J Korean Fract Soc.  2023 Jan;36(1):1-9. 10.12671/jkfs.2023.36.1.1.

Computational Simulation of Femoral Neck System and Additional Cannulated Screws Fixation for Unstable Femoral Neck Fractures and the Biomechanical Features for Clinical Applications

• Kim JY

• KMID: 2538542
• DOI: http://doi.org/10.12671/jkfs.2023.36.1.1

Abstract

Purpose
To identify the biomechanical features for clinical applications through a computational simulation of the fixation of the Femoral Neck System (FNS) with additional cannulated screws for a Pauwels type III femoral neck fractures.
Materials and Methods
Thirty cadaveric femurs underwent computed tomography, and the images were transferred to the Mimics ^® program, resulting in three-dimensional proximal femur models. A three-dimensional scan of the FNS and 6.5 mm and 7.0 mm cannulated screws was performed to enable computerized virtual fixation of FNS with additional cannulated screws for unstable femoral neck fractures. Furthermore, the cannulated screw used for additional fixation was modeled and used as a cylinder within the Ansys program. The biomechanical characteristics of these models were investigated by applying a physiological load virtually.
Results
The maximum von Mises stress value at bone was 380.14 MPa in FNS and 297.87 MPa in FNS+7.0 mm full-thread cannulated screw. The maximum von Mises stress value at FNS was 786.83 MPa in FNS and 435.62 MPa in FNS+7.0 mm full-thread cannulated screw. The FNS group showed the highest maximum von Mises stress values at bone and FNS. For total deformation, the maximum deformation value was 10.0420 mm in FNS and 9.2769 mm in FNS+7.0 mm full-thread cannulated screws. The FNS group represented the highest maximum deformation compared to the other groups.
Conclusion
Considering the anatomical spatiality and biomechanical characteristics of the FNS in unstable femoral neck fractures, when one 7.0 mm full thread cannulated screw was also fixed to the anterosuperior portion of the FNS, significant biomechanical stability was demonstrated.

Keyword

Femur; Femoral neck fracture; Pauwels type III; Femoral Neck System; Additional cannu-lated screw fixation; Computational simulation