The posterior cruciate ligament (PCL) is in the knee, next to the anterior cruciate ligament (ACL). It passes backwards and downwards from the bottom of the thigh bone to the top of the shin bone and stops the shin bone moving backwards against the thigh bone.

The PCL is two to three times stronger than the ACL. An injury to the PCL is relatively rare in football; it is more common in rugby, due to the nature of required movements and the game.

Posterior cruciate ligament football injuries can occur by falling on the bent knee. Imagine a goalkeeper coming down after collecting a cross and landing on a defender or attacker in the area; the shinbone is driven backwards, resulting in a tear of the ligament.

Certain twisting movements can cause injuries to it along with other ligaments around the knee, including the medial (inside) and lateral (outside) collateral ligaments. A prominent Tibial Tuberosity (lump just below the knee cap) resulting from previous Osgood Schlatter's disease may fortify the impact when the tibia strikes the ground.

In severe cases, similar to what happened to Jimmy Bullard when he was playing for Fulham, the knee can dislocate, resulting in injury to the anterior and posterior ligaments.

One study estimates that PCL injuries make up as many as 20% of all knee ligament injuries, but the diagnosis is often missed; this is due to the fact that many people can function normally without a PCL. However, detection of a PCL football injury is important because untreated PCL ruptures will lead to significant degeneration (i.e. osteoarthritis) of the knee and, maybe disability in later life.

Signs & symptoms

Unlike those with ACL injuries, patients who have PCL injuries do not usually experience much knee pain or swelling. They usually report vague symptoms such as unsteadiness or insecurity of the knee. Patients who have longstanding PCL injuries that have never been diagnosed may report pain around the kneecap.

There are a number of physical tests that can be used to detect a PCL injury. One of the most widely recognised is the posterior drawer test. The test is done with the patient lying on their back, the knee bent to a right-angle, and the foot flat on the table. In this position, the Tibial Plateau should lie 1 cm in front of the Femoral Condyles. The degree of PCL injury is determined by the extent that the tibia can be pushed backwards by the examiner:

X-rays are useful to rule out avulsion fractures (where the PCL has been pulled away from one of its bony attachments). An MRI scan is useful in confirming the diagnosis. However, when the injury is longstanding, an MRI may show an apparently normal PCL even though laxity may be present. 

Is there a treatment?

PCL injury treatment varies greatly; however, some of them are not as sensible as others. 

Patients who have grade 1 or 2 PCL injuries normally first receive non-operative treatment; that includes aggressive quadriceps strengthening and full range-of-movement maintenance. Patients may return to sports when quadriceps and hamstring strength reaches 90% of the opposite side - this may take as long as 4-6 weeks.

Doctors follow this up every 2 years with x-rays and a bone scan, to monitor joint status. If early signs of degenerative joint disease appear on the bone scan, PCL reconstruction might be considered. Surgical treatment may also be considered if symptoms develop or if function declines.
 

FOLLOW UP: X-rays are taken every 2 years to monitor the joint status

Patients who have grade 3 injuries are usually treated with PCL reconstruction. Before surgery, the patient undertakes rehabilitation to regain full range of motion and quadriceps strength.

Patients who have avulsion fractures (where the PCL has been pulled away from one of its bony attachments) are generally treated surgically.

Patients with PCL injury combined with other significant ligament injuries will be treated with PCL reconstruction and repair of other injured structures.

Following surgery, rehabilitation with a physiotherapist is very important. The initial goals of physiotherapy treatment are to reduce knee pain and swelling. Ice Packs can be used for that, applied for periods of twenty minutes every couple of hours (never apply ice directly to the skin as it can cause an ice burn). The ice packs relieve pain and reduce bleeding within the tissue. 

ICE IT: Ice packs can help with swelling post surgery

Following reconstruction, PCL injury recovery usually means being immobilised for a month, but now some pioneering surgeons are beginning knee range of motion exercise one week after surgery. Recent research has shown that it is safe to move the knee in closed-chain exercises (where the foot is in contact with a firm surface) -  this should not be done without permission from the surgeon and only under medical supervision. Generally, regardless of surgical technique, patients remain in a Knee Brace and on crutches for 6 weeks.

Injured players should always consult their physician, or the medical staff at their club, and follow the instructions they have been given.

How to prevent

Proprioception (Balance) and strength training for the knee, for example using a Wobble Board, can help to reduce the risk of sustaining a knee ligament injury. Also, sport should be avoided if you are in a fatigued state as this can increase the risk of injury.