Dislocations after use of dual-mobility cups in cementless primary total hip arthroplasty: prospective multicentre series

Background The purpose of this study was to investigate the incidence of dislocation and specific complications of the dual-mobility cup. Methods The arthroplasties involved 167 hips in 165 patients; 51 hips (30.5%) were in men and 116 (69.4%) were in women. The active articulation E1 (R) dual-mobility cup (Biomet, Warsaw, IN, USA) was used, and the surgical approach was posterolateral in 120 hips and anterolateral in 47 hips. Results Four (2.3%) dislocations were observed. Mean time of dislocation was 30.5 days post-operatively. Three incomplete reductions occurred during closed reduction. When comparing parameters between dislocation and no-dislocation groups, there were no differences in patient and surgical parameters. However, all dislocations occurred in patients with femoral neck fractures and in the posterolateral approach group. Conclusion The incidence of dislocation in total hip arthroplasty (THA) using a dual-mobility cup was acceptable, and cup diameter of the dislocation group was substantially larger than that of no-dislocation group. Based on clinical outcomes of our study, we conclude that the dual-mobility cup is a reliable option in THA, and further studies are necessary.