knock-knee vs tibia valga

knock-knee and tibia valga both are nouns.

Word	Noun	Adjective	Verb	Adverb
knock-knee	Yes	No	No	No
tibia valga	Yes	No	No	No

As nouns, knock-knee and tibia valga are synonyms defined as:

Other synonyms of knock-knee include genu valgum.

knock-knee (noun)	tibia valga (noun)
an inward slant of the thigh	an inward slant of the thigh