The Posterior Cruciate Ligament (PCL) lies just behind the ACL and similarly connects femur and tibia but runs in a different direction. The PCL is the primary stabilizer of the Knee and the main controller of how far backward tibia moves under femur. This motion is called posterior translation of tibia. If tibia moves too far back, the PCL can rupture.
Recent studies have suggested that the PCL also prevents medial-lateral (side-to-side) and rotatory movements. Thus the PCL's effect on Knee Joint function is more complex than previously thought.
The PCL is made of two thick bands of tissue bundled together. One part of the ligament tightens when the knee is bent; the other part tightens as the Knee straightens. This is why the PCL is sometimes injured along with the ACL when the Knee is forced to straighten too far, or hyperextend.
Both bundles of the PCL change in length as well as orientation (direction of the fibers) from front-to-back and side-to-side with Knee flexion and extension. This function allows the ligament to keep tibia from sliding too far back or slipping from side-to-side.
PCL injuries can occur with low-energy as well as high-energy trauma. Isolated PCL Tears occur in sports, but they are less frequent and less disabling than ACL tears. PCL Tears are often missed or misdiagnosed, and therefore probably more common than believed.
The most common way for the PCL alone to be injured is from a direct blow to the front of the Knee Joint Pain while the Knee is bent. Since the PCL controls tibia’s movement in backward direction in relation to femur, if tibia moves too far, the PCL can rupture. Sometimes the PCL is injured during an automobile accident. This can happen if a person slides forward during a sudden stop or impact and the Knee hits the dashboard just below the Kneecap and there is extreme Knee Joint Pain. In this situation, tibia is forced backward under femur, injuring the PCL. This injury is termed as a dashboard injury. The same problem can happen if a person falls on a bent Knee. Again, tibia may be forced backward, stressing and possibly tearing the PCL.
Most PCL Tears are interstitial and heal with time, developing a firm endpoint although in a lax position. Most people are able to return to full activities with nonsurgical therapy. However, chronic PCL laxity causes significant patellofemoral problems (Anterior Knee Joint Pain), because of the chronic posterior translation of tibia and increased pressure on patellofemoral articular cartilage. Long-term follow-up after nonsurgical management has revealed that most patients rate the Knee as good enough and are able to return to sports.
Other parts of the Knee may be injured when the Knee is violently hyperextended, but other ligaments are usually injured or torn before the PCL. This type of knee ligament injury can happen when the Knee is struck from the front when the foot is planted on the ground.
Knee Joint Pain at the time of impact which over time may also be felt in the calf region.
Swelling, although this may be minimal.
Instability of the joint, perhaps associated with the feeling of the Knee giving way.
Posterior Sag Test
Hyperextension Test
Posterior Drawer Test
Reverse Lachman's Test
The Posterior Sag Test is performed by raising the lower leg to a horizontal position, with the knee bend. The therapist observes if tibia drops down, forming a sag or dent at the front of the upper shin. Always compare to the other Knee.
Over straightening or hyperextending the knee may be painful in PCL injuries.
The Posterior Drawer Test involves pushing tibia (shin bone) backwards whilst the Knee is bent. A positive result is recorded if tibia moves back further than on the uninjured side.
Normal PCL
Torn PCL
Goal - To control swelling and Knee Joint Pain, maintain the ability to straighten and bend the leg and to begin strengthening exercises for the leg muscles when possible.
Goal - To completely eliminate swelling, regain full mobility and build on strengthening exercises. By the end of this phase the athlete may be able to do 'proper' cycling or light swimming.
Goal - To return to sports specific training and competition.
In general, most partial or isolated PCL Tears can be treated non-operatively because the PCL, with its synovial covering, has some ability to heal.
However, PCL Reconstruction Surgery is usually recommended for PCL Tears that occur in combination with other ligament tears of the Knee
It is usually recommended that acute PCL Tears in combination with and ACL, Posterolateral Corner, or MCL Tears should be reconstructed within the first three weeks of injury. In rare occasions, the PCL may be repaired when it occurs as a peel off or bone avulsion injury. In patients with chronic PCL isolated injuries, who are symptomatic for pain and instability, reconstruction may be indicated. It is important that in these chronic injuries that a workup for possible concurrent other ligament injuries, as well as an assessment of the extremity alignment, should be performed.
PCL Reconstruction Surgery is typically done as an outpatient procedure. Depending on graft choice, open incisions may be necessary to harvest the tissue that is to be used as the new PCL. Knee Arthroscopy is then performed to inspect the knee, treat additional knee injuries (meniscus tears or cartilage damage), and to prepare the knee for the new PCL.
Once the graft tissue has been prepared and the torn PCL Tissue has been removed, the surgeon is ready to place the ligament within the knee. Small tunnels (7-10 mm) are drilled in tibia and femur to allow the ligament to be pulled up into the Knee.
Accurate placement of these tunnels is critical to success of the PCL Reconstruction Surgery. After the PCL graft is in position, fixation devices (screws, washers, buttons, etc.) are used to keep it there until it can heal the place.
Postoperative Rehabilitation Protocol for
PCL Reconstruction
PCL / ACL Reconstruction
Posterolateral Corner Surgery
Formal visits by a physiotherapist begins after removal of sutures, about 2 weeks.
This supervised therapy continues initially every alternate day and later about twice a week for about 3 months.
Patient has to continue home exercises, as instructed by the physiotherapist on a daily basis.
Patient may start with the following activities of daily living as follows:
This is the phase immediately after PCL Reconstruction Surgery till about 4 weeks. In this phase the patient performs hip, knee and ankle strengthening exercises.
The goal of rehabilitation in phase 1 is to protect the healing of soft tissue and bones, as wells as to mobilize the knee to prevent stiffness of the joint.
0-2 weeks
2-4 weeks
All the above as well as the following :
The brace is unlocked for passive range of motion to 60 degrees with patients.
Instructed for passive flexion and active knee extension to prevent posterior tibial translation.
Begins at 1 month after surgery, and continues till 3 months after surgery.
> 4-6 weeks :
Begins approximately three months after PCL Reconstruction Surgery, and continues till about nine months after surgery.
Return to sport at approximately 6 months to 9 months.