Tibia-based referencing for standard proximal tibial radiographs during intramedullary nailing.

Limited information exists to define standard tibial radiographs. The purpose of this study was to define new landmarks on the proximal tibia for standard anteroposterior and lateral radiographs. In 10 cadaveric knees, fibular head bisection was considered the anteroposterior image, and femoral condyle overlap the lateral image. In another 10 knees, a "twin peaks" anteroposterior view, showing the sharpest profile of the tibial spines, was used. The "flat plateau" lateral image was obtained by aligning the femoral condyles then applying a varus adjustment with overlap of the tibial plateaus. Medial peritendinous approaches were performed, and an entry reamer used to open the medullary canal. A priori analysis showed good to excellent intra-/inter-observer reliability with the new technique (intra-class correlation coefficient ICC 0.61-0.90). The "twin peaks" anteroposterior radiograph was externally rotated 2.7±2.1° compared to the standard radiograph with fibular head bisection. Portal position and incidence of damage to intra-articular structures did not significantly differ between groups (P>.05). The "twin peaks" anteroposterior view and "flat plateau" lateral view can safely be used for nail entry portal creation in the anatomic safe zone. Tibia-based radiographic referencing is useful for intramedullary nailing cases in which knee or proximal tibiofibular joint anatomy is altered.