Recipe #1
create normal pv and keep it in world space
create a group above it point-constrained to various places that you
might want the pole vector to follow--ie., in the case of the leg,
it could follow the world, the hip, or foot ik control
Recipe #2
Create normal pv
parent it under arrow control parented at the upr leg position
Aim-constrain group above that control to the movement
of the foot ik control
Now when you translate/rotate the foot control, the arrow control
follows. Chill & enjoy immediately!
Zeth Willie's No-Flip Leg