Finite Element Analysis of Fixation Device for Femoral Neck Fracture: Dynamic Hip Screw versus Cannulated Screws
Hamed Reza Seyyed Hosseinzadeh PhD1*, Alisina Shahi MD2, Touraj Shafaghi MD3
1 Amirkabir University of Technology, Tehran, Iran
2 Rothman Institute, Philadelphia, USA
3 Shahid Beheshti Medical University, Tehran, Iran
* Corresponding Author
Introduction: Femoral neck fracture usually occur in elderly patients and it is one of the common injuries. Dynamic hip screw (DHS) and cannulated screws are well-known techniques for treatment of femoral neck fractures. Dynamic hip screw is a device to fix fractured femoral neck and in comparison to cannulated screws has more engineered design.
Materials and methods: In this research, stress distribution in these devices were examined by computer simulation. In addition, overall performance of these devices were also explained and tried to disclose parts of this device carrying more stress during loading in human body.
Results and Conclusion: According to the calculated results, it was confirmed that mean stress in dynamic hip screw (lower than 70 MPa) and femur (lower than 48 MPa) is reasonably less than yield point of bone and implant grade stainless steel and fixation device carry more stresses than the femur itself. It was also confirmed that mean stress in cannulated screws (lower than 140 MPa) and femur (lower than 42 MPa) in reasonably less than yield point of bone and implant grade stainless. Simulation results also showed that dynamic hip screw is dissipating more applied external stress and therefore, less stress is transmitted to bone in comparison to fixation by cannulated screws.
Keywords: Dynamic Hip Screw, Cannulated Screw, Finite Element Analysis, Femoral Neck Fracture, Fixation Device, Orthopaedics, A.6, J.1, J.2