Explanation
The anatomical orientation of the distal fibula relative to the distal tibia is critical for screw placement. The fibula sits slightly posterior to the midline axis of the tibia at the level of the syndesmosis. Therefore, a screw inserted directly horizontally (in the coronal plane) through the fibula will often miss the tibia entirely or merely glance off its posterior cortex. To solidly engage the center of the tibial metaphysis, the drill and screw must be angled 20 to 30 degrees anteriorly relative to the coronal plane when passing from lateral (fibula) to medial (tibia).

**References:**
1. Xenos JS, et al. 'The tibiofibular syndesmosis. Evaluation of the ligamentous structures, methods of fixation, and radiographic assessment.' *The Journal of Bone and Joint Surgery (American)*. 1995;77(6):847-856.
2. *Rockwood and Green's Fractures in Adults*, 9th Edition. Chapter: Ankle Fractures.