80 patients with primary patellar dislocation were included in this study. All patients received treatment with a brace and underwent arthroscopy. Patients were then randomized to receive either surgical repair and re-insertion of the medial patellofemoral ligament (MPFL) to the adductor tubercle, or were randomized to conservative treatment (did not undergo repair). The 2 year follow-up results indicated that primary repair of the MPFL was not superior to conservative treatment in reducing the risk for patellar re-dislocation and improving clinical results. However, significant improvements in the patellar stability were seen in patients that received MPFL.