The story
Both orthopod and orthoped are of jocular origin in the informal jargon of medicine; the first is a play on -pod (as in gastropod) and the second is a play on -pede (as in centipede). Each trades on the humorous portrayal of colleagues in other specialties (as opposed to one's own specialty) as strange critters (as if odd ducks).
Etymology from Wiktionary, CC BY-SA 4.0.