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 .
Long-term comparison of Charnley and Stanmore design total hip replacements.
We review ed the records of the long-term outcome of 208 Charnley and 982 Stanmore total hip replacements ( THR ) performed by or under the supervision of one surgeon from 1973 to 1987 . The Stanmore implant had a better survival rate before revision at 14 years ( 86 % to 79 % , p = 0.004 ) , but the difference only became apparent at ten years . The later Stanmore implants did better than the early ones ( 97 % to 92 % at ten years , p = 0.005 ) , the improvement coinciding with the introduction of a new cementing technique using a gun . Most of the Charnley implants were done before most of the Stanmore implants so that the difference between the results may in part be explained by improved methods , but this is not the complete explanation since a difference persisted for implants carried out during the same period of time . We conclude that improved techniques have reduced failure rates substantially . This improvement was much greater than that observed between these two design s of implant . Proof of the difference would require a very large r and omised controlled trial over a ten-year period
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 .