four hundred and fifty two Charnley cups were assessed with a mean follow-up period of 20 years. Seventy-five of them were loosed. Migration was observed in 21% and 33% showed demarcation in the whole contour of the cup. There was a statistically correlation between the grade of initial demarcation and migration (p<0.0001). the mean acetabular wear rate was 0,13 mm/years. Annual wear over 0,2 mm was related with an age under 50 years, and weight over 80 kg. Of the 75 loosened cups, 35 were diagnosed within 10 years of the operation (early loosening), and 40 after 10 years (late loosening). Early loosening was related to poor acetabular bone stock, with cup migration and pain as frequent findings. Late loosening was related with acetabular wear of more than 2 mm, with less incidence of migration and pain.... [Leer más...]