Background: The medial collateral ligament is the most frequently injured ligament of the knee, but it infrequently requires surgical treatment. In cases of multiple ligament injury or severe medial collateral ligament lesion, non-operative treatment of the medial collateral ligament lesion may lead to chronic valgus instability or rotatory instability. Objective: To study a new technique of medial collateral ligament and posterior oblique ligament reconstruction in patients with medial knee instability. Patients and Methods: This was a prospective descriptive clinical study contained twenty patients aged 19 – 35 years old with medial knee instability and followed up at the orthopedic department, AL-Azhar university hospital over the period from January 2019 to November 2019. Results: Before surgery, the Lysholm knee score was poor in all patients (100%). After surgery, the Lysholm knee score was excellent in 5 patients (25%) ,good in 12 patients (60 %), and 3 patients (15%) was classified as fair, while no one was poor.      According to sressvulgus test, there was a significant postoperative reduction in degree of gapping after reconstruction in both extension and in 30° flexion positions. Conclusion: Acceptable clinical results with the combined medial collateral ligament and posterior oblique ligament reconstruction technique were achieved in patients suffering from chronic valgus instability.