ankle vs ankle joint

ankle and ankle joint both are nouns.

Word	Noun	Adjective	Verb	Adverb
ankle	Yes	No	No	No
ankle joint	Yes	No	No	No

As nouns, ankle and ankle joint are synonyms defined as:

ankle and ankle joint: a gliding joint between the distal ends of the tibia and fibula and the proximal end of the talus

Other synonyms of ankle include articulatio talocruralis, mortise joint.

ankle (noun)	ankle joint (noun)
a gliding joint between the distal ends of the tibia and fibula and the proximal end of the talus	a gliding joint between the distal ends of the tibia and fibula and the proximal end of the talus