (he was making himself intentionally visible part of the time), there is no mention of any wound. This is unlike Regensburg, where the incident is well–recorded and there was even something of a competition among medical personnel to claim being the first to attend the injured emperor. Likewise, it is well known that N was ill after Wagram (likely from fatigue), but no mention of a wound.
This all leads one to conclude that Las Cases erred about Wagram, and that N was only wounded once during 1809 (at Regensburg) as famously memorialized in the oft–reproduced painting and other similar artworks of the era (in other words, no one was trying to hide his injury in April, unlikely to do so or be able to do so in July).