I have hyperextension loss according to my doctor which i think is causing patella shifting. She didn't explain it in detail but according to her my knee doesn't get completely straight (they were looking straight to me). Now i have to make those exercises every day to be able to reach full extension. Weird thing is my knees also don't have full flexion. I can't sit on my knees in a packed up position. They are kind of locking after a certain degree.