Why Is The Knee Swollen Post An Arthroscopy?

5 months ago i dislocated my patella, I had an arthroscopy 8 weeks ago, where I had to have some damaged cartalidge removed and apparently a small bit of bone that had broken off?! I am unable to walk down stairs properly or bend down with weight on my knne. I have been advised that I may always have problems with pain on bending down. My knee is also very swollen, what is the long term outcome going to be for me?