Hello Melissa-
I had a pretty bad MCL tear and for some reason it resulted in the scarring of my medial plica as well. I had a scar resection surgery for arthrofibrosis and my OS said my medial plica looked like bubblegum and he removed most of it. I wasn't sure if it was my plica hurting before surgery or my MCL, or both. I do know that after the surgery, the part that hurt the worst was the medial plica! I was really focusing on extension after that surgery because gaining ROM was the entire purpose, BUT i was so distracted as far as any other pain goes because the plica was SOOOO sensitive after being in extension and then going to flexion. And also during Straight Leg Raises....and quad sets. For the most part, I didn't have resting pain, it was activity related.
I would say that it actually took several months for that to heal and stop being inflammed. After the surgery, a couple of months later, I received a cortisone shot into the plica area because I was still having a issues. This helped immensely and I think things just need to cool down a little bit more. Funny how one of the only useless things in the knee can cause so much pain.
I would recommend very frequent icing, very frequent anti-inflammatories, biking or something to keep the joint moving, and if you're not opposed, or your OS isn't opposed, perhaps an anti-inflammatory injected into the plical area (not the joint itself) would help. Good luck!