Objective To study surgical therapy of the serious medial collateral ligament ruptures of the knee. Methods 12 patients with acute medial collateral ligament ruptures were treated operatively.Their degrees of injury were all Ⅲdegree that superficial and deep collateral ligaments were completely ruptured.Some of them were accompanied with the injury of medial joint capsule ligament or anterior cruciate ligament or posterior cruciate ligament.The torn medial collateral ligaments were anatomically corrected by their ends with direct suture or staple internal fixation.They were followed 6 to 18 months. Results 12 patients were graded with the Lysholm score .The postoperative score (mean, 76; range, 59 to 90) was higher compared with the preoperative score (mean, 35; range, 20 to 54), P