The Impact of Waiting Time for Total Hip Arthroplasty on Progression of Hip Osteoarthritis

Abstract Aims: The aim of this study was to discover possible correlations between longer waiting times and radiologically visible deterioration of hip osteoarthritis in a retrospective, single-centre study. Methods: Radiographs of the affected hip taken at time of registration in the institution’s waiting list as well as x-rays of the same hip at time of hospital admission for THA were ascertained together with demographic and clinical variables. Correlations between waiting time and changes in radiological criteria, as well as deterioration of hip osteoarthritis and clinical variables, were analysed with uni- and multivariate logistic regression analysis. Results: Median waiting time was 19.5 weeks (IQR: 8.3 – 29.7 weeks). Patients experiencing deterioration of hip osteoarthritis from initial to preoperative x-ray, as reflected by increasing KL score (n=47; median waiting time 26.7 weeks [IQR: 15.0 – 39.4]) had a significantly longer waiting time for THA than patients without worsening of hip osteoarthritis (n=245; median waiting time 18.9 weeks [IQR: 7.7 – 29.0]; p<0.001). There was no significant difference in waiting time depending on gender (p=0.545), cup destruction (p=0.682), or patient age (F(1.290) = 0.11; p=0.835). Notably, no significant correlation between likelihood of hip osteoarthritis progression and patient age (p=0.813), CAM-type impingement (p=0.319), coxa profunda (p=0.116) or gender (p=0.064) was found. In the multivariate logistic regression model, time delay until THA remained significantly associated with worsening of hip osteoarthritis, irrespective of gender, CAM type impingement and coxa profunda at baseline. Conclusion: Our findings support the assumption that longer waiting times may lead to worsening of radiological signs of hip osteoarthritis.