Santa's vehicle broke his leg (6)
I believe the answer is:
sleigh
'santa's vehicle' is the definition.
(Santa Claus' sleigh)
'broke his leg' is the wordplay.
'broke' indicates an anagram.
'his'+'leg'='hisleg'
'hisleg' anagrammed gives 'SLEIGH'.
(Other definitions for sleigh that I've seen before include "Santa's vehicle" , "13 ac's transport" , "Vehicle suitable for snow" , "Vehicle for transport over snow" , "transport in snowbound area" .)