Whilst the anterior cruciate ligament is much more frequently torn and receives a lot more press coverage, injuries to the posterior cruciate ligament can be even more disabling.
Patients with a torn PCL may complain of instability but more often just have vague anterior knee pain that is worse going down the stairs or down a hill. Partly because of the vague nature of the symptoms, the injury is frequently missed by even experienced healthcare providers.
As well as a full history and examination of your knee to assess the degree of instability, an MRI scan will be performed to look for other injuries. A PCL tear is frequently accompanied by an injury to the posteromedial or posterolateral corner and this may also need to be addressed.
Many patients, especially those with a relatively stable knee can be managed without surgery and can even return to sports. Some may require the use of a brace for support and some will benefit from surgery.
Whilst a PCL reconstruction is routinely performed, it is not as straightforward as an ACL reconstruction. The PCL arises from the back of the tibia and is closely related to the main artery of the leg, the popliteal artery at this point. Injury to the artery is certainly possible and should be considered prior to surgery.
The rehabilitation following PCL reconstruction is also more prolonged and difficult than after an ACL reconstruction. In addition, you will need to wear a special knee brace after surgery to help protect the new graft from stretching out. Stretching of the graft is one of the most common problems after a PCL reconstruction and can even lead to a recurrence of instability in the future.
As for an ACL reconstruction, a PCL reconstruction requires the use of a graft i.e a piece of normal tissue from elsewhere in the body that is used to fashion a new ligament. With ACL surgery, the graft is usually from either the kneecap tendon (patellar tendon) or from the hamstrings tendons (two of the smaller hamstrings are taken so any impact on hamstring strength is minimal). In addition, with PCL surgery, another option is to use allograft i.e tendon from a cadaveric donor (similar to the way we get kidneys etc. from organ donors). This is especially considered if you require more than one ligament reconstructed.
An arthroscope is introduced into the knee and the remnant of the old PCL is cleared. Tunnels are then carefully drilled in both the tibia and femur to allow the graft to be passed through the knee and secured at either end. An extra incision is usually made toward the back of the knee to protect the artery, especially whilst the tibial tunnel is prepared.
A special brace is required for up to 6 months after PCL reconstruction. The brace helps to keep the tibia pulled forward and thus reduces the risk of the graft stretching out with time. This should be worn at all times except when you are showering.
Whilst approximately 90% of patients do very well after an ACL reconstruction, this figure is considerably lower for a PCL reconstruction, in the order of 60 – 70% satisfaction and it is important to realize this before undergoing a procedure with a lengthy rehabilitation.
Post-operative x-rays of a patient following a combined PCL, LCL and PLC reconstruction. In this case the graft used was Achilles tendon allograft i.e tendon from a cadaveric donor.
Compiled October 2015
Review date: March 2016
Review date: March 2016