The recent ACL rupture in Tom Brady’s knee and the reconstructive surgery that Tiger Woods recently underwent has highlighted the ligaments of the knee. There are 4 primary ligaments of the knee. These include the anterior cruciate ligament (ACL), the posterior cruciate ligament (PCL), medial collateral ligament (MCL) and lateral collateral ligament (LCL). The cruciates are major stabilizers in the knee. The ACL is important in maintaining stability in the knee during dynamic activities such as cutting, turning, pivoting and changing direction. The ACL prevents the anterior translation of the tibia beneath the femur. The tear of the ACL allows the uncontrolled movement of the femur on top of the tibia. That uncontrolled movement may cause menisical damage. Meniscal damage may lead to arthritic changes in the knee. Click the link below to watch the review of the major ligament structures in the knee.