The gamma nail and dynamic hip screw have been widely used for the treatment of proximal femur fracture. From the clinical point of view, the implants may fail and caused loss of fracture fixation in the impairment of fracture healing. The purposes of this study were to evaluate the performance of the available fracture fixators. Moreover, the performances of a newly designed implant (double screw nail) and two types of commercial available implants (gamma nail and dynamic hip screw) were evaluated in treating proximal femur fracture under typical physiological conditions by using finite element analysis. The von Mises stress and strain energy density criteria were assigned to predict implants failure, while the total displacement criterion was assigned to investigate the fixation rigidity.
The finite element results showed that the maximum von Mises stresses mostly occurred around the hole and neck region of the implant, which can draw a conclusion that the failure mode of fracture fixation is due to the stress concentration. In addition, the maximum von Mises stresses occurred at double screw nail were the lowest. It meant that the double screw nail has the lowest risk of implant failure during the fixation because it can minimize the effect of stress concentration.
This study could assist engineers in designing new orthopedic implants and help the surgeons to select suitable implants for the patients especially during treatment of proximal femoral fracture. Finally, it is known that the actual performances of fracture fixation are affected by several factors, such as stress concentration, structure rigidity, and type of fracture treated.

The gamma nail and dynamic hip screw have been widely used for the treatment of proximal femur fracture. From the clinical point of view, the implants may fail and caused loss of fracture fixation in the impairment of fracture healing. The purposes of this study were to evaluate the performance of the available fracture fixators. Moreover, the performances of a newly designed implant (double screw nail) and two types of commercial available implants (gamma nail and dynamic hip screw) were evaluated in treating proximal femur fracture under typical physiological conditions by using finite element analysis. The von Mises stress and strain energy density criteria were assigned to predict implants failure, while the total displacement criterion was assigned to investigate the fixation rigidity.
The finite element results showed that the maximum von Mises stresses mostly occurred around the hole and neck region of the implant, which can draw a conclusion that the failure mode of fracture fixation is due to the stress concentration. In addition, the maximum von Mises stresses occurred at double screw nail were the lowest. It meant that the double screw nail has the lowest risk of implant failure during the fixation because it can minimize the effect of stress concentration.
This study could assist engineers in designing new orthopedic implants and help the surgeons to select suitable implants for the patients especially during treatment of proximal femoral fracture. Finally, it is known that the actual performances of fracture fixation are affected by several factors, such as stress concentration, structure rigidity, and type of fracture treated.

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