Abstract
Objective: The potential instability of tibial fracture fixation with intramedullary nails due to gap coordination between locking nails and holes was investigated. The aim of this study was to explore a more stable and reliable internal fixation method using intramedullary nails designed with new locking mechanisms.
Methods: Tibial CT image data from a healthy female were obtained to create a tibial fracture model in the middle section using finite element digital technology. Subsequently, two different intramedullary nails were utilized for fixation. The experimental group employed intramedullary nails designed with new locking mechanisms, while the control group used conventional intramedullary nails. The specimens were subjected to axial loading of 2500 N, lateral bending of 1000 N, and rotational forces of 15 Nm. The maximum stress and displacement of the bone and internal fixation were recorded for both groups.
Results: Under an axial stress of 2500 N, the maximum stress on the internal fixation in the experimental group was 247.0 MPa, with the maximum displacement of the fracture end reaching 0.200 mm. In the control group, the maximum stress on the internal fixation was 434.9 MPa, and the maximum displacement of the fracture ends was 0.538 mm. For a lateral bending stress of 1000 N, the maximum stress on the internal fixation in the experimental group was 678.0 MPa, and the maximum displacement of the fracture end was 0.255 mm. In the control group, the maximum stress on the internal fixation was 413.7 MPa, and the maximum displacement of the fracture end was 0.826 mm. When subjected to a rotational stress of 15 Nm, the maximum stress on the internal fixation in the experimental group was 626.8 MPa, with the maximum displacement of the fracture end measuring 0.839 mm. In contrast, the control group exhibited a maximum stress of 289.1 MPa on the internal fixation, along with a maximum displacement of the fracture end of 1.802 mm.
Conclusion: Compared with traditional intramedullary nail designs, the new intramedullary nail design provides superior mechanical support for middle tibial fractures and offers more biomechanical advantages.