Review Question - QID 4784

The ideal entry point is just medial to the lateral tibial spine (AP view), and anterior to the anterior articular margin (lateral view).

The ideal insertion point allows nail placement (1) without injury to the menisci or articular cartilage, and (2) allows the nail to travel down the center of the intramedullary canal of both fracture fragments, ending in the center of the ankle perpendicular to the joint. An excessively medial insertion point leads to valgus malalignment. Malposition in the sagittal plane may cause anterior knee pain from unrecognized intra-articular injury.

Mcconnell et al. reviewed the anatomic safe zone for tibial portal placement. The safe zone measures 12.6-22.9 mm wide. With proximal tibial fractures, a superolateral portal minimizes stress during nail insertion and decreases angulation and rotation. The center point is slightly medial to the lateral tibial spine (on AP radiograph) and adjacent and anterior to the anterior articular margin (on lateral radiograph).

Song et al. evaluated the insertion point by examining the intramedullary canal with CT. The mean length from the LTS to the canal axis center was medial 1.1 mm (medial 1.5 mm in males, medial 0.9 mm in females).

Illustration A shows the safe zone on an AP radiograph. The black arrow represents the center of the safe zone. The white arrows indicate the medial-lateral boundaries of the safe zone. Illustration B is a lateral view of the proximal tibia. The black arrow shows the starting portal adjacent to the anterior articular margin.

Incorrect Answers:
Answers 1, 3, 4, 5: The ideal entry point is medial to the lateral tibial spine and anterior to the anterior articular margin.