IDK if they gave you an actual diagnosis - I had some 'surface irregularity' of the patella which they cleaned up surgically. I was told at the time it was likely a stopgap measure that I'd need more work done 10-15 yrs later I'm around yr 20 and having quite a bit of trouble but with both knees.
Cortisone shots for me have been magic till this latest injury - which we're still trying to determine exactly wtf I did. Nerve damage at the least.
I would try the cortisone shot b/c there isnt too much downside. You'll know in a week if it works. I've gotten almost 11w of significant relief - I'm sure if I hadnt injured the other knee, my left one wouldnt be in as rough shape so soon. Then move on to the surgery.
dd1 10/05
dd2 11/09
and ... a mini poodle!