The purpose of this study is to elucidate surgical techniques for reconstructing MPFL in the treatment of chronic patella instability. The two techniques are conventional technique with the gracillis and screw fixation in the femur which is compared with new technique where the QT tendons and anchor fixation in the femur are used.

It would be investigated which technique provides the best stability with the least postoperative pain from the reconstruction and the lowest frequency of patellar reluxation.

Inclusion Criteria:

• Patients between 15 and 40 years of age with chronic tendency to lateral patellar dislocation (defined as 2 or more verified dislocation cases)
• The growth zones must be found closed - verified by MRI scan

Exclusion Criteria:

• Patients with known rheumatoid arthritis.
• Patients with arthroscopically detected osteoarthritis (grade 3 cartilage lesion)
• Inability to follow a normal rehabilitation regime.
• Previous ligament surgery in injured knees.