A Comparison of Tip-Apex Distance at Various Angles of Fixation Devices in Hip Fractures

Background Intertrochanteric neck of the femur (NOF) fractures are very common, and the majority are fixed using dynamic hip screws (DHS) or intramedullary (IM) nails with a fixed angle. The aim of this study was to assess which angle of fixation has a better tip-apex distance (TAD) on X-ray and lower complication rates. Methods We included patients with intertrochanteric hip fractures fixed using a DHS or an IM nail. We included patients who had complete radiological and clinical records and a minimum follow-up of 24 months. We measured the TAD and recorded the number of implant cutouts, fracture site nonunions, and periprosthetic fractures. Results A total of 107 patients were included, 35 IM nails and 72 DHS. There were four cases of implant cutouts within the DHS group and none in the IM nail group. All four cutout cases were fixed using 135° angle DHS, and two had TAD of more than 25 mm. Multivariable regression analysis revealed that the implant fixation device (p=0.002) and the angle of fixation (p<0.001) are the most important predictors of TAD. Conclusion Smaller angle (130° or 125°) fixation devices allow better positioning of the lag screw and consequently better TAD, which leads to a lower probability of implant cutout in patients undergoing fracture of the neck of the femur surgery.