He's wearing a really high boot. No need for you to worry.
I have seen some go up past the knee. Not the norm but have seen it. If it does, it could def have a bracing effect on the knee. Who knows. I do know that RWS does NOT know the all facts surrounding it so to speculate is just stupid and pointless.
Now, if it were concerning goat prostate or anus, he may would have something important to contribute here.