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 hydroxyapatite-ABG hip system: 5- to 7-year results from an international multicentre study. The International ABG Study Group.
A proximally hydroxyapatite (HA)-coated hip prosthesis design ed for proximal stem bonding and stress transfer was studied in a consecutive series of 398 patients in an ongoing , prospect i ve multicenter study . Follow-up was 5 to 7 years . The clinical results were excellent with a mean preoperative Merle d'Aubigné score of 8.5 and 17.3 at 5 years . Only mild thigh pain not necessitating analgesics or a walking stick was reported in 3.6 % at 5 years . Three cups and 3 stems had to be revised , all before the 2-year assessment and mainly for technical reasons . No components needed revision after 2 years . The 5-year HA-coated component  survival was 99.2 % . Serial radiographs showed excellent osseointegration , which was independent of pre-existing bone stock . The rate of radiographic bone remodeling was highest during the first 3 years , and positive bone remodeling ( bone formation ) preceded negative bone remodeling ( bone resorption ) . The concept of transitional load transfer from proximal to distal could be acknowledged , with proximal load transfer highest in 77 % . The combination of anatomic stem design with distal overreaming and proximal HA coating was thought to be the reason for these excellent results . Proximal circumferential osseointegration seems to be real because no linear or distal osteolysis was observed
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 .