Vertical Neck angle and long-term outcomes of femoral neck fractures treated with cannulated screws

Abstract

Objective To analyze the associations between long-term outcomes of fresh femoral neck fractures treated with cannulated screws and the classification based on vertical neck (VN) angle. Methods A retrospective study was conducted of the 162 fresh femoral neck fractures treated with 3 cannulated screws at Department of Orthopaedics, The Sixth People’s Hospital of Shanghai from January 2012 to December 2014. The relationships were analyzed using Logistic Regression between long-term complications and VN classification, including fixation failure, fracture nonunion and osteonecrosis of femoral head (ONFH). Results All the patients were followed up for an average of 25.7 months (from 6 to 36 months). Of them, 151 obtained fracture union after an average of 4.5 months (from 3 to 9 months). Internal fixation failure occurred in 23 cases, nonunion of femoral neck in 11, ONFH in 21 and femoral neck collapse in 13. Logistic Regression analysis showed no significant associations between internal fixation failure, nonunion or ONFH and gender, age or reduction method (P>0.05) but significant associations of VN classification with fixation failure (P<0.001) and nonunion (P=0.001) and insignificant association of VN classification with ONFH (P= 0.109). Conclusion VN classification, a new classification method for femoral neck fractures, may be closely related with incidences of fixation failure and nonunion. Key words: Femoral neck fracture; Bone nails; Prognosis; Vertical neck angle; Classification