Abstract
Introduction:
The ASR™ Articular Surface Replacement and ASR™ XL Metal-on-Metal systems were recalled due to high revision rates at five years. A worldwide clinical follow-up of patients was initiated. This paper summarizes current findings in South Africa (SA) in comparison with those outside SA (OSA).
Methods:
Patients were followed annually, or until revision, from 10 clinical centers worldwide. Data collected includes demographic, surgical, radiographic, blood metal ion levels, and patient reported outcome measures (PROM).
Results:
There were 715 (353 ASR/336 ASR-XL) hips enrolled in the study; 187 ASR and 32 ASR-XL from South Africa. The average time from index surgery was 6 years (2–10) for both SA and OSA. Since enrollment, 2.7% (19) hips were revised (none from SA) and of these 58% (11) had adverse local tissue reaction. Blood metal Co/Cr ion levels decreased by about 50% post-revision. There was no difference in average blood metal ion levels between patients in SA and OSA. Globally, the average blood cobalt ion level was higher for patients with ASR-XL than patients with ASR. The average cup abduction was 43.2° (20°–65°) with little difference between SA and OSA. The average EQ-5D index for SA patients was 0.93 vs. 0.82 for OSA.
Discussion:
Currently, South Africa represented the majority of ASR surface replacement implants in the study, which were predominantly in males. This may have contributed to the higher PROM scores in SA compared to the OSA. While no revisions were reported from SA in this study so far, metal ion levels were lower after revision surgery.
