I had a numb leg from knee down and totally numb foot. like you said rubber when you stand up and feels like walking on gravel. Foot was cold and toes turned purple. Surgeon said it was normal - nerve damage. long story short...the surgeon pinched the popliteal artery behind my knee during surgery which cut off all blood supply to my lower leg and foot. 6 weeks later my primary said NOT NORMAL. did an ABI test (blood pressure test of legs) and then angiogram that found the pinched artery. Had to have yet another surgery where that surgeon took out a dead dried blood clot and opened the artery so I now have blood flow again, but since it was almost 2 months no blood to foot I have permanent tissue and cell damage and numbness to toes and other parts of foot. My knee dr.,when I told him what he did just said..."Why did you wait so long to get it fixed...you could have lost your leg" REALLY
Don't give up keep looking for answers! I did have a spinal injection to see if that would help and it did for about a year, but never go rid of all the issues. That Dr. just told me your knee dr. damaged more that the popliteal artery. It has been 3 1/2 years now. no change.