Although it is crucial for knee stability, injury to the posterior cruciate ligament is, fortunately, relatively rare. The posterior cruciate ligament sits behind the ACL, and is responsible for stopping the tibia from sliding too far backwards. It also works to keep the tibia in alignment beneath the femur.
Injuries occur in two different ways:
- When the knee is bent, and something forces the tibia backwards - the so-called "dashboard injury."
- Hyperflexion of the knee, with the foot pointing downwards.
Either of these movements can stress the posterior cruciate ligament, resulting in a tear.
Symptoms of a PCL injury include knee pain, swelling, and decreased range of motion. Diagnosis will involve a history of the mechanism of injury, maneuvers to test the function of the PCL, and quite possibly X-rays or an MRI - it is quite common for other damage to occur alongside a PCL tear.
Unfortunately there is little agreement within the medical community on the best treatment of a PCL tear. Pain and swelling can be reduced with ice, elevation, and the use of crutches, and physiotherapy can help to improve knee function and to maximize the strength of the other structures of the knee.
Surgery is controversial. It is technically difficult, and many surgeons do not see the benefit of PCL reconstruction. Typically surgery will only be recommended for patients who have injured several knee structures, or are unable to perform normal activities due to recurrent instability in the knee.