BACKGROUND: Injuries to the posterolateral corner of the knee are disabling. Despite improved understanding of this group of tendons and ligaments, the best surgical treatment of an unstable corner is not clear. HYPOTHESIS: Surgical repair of acute tears of the posterolateral corner has outcomes that are as good as those from reconstruction combined with an early motion rehabilitation protocol. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Sixty-three patients with 64 posterolateral corner tears were included in this study, with 39 posterolateral corner repairs and 25 reconstructions using the modified 2-tailed technique. Patients were evaluated with clinical and KT-2000 arthrometer examinations, as well as with Lysholm, International Knee Documentation Committee, and Short Form-36 scores. RESULTS: Fifty-six patients with 57 corner tears had minimum clinical follow-up of 24 months (range, 24-59 months). Acute primary repairs were performed on 35 patients, with 22 successful outcomes and 13 (37%) failures. Primary reconstructions were performed on 22 patients, with 20 successful outcomes and 2 (9%) failures. The difference in stability on clinical examination between repairs and reconstructions was significant (P < .05). Fourteen of 15 patients with failures of the primary posterolateral corner repair or reconstruction underwent successful revision reconstruction. The final patient with failure of the primary repair elected not to have a revision reconstruction. The final mean Lysholm knee score for both repair and reconstruction patients was 88.7 (range, 53-100). Final International Knee Documentation Committee objective scores yielded 14 (26%) normal, 28 (52%) near-normal, 9 (17%) abnormal, and 3 (6%) severely abnormal knees; the mean score was 60 at the most recent clinical evaluation. CONCLUSION: Results with repair followed by early motion rehabilitation have been significantly inferior when compared with results from reconstruction using the modified 2-tailed technique. The authors now use reconstruction rather than repair in the majority of patients who sustain posterolateral corner tears after high-energy injuries.