There has been an increased awareness towards ACL (anterior cruciate ligament) injuries for Norwegian teams, particularly in handball and soccer. The reported number of reconstructions in Norway ranges from 1500 to 2000 per year, and in the United States from 50,000 to 100,000 per year, making ACL reconstruction one of the most common orthopaedic procedures performed, especially among young, active and healthy individuals. However, reports state that there is a subset of patients (10-40%) who remain subjectively and objectively unstable and/or are unable to regain prior function. Additionally, it has been reported that degenerative joint disease is associated with traditional single-bundle ACL reconstructions in up to 50% of the patients in long term follow up studies.

It is well known that the ACL is composed of 2 functional bundles named after their tibial attachments, the anteromedial (AM) and posterolateral (PL) bundles.

It is believed that the current single-graft, single-bundle technique for reconstructing the anterior cruciate ligament does not anatomically reconstruct either one of these bundles.

In the last two years, the double bundle technique has been introduced and a few clinical studies are available, however only a few RCTs.

Further study is very important to determine if double-bundle ACL reconstructions should be performed, if single-bundle reconstructions can be adjusted to better adapt to their biomechanical insufficiency in restoring internal rotation torques and valgus moments, and also in trying to identify which patients might better benefit from single-bundle versus double-bundle ACL reconstructions.

The aim of this study:

The primary aim is to compare the two operational techniques: single bundle hamstrings versus double bundle hamstrings ACL reconstruction, using the KOOS (Knee Osteoarthritis Outcome Score) Quality of Life(QoL) subscore as the primary outcome and clinical examinations, functional tests and standing radiographs (Kellgren Lawrence method) as secondary outcome measurements. Those assesments will be measured after 1,2 and 5 years after the operation.

Hypothesis:

There are no difference between the two methods as judged by the KOOS QoL subscore.

Questions to be answered:

Is there a difference between double-bundle and single-bundle technique in the subjective outcome scores as measured by the KOOS score? Are there differences between hamstrings single bundle and double bundle technique when the Lachman test and the pivot shift test are being used? Is there a difference between hamstrings double-bundle technique and single-bundle technique in return to sports and activity level? Are there differences between double-bundle technique and single -bundle technique in functional tests (one-leg hop test)? Is there a difference in the development of osteoarthritis between the two techniques?

Inclusion Criteria:

• Clinically verified ACL rupture (history, Lachman test 2+ or more with no endpoint; pos pivot shift and arthroscopically verified) The graft used for AM bundle has a minimum size of 6.0 mm and 5.0 mm for t he PL bundle.

Exclusion Criteria:

• PCL injury,
• ACL injury to the contra lateral knee
• > 1+ medial or lateral-posterolateral ligament instability at operation date
• Previous ACL reconstruction
• Meniscal injury leaving < 50% of the meniscus intact
• Established OA as judged by Kellgren 3-4.