Interprosthetic dislocations of the Charnley/Hastings hemiarthroplasty — Report of 11 cases in 350 consecutive patients

SummaryWe report 11 cases of interprosthetic dislocation of the Charnley/Hastings hemiarthroplasty in a retrospective study of 350 consecutive patients treated for an acute femoral neck fracture. We found a total of 14 dislocations (4.0%), 11 were interprosthetic. The median age of the 350 patients was 79 (36–99) years and the median age of the 11 patients with an interprosthetic dislocation was 85 years (82–94). The median time from surgery to radiologically acknowledged dislocation was 18 (4–64) days. These interprosthetic dislocations may be caused by either an assembly mistake perioperatively, by maximum angulation and impingement between the components, or by trauma.