Reewee said: But...... they're robots... does that even count?
Browsing through the "amputee" section, there are a few robots who have been included. However, those robots are very humanoid (and female), such as Hatsune Miku and KOS-MOS.
Well there's no other way, as of this moment, to describe the RX-78-2's condition. Broken and damaged are broad tags so amputee is a good way of getting a bit more specific and it can be combined with broken and damaged in a tag search.