Finite element analysis of intramedullary nailing and nail-plate combinations for treating unstable proximal tibial metaphyseal fractures.

BACKGROUND

The anatomy of the proximal tibia presents treatment challenges, and there is currently no widely accepted surgical fixation method for fractures in this region. The aim of this study is to evaluate the efficacy, benefits, and differences between intramedullary nailing (IMN) with a 4-hole Limited Contact Dynamic Compression Plate (LC-DCP) combination and IMN with an 8-hole LC-DCP combination in unstable fractures of the proximal metaphyseal region of the tibia.

METHODS

An oblique fracture was created in the metaphyseal region, forming a 30-degree angle in the sagittal plane in three tibial models. The fracture was designed to be 5 cm distal to the knee joint anteriorly and 8 cm distal to the knee joint posteriorly. One model was fixed with intramedullary nailing alone, while the others received additional fixation with either a 4-hole or an 8-hole plate in addition to the nail. Finite element analysis was performed using 3D computed tomography images of the models. Deformation, displacement, von Mises stress, and maximum principal strain values resulting from axial, lateral, coronal, and rotational forces applied to the models were analyzed.

RESULTS

The model fixed with intramedullary nailing alone demonstrated greater maximum stress, maximum deformation, and displacement under all applied forces. In the model with nail and 8-hole plate, unlike the other models, the highest amount of stress in the nail was concentrated on the distal locking screw under axial force. We observed that the maximum principal strain in the tibia was higher in the models with combined nail and plate fixation than in the model with intramedullary nailing alone.

CONCLUSION

The results of this study indicate that the combination treatment with an 8-hole DCP plate is biomechanically superior for treating unstable proximal tibial fractures with nails. Although the nail-plate combination requires an additional surgical incision and extra implants, it provides advantages in terms of stability and the sustainability of fracture reduction in unstable fractures.