Knee pain and foot numbness

Hello, Thanks in advance for any advice.

My husband has knee pain, it pops, gives out, swells sometimes, but always hurts, either a little or allot depending on the day.  Recently the pain has been accompanied by numbness and chill in the bottom of his right foot, you can actually place your hand on his foot and feel the temperature difference, this is the same leg as the knee pain.  He has had two MRI's and both orthopedic specialists assured us there were no torn ligaments, or meniscus etc.  He had surgery on this knee for a torn meniscus 10 years ago.  I can't find anyone to help him.  Is this a neurological problem because of the numbness?  What type of doctor should I try next?  He is so uncomfortable and this has been going on for over a year now, but it is not getting any better.

[Londres70]

I would recommend you consult a Neurologist about this.