The posterior cruciate ligament (PCL) is in the posterior central knee and keeps the tibia from shifting backwards, relative to the femur. The PCL can be partially or completely torn.
Sports related causes.
PCL injuries occur when the tibia is shifted posteriorly relative to the femur as in a car accident (dashboard type injury), hyperflextion of the knee, falling onto a flexed knee, and an awkward landing after a jump.
Patient with PCL injuries may experience knee pain, swelling, difficulty walking, and instability.
A physical exam by a doctor is performed to determine if the tibia maintains a normal relationship with the femur when pushed posteriorly.
If the physical exam in inconclusive, then an MRI may be used to evaluate the integrity of the PCL and evaluate for other causes of knee pain.
PCL Injury Grades
Doctors use a grade to indicate how severe your PCL injury is and to choose the appropriate treatment.
- Grade 1: Partial tear (sprain) from stretching of the ligament fibers and minimal laxity ((1-5 mm of posterior translation of the tibia relative tothe femur).
- Grade 2: Complete tear of the PCL but no other significant injuries (6-10 mm of posterior tibial translation).
- Grade 3: Complete tear of the PCL and injury of the joint capsule and/or other knee ligament. The tibia is shifted posterior to the femoral condyles (>10 mm of posterior tibial translation.
PCL tears typically heal and treatment is supportive with rest, icing, elevation, ace bandaging, and anti-inflammatory medicines.
Grade 1 or 2 injuries: Braces and physical therapy will help support while strengthening the muscles and allowing the PCL to heal which may take 2 to 4 weeks.
Grade 3 injuries:Immobilization of the knee for one month followed by passive range of motion therapy and eventual muscle strengthening.
Surgery for the PCL is rare and is reserved for the most severe injuries that may be associated with knee dislocation, bone avulsion fractures, tears of the joint capsule and ligaments, and complex mensicus tears. Surgery may also benefit patient with chronic PCL tears that have failed conservative therapy and continue to cause knee pain and instability.