I'm sorry to hear this. Question - what has been your post-op exercise/rehab regimen? People who get TKRs should be doing rehab exercises as soon as they get out of surgery, see a PT about twice a week for 8 weeks, and again, doing the exercises 3 times a day at home.

If you did all this and are still experiencing this pain and inability to put full weight on it, something is wrong. I don't want to guess what it could be. Regardless, you should definitely see your surgeon. All the best.