Biomechanical behavior of fibula fracture fixation using the Stryker VariAx 2 system: A finite element analysis of lower limb load distribution

Abstract

Aims

In this study, we used finite element analysis to evaluate the mechanical behavior of the lower extremity under three conditions: an intact fibula, a fractured fibula without fixation, and a fractured fibula stabilized using the Stryker VariAx 2 One-Third Tubular Plating System.

Methods

Three-dimensional solid models incorporating detailed representations of bones, ligaments, and tendons were developed from CT and MRI data. Loading conditions were imposed simulating an axial compressive load of 700 N applied to the upper extremity of the resected femur and a torsional load of 6000 Nmm applied to the proximal femur, and a fixed constraint was imposed on the foot, simulating physiological conditions encountered during gait.

Results

indicated that the absence of the fibula leads to significant increases in stress and angular displacement across key anatomical regions, including the tibia, femur, patella, and foot, underscoring the fibula's role in load sharing. Although reintroducing a fibular implant partially ameliorates these effects, the implant itself exhibits elevated stress compared to a natural fibula.

Conclusion

These findings highlight the need for careful preoperative planning and individualized treatment strategies in fibula fracture management, while also informing future improvements in implant design.