knuckle joint vs hinge joint

knuckle joint and hinge joint both are nouns.

Word	Noun	Adjective	Verb	Adverb
knuckle joint	Yes	No	No	No
hinge joint	Yes	No	No	No

As nouns, knuckle joint and hinge joint are synonyms defined as:

knuckle joint and hinge joint: a joint allowing movement in one plane only

knuckle joint (noun)	hinge joint (noun)
a joint allowing movement in one plane only	a joint allowing movement in one plane only
a joint of a finger when the fist is closed	a freely moving joint in which the bones are so articulated as to allow extensive movement in one plane