Whattheactualfu "When I answered him I was really distracted."
It happens but I would suggest being on the ball. I once had a whole conversation with a man who I thought was a concert pianist (well, a professional musician) and music was a hobby. I had got him mixed up,. not the dating agency!
"This is my first attempt at dating after escaping a highly abusive relationship with my DDs Dad. It's been a while! I'm out of practice and still terrified of men a bit. Trying to get over it by doing this!"
PLEASE, PLEASE get some counselling and find a way to make casual friends through hobbies and activities, a cooking class or motor mechanics, art whatever, gently ease back into social life. Dating is BRUTAL and you do need to heal. No wonder you terrified of men, some are appaling. But some are not. Internet dating is IMHO not the best way to find a man if you are scared of men.
"Sod it. I'm just not going to date again. Not for many many years anyway. If ever. I'm clearly not cut out for it." You do not need to make rash decision like this. Just say to yourself, I am going to focus on making new friends, (or either sex) getting confident around people, developing some skills, etc etc, IMHO.
"There are complex issues with my knee and I didn't want to bore him!" Then I would avoid all talk of your knee. Just talk about work (with friends etc) and be general. If you need to say anything, say I twisted my knee and I'm off work at the moment. But no one is going to ask this so you can avoid talking about you knee quite easily, IMHO.