The Norwegian Arthroplasty Register - 11 years and 73,000 arthroplasties

In 1985, the Norwegian Orthopaedic Association decided to establish a natio nal hip register, and the Norwegian Arthroplasty Register was started in 19 87. In January 1994, it was extended to include all artificial joints. The main purpose of the register is to detect inferior results of implants as e arly as possible. All hospitals participate, and the orthopedic surgeons ar e supposed to report all the primary operations and all revisions. Using th e patient's unique national security number, the revision can be linked to the primary operation, and survival analyses of the implants are done. In g eneral, the survival analyses are performed with the Kaplan Meier method or using Cox multiple regression analysis with adjustment for possible confou nding factors such as age, gender, and diagnosis. Survival probabilities ca n be calculated for each of the prosthetic components. The end-point in the analyses is revision surgery, and we can assess the rate of revision due t o specific causes like aseptic loosening, infection, or dislocation. Not on ly survival, but also pain, function, and satisfaction have ben registered for subgroups of patients. We receive reports about more than 95% of the prosthesis operations. The re gister has detected inferior implants 3 years after their introduction, and several uncemented prostheses were abandoned during the early 1990s due to our documentation of poor performance. Further, our results also contribut ed to withdrawal of Bonelec cement. The register has published papers on ec onomy, prophylactic use of antibiotics, patients' satisfaction and function , mortality, and results for different hospital categories. In the analyses presented here, we have compared the results of primary cem ented and uncemented hip prostheses in patients less than 60 years of age, with 0-11 years' follow-up. The uncemented circumferentially porous- or hyd roxyapatite (HA)-coated femoral stems had better survival rates than the ce mented ones. In young patients, we found that cemented cups had better surv ival than uncemented porous-coated cups, mainly because of higher rates of revision from wear and osteolysis among the latter. The uncemented HA-coate d cups with more than 6 years of follow-up had an increased revision rate, compared to cemented cups due to aseptic loosening as well as wear and oste olysis. We now present new findings about the six commonest cemented acetabular and femoral components. Generally, the results were good, with a prostheses su rvival of 95% or better at 10 years, and the differences among the prosthes is brands were small. Since the practice of using undocumented implants has not changed, the regi ster will continue to survey these implants. We plan to assess the mid- and long-term results of implants that have so far had good short-term results .