To identify the radiographic correlate of the anatomic safe zone for tibial portal placement.

Cadaveric, anatomic, and radiographic study using twenty cadaveric knees. Kirschner wires were placed in the anatomic safe zone. Anteroposterior and lateral radiographs were taken to evaluate the portal placement.

Anatomy laboratory.

Radiographic measurements of Kirschner wires placed in the anatomic safe zone.

The safe zone for tibial nail placement as seen on radiographs is just medial to the lateral tibial spine on the anteroposterior radiograph and immediately adjacent and anterior to the articular surface as visualized on the lateral radiograph. There is some variance on the anteroposterior radiograph but no variance on the lateral radiograph.

The placement of tibial nails in the superior portion of the tibia in the documented position generates the least risk to the intraarticular structures of the knee.