The burning is probably caused by nerve damage, especially after four surgery's. P.T is very painful. I was able to get to -5 on straightening and 84 degrees range of motion. So, those numbers are very positive I feel.

Good afternoon @4tkr,
You are being challenged by another surgical revision for your TKR. Let me see if I understand. Although your pain has escalated you are concerned that once again the surgery was not performing as you had hoped. Actually, 5 days is not a lot of time and you do need to be very loyal to the recommended exercises and post-surgery care.

Remember that knee surgery, especially a complete new TKR, disturbs a lot of soft tissue, muscles, ligaments, and tendons. And all of those elements are surrounded by connective tissue called fascia. Sometimes that fascia becomes restricted and must be released. Especially if you are doing PT post-surgery, you will also benefit from Myofascial Release Therapy (MFR). Did you have MFR treatments after any of your three other surgeries? If not, you may want to make sure you avoid building scar tissue. Every surgery creates more.

Of course the other must do is "ice and elevate" frequently. I am 3 mos post-surgery for my second TKR. Ten years after my left knee, I knew that the right knee was next. The recovery has gone quite well. My MFR therapist is able to find those restricted pain areas and release them.

Here is the heading of the MFR story on Connect. Just copy it in the search bar at the top of the page.
Myofascial Release Therapy (MFR) for treating compression and pain

How are your ROM numbers or is it too early to tell?

May you be free of suffering and the causes of suffering.
Chris

Myofascial Release Therapy (MFR) for treating compression and pain