Even though there are multiple studies documenting the outcome of the Charnley low-friction arthroplasty as well as abundant studies on uncemented arthroplasties, there is a dearth of comparative studies of the uncemented acetabular component and a cemented component. In this study we aimed to document the long-term clinical and radiographic outcome as well as component survival in a randomized controlled trial.
Two hundred fifteen patients (240 hips) were randomly allocated to receive a cemented Charnley cup or uncemented Duraloc 1200 cup. All patients received cemented Charnley stems and were evaluated clinically and radiographically after 6 months, and 2, 5, and 10 years.
Harris Hip Scores improved from 48.3 [95% confidence interval (CI) 45.0-51.6] to 90.2 [95% CI 87.9-92.6] in the Charnley group and from 49.3 [95% CI 86.9-91.3] in the Duraloc group at 6 months. After 10 years, the Charnley group's Harris Hip Score was 89.8 [95% confidence interval (CI) 87.0-92.6], and the Duraloc group's score was 87.3 (95% CI 84.1-90.6). In the radiographic analysis after 10 years, there was no statistical difference in the prevalence of radiographic signs of loosening. Nine cups were revised in the Charnley group, and five cups were removed in the Duraloc group. The difference was not statistically significant. There was no statistical difference between the cups when aseptic loosening was the end-point, nor in survival analyses.
There is no statistically significant difference in clinical or radiological outcome between the Charnley cup and the Duraloc after 10 years, and no difference in implant survival after 12-14 years. The uncemented Duraloc cup is as good as the cemented Charnley cup after 10 years.