PCL

As discussed in the anatomy section, the posterior cruciate ligament (PCL) keeps the lower leg (tibia) from sliding too far backward (posterior) on the upper leg (femur). If the tibia does move too far posteriorly, the PCL can tear. The PCL is not injured as frequently as the ACL. PCL injuries disrupt knee joint stability because the tibia can move back on the femur causing them to rub directly against each other resulting in wear and tear to the thin, smooth articular cartilage. This abrasion may lead to arthritis in the knee.

Tears to the posterior cruciate ligament (PCL) requires a sharp blow to the lower leg (tibia) so this type of injury is relatively rare. Accidents involving high impact to the tibia are seen in serious automobile accidents where the tibia hits the dashboard and in serious falls. Tears of the PCL are often accompanied by a torn meniscus.