Strain Analysis in Cementless Hip Femoral Prosthesis using the Finite Element Method - Influence of the Variability...

Objective  The present study aims to evaluate the influence of different positioning of the hip femoral prosthesis on the stress and strain over this implant. Methods  A femoral prosthesis (Taper - Víncula, Rio Claro, SP, Brazil) was submitted to a stress and strain analysis using the finite element method (FEM) according to the International Organization for Standardization (ISO) 7206-6 Implants for surgery - Partial and total hip joint prostheses - Part 6: Endurance properties testing and performance requirements of neck region of stemmed femoral components standard. The analysis proposed a branch of the physical test with a +/- 5° angle variation on the standard proposed for α and β variables. Results  The isolated +/- 5° variation on the α angle, as well as the association of +/- 5° variation on the α and β angles, presented significant statistical differences compared with the control strain ( p  = 0.027 and 0.021, respectively). Variation on angle β alone did not result in a significant change in the strain of the prosthesis ( p  = 0.128). The stem positioning with greatest implant strain was α = 5° and β = 14° ( p  = 0.032). Conclusion  A variation on the positioning of the prosthetic femoral stem by +/- 5° in the coronal plane and/or the association of a +/- 5° angle in coronal and sagittal planes significantly influenced implant strain.