The Stability Study was a multicenter, pragmatic, parallel groups, randomized clinical trial comparing hamstring tendon autograft anterior cruciate ligament reconstruction with or without the addition of lateral extra-articular tenodesis in young patients at high risk of graft failure. Having recruited 618 patients with a 5% loss to follow up, we were able to demonstrate a clinically and statistically significant reduction in clinical failure and graft rupture at 2 years postoperative. No differences in patient-reported outcomes (PROs) were demonstrated between groups; however, patients who experienced an adverse event had significantly worse PROs than those who did not.