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 .
The Charnley versus the Spectron hip prosthesis: clinical evaluation of a randomized, prospective study of 2 different hip implants.
Prospect i ve , r and omized studies must be performed when new surgical techniques or implants are evaluated . In this study , a new implant system was compared with the Charnley prosthesis , which over the years has been the most used hip implant in Sweden . Between 1985 and 1989 , 410 hips were r and omized to treatment with a Charnley or a Spectron total hip arthroplasty : 206 Charnley and 204 Spectron prostheses were implanted . The patients were operated on by a st and ardized procedure using a contemporary cementing technique . The patients were followed prospect ively by an independent observer after 1 , 3 , 5 to 6 , and 10 years . Harris Hip Score and patient satisfaction were recorded in the outcome evaluation . A total of 144 patients with 164 hips were deceased , and 15 patients ( 8 Charnley and 7 Spectron ) have required a revision . Nine hips were revised because of aseptic loosening ( 5 Charnley stems and 4 Spectron metal-backed cups ) . The Charnley stem as well as the metal-backed Spectron cup had a higher risk for revision because of aseptic loosening . The Charnley ogee cup and the Spectron stem have performed remarkably well with no revision of these components . Seven Charnley prostheses dislocated , but no dislocation was recorded in the Spectron group . Survivorship calculations with a mean follow-up of 10 years revealed an overall 11-year survivorship of 94.5 % + /- 3.4 % ( Charnley , 93.2 % + /- 5.8 % ; Spectron , 95.9 % + /- 3.0 % ) . The clinical outcome did not differ between the 2 systems . The overall results in this old population , using a contemporary surgical technique , illustrate that cemented hip arthroplasty is an excellent treatment alternative for elderly patients
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 .