I had surgery for plica removal and chondroplasty. Still have pain 5 months later I had a new MRI that shows displacement how can that be. Menical?

Quadriceps weakness. It is very important to strenthen your quad muscle especially when you have surgery as a weak muscle will allow some patellar subluxation and also effusion.The cartlage that forms after a chondroplasty is not normal cartlage but more of a scar and this also can cause persistent pain.
Cartilage injury. After joint surgery, the knee may be more vulnerable to cartilage injury. Keep the knee elevated and warm compresses or a heating pad on the area as long as there is pain or swelling.