MITTELMEIER CERAMIC-CERAMIC PROSTHESIS AFTER 10 YEARS

The clinical status of 83 Mittelmeier ceramic-ceramic (Mark II) cement less total hip prostheses (Autophor, Osteo AG, Selzach, Switzerland) i mplanted between 1978 and 1984 was analyzed. Retrieved tissue from the revised hips was studied histologically. The mean patient age was 47. 5 years (range, 19-71 years). One or both components of 12 hips were r evised (16% at 16 years in the survival study). Eleven acetabular comp onents and seven sta-ns were revised, with three of the sockets fractu red. The mean follow-up period for the patients with unrevised hips wa s 12.3 years. Osseointegration was uncommon in both the cup and stem. Radiographic cup loosening was observed in 53% of hips at 16 years in the survival study with most having a complete radiolucent line of 2 m m around the cup. Radiographic stem loosening appeared in 15% of hips at 16 years. Fibrous stable fixation was present in 64% of stems. Sign ificant radiographic acetabular wear was not observed in any hip. The Mittelmeier Mark II prosthesis had worse long-term results than report ed with cemented or other uncemented prostheses. Although there was no significant acetabular wear, intracellular ceramic wear debris was se en in the retrieved tissues.