Think ankles are not like knees, but maybe a bit like hips as it's a ball and socket set up, my doctor explained when I did my left ankle that they do not break as such, the ball bit when badly twisted fractures and expands the socket, which never goes back to its original tightness = weak ankle.
Knee op I found fantastic, ok you lose some movement (120 degrees is good) and takes about two years for swelling to go down and muscle recovery (I hope) but in one day out the next and after a week or two that damn pain gone, gone, gone along with the morphine and it's side affects