Improving patient outcome after joint replacement - the power and limits of arthroplasty registries

National arthroplasty registries around the world have an increasingly important role in monitoring population-based quality outcomes in total hip and knee arthroplasty since the first registry was started in 1979. The registries combined with design, material and surgical improvements have led to significant improvements in the outcome of primary hip and knee replacement. Today survival rates of 95% 10 years after surgery are the gold standard, making Total Joint Replacement (TJR) one of the most successful surgeries in orthopaedics. Poor implant designs and materials have widely been removed from the markets based on registry results and patient safety has greatly improved. To move beyond the safety aspect and address the performance of TJR, registries will have to collect detailed implant data and link those to anonymised medical patient records. Early results of the German Arthroplasty Registry are presented to underline the power and the limitations of such an approach.