Aims This study aimed to determine the diagnostic performance of radiographic criteria to detect aseptic acetabular loosening after revision total hip arthroplasty (THA). Secondary aims were to determine the predictive values of different thresholds of migration and to determine the predictive values of radiolucency criteria.
Patients and Methods Acetabular component migration to re-revision was measured retrospectively using Ein-Bild-Rontgen-Analyse (EBRA-Cup) and manual measurements (Sutherland method) in two groups: Group A, 52 components (48 patients) found not loose at re-revision and Group B, 42 components (36 patients) found loose at re-revision between 1980 and 2015. The presence and extent of radiolucent lines was also assessed.
Results Using EBRA, both proximal translation and sagittal rotation were excellent diagnostic tests for detecting aseptic loosening. The area under the receiver operating characteristic (ROC) curves was 0.94 and 0.93, respectively. The thresholds of 2.5 mm proximal translation or 2° sagittal rotation (EBRA) in combination with radiolucency criteria had a sensitivity of 93% and specificity of 88% to detect aseptic loosening. The sensitivity, specificity, positive predictive value and negative predictive value (NPV) of radiolucency criteria were 41%, 100%, 100% and 68% respectively. Manual measurements of both proximal translation and sagittal rotation were very good diagnostic tests. The area under the ROC curve was 0.86 and 0.92 respectively. However, manual measurements had a decreased specificity compared with EBRA. Radiolucency criteria had a poor sensitivity and NPV of 41% and 68% respectively.
Conclusion This study shows that EBRA and manual migration measurements can be used as accurate diagnostic tools to detect aseptic loosening of cementless acetabular components used at revision THA. Radiolucency criteria should not be used in isolation to exclude loosening of cementless acetabular components used at revision THA given their poor sensitivity and NPV.
Cite this article: Bone Joint J 2017;99-B:458–64.
- Diagnostic performance
- Aseptic loosening
- Revision total hip arthroplasty
- Acetabular migration
J. M. Abrahams: Ethics submission, Study design, Analysis of results, Wrote initial draft.
Y. S. Kim: Data collection, Analysis of results, Edited manuscript to publication.
S. A. Callary: Planned the study, Analysis of results, Edited manuscript through to publication.
C. De Ieso: Data collection, Analysis of results, Critical review of manuscript.
K. Costi: Assisted with data collection, Critical review of manuscript.
D. W. Howie: Planned the study, Interpretation of results, Critical review of manuscript.
L. B. Solomon: Planned the study, Ethics submission, Interpretation of results, Edited manuscript through to publication.
The authors wish to thank V. Kamalesh (Principal Statistician and Head Health Statistics Unit, Epidemiology, SA Department for Health and Ageing) for his invaluable statistical support for this project.
The authors also wish to acknowledge the non-commercial project grant funding received from the Royal Adelaide Hospital Research Fund (Callary et al, 2014; $AU40,000).
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
This article was primary edited by G. Scott.
Supplementary material. Two tables showing the sensitivity, specificity, PPV, NPV and percentage of correctly identified cases for different thresholds of proximal translation and sagittal rotation determined using EBRA-Cup and manual measurements, combined with radiolucency criteria are available alongside the online version of this article at www.bjj.boneandjoint.org.uk
- Received August 11, 2016.
- Accepted December 8, 2016.
- ©2017 The British Editorial Society of Bone & Joint Surgery