Posterior Cruciate Ligament Tear
What is it?
A posterior cruciate ligament (PCL) tear is a rupture of the biggest and strongest ligament in the knee. Since it sits in the center of the knee, if it’s injured, the knee must be held to keep it from slipping backward. Due to the PCL’s size and strength, it takes an immense amount of stress or trauma to injure the PCL.
How does it get hurt/damaged?
Most PCL tears occur with other injuries to the knee. When a knee contact injury happens to either the outside or the inside of the knee, it commonly results in tears of the collateral ligaments on the affected side as well as the PCL and the ACL.
A PCL tear by itself, called an isolated PCL tear, happens only 10-20% of the time. Most isolated PCL tears occur as a result of an injury to the front of the knee when it is bent. Falling on a flexed knee while playing sports, slipping once, or hitting a dashboard during a traffic accident are some common ways that the PCL is torn. With an isolated PCL tear, it is common to have a little bit of soreness and a slight amount of swelling within the knee.
PCL tears do not bleed as much as other tears. The knee may feel unstable, especial when going down inclines, decelerating, or going downstairs, however sometimes you may limp for a while with no signs of any symptoms. Sometimes a patient won’t perceive a PCL injury until weeks after the incident when it occurred. For patients who have PCL tears with ligament injuries, there may have been a dislocation, which classifies as a surgical emergency.
How common is a PCL tear?
PCL tears occur to roughly 6500 people per year.
When should you be worried about a PCL tear and what should you do initially?
Due to PCL tears being not immediately noticeable, it can often be a while before a patient is able to receive care for the injury. Still, a patient should see a doctor relatively quickly because a dynamic PCL brace, which holds the knee forward against the forces of gravity, may be able to let your PCL heal without surgery. For patients who have PCL tears with additional ligament injuries, there may have been a dislocation, which classifies as a surgical emergency. When your knee feels grossly unstable or shifts with weight-bearing and is painful, you should be carefully evaluated soon after the injury either by your primary care provider or in the emergency room.
What is the severity of the injury and the treatment options?
Similar to ACL tears, PCL tears are graded on a scale of one to three. Grade 1 tears are classified as minor tears causing only partial tear of the PCL, and often these can be treated with conservative therapy. Grade 2 tears are isolated complete tears to the PCL. These will likely require surgical repair. Grade 3 tears are complete tears of the PCL with other associated tears or injuries to the ligaments in the knee.
Extensive research has gone into understanding the PCL and PCL tears over the last ten years. This includes detailed anatomy and biomechanical studies, and the development of new surgical techniques to reconstruct the PCL. In addition, the use of a special PCL brace to protect the PCL graft against gravity has allowed knees to be moved in physical therapy as soon as one day after a PCL reconstructive surgery.
If you do need a reconstruction, the first option is to see a surgeon who is trained in newer PCL reconstruction techniques, rehabilitation techniques, and use of dynamic PCL reconstruction techniques, as results this newer program have now been shown to equal those of ACL reconstructions. The second option is conservative therapy, involving rest, ice, acetaminophen, physical therapy, and a brace. Conservative therapy is reserved for isolated tears, usually partial tears, and tears in patients who are less active or will not be exposed to significant force to the knee.
What is my recovery timeline and the anticipated outcome?
PCLs can heal well on their own for the right patient, however, complete tears often heal loose. Similarly to a rubber band that has been stretched beyond its ability to bounce back to how its originally designed, the PCL will often heal as such, leading to recommended surgical procedures. Outcomes for surgery are variable depending on on the technique and surgeon.
Patients can usually return to driving 2-3 weeks after being able to walk, are generally back to walking within six weeks. The total average recovery time is about 9-12 months for a return to sports.
