Kus, I disagree with everyone. If you have hurt a joint, but certain exercises don't bother it, do them! No need to have leg attrition when not necessary. Now that assumes curls and extensions don't hurt it AT ALL. I have bad knees and they hurt from time to time when I squat. Extensions actually make my knees feel better. Often I can only squat after thoroughly warming up with extensions.
Dont bother with one leg presses though!
If I were you I'd superset extensions and curls and train them MORE frequently than you usually do (maybe even every other day) for about two weeks to kick start the muscles. After two weeks you can go back to once a week or whatever and then do the superset as a warm up; then try some light squats and see what happens.
Feel better dude!