“…National or local arthroplasty registries have been set up in many countries such as Sweden, Finland, Norway, Denmark, Germany, Canada, New Zealand, Australia, England, and many other countries. 8,12,13,27,38,39,43,48,49 To determine whether randomised trials can be replaced by register studies, Garellick et al 9 compared the long-term survival results of a randomised and prospective study of 2 different hip implants with the results of the same implants obtained from the Swedish National Hip Registry. The authors concluded that despite the enormous amount of data, there are drawbacks, and registries can never replace a prospective, randomised trial.…”