Rethinking the Coronal Anatomic Axis of the Distal Tibia for Intramedullary Nail Placement: A Cadaveric Study

Background: Recent studies have reported that targeting a center-center position at the distal tibia during intramedullary nailing (IMN) may result in malalignment. Although not fully understood, this observation suggests that the coronal anatomic center of the tibia may not correspond to the center of the distal tibia articular surface. Questions/Purposes: To identify the coronal anatomic axis of the distal tibia that corresponds to an ideal start site for IMN placement utilizing intact cadaveric tibiae. Methods: IMN placement was performed in 9 fresh frozen cadaveric tibiae. A guidewire was used to identify the ideal start site in the proximal tibia and an opening reamer allowed access to the canal. Each nail was then advanced without the use of a reaming rod until exiting the distal tibia plafond. Cadaveric and radiographic measurements were performed to determine the center of the nail exit site in the coronal plane. Results: Cadaveric and radiographic measurements identified the IMN exit site to correspond with the lateral 59.5% and 60.4% of the plafond, respectively. Conclusions: Tibial nails inserted using an ideal start site have an endpoint that corresponds roughly to the junction of the lateral and middle third of the plafond. Further studies are warranted to better understand the impact of IMN endpoint placement on the functional and radiographic outcomes of tibia shaft fractures.