MCL injuries of the knee: current concepts review.

Medial collateral ligament (MCL) injury is one of the most common knee injuries, especially in young athletic patients. Most MCL injuries can be managed conservatively with good results. However, a complete understanding of knee anatomy and the involved structures is necessary to make intelligent treatment decisions. We will review the anatomy and biomechanics of the MCL, classification systems for MCL injuries, and operative and nonoperative treatment for acute and chronic MCL injuries.