Isolated proximal fibula fractures are managed conservatively. If there are other fractures, concern for ligamental or nerve injury, then operative management may be indicated.  Many sources recommend initially placing in a posterior mold or a combination of posterior mold/sugar tong splint. They should be made non-weight bearing and referred to orthopedics.  In practice, however, if associated injuries have been ruled out, many orthopedists will use a knee immobilizer or bulky dressing, allowing weight bearing as tolerated.