The Swedish Knee Register was founded in 1976 and is regarded as a trailblazer in evidence-based surgery [117].
The Swedish Hip Register started in 1979 [118], and soon Norway and Denmark followed ahead of Europe, Canada, and Australia [118].
These large national databases overcome single institution bias and allow independent and robust data in a heavily industry driven market. National registers can highlight changes in trends, such as the use of certain surgical approaches ,techniques (cemented versus uncemented), common complications ,or catastrophic failure of an implant [119].