Wrenching of a joint (6)
I believe the answer is:
sprain
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">wrenching of a joint</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for sprain that I've seen before include "Muscular injury caused by wrench" , "Injure joint by wrenching it violently" , "Wrench (an ankle) 6)" , "Wrench or twist" , "Injury to the ankle, say" .)