Abstract
Introduction and Aims: Recently, concerns have emerged regarding the high stiffness of acetabular components inserted with alumina ceramic liners, which might potentially cause early migration and loosening. This study was designed to investigate in-vivo the migration pattern of these constructs
Method: Fifty patients (50 hips) operated on using the same surgical technique and the same prosthesis were randomised in two groups. The study group of hips was treated with an alumina ceramic liner, the control group of hips received a polyethylene liner. An alumina femoral head with a diameter of 28mm was used in all hips. Radiostereometric analysis (RSA) was performed to assess migration using serial follow-up radiographs.
Results: The median pre-operative Harris hip score (HHS) was rated 48.9 points in the alumina group, and 47.7 points in the polyethylene group. At the two-year follow-up, the median HHS of the alumina group was rated 94.1 points, and was rated 93.7 points in the polyethylene group. There were no clinical or radiological signs of aseptic loosening. RSA of the alumina group of cups showed a median axial displacement of 0.026 mm (SD 0.35mm). The median axial displacement of the polyethylene group was 0.047 mm (SD 0.26 mm) (p=0.9). The median tilting of the cup was 0.21 degrees (SD 0.54 degrees) in the alumina group, and 0.35 degrees (SD 0.71 degrees) in the polyethylene group (p=0.12).
Conclusion: At an average of two years post-operatively, the cups inserted with an alumina ceramic liner appeared stable, RSA showed low rates of non-progressive migration. Results did not differ from those observed using the same cup inserted with a polyethylene liner.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
At least one of the authors is receiving or has received material benefits or support from a commercial source.
