Horrible nerve pain from back L3/4 spinal compression

Hi. TKR right side on 2/26/2019. Knee recovery is going well, still on home health visits as was put on antibiotic due to onset of infection. So, beginning outpatient PT on 3/22, have been working at home diligently with extension and flexion, and with my home PT person.

Feeling well outside of severe nerve issues from surgery. They have me on nerve meds/muscles relaxers which help. I have spondylitis and spinal stenosis, and will have lumbar fusion eventually after knee heals completely. The nerve pain is excruciating and standing is my only relief at times. I can note, even without seeing my spinal Dr yet, L3/L4 and S1/S2 have slipped forward and compressing my nerve.

Standing if I make the slightest stretch in my back the nerve pain shoots down the inside of my leg into my knee, I know what is causing it. Some of the exercises aggravate this nerve. I did not have this issue prior to surgery.

Has anyone else dealt with this as a result from the manipulation in the TKR? Any suggestions as I cannot do my usual yoga and am not certain, with the compression, if I can do my yoga well yet.

Also, any suggestion on how to increase my angle of bend in my knee?

Thank you so much in advance, have a beautiful day