The value of outcome quality data from clinical studies is an issue of controversial debate particularly in the context of adverse events. The aim of this study is to present and evaluate the data available from clinical studies for products that show inferior outcome in registers and to assess the possibility to draw valid conclusions from these data. Study desgin and analytical methods: Based on a structured literature research, a comparative analysis was made of the revision rates of 12 products showing significantly inferior average results in registers. The primary outcome parameter was the revision rate for any reason calculated using a standardized methodology and the parameter of revisions per 100 observed component years.