Hi Dave,
I'm a med student and a former EMT, so I'll try to answer as best as I can.
My first question is - does the fracture need to be reduced?
In trauma, we reduce a fracture if it is cutting off circulation to the extremity, in this case that would be the foot. If the patient has no pulses in the foot and it appears pale, clammy or the patient has lost sensation, then the fracture would be reduced. The physician would likely use a sedative (midazolam, ketamine or morphine, depending on what's available), and then manually reduce the fracture by pulling on the foot and tying it into a traction splint, which would provide traction (a pulling force away from the patient's pelvis) until the patient could be seen in surgery. He could improvise this from tent poles, ropes, and box splints available in most ERs or ambulances.
However, I think most physicians would be wary of reducing an open fracture outside of a well-equipped ER because of the risk of haemhorrage. This is not such a risk with a closed fracture. Also, does he have an X-ray available? If not again, I suspect he would only reduce the fracture if the foot had totally lost circulation.
Hope that helps,
Alex