Dislocations after total hip-replacement arthroplasties

Abstract

In this review of 300 total hip arthroplasties there were 9 hip dislocations. These dislocations were analysed by performing measurements of the acetabular cup angle. It was found that an increased acetabular component anteversion angle was seen in anterior dislocations. A dislocation rate of 1.5 % occurred for cup orientation with anteversion of 15° ± 10° and lateral opening of 40° ± 10°. Acetabular orientation that did not lie within these value ranges, was associated with a dislocation rate of 6.1 %. It was found that dislocation was more likely to occur if less than 30 days had passed since surgery and if the hip had been operated on previously. Posterior dislocation was not found to have any signifi cant relationship with acetabular cup orientation.