gms | German Medical Science

Objectives: The incidence of intertrochanteric fractures is increasing due to the world's aging population. Internal fixation by intramedullary nailing is commonly considered a safe and a reliable method to treat these fractures. However, postoperative varus displacement and consecutive cut-out are reported in 6.5-21.2% in literature and are associated with an increase of postoperative mortality and morbidity.

The primary objective of this study was to analyse the number of complications after intramedullary nailing of intertrochanteric fractures with PFN-A and secondly to identify risk factors for secondary varus displacement.

Methods: Between January 2012 and January 2016, records of all patients suffering from an intertrochanteric fracture treated with PFN-A in our hospital (level 1 trauma centre) were reviewed. Only patients with strictly standardised pre-and postoperative radiographs were included and analysed concerning the following parameters: fracture classification, caput-collum-diaphyseal (CCD) angle, adequacy of reduction, blade position, tip-apex distance (TAD) and nail position in the femoral shaft. Minimum follow-up was at least three months.

Results and Conclusion: One hundred and one patients met the inclusion criteria of which 24 patients experienced complications. They are divided into non-implant related complications (33%) and implant-related complications (66.67%) such as cut-out (29.17%), nail breakage (4.17%) and tractus irritation symptoms (29.17%). Initial postoperative varus alignment, an improper location of the blade in the femoral head and a TAD greater than 25mm were significant risk factors for postoperative varus collapse and cut-out. Additionally, we could show that an inadequate lateral offset of the nail in the ap x-ray is one of the major risk factors for further varus displacement.

Two-thirds of complications following intramedullary nailing of intertrochanteric fractures are implant-related. In addition to already known risk factors for secondary varus displacement and cut-out, this study identified a lateralised nail entry which is increasing the lateral offset compared to the healthy hip as one of the major risk factors. Knowing about this factor and avoiding it by using a more medial entry point to prevent medialisation of the proximal fragment through the nail insertion may help to further decrease postoperative morbidity and mortality.