Review Question - QID 5545

In proximal third tibial shaft fractures, due to the deforming forces of the pes anserine and the extensor mechanism, utilizing standard starting points during intramedullary nailing (IMN) will result in a valgus and apex anterior deformity.

There are several tips and tricks to avoid subsequent deformity following tibial IMN of a proximal third fracture. One way to avoid deformity is to use a more lateral starting point than normal to ensure nail placement in the true center of the canal, which is more lateral when compared to the tibial plateau.

Walker et al. studied 12 cadaveric tibias and inserted a Kirschner wire depending on rotated views of the knee. In order obtain a perfect starting point, a perfect anteroposterior as well as lateral of the knee must be obtained; otherwise, the authors noted that malrotation is bound to occur. With a perfect view, a more lateral starting point correlated with the center of the tibial canal.

McConnell et al. studied cadaveric and subsequent radiographic correlation on a lateral knee x-ray to determine the ideal 'safe zone' for the starting point of a tibial nail. This safe zone is more lateral and posterior, when looking at the axial cut of the plateau.

Figure A exhibits a proximal third tibia fracture with starting points that are not lateral enough, and too distal (on the lateral view), which will result in apex anterior and valgus deformity.

Incorrect answers:
Answer 1 (neutral alignment) will occur if a more lateral and more proximal start point is used.
Answers 2,3, and 5 are deformities that will typically be seen following tibial IMN if desired start points are utilized.