|Beitragstitel||Excellent long-term results of the Müller acetabular reinforcement ring in primary cup revision|
The original Müller acetabular reinforcement ring (ARR) was developed for acetabular revisions with small cavitary and/or segmental defects or when acetabular bone quality is poor. Long-term data for this device are scarce. We therefore investigated long-term survival and radiological results for revision THA using the ARR.
Between 01/1984 and 12/2005, 259 consecutive primary acetabular revision using an original ARR were performed in 245 patients. The mean follow-up time was 10 (0 – 27) years, 8 hips were lost to follow-up. For survival analysis, we investigated 259 hips and the end of the follow-up was defined either by the date of revision, date of death, or the last patient contact date with implant still in situ. Radiological assessment was performed for 90 hips with a radiological follow-up of a minimum of 10 years. It included evaluation of osteolysis, migration and loosening.
16 ARR were re-revised: 8 for aseptic loosening, 6 combined with the stem, 6 for infection, 1 due to mal-positioning of the cup and 1 for suspected infection. The cumulative re-revision rate for all components, for any reason, at 20 years was 16 (95% CI: 10-23), while for the ARR only it was 11% (95% CI: 5-17) for any reason and 6% (95% CI: 2-11) for aseptic loosening. 21 (23%) of the 90 radiological examined ARR had radiological changes: 12 showed isolated osteolysis but were not loose. 9 ARRs were determined radiologically loose on follow-up, 5 of them had been revised.
Our data suggests that the long-term survival of the ARR in primary acetabular revision is excellent.