The thought of giving up judo crossed my mind after my 1st, 2nd, and 3rd MCL sprain last year and after my second should surgery but never more than a brief thought. I would more likely give up due to the BS you have to sometimes deal with in running a club than from an injury. I told my Sensei I was quitting after something happened back in college and she make me take 2 weeks off and come back, and that is the last time I ever gave any serious thought to quitting.