The Norwegian and Swedish registries depend on surgeons reporting on a voluntary basis to the registries. In Denmark, a law passed in June 2006 made it compulsory for all public and private hospitals and clinics to report to the approved national, clinical databases. Reporting to the databases in Denmark and Sweden is organized through a secure internet portal, thus minimizing the costs of daily running. In Norway, the registry relies on paper-based reporting, mainly due to the close cooperation with the Norwegian Arthroplasty Register (NAR), which makes use of an identical system.
In Denmark, 90% of all orthopedic departments have been contributing to the registry, with an average compliance of 85% of the primary ACL reconstructions performed. In Norway, all hospitals performing ACL surgeries have contributed, with a total compliance of 97%. In Sweden, some of the smaller hospitals with small volumes of ACL surgery have not been included in the registry, yet more than 71% of the hospitals have contributed to the registry.
Follow-up with KOOS (Knee injury and Osteoarthritis Outcome Score) forms is carried out by all 3 registries. In Denmark, these follow-ups are done at 1, 5, and 10 years postoperatively. In Norway they are done at 2, 5, and 10 years postoperatively, and in Sweden they are done at 1, 2, 5, and 10 years postoperatively.
All registries provide annual reports, both on a national basis and for the individual hospitals. Sweden also offers an online database where clinics can analyze their own statistics at any time. The Danish database is managed by a special university center that manages all Danish national orthopedic databases. In Norway, the technical responsibility rests with Helse Vest IKT AS, which manages all Norwegian national orthopedic databases. In Sweden, the Capio Artro Clinic in Stockholm is responsible for the registry on a daily basis.
For the present study, data regarding common and comparable variables related to the primary ACL reconstruction were extracted (hospital, sex, age at injury and surgery, activities causing injury, time to surgery, frequency of cartilage and meniscal injuries, meniscal resections, and cartilage treatments, choice of graft, choice of graft fixation devices, duration of surgery, prophylactic antibiotics and anticoagulation, outpatient surgery, number of reconstructions, and preoperative and postoperative KOOS).