Natural Course and Recovery After ACL-injury

The natural course after ACL injury is not well described in the literature. Every year about 7000 people, a majority aged 15-30 years old, injure their anterior cruciate ligament (ACL) in Sweden. About 3500 go through surgical treatment and rehabilitation. Despite the large amount of research on ACL-injuries, there are still many patients who have unsatisfactory outcomes regarding instability, decreased activity level, and quality of life, not being able to return to sport as well as an increased risk for osteoarthritis. The general aim of the study is to evaluate the natural course and recovery after ACL injury. Specific aims: * To evaluate physical, psychological and contextual factors affecting recovery after anterior cruciate ligament (ACL) injury. Recovery is related both to natural course and to treatment chosen * To evaluate factors affecting the decision for which treatment to choose (ACL reconstruction and rehabilitation or rehabilitation alone) * To evaluate factors affecting the decision for return to sports * To study development of knee osteoarthritis after ACL-injury * To study epidemiology of acute knee trauma * To study risk factors for new injuries after ACL-injury These aims will be pursued by consequently and prospectively following patients who sustain a new ACL injury in a multicenter study including approximately 800 patients. Assessment methods will be questionnaires to patients, orthopedic doctors and physical therapists. A sub-cohort of 130 patients will undergo multiple clinical and functional examination as well as MRIs and blood, urine and joint fluid samples.