Infrasyndesmotic fractures are caused by adduction of the talus in the ankle mortise (Lauge-Hansen adduction injury), resulting in lateral traction and medial compressive forces. The typical displacement is medial shift and varus angulation.
If x-rays are not available, it is safer to correct the deformity clinically, rather than to leave it unreduced.
Regard the injury as a two-part fracture between the lower leg (tibia and fibula) proximally, and the foot distally. The task will be to place the foot in correct alignment with the leg.