[The European Arthroplasty Register (EAR), development and rationale for supranational cooperation of arthroplasty registers].

In Scandinavia national arthroplasty registers are accepted instruments in the assessment of joint implants. They have contributed essentially to the rapid detection of inferior products and, by encouraging a continuous process of quality improvement through feedback, have helped to avoid revision operations. However, national registers have a limited significance with regard to other countries and rarely used implants. In recent years, a great number of registers have been founded. The European Arthroplasty Register (EAR), an EFORT project, aims at supporting these projects, enhancing cooperation within a network, realising further benefit through registers, and fostering scientific activities. The registers have been conceived according to the successful Scandinavian model. It is, however, necessary to adapt the concept to the individual national circumstances. In order to increase the value of register publications for other countries, it makes sense to achieve a minimum of stardardisation in datasets, definitions, product designations, as well as in evaluation and publication methods. Since the datasets of national registers implicitly reflect the prevailing national circumstances, they are always more valuable for use in the respective country than evaluations from aggregated, supranational and therefore larger datasets. Supranational evaluations may yield additional findings, but they cannot replace a national register. Therefore, EAR has been conceived as a network of independent national registers considering itself as a supplement and by no means as a competitor of the established national registers.