Ekic, I've returned to training twice following knee surgeries (and will do so a third time soon; just recovering from a minor arthroscopy). I found that there are both physical and emotional fear issues on returning to training, so be sensitive to them and respect the physical, in terms of really letting your return to training be at your body's needed pace, while not letting emotional issues hold you back.
Some of this we talked about in our first Mirror column
http://www.aikiweb.com/columns/themirror/2004_03.html
best of luck