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 .
Outcome after total hip arthroplasty: Part II. Disease-specific follow-up and the Swedish National Total Hip Arthroplasty Register
The Swedish National Total Hip Arthroplasty Register records primary hip replacements , revisions and surgical technique/environmental factors . The end-point for failure is revision . A prosthesis still in place , however , does not mean success . Clinical and radiographic outcomes should describe in more detail the efficacy of hip replacement surgery instead of the relatively blunt outcome measure that the register can provide . We performed a clinical outcome analysis on patients with primary total hip replacement thus testing the adequacy of the end-point for failure in the Swedish register . 1,113 r and omly selected patients who had had total hip replacement surgery between 1986 and 1995 answered a diseasespecific self-administered question naire ( WOMAC ) . A cohort of 344 patients was studied , using the  Harris Hip Score and a conventional radiographic examination  as outcome measures . We found clinical failure rates of 13 % and 20 % for all implants after 10 years , using 60 points or revision as the definition of failure in the Harris Hip Score and WOMAC , respectively . The result , according to the register during the same period , was a 7 % revision rate . The clinical failure rate depended on the type of evaluation tool , definition of failure and demographics , which made it difficult to decide whether there was a need for revision . With the exception of pain measured by the Harris Hip Score , the results showed no significant correlation between clinical failure and radiographic failure . Hence , with the knowledge that there is a difference between the revision rate according to the register and clinical outcome , the strict definition of failure in the register is useful as an end-point for primary hip replacement surgery
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 .