Case: A 13-year-old adolescent boy and a 12-year-old girl, with torn anterior cruciate ligament (ACL) and increased posterior tibial slopes (PTS) of 17° and 19°, underwent transphyseal anterior tibial hemiepiphysiodesis and ACL reconstruction using a quadriceps autograft. Epiphysiodesis plates were removed after epiphyseal closure in the girl and after 12 months in the boy. Follow-up at 12 and 15 months showed Tegner and Lysholm scores of 4 and 100, with PTS reduced to 8° and 9°. Both resumed sports without further instability. Conclusion: Anterior tibial hemiepiphysiodesis effectively reduced the increased PTS to physiological levels in both cases.