Introduction and purpose: Different bearing surfaces have been used to prevent osteolysis, such as alumina-alumina. We present here an analysis of the results of a prospective multi-center study of complications related to the use of alumina-alumina bearings.

Materials and methods: In 4 hospitals 319 cups with hydroxyapatite stems and alumina-alumina bearing surfaces were implanted with a mean follow-up of 5.6 years (range: 3–8). The mean age of the patients was 52.7 (range: 14–70). Alumina wear was calculated by means of a special program.

Results: Revision was performed of 5 cups and 2 stems. In one hip with a horizontal acetabular angle (35°) and a thin alumina liner (size 50/32), an acetabular liner fracture occurred 36 months after surgery. The probability of not undergoing revision due to any cause was 96.9% (CI 95%:94.7–99.1%). None of the patients reported any type of noise. All the non-revised cases showed good results both on clinical and X-ray exam at the end of the follow-up. The difference between the center of the head of the femur and the center of the head of the cup at 6 weeks after surgery was −2.45+0.53 mm, with no further changes seen during the follow-up.

Conclusions: These data suggest that the prosthetic alumina-alumina bearing surface has excellent results over 5 years and that alumina fractures are infrequent. No changes were seen in terms of the penetration of the femoral head in any case. Longer follow-ups are necessary to determine if the reduction of wear translates into less osteolysis and loosening.

Introduction. Alternative bearing surfaces to polyethylene have been introduced to avoid the appearance of osteolysis in THR. The aim of this study has been to perform prospective analysis of the data from a multi-center clinical trial for assessing the incidence of early alumina-specific-complications.

Material and Methods. We analysed 310 Cerafit cups associated with a Multicone-HA stem using alumina-on-alumina bearings implanted in four institutions from 1999 to 2003, with a mean follow-up of 4.7 years. Patients’ mean age was 52.8+13.4 years. Linear femoral head penetration was analysed using a software package.

Results. There were 4 revisions: 2 revisions due to dislocations resulting poor surgical technique (1 cup and 1 stem) and 2 revisions after a trauma (1cup and 1 stem). There was 1 alumina liner fracture 36 months after implant in a hip with a horizontal acetabular angle (35°) and a thin alumina liner (size 50/32). The other cases showed good clinical and radiographic results at the end of follow-up. The radiographic difference between the femoral head and cup centres at 6 weeks postsurgery was 2.48+0.60 mm, without changes in the course of the follow-up. The mean linear femoral head penetration was unreliable (0.00186+0.0032 mm/year) because it was below the mean error for the measurement system.

Conclusions. These data demonstrate that Cerafit Alumina-on-Alumina prostheses show excellent results after 5 years. Liner fractures are uncommon. Despite the blurred alumina images, the digitized method, although not totally accurate and used only for a general estimate, allows us to measure the approximate distance between the centre of the cup and the centre of the femoral head. Changes in linear femoral head penetration were not seen in any hip. Continued follow-up should determine if reduction in wear among the alumina-on alumina bearings results in less osteolysis.