Intramedullary nailing at different distal tibial fracture levels: A biomechanical study

Distal tibial fractures remains a significant challenge in orthopedic trauma surgery. As the fracture level approaches the joint, alternative fixation options instead of intramedullary nailing (IMN) come to the fore. The present study aimed to assess the biomechanical stability of IMN at different distal tibial fracture levels and the number of locking screws required.

Using a total of 21 sawbone models, 3 different tibial fracture levels (3, 4.5, and 6 cm proximally to the talocrural joint) were created and the fractures were fixed using 2, 3, or 4 distal locking screws. A single compression force at a speed of 30 mm/min with a maximum force of 800 Newton and a cyclic compression force of 60 cycles at a speed of 60 mm/min was applied to all tibia models. The applied weight and displacements from the fracture lines were recorded and evaluated.

There was no statistically significant difference in fixation with 2 distal locking screws in groups 1, 2, and 3 (single test P =.9689) (cyclic test P =.8050). Therefore, if 2 distal screws are used, the fracture level does not affect the strength of fixation. In fractures located 6 cm proximal to the talocrural joint, all 4 holes of the nail can be used to insert screws, which provides a stronger fixation. When 2 screws are used, a statistically weaker fixation is obtained than with 3 or 4 screws. However, there is no significant difference between using 3 or 4 screws.

Our findings support the use of IMN with 2 distal locking screws as a viable option for the management of distal tibial fractures. We found that it provides sufficient fixation regardless of the fracture level, suggesting that there is no need to choose an alternative fixation technique due to concerns of inadequate fixation as the fracture line moves distally. In cases where more stable fixation is desired, an additional locking screw can be used, but the potential increase in procedure and fluoroscopy time should be considered.