Knee Ligament Instability/Tear

There are four main ligaments in the knee that contribute to the stability of the knee.

The Anterior Cruiciate Ligament (ACL)

prevents the knee from translating forward with sudden movements including stopping and turning. A tear of the ACL usually occurs with high impact activity including pivot and twist or direct forward impact below the knee.

The Posterior Cruciate Ligament (PCL)

prevents the knee from translating backward. A tear of the PCL is less common than an ACL tear. Commonly, a PCL tear can occur with excessive hyperextension of the knee or twisting of the knee.

The Medial Collateral Ligament (MCL)

is located on the inside of the knee joint and prevents the knee from excessive side to side movements. The MCL sprain or tear can occur with an ACL and medial meniscus tear with high impact blows or twisting of the knee.

The Lateral Collateral Ligament (LCL)

is located on the outside of the knee joint and also prevents the knee from excessive side to side movements.