From Anatomy to Complex Reconstruction: A Modern Review on the Medial Collateral Ligament of the Knee

Medial knee injuries are prevalent, especially in young athletes. A detailed history and physical examination areneeded to accurately diagnose injuries to the superficial medial collateral ligament (sMCL), deep medial collateralligament (dMCL), and posterior oblique ligament (POL). The mechanism of medial knee injury often involves acoupled valgus and external rotation force with pain and tenderness across the medial joint line. Valgus stressradiographs assist with the diagnosis of medial knee injuries based on the quantitative extent of medial jointgapping. Specifically, 3.2 mm of increased medial gapping is observed with an isolated grade-III sMCL injury andgreater than 9.8 mm of gapping indicates a complete medial knee injury. Nonoperative treatment is recommendedfor grade-I and II medial knee injuries. Patients with chronic medial knee instability, or a complete tear of the medialknee structures, may require operative treatment. Anatomic surgical techniques have proven to be highly effectivein restoring functional knee stability.Level of evidence: V