Objective To retrospectively study the factors which contribute to the failed internal fixation of osteoporotic femoral intertrochanteric fractures in the elderly patients.Methods A total of 219 elderly patients with osteoporotic femoral intertrochanteric fracture were treated by open reduction and internal fixation from January 2006 to September 2011.They were 98 males and 121 females,aged from 65 to 99 years (average,77.8 years).The incidence of failed fixation and the Harris hip scores at the last follow-up were documented.The factors which might have contributed to the failure were analyzed by SPSS20.0.The logistic multiple regression was used to analyze the influencing factors related to the failed internal fixation (P ＜ 0.05).Results The 219 patients obtained a mean follow-up of 42 months (from 24 to 70 months).Failed internal fixation occurred in 41 cases (18.7％).The Harris hip scores at the last follow-up averaged 82.7 points (from 58 to 94 pints).There were 33 excellent,145 good,12 fair and 29 poor cases,giving an excellent to good rate of 81.3％.Logistic regression analyses found unstable fracture [OR =9.183,95％ CI (1.453,14.212),P=0.013],severeosteoporosis [OR =8.941,95％ CI (1.328,13.871),P =0.015],lateral femoral wall fracture [OR =7.097,95％ CI (1.107,7.481),P =0.020],concomitant internal disease [OR =5.954,95％ CI (0.926,5.609),P =0.027],non-anatomic reduction [OR =5.198,95％ CI (1.052,4.857),P =0.034] and tip-apex distance (TAD) [OR =3.627,95％ CI (0.501,6.149),P =0.041] to be the independent risk factors which had been significantly associated with failed internal fixation.Conclusions Unstability of the fracture is the most crucial factor that may lead to failed fixation in the treatment of osteoporotic femoral intertrochanteric fracture in the elderly patients.Severe osteoporosis,lateral femoral wall fracture,concomitant internal disease and great TAD may also increase the risk of failed internal fixation.