I am not. But I had arthroscopic surgery done on my right knee back in high school. When I bent my knee it would catch...meaning you could feel like a pop... that was torn cartilage catching. It popped very loudly one time when I was playing soccer and people on the side could hear it. It was very painful and sent me to the ground and I had to leave immediately to the ER.
Recovery time seemed slow going only because I wanted to get back to my soccer season but I was not able to because the strength of my knee was not where my therapist wanted it. And I was doing therapy 3x a week trying to push myself...but it still didn't happen. Very upsetting for my senior year.
I assume since you said that "does" knees you may be referring to replacing the knee?
At any rate, if you have any questions for me I'd be happy to try to assist. Other wise, I would suggest you seek the treatment of an orthopedic surgeon and if it is you didn't care for the 1st diagnosis then may I suggest you seek another opinion of another orthopedic surgeon?
I hope you the best in what ever it is that has befallen unto you.
Regards,
Gretchen