He had got a prosthesis as far as I know.
He lost his left forearm (and he got a prosthesis) and it also seems that his right forearm was also damaged:
He was WIA by Polish artillery fire (14. heavy artillery dyon) around 6:00 on 10th of September near his headquarters in Piątek, when he went on the first line to try to stop his last reserves, which also started to withdraw.
I don't know who - but some German probably - invented a legend, that he was personally leading a counterattack of his last battalion, and that it was succesfull and stopped the Poles.
While in fact he was not leading any counterattack personally and he also did not stop the Poles - they captured Piątek very soon.