They're nice and round and have nothing to do with broken legs! (7)
I believe the answer is:
bangles
'they're nice and round and' is the definition.
The definition suggests an adverb but the answer is not.
'nothing to do with broken legs' is the wordplay.
'nothing to do' becomes 'ban' (I can't explain this - if you can you should believe this answer much more).
'with' says to put letters next to each other.
'broken' indicates an anagram.
'legs' with letters rearranged gives 'gles'.
'ban'+'gles'='BANGLES'
'have' is the link.
Can you help me to learn more?
(Other definitions for bangles that I've seen before include "Ornaments" , "Baubles, - - , and beads" .)