Investigation of dynamic hip plate screw systems in different lengths with finite element analysis

Objectives: Dynamic systems aim to create an environment that encourages bone healing while minimizing stress shielding, which is a phenomenon where the bone loses density due to a lack of stress during the healing process. In this study, it was aimed that the stress distributions on plates of different lengths in the dynamic hip plate screw system were investigated. Materials and methods: In our study, the human proximal femur model (3-D) obtained from computerized tomography was transferred to Finite Element Analysis (FEA) computer simulation. Plates with 2-4-6 holes were placed on the knitted bone model. The models used in this study were mainly determined as five components: cortical-cancellous bone, lateral plate, cortical screws, and compression neck screws. A 1 mm intertrochanteric fracture area was created from the trochanter major region. Results: When plates of different lengths were applied, there was no significant difference in the stress in the compression screw and the chamber it was located in. It shows that when a 2-hole plate is used, the stress will be high, especially between the lower cortical screw and the cortex. In these three groups, it was observed that the stress points were in at least 6-hole plates. Conclusion: The results of this study showed that the shorter the plate applied, the greater the stress on the plate and cortical screws in the femur diaphysis.