Broke his leg using snow transport (6)
I believe the answer is:
sleigh
'snow transport' is the definition.
'sleigh' can be an answer for 'transport' (sleigh is a kind of transport). I am not sure about the 'snow' bit.
'broke his leg' is the wordplay.
'broke' is an anagram indicator.
'his'+'leg'='hisleg'
'hisleg' is an anagram of 'SLEIGH'.
'using' is the link.
Can you help me to learn more?
(Other definitions for sleigh that I've seen before include "Travel over snow" , "Toboggan" , "13 ac's transport" , "transport (with bells on!)" , "Transport in winter" .)