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 .
Early failure of a press-fit carbon fiber hip prosthesis with a smooth surface.
We investigated a press-fit anatomically shaped hip stem made of carbon fiber-reinforced composite material in a prospect i ve clinical study . The intention of the design was that a surface of interlaced carbon fibers in the proximal part would achieve metaphyseal fixation . A total of 51 carbon stems were implanted in 48 patients ( 30 women and 22 men ) . Mean age at operation was 59 years . The patients were followed clinical ly , radiologically , and with computed tomography . At 6-year follow-up , aseptic loosening was observed in 47 hips ( 92 % ) . Forty stems were revised on average 30 months ( range , 9 - 58 months ) postoperatively . All revised carbon stems showed fibrous fixation without any bony on-growth . No osteolysis was seen . Histologically , no carbon wear or inflammatory reactions were observed . Only 4 cases had a good clinical result with bony fixation on computed tomography scan . The carbon fiber prosthesis without effective ingrowth or on-growth irregularities showed a high rate of early loosening
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 .