Epic Knees γνυ- / ἰγνυ

The common Greek word for "knee", γόνυ, γόνατοϛ, τό, has sterling Indo-European credentials: Latin genu; Gothic kniu; Hittite genu; etc., all pointing to I.E. *gonu-. This tidy picture is blurred, however, by the single appearance in Homer of another, rather strange-looking, reflex of the word: ἰγνύη, -ηϛ, ἡ (Il. 13.212). Since γνυ- is clearly the inherited I.E. form, how can we explain the prefixed iota of ἰγνυ- All previous proposals, which have been based largely on semantics (prepositional prefix, etc.), have serious deficiencies. I propose that an answer is to be found instead in the realm of phonetics: i.e., the secondary form ἰγνυ- was a result of resegmentation in some of the common phrases that include the word for "knee": e.g., ἀμφὶ γνυ- > ἀμφ᾽ ἰγνυ-; ἀντὶ γνυ- > ἀντ᾽ ἰγνυ-; ἐπὶ γνυ- > ἐπ᾽ ἰγνυ-; cf. ἐνὶ γνυ- > ἐν ἰγνυ-.