Objective To analyze the risk factors for failures of intramedullary and extramedullary internal fixation in surgery of femoral intertrochanteric fractures in elderly patients.Methods A retrospective study was conducted of the 205 elderly patients with osteoporotic femoral intertrochanteric fracture who had accepted closed reduction together with intramedullary and extramedullary internal fixation between September 2005 and August 2014.They were 89 men and 116 women,from 65 to 98 year of age (average,78.8 years).By AO classification,137 cases were of types AI.1-A2.1 (stable fractures),and 68 of type A2.2-A3.3(unstable fractures).The incidence of internal fixation failure and Harris scores at the last follow-up were recorded.The factors possibly contributing to the failure were analyzed using the univariate analysis and multivariate logistic regression analysis.Results Of the patients,192 obtained a mean follow-up of 39 months (from 14 to 60 months),but 13 were lost after a 10-month follow-up.Of the 205 patients,internal fixation failure occurred in 12 (incidence of 5.9％).Five failed cases received DHS fixation and 7 accepted PENA fixation.At the last follow-up when the 13 cases were lost after 10-month follow-up,the mean Harris hip score was 81.6 (from 57 to 92),and the excellent to good rate was 84.9％ (29 excellent cases,145 good ones,10 fair ones and 21 poor ones).The multivariate regression analysis revealed that tip-apex distance (TAD) ＞ 25 mm(OR ＝ 333.33),severe osteoporosis (OR =267.44),AO types A2.2-A3.3 (OR ＝ 22.24),functional reduction of fracture (OR =20.79),and concomitant medical diseases (OR =4.59) were independent risk factors for failures of internal fixation.Conclusions DHS and PFNA fixations are effective treatments for elderly patients with femoral intertrochanteric fractures.TAD＞ 25 mm,severe osteoporosis,unstable factures,functional reduction of fracture,and concomitant medical diseases may lead to internal fixation failure in surgery of femoral intertrochanteric fractures in elderly patients.