Transport needed by Santa — his leg is broken (6)
I believe the answer is:
'transport needed by santa' is the definition.
'sleigh' can be an answer for 'transport' (I've seen this before). I'm not sure about the 'needed by santa' bit.
'his leg is broken' is the wordplay.
'is broken' is an anagram indicator.
'hisleg' anagrammed gives 'SLEIGH'.
Can you help me to learn more?
(Other definitions for sleigh that I've seen before include "13 ac's transport" , "Travel over snow" , "Dancer pulled this" , "Carriage to run on snow" , "Transport in winter" .)