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 DESIGN 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. For 5 out of 12 products not a single comparable study was available and relatively few data were available for the remaining products. A conventional meta-analysis revealed that only three products showed results that were comparable with those from registers. For 75% of products good results were published. There was not a single case where it would have been possible to identify or isolate the problems that had led to the underperformance observed on the basis of clinical studies alone. Clinical sample-based studies are not a suitable and reliable means to recognize potential product or handling problems and avoid risks for patients and physicians. In this respect registers can provide an essential contribution.