Wing-augmentation reduce femoral head cutting out of dynamic hip screw

The dynamic hip screw (DHS) is standard for femoral intertrochanteric fracture treatment. However, post-operative failure does occur in some patients, resulting in poor prognosis. The most common failure mechanism is femoral head superior cut-out through the femoral head. We designs an improved lag screw combined with a conventional lag screw and two supplemental horizontal blades. The implant structure is designed to provide larger contact surface to prevent superior cut-out and femoral head rotation, thus improving the fixation stability. The biomechanical studies simulated hip motion of normal gait were performed for comparison. The innovative DHS exhibited significantly less axial migration and sustained many more loading cycles in comparison to the conventional DHS. The tip-to-apex distance (TAD) change, varus angle change, and rotational angle change were significantly less in innovative DHS. The new DHS had two additional horizontal wings, which would increase the bone-implant interface contact surface and. The increased surface area would dissipate the load to the screw itself, improve the migration resistance and increase the anti-rotational implant effect.