Tip Apex Distance – Is It Enough To Predict Implant Failure?

Abstract

The aim of this study was to establish any association between implant cut-out and a Tip Apex Distance (TAD), ≥25mm, in proximal femoral fractures, following closed reduction and stabilisation, with either a Dynamic Hip Screw (DHS) or Intramedullary Hip Screw (IMHS) device. Furthermore, we investigated whether any difference in cut-out rate was related to fracture configuration or implant type. WE conducted a retrospective review of the full clinical records and radiographs of 65 consecutive patients, who underwent either DHS or IMHS fixation of proximal femoral fractures. The TAD was measured in the standard fashion using the combined measured AP and lateral radiograph distances. Fractures were classified according to the Muller AO classification. 35 patients underwent DHS fixation and 30 patients had IMHS fixation. 5 in each group had a TAD≥25mm. There were no cut-outs in the DHS group and 3 in the IMHS group. 2 of the cut-outs had a TAD≥25mm. The 3 cut-outs in the IMHS group had a fracture classification of 31-A2, 31-A3 and 32-A3.1 respectively. In addition, the fractures were inadequately reduced and fixed into a varus position. A TAD