A tip apex distance of 25 mm or less has been shown to be a predictor of prevention of lag screw cut out leading to greater success of fixation, when DHS was used to  treat intertrochanteric fractures. This study was aimed to determine whether tip–apex distance (TAD) was also useful as a predictor when proximal femoral nails (PFN) are used to treat intertrochanteric fractures. A total of 147 patients were included in this study. The TAD values were determined by post operative radiographs.124 patients had adequate follow up of four months till union of the fracture or cut out leading to implant failure.

All 124 patients had intertrochanteric hip fractures. Overall, 23 patients (18.5%) had lag screw cut–out. The average TAD of the patients who did not cut–out was 20 mm, compared to 36 mm for those who did. The percentage of cut–outs correlated directly to both the severity of intertrochanteric fractures and the TAD. Surgeons should try and keep the TAD below 25mm in PFN as this is likely to prevent complication.