My DH tore cartilage, his PCL & medial ligaments. He had what is called an Arthroscopy. He had it twice. First in 1996 and the 2nd in 1999. The first time they left a piece of cartilage in there that ended up calcifying which then tore into the cartilage... so it all needed to be repaired again in 1999.

The pain wasn't too bad for him with thanks to the pain medication. He said the pain was more of a discomfort during the nights as he tried to sleep.
He was meant to be bed-bound for 2 weeks but he was up the next day and out off bed all the time after a week.
Because of his job which had him climbing stairs a lot, he was on crutches for 2 weeks... after that he could walk fairly normally with help from the knee support he had. It took him about 6 months before he could run properly, but there was still some pain. It was about a year before he could do more involved/heavy sports again like waterskiing. He was doing physio 3-4 times a week.
The Dr told him that everyone heals differently so you could heal much faster than he did... but DH did aggravate his a lot though his work too.

HTH. All the best for your Op and I hope the recovery is nice & quick for you