Patient-reported outcome after dislocation of primary total hip arthroplasties: a cross-sectional study derived from the Danish Hip Arthroplasty Register

Abstract

Background and purpose - Knowledge regarding patient-reported outcomes (PROs) after dislocation and closed reduction is lacking. We report health- and hip-related quality of life (QoL) after dislocation, following primary total hip arthroplasty (THA). Patients and methods - We conducted a crosssectional study with patients registered in the Danish Hip Arthroplasty Register from 2010 to 2014. Dislocations were captured based on diagnosis/procedure codes and patient file reviews. Patients with dislocation were matched 1:2, according to age, sex, date, and hospital of primary surgery, to patients without dislocation. 2 PRO questionnaires were applied (EQ-5D, HOOS). Results - We identified 1,010 living patients with dislocation. Mean follow-up was 7.2 years from index surgery and 4.9 years (range 0.6-9.7) from the latest dislocation. Patients without dislocation reported a higher EQ VAS score of 76 (95% CI 75-77) compared with 68 (CI 66-70) for the dislocation group. The EQ-5D-5L mean index score was 0.89 (CI 0.88-0.90) for the control group, compared with 0.78 (CI 0.76-0.80) for the cases with dislocation without revision. Patients with dislocation reported a lower HOOSQoL domain score of 63 (CI 60-65), compared with 83 (CI 82-84) for the control group. Even 5 years after the latest dislocation, the HOOS-QoL score remained low, at 66 (CI 62-69). The other HOOS domains were consistently 8-10 points worse after dislocation. Interpretation - Both health- and hip-related QoL were markedly and persistently reduced among dislocation patients compared with those in controls, for several years. Therefore, the avoidance of the initial dislocation episode is important because the THA does not appear to achieve the full relieving potential.

Figure 1

Flowchart of the inclusion/exclusion process: selection process from DHR data retrieval to the return of questionnaires.

Figure 2

EQ-5D-5L scores. The diagrams present the distribution (proportions) between the 5 levels (No problems/Slight problems/Moderate/Severe/ Unable or extreme) for each of the 5 domains within the EQ-5D questionnaire for controls (eligible no. = 1,399), cases with dislocation(s) (eligible no. = 482), and cases with subsequent revision(s) due to dislocation (eligible no. = 154). The cases groups are more likely to indicate problems in various degrees in every domain of the score compared to the control group.

Figure 3

HOOS domain scores presented as means with 95% CIs for all cases with dislocation, cases with dislocation and revision(s), and the control group. A score of 100 indicates no problems and 0 indicates extreme problems. We compared the control group with cases with dislocation (no revision) by multiple linear regression analysis adjusting for CCI and stated statistical significance for all 5 domains (p-value < 0.001).

Figure 4

Predicted HOOS QoL score after hip dislocation: graph illustrating the predicted HOOS QoL domain score as a function of time elapsed since the latest dislocation, irrespective of the number of dislocations per patient.