The Charnley prosthesis had by far the best and most comprehensive evidence base with better than 90 % implant survival after about 10 years .
Some uncemented stems have shown promising medium-term outcome , but no combination of uncemented cup and stem fulfilled the benchmark criterion of > or = 90 % implant survival at 10 years , which we propose as a minimum requirement for unrestricted clinical use for prostheses used in primary THR .
We have conducted a systematic review of the scientific literature concerning outcome and clinical effectiveness of  prostheses used for primary total hip replacement ( THR ) in Norway .
Total Hip Arthroplasty with the Charnley Prosthesis in Patients Fifty-five Years Old and Less. Fifteen to Twenty-one-Year Results*
Data on 240 primary Charnley total hip arthroplasties , performed in 211 patients from October 1968 to July 1974 , were recorded prospect ively . Fifty-two prostheses were implanted in forty-six patients who were thirty-four to fifty-five years old , and 188 prostheses were implanted in 165 patients who were more than fifty-five years old . The results for the younger patients were compared with those for the older patients . Twenty hips were revised over-all , and all five of the infections and four of the five fractures of the femoral stem that occurred in this group were in the older patients . However , the rate of aseptic loosening was similar for the two age-groups ( three of the hips in the younger patients and five in the older patients ) . The probability of revision after twenty years for the two groups , as determined with Kaplan-Meier analysis , was 11.7 per cent for the younger patients and 10.7 per cent for the older patients . There was no significant difference between the two groups with regard to either the number of revisions or the percentage of patients who had radiographic signs of loosening . The median Charnley hip scores during the course of the study were also similar for the two groups . We recommend that Charnley low-friction arthroplasty be used even in younger patients , as the long-term results were excellent and were comparable with those in the elderly age-group
The Charnley prosthesis had by far the best and most comprehensive evidence base with better than 90 % implant survival after about 10 years .
Some uncemented stems have shown promising medium-term outcome , but no combination of uncemented cup and stem fulfilled the benchmark criterion of > or = 90 % implant survival at 10 years , which we propose as a minimum requirement for unrestricted clinical use for prostheses used in primary THR .
We have conducted a systematic review of the scientific literature concerning outcome and clinical effectiveness of  prostheses used for primary total hip replacement ( THR ) in Norway .