10-12 year survivorship analysis of 811 primary or conversion Charnley arthroplasties showed 89 percent probability of mechanical survival (revision excluding sepsis). The mechanical failure rate was 7 percent, and more stems required revision than sockets. The anterio-posterior radiographs of 630 unrevised hips, with a minimum 3-year follow-up, were evaluated using the CART system of terminology. Cement-bone radiolucency was present in 50 percent of sockets and 18 percent of stems. Substantial loosening was present in 6 percent with 94 percent probability of survival at 10-12 years.