Stability of hip hemiarthroplasties.

It has been stated in the literature that a bipolar hemiarthroplasty has a lower risk of dislocation compared to a unipolar hemiarthroplasty. As this statement has not been substantiated we undertook a systematic review of the literature of published articles from the last 40 years. In addition we used our own database of hip fractures. One hundred and thirty-three published articles were included in the review to give a total of 23,107 cases. The overall dislocation rate for all types of hemiarthroplasty was 791/23,107 (3.4%). An increased risk of dislocation was associated with a posterior surgical approach and the use of a cemented prosthesis. After adjustment for surgical approach and the use of cement there was no difference in risk of dislocation between unipolar and bipolar hemiarthroplasties. There was an increased risk of open reduction for a bipolar hemiarthroplasty.