Quality of life after dislocation of hip arthroplasty: a prospective cohort study on 319 patients with femoral neck fractures with a one-year follow-up

A primary arthroplasty constitutes a standard procedure in the treatment of patients with displaced fractures of the femoral neck. Although dislocation of the prosthesis remains a significant clinical problem, there are no previous reports on its influence on health-related quality of life (HRQoL). We analysed how a dislocation of the hip arthroplasty influenced the patients' HRQoL. In total 319 consecutive patients with a displaced fracture of the femoral neck treated with a primary arthroplasty were included in a prospective cohort study. We used a mixed-effects model regression analysis to evaluate factors of importance for HRQoL (EQ-5D(index) score) during the first 12 months following surgery. A dislocation of the arthroplasty occurred in 21 of the 319 patients (7%), 8 of whom had a single dislocation and 13 recurrent dislocations. At 4 months, the EQ-5D(index) score displayed a significantly worse outcome for patients with recurrent dislocations compared to patients with no dislocation (P = 0.001), and a trend towards a worse outcome for patients with a single dislocation (P = 0.08). At 12 months, the mean EQ-5D(index) score of patients with recurrent dislocations was still substantially lower (P = 0.001), while the EQ-5D(index) score for patients with a single dislocation had returned to a level similar to that of patients with no dislocation. Our analysis of the EQ-5D dimensions indicates that the difference was mainly due to perceived difficulties in self-care and usual activities and increased problems with anxiety/depression. A recurrent dislocation of the hip arthroplasty in the treatment of patients with femoral neck fractures seems to result in a persisting deterioration in the HRQoL, while patients with a single dislocation seem to experience only a temporary deterioration.