Evaluation of the effect of healing of tibia shaft fracture with rotational deformity on ankle joint loads

Introduction and Aim: Tibial shaft fractures are among the most common long bone fractures. Locked intramedullary nailing is currently the standard approach in the treatment of tibial shaft fractures. It has been reported that the incidence of malrotation in tibial shaft fractures with intramedullary nailing is between 19-41%. In this study, it was aimed to evaluate the loads on the ankle joint and implant caused by rotational deformity in tibial shaft fractures with intramedullary nailing. Material Method: A total of 7 models were created as neutral, 5° internal rotation (IR), 15° IR, 25° IR, 5° external rotation (ER), 15° ER and 25° ER. The loadings in all models were evaluated using the finite element analysis method. Results: The highest loading on the tibiotalar cartilage occurred in the 25° IR model. On the other hand, the least loading was observed in the neutral model. In the 25° IR model, it was observed that the maximum principle stress (3,742 MPa) and Von Mises (1,988 MPa) values were highest in the posteromedial region of the cartilage. Conclusion: Malrotation causes increased stress on the cartilage in the treatment of tibial shaft fractures with intramedullary nailing. As the malrotation increases, the loads also increase. Internal rotation causes increased loads compared to external rotation. Keywords: Tibial Shaft Fractures, Malrotation, Intramedullary Nailing, Finite Element Analysis