Risk factors for failed internal fixation with proximal femoral nail antirotation for reverse intertrochanteric hip fractures / 中华创伤骨科杂志

ABSTRACT

Objective To identify the risk factors for failure of internal fixation with proximal femoral nail antirotation (PFNA) for reverse intertrochanteric hip fractures.Methods A retrospective study was conducted of the 45 patients with reverse intertrochanteric hip fracture who had been treated with PFNA fixation from January 2006 through January 2018 at the Department of Traumatic Orthopaedics,The Third Affiliated Hospital to Peking University.They were 19 males and 26 females,aged from 19 to 97 years (average,71.9 years).According to the AO/OTA classification,there were 7 cases of type 31-A3.1,4 cases of type 3 1-A3.2 and 34 cases of type 3 1-A3.3.Fracture healing was judged according to the X-ray at the time of last follow-up.The patients were assigned into a healed group and a failed group.The 2 groups were compared in terms of gender,age,body mass index (BMI),mechanism of injury,AO classification,type of main fracture line,reduction method,reduction quality,status of lateral femoral wall and tip-apex distance.A multivariate logistic regression model was designed to analyse the dependent variable'implant failure'with a set of independent variables as risk factors.Results The 45 patients were followed up for 12 to 62 months (average,28.4 months).Implant failure was observed in a total of 6 patients (13.3％),3 of whom had helical blade perforation,2 main screw breakage,and one cut-out of helical blade.The single factor analysis revealed significant differences in reduction quality and type of main fracture line between the patients with successful fixation and those with failed fixation (P ＜ 0.05).The multiple logistic regression analysis identified poor reduction quality (OR=30.809,95％ CI1.052～902.298,P=0.047) and a transverse fracture line (OR =25.639,95％ CI1.636 ～ 401.917,P =0.021) as risk factors for implant failure.Conclusion Poor reduction quality and a transverse fracture line may be predictors of implant failure in reverse intertrochanteric hip fractures treated with PFNA fixation.