Posterior cruciate ligament tear is a sprain (tear) of one of the four major ligaments of the knee. The posterior cruciate ligament (PCL) is a ropelike structure that helps keep the normal relationship of the femur (thigh bone) and the tibia (leg bone), so that the leg bone does not slip back over the femur. This ligament is the largest and strongest within the knee. When torn, this ligament may heal in a lengthened (stretched out) position or it may attach to other structures of the knee via scar tissue. PCL tears are caused by a force that exceeds the strength of the ligament. This injury may be a result of a noncontact injury (excessively straightening the knee) or may result from contact, such as getting tackled at the knee (especially forced bending of the knee) or landing on the knee, The PCL has a complex structure and has yet to be replicated with surgery. Therefore, rehabilitation is the best treatment choice at this time.