Risk Factors of Cut-Out in Treatment of Femoral Intertrochanteric Fractures by Proximal Femur Nail / 대한정형외과학회잡지

ABSTRACT

PURPOSE: The purpose of this study is to evaluate the risk factors for the occurrence of cut-out of proximal femoral nail by a lag screw as the treatment for intertrochanteric fractures. MATERIALS AND METHODS: A total of 151 patients (76 males and 75 females; mean age, 73.7±12.1 years), who were diagnosed with intertrochanteric fracture at Gyeongsang National University Hospital between January 2011 and March 2016, with a follow-up of at least for 6 months were included in this retrospective study. Various risk factors, such as demographic data, osteoporosis, collodiaphyseal angle (CDA) (≤130° or >130°), tip-apex distance (TAD) (≤25 mm or >25 mm), and the position of lag screw in the femur head (quadrant) related to the occurrence of cut-out were taken into consideration. The strength of association for each factor was determined through the calculation of the odds ratio (OR), within the 95% confidence interval (CI). First, we performed univariate logistic regression analyses for all variables; then, we performed a multivariate logistic regression analysis, using only the significant variables that had resulted from the univariate analysis. RESULTS: Among the 151 cases, the occurrence of cut-out was observed in 14 cases (9.3%). In a univariate analysis, the fracture patterns based on the AO/OTA classification (p=0.045), CDA (p<0.001) and the position of lag screw in the femur head (quadrant) (p=0.001) showed a significant association with the occurrence of the cut-out. However, TAD was not significantly associated with the cut-out (p=0.886). Various factors, which were significant in univariate analyses, were included in multivariate analyses. In multivariate analyses, CDA (OR, 12.291; 95% CI, 2.559-59.034; p=0.002), and quadrant (OR, 7.194; 95% CI, 1.712-30.303; p=0.007) were significantly associated with the cut-out. CONCLUSION: Valgus reduction and proper position of lag screw were critical for the prevention of occurrence of cut-out when treating intertrochanteric fracture using proximal femur nail.