The anatomy of the tibial intramedullary canal.

An autopsy study was done to determine the relationship of the tibial plateau and the intramedullary canal of the tibia. Rods were placed in 10 adult anatomic specimen tibias. Computed axial tomography scans were obtained of the proximal tibia at 1 cm, 1.5 cm, 2 cm, and 2.5 cm from the most proximal plateau. Based on these sections, the position of the tibial canal was measured relative to the plateau. The center of the tibial canal on the plateau varied from 28% to 53% of the depth of the tibia from the anterior cortex and from 37% to 56% of the width of the tibia from the medial cortex. Actual measurements ranged from 15 mm anterior to the center to 1.5 mm posterior to the center and 8 mm medial to the center to 4.5 mm lateral. Because of this variability in location of the tibial canal, a mobile stem attachment site on the tibial tray or an offset stem may be beneficial for some patients having total knee arthroplasty.