Long-term results of alumina-on-alumina total hip arthroplasty

Purpose of the study Mechanical failure in total hip arthroplasty is usually related to aseptic loosening itself related to wear particles as seen with polyethylene bearings. Alumina has bee proposed to avoid wear problems. In vitro and mid-term clinical studies have shown tribological advantages but early acetabular fixation remains an issue. Since alumina-on-alumina bearings are currently used with new fixation techniques, updated evaluations of older series are informative regarding the long-term tolerance of alumina in vivo. Material and methods We investigated 104 consecutive alumin-on-alumina cemented total hip arthroplasties (Cervaer-Osteal, Roissy, France) implanted 20 years ago in 81 patients (from 1979 to 1983). A32-mm alumina femoral head was used. The alumina acetabular socket and the titanium femoral stem were cemented. The Postel-Merle-d'Aubigne score was used for clinical evaluation. Radiological wear and development of osteolysis or loosening were noted for establishing actuarial curves. When accessible, histological samples from revision procedures were analyze. Results Six infected cases were not taken into account for data analysis. The average follow-up was 11 years, reaching 18 years in 38 cases. Twenty-three hips were revised for changing 23 acetabular sockets, 12 femoral heads, and one femoral stem. We noted one femoral head fracture, 24 definite acetabular loosenings, 12 probable acetabular loosenings, and 3 definite femoral loosenings. Radiological acetabular osteolysis was present in 4 cases, always limited to De Lee zone 1, and associated with loosening. Radiological wear was below eye detection. Periprosthetic tissue showed non-specific histological reactions to cement particles. Survival rate at 20 years was 62.8% [49.3-76.2%], in terms of revision 57.1% [42.5-71.7%] and 95.2% [89.9-100%] in terms of definite acetabular and femoral loosening. Discussion Besides the high rate of cemented fixation failure of the socket, loosened and non-loosened cases showed an excellent long-term tolerance of the alumina-on-alumina bearing with normal wear and osteolysis. This may also have protected the femoral component from complications. This study confirms in vivo the long-term tribological benefit of the alumina-on-alumina bearing in total hip arthroplasty and suggests that acetabular fixation should be improved to achieve full benefit.