A primary research area over the last 10 years has been advanced and general ligament reconstruction surgery. A number of clinical trials within the anterior cruciate ligament, collateral ligament and patella instability surgery with some of the largest patient series in the world and RCTs have been conducted. Moreover, cooperation with a number of orthopedic companies for clinical testing of new implants and surgical techniques. The ligament reconstruction studies have been extended with robotic biomechanical analyzes of ligament reconstructions at the SteadmanPhilipponResearchCenter in Vail, Colorado, USA. As an important adjunct to the clinical research epidemiologic studies of knee injuries from a national clinical database on knee ligament reconstructions have been conduction for more than 10 years. A number of studies have been published from the database, including studies in cooperation with the other Scandinavian registries. This work has attracted great international interest. In particular, it has been possible to follow treatment outcomes and complications after new anatomical reconstruction techniques where Danish results have showed poor outcome.