Three-dimensional analysis of the intramedullary canal axis of tibia: clinical relevance to tibia intramedullary nailing

IntroductionThe aim of this study was to evaluate the appropriate insertion point for a tibial intramedullary nail by measuring the intramedullary canal axis of the tibia in three dimensions.MethodsForty-three pairs (14 males and 29 females) of cadaveric low extremities (mean age 51 years, range 21–60 years) were analyzed to evaluate the appropriate insertion point for a tibial intramedullary nail by measuring the intramedullary canal axis of the tibia in three dimensions. Computed tomography was performed on 86 lower extremities from the hip to the ankle on cadavers. The location of the intramedullary canal axis of the tibia passing through the tibial plateau, the canal axis center (CAC), was measured. The correlations between the lateral tibial spine (LTS) and the mediolateral coordinates of the CAC were analyzed.ResultsThe CAC was located at 56.5% distance from the medial cortex. On average, the CAC was located 1.1 mm medial from the LTS. The mean length from the surface center to the CAC was lateral 4.5 mm.ConclusionThe appropriate insertion point for a tibial nail was the slightly medial aspect of the LTS. However, it led to the point with a broad range, increasing the necessity to take individual variations into consideration.