[Screwed acetabulum: results of 72 cases with a mean follow-up of 5 years]

Ninety-seven threaded acetabular prostheses (44 cups of Lord and 53 Motta, type cups) were implanted among which 72 were examined at an average follow-up of 5.9 years. After an initial phase of good tolerance, the results became rapidly degraded. Clinically, the lack of fixation was translated by a start up pain. On examination, the pain provoked by the opposed hip flexion was pathognomonic. A radiographic analysis of our checks allowed us to classify them in four types: Type I: painful hip, normal radiography or presence of a radiolucent line in one of the DeLee's zones; increased uptake at bone scanning. Type II: total radiolucent demarcation; Type III: axial migration; Type IV: migration and tilting; Finally analysis of our series with Kaplan-Meier method showed a survivorship rate at five years of 59.3 per cent. It is concluded that this kind of implant must be abandoned.