Risk factors for nonunion after intramedullary nailing of subtrochanteric femoral fractures

Abstract

Introduction Nonunion is a common complication after intramedullary nailing of subtrochanteric femoral fractures. A more detailed knowledge, particularly of avoidable risk factors for subtrochanteric fracture nonunion, is thus desired to develop strategies for reducing nonunion rates. The aim of the present study therefore was to analyse a wide range of parameters as potential risk factors for nonunion after intramedullary nailing of subtrochanteric fractures. Materials and methods Seventy-four patients who sustained a subtrochanteric fracture and were treated by femoral intramedullary nailing at a single level 1 trauma centre within a 6-year period were included in this study. A total of 15 patient-related, fracture-related, surgery-related, mechanical and biological parameters were analysed as potential risk factors for nonunion. Furthermore, the accuracy of each of these parameters to predict nonunion was calculated. Results Nonunion occurred in 17 of 74 patients (23.0%). Of the 15 potential risk factors analysed, only 3 were found to have a significant effect on the nonunion rate ( p < 0.05): postoperative varus malalignment, postoperative lack of medial cortical support and autodynamisation of the nail within the first 12 weeks post-surgery. Accuracy of each of these 3 parameters to predict nonunion was > 0.70. Furthermore, the nonunion rate significantly increased with the number of risk factors (no risk factor: 2.9%, one risk factor: 23.8%, two risk factors: 52.9%, and three risk factors: 100% [Chi-square test, p = 0.001)]. Conclusions Our study indicates that intraoperative correction of varus malalignment and restoration of the medial cortical support are the most critical factors to prevent nonunion after intramedullary nailing of subtrochanteric femoral fractures. In addition, autodynamisation of the nail within the first 3 months post-surgery is a strong predictor for failure and should result in revision surgery.

Hardware considerations in infection and nonunion management

“…[ 47 ] Similarly, Krappinger et al recently demonstrated varus malalignment of greater than 5 degrees and loss of medial support were both significant risk factors for nonunion. [ 49 ] Peschiera et al examined a series of nonunions in distal femoral fractures and found varus alignment of the distal fragment of more than 5 degrees in greater than half of their nonunion cases. [ 45 ] This was attributed to medialization of the distal articular block—a common technical error with the use of a distal femoral locking plate.…”

Open Reduction in Subtrochanteric Femur Fractures Is Not Accompanied by a Higher Rate of Complications

“…Krappinger et al studied risk factors for nonunion after intramedullary nailing of subtrochanteric fractures. In their study, neither open reduction nor the use of wire cerclage were significant risk factors for nonunion [ 10 ]. This is in contrast to malalignment, which has been shown to be a risk factor for nonunion [ 8 , 9 , 10 ].…”

“…In their study, neither open reduction nor the use of wire cerclage were significant risk factors for nonunion [ 10 ]. This is in contrast to malalignment, which has been shown to be a risk factor for nonunion [ 8 , 9 , 10 ]. Kasha et al concluded that regardless of the method chosen, the key point to reduce the risk of complications is adequate reduction [ 11 ].…”

“…Intramedullary stabilization is the favored surgical procedure for these fractures [ 3 , 7 ]. However, it is not clear which type of reduction (open vs. closed) is best [ 8 , 9 , 10 , 11 , 12 ]. Some studies have found that open reduction leads to a more anatomic reposition and lower malunion rates [ 2 , 8 , 9 , 11 ].…”

Letter to the editor about the article “Different surgical outcomes in a patient with bilateral atypical femoral fracture related to bisphosphonate use with or without teriparatide treatment”

“…We are doubtful about the success of the surgical treatment because of the discordance in the fracture reduction between both hips. Subtrochanteric femoral fractures have higher nonunion rates compared with other anatomical regions besides atypical femur fracture (AFF) [2]. Risk factors for nonunion include varus malreduction, residual displacement after reduction, lack of medial cortical support, and bisphosphonateassociated fractures.…”