It gets better. Then, alas, it can get worse, too., before getting better again. Not a linear progression at all.
My mare Sadie was all about non linear progress. She'd balk and get light in front and stick her head in the air and say I Won't and You Can't Make Me, then next day be a little angel but the day after that, look out, pure beeyotch again... knees can be like strongwilled mares. Some days you just have to ask the knee to do something simple you know it can do perfectly, praise it and end the day on a high note. A Knee is a wonderful opportunity to learn patience.