The risk factors of early acetabular failure after bipolar hemiarthroplasty because of fracture of the femoral neck

Background The aim of this study was to evaluate the influence of leg length discrepancy in geriatric patients with early failure of bipolar hemiarthroplasty and to identify related failure patterns and risk factors. Methods In this retrospective study, the risk factors of early acetabulum failure within 5 years of hemiarthroplasty for displaced femoral neck fracture were compared with a control group of patients who had implant survival for at least 5 years after hemiarthroplasty. The basic data, leg length discrepancy, femoral offset, and the shell size were evaluated. Results Of all risk factors, there was a significant difference in increased leg length between the two groups. The mean difference in leg length was 7.8 ± 5.9 mm in the early acetabular failure group and -1.7 ± 6.2 mm in the control group. For an increase in leg length of >6 mm, the odds ratio of early acetabular failure was 25-fold greater when compared with the control group. Conclusion Increased leg length was significantly associated with early acetabular failure after bipolar hemiarthroplasty for femoral neck fracture among geriatric patients. It is critical to avoid increase in leg length after bipolar hemiarthroplasty.