Objective To summarize effect of hemiarthroplasty in treatment of femoral neck fractures in the elderly.Methods From January 1998 to January 2008,hemiarthroplaaties were performed in 84 patients with femoral neck fractures,including 24 males and 60 females,at age range of 75-97 years (mean 80 years).Of all,40 patients were treated with unipolar hemiarthroplasty and 44 with bipolar hemiarthroplasty.In the meantime,29 patients were treated with cement fixation and 15 with biological fixation with old femoral stems,and 40 with biological fixation with contemporary femoral stem.Results There were 50 patients(24 in unipolar and 26 in bipolar group)were followed up for average five years (1-10 years).X-ray showed total acetabular erosion rate of 50%(25/50),with 83%(20/24)in unipolar group and 19%(5/26)in bipolar group.Total definite loosening rate was 40%(20/50),which was distributed in six patients treated with cement fixation and 14 with biological fixation.Total revision rate was 24%(12/50),with 37.5%(9/24)in unipolar group and 12%(3/26)in bipolar group.Statistical analysis showed that acetabular erosion rate and revision rate in bipolar group were lower than those in unipolar group(P＜0.01).Definite loosening rate in cement fixation group was significantly lower than biological fixation group,with no statistical difference compared with biological fixation of contemporary stem(P＞0.05).Conclusions Bipolar replacement is significantly better than unipolar replacement for femoral neck fracture in the elderly.Cement fixation with old femoral stem is significantly better than biological fixation with old femoral stem,which is similar to biological fixation with contemporary femoral stem.