Energy Required for Fracture in Synthetic Proximal Femoral Models After Synthesis Material Removal: a Biomechanical Study Using Cannulated Screws, Dynamic Hip Screws, and Proximal Femoral Nails.

The present study aims to identify the energy required for synthetic proximal femoral fracture after removal of three implant types: cannulated screws, dynamic hip screws (DHS), and proximal femoral nail (PFN).  Twenty-five synthetic proximal femur bones were used: 10 were kept intact as the control group (CG), 5 were submitted to the placement and removal of 3 cannulated screws in an inverted triangle configuration (CSG), 5 were submitted to the placement and removal of a dynamic compression screw (DHSG), and 5 were submitted to the placement and removal of a proximal femur nail (PFNG). All samples were biomechanically analyzed simulating a fall on the greater trochanter using a servo-hydraulic machine to determine the energy (in Joules [J]) required for fracture.  All samples presented basicervical fractures. The energy required for fracture was 7.1 J, 6.6 J, 6 J, and 6.7 J for the CG, CSG, DHSG and PFNG, respectively. There was no statistically significant difference (considering a 95% confidence interval) in energy among the study groups (  = 0.34).  There was no statistically significant difference in the energy required to cause a synthetic proximal femoral fracture after removing all three implant types and simulating a fall over the greater trochanter.