Abstract
We developed a grasping pin with a hook for osteosynthesis of proximal femoral fractures and compared its performance with that of a lag screw. Cyclic compressive tests were performed to simulate cut-outs, and quasi-static torsion, tests were conducted to simulate rotational displacement in polyurethane model bones and femoral heads collected after hip replacement surgery, and cadaveric femoral heads. In the polyurethane model bones and femoral head collected after hip replacement surgery, implant displacement was increased in the cut-out simulation test in both the grasping pin group and lag screw group, deformation was less in the grasping pin group than in the lag screw group. In polyurethane bones and cadaveric bones, the grasping pins showed higher rotational resistance compared with the lag screws in the quasi-static torsion test because of the high compression force generated during implantation. In contrast, in the collected femoral head after hip replacement surgery model, the lag screws destroyed bone tissue, the lag screw group exhibited a higher rotational resistance and a lower risk of rotational displacement than the grasping pin model. The depth of cadaveric femoral heads was 60mm compared with 30mm for femoral heads obtained after surgery; therefore, the pins could be completely inserted up to the octagonal portion in the cadaveric bones, resulting in higher rotational resistance.
