Patients who don't follow requests

At the moment I have a pt who has a damaging gait pattern to his knee. He is independent with all mobility but I have restricted him to only walking short distances to the toilet and shower. On numerous occassions I have caught him walking the corridors, taking the long way to the toilet because he hates being stuck in his room. We joke about it during physio session but I have given him firm warnings about the damage which could be caused. I have spoken to his fiancee and she has spoken to him and is trying to get him to follow orders. I have alerted nursing and other allied health staff but still this hasn't seemed to work. My supervisor has caught him recently walking around the ward and just the other day we both saw him walking back to his room. So I put to you how do you stop a pt from doing something which at the moment isn't causing any pain but is likely to cause future damage?