30-Years of experience with the cementless implanted Alloclassic CSF screw cup total hip arthroplasty system - An ultra-long-term follow-up.

The aim of this study was to evaluate our long-term results with the Alloclassic CSF screw cup total hip arthroplasty system. This is the first study to provide a 30-year follow-up, based upon our 30-year follow up study on the Alloclassic stem system. We reviewed 178 Alloclassic CSF screw cup systems, implanted in 171 patients from 1986 to 1987. The Zweymüller stem family was used in all cases. 136 patients had died over the last 30 years, so twenty-nine out of 35 patients being still alive, with a mean follow-up of 29,46 years (SD 0,48), were contacted by telephone and evaluated radiologically and clinically. Our loss-to-follow up was 17,14%. The mean age at follow-up was 83,01 years (72,4-95,2; SD 6,86). If the endpoint is defined as the removal of the cup for aseptic loosening (3 cases), the overall survival rate is 98,31%. If the endpoint is revision for any reason (27 cases), the survival rate is 84,83%. Eleven patients needed an exchange of head and liner. The mean time from implantation until change of head and liner was 21,44 years (SD 5,92). After 30 years of monitoring we can state that the evaluated system is very reliable in primary and secondary THA.