What is the clunking noise and shifting noise i hear in my knee? it is very painful something is moving i don't think it is kneecap. what could it be?

Cartilage tear: You can have have locking and popping of the knee if you have a tear of the meniscus. This shifting can cause pain and in some cases swelling. Exercise can help. You may want to get an evaluation. See a sports medicine physician first to get an exercise program.

Get seen: You have 4 separate posts about meniscal roottear, osteochondritis dessicans and tibia slipping- the possiblities are too broad to figure out online, you need to have a open discussion with your surgeon - he or she knows your knee better than anyone else on earth and can address specific questions about the mri. Seek a second (not 3rd, 4th and 5th) opinion if you arent satisfied with the answer.