Optimal position of intramedullary nails in the femoral head following spiral blade resection for revision of intertrochanteric fractures: a biomechanical analysis

Our biomechanical analysis demonstrates that intramedullary fixation confers greater stability than extramedullary fixation when salvaging failed internal fixations in intertrochanteric fractures. Our simulation results indicate that under revision scenarios, there may be optimal position trends specific to internal fixations. For PFBN revision of intertrochanteric fractures, posterior placement of the lag screw within the femoral head appears biomechanically favorable. For PFNA, central helical blade placement yielded minimal femoral and internal fixation displacement; however, implant-bone interface stress was higher. During revision surgery, screw trajectory should be altered whenever possible to ensure implantation into healthy bone while avoiding previous screw tracks. If utilization of original screw tracks is unavoidable, restoration of screw-bone contact through bone grafting should be considered. These findings warrant further validation through more sophisticated biomechanical models and clinical studies.