Foot is really cold after leg surgery

My husband had surgery on his leg for the second time after putting a machete in the side of it. The orthopedic dr. had to drill a hole through his tibia and put the peroneal nerve through there. well now its been a week since surgery and when he has his leg down for a short to long period of time his foot gets ice cold, and he is still using crutches. once he puts it back up with some blankets it warms up again..... What is going on? is something wrong that we need to worry about? He went back to Orthopedic dr. and he said he didn't know what would be causing that....

[FootDoc]

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I have no idea why the peroneal nerve might have been diverted through the tibia. Are you sure you got that right? But, moving on . .
I've gotta suggest that a foot getting "ice cold" could NOT be considered a good sign, whether after surgery or not. My best thought would be that the appropriate next stop after all your doctor's orthopedic surgeon could say was that he didn't know what could be causing it would, in my opinion, NOT be the Internet.