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 .
Six-year results of a cementless stem with prophylaxis against heterotopic bone.
The hypothesis of a possibly diminished bony ingrowth revealed by the development of radiolucency or a radiodense line with time around a cementless femoral stem subsequent to indomethacin administration for prevention of heterotopic ossification was investigated . Eighty prospect i ve patients with indomethacin prophylaxis were compared with 82 patients without indomethacin prophylaxis chosen retrospectively . The same cementless implant was used in all cases , and patients were observed clinical ly and radiologically for a minimum of 6 years . The mean postoperative Harris hip score at 6 years was 91 versus 88 points , respectively , and there were significantly more excellent results ( Harris hip score > 90 ) in the indomethacin group . None of the patients underwent revision surgery . Radiologic signs such as loss of bone density and radiodense lines were observed around the shoulder of the prosthesis in a similar percentage in both groups . Significant subsidence of the stem was observed in one instance in the indomethacin group and in three instances in the control group . The results of this study are a strong indication that indomethacin does not influence the development of radiolucency or other radiologic changes around a cementless stem after 6 years
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 .