Well i've had a bit of bad luck - I managed to trip over a bag in my living room and landed on my operated foot with the foot turning inward. My knee twisted and I felt it start to go, but then there was a restraining force (ACL?), and everything snapped back into place. I was terrified I had done damage, especially as I had some trouble with bending and pain on the lower lateral side of the knee afterwards.
My OS gave my knee a thorough test (in fact the test was almost as bad as the trip) and said my knee feels stable, but recommended a scan just in case. This I will have done on Friday. My physio thinks I may just have bruised my fat pad, and it does seem to have swelled on the lateral side of the knee. After a couple of iffy days my knee feels better day, but I am taking it easy on the rehab for a while. Hopefully it's just a temporary glitch, as everything was going perfectly until now. In fact just prior to the accident, my knee felt almost normal...
So I just hope that the graft is fine and strong enough for these small slip ups. The lesson I draw is to be careful and not get complacent - the knee is not yet ready for normal levels of abuse!