A finite element analysis of biomechanical performance of Proximal Humeral Internal Locking Plate System in treatment of femoral periprosthetic fracture of Vancouver type B1 / 中华创伤骨科杂志

ABSTRACT

Objective:To explore mechanical stability of Proximal Humeral Internal Locking Plate System (PHILOS) in the treatment of Vancouver B1 femoral periprosthetic fractures by three-dimensional finite element analysis.Methods:A three-dimensional finite element model of the femur was established by digital medical software (Mimics 21.0, 3-matic12.0, Geomagic12.0 and Hypermesh 2017.0) using the CT data of a femur from a volunteer (male, 34 years old, 173 cm in height and 65 kg in weight). After the femoral trochanter was cut in the femoral models, a femoral stem was implanted. PHILOS fixation (PHILOS group) and Cable-Ready GTR fixation (Cable group) were applied respectively. Loads of 700 N, 1,400 N and 2,100 N were applied to the 2 groups of finite element models. Distributions of Von Mises stress and deformation were investigated in the finite element models of 2 internal fixations; the mechanical stability was compared between the 2 groups of models.Results:The maximum deformation occurred on the femoral ball head in the 2 groups of models. At the load of 2,100 N, the maximum deformation was 3.77 mm in the PHILOS group, larger than 3.58 mm in the Cable group, and the maximum stress peak value in the PHILOS group was 491.54 MPa, about 49.2% lower than that in the Cable group (733.61 MPa). The peak stress in the PHILOS group was mainly distributed on the 4th and 5th fixation ends at the bone plate while the peak stress in the Cable group was mainly distributed on the second titanium cable under the fracture line.Conclusions:Under various loads, both PHILOS fixation and Cable-Ready GTR fixation can provide sufficient mechanical stability. As the peak stress of PHILOS fixation is much lower than that of Cable-Ready GTR fixation, PHILOS can be used as an effective fixation method for Vancouver B1 femoral periprosthetic fractures.