Intramedullary tibia nailing with external fixation.

Abstract

This study introduces an intramedullary nailing technique with external fixation and aims to determine the safest position of Schanz screws for this technique. Patients undergoing intramedullary nailing were evaluated by computed tomography to assess the anteroposterior (AP) length of the medullary canal and the distance between the posterior cortex and the posterior border of the nail at the level of interest in the proximal and distal tibia. In this cadaveric study, screws were inserted at the level of interest, followed by a determination of the anatomical relationship between inserted screws and nearby neurovascular structures. The safe area for inserting Schanz screws in the medial to lateral direction in the proximal tibia was found to be 1.5-4.5cm distal to the knee joint line on the AP view, 1cm anterior to the posterior cortex at the distal 4.5cm level, and ≤ 24mm from the posterior cortex on the lateral view. In males, the area 1.5-3.0cm proximal to the tibial plafond and 0.5cm anterior to the posterior cortex on the lateral view was found to be a safe zone. However, in females, the safe zone was defined as an area 1.5cm proximal to the tibial plafond and just anterior to the posterior cortex. This study defined the safe zones of Schanz screws for intramedullary nailing with an external fixator. These safe zones would be helpful for external fixation during intramedullary tibia nailing.