The posterior cruciate ligament (PCL) is one of four major ligaments of the knee. It is one of several ligaments that connect the femur (thighbone) to the tibia (shinbone). 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. Its primary function is to keep the tibia from moving backward abnormally in relation to the femur. It is one of the four important ligaments for stabilizing the knee and preventing it from bending back the wrong way.
There are many possible causes of a torn PCL. It is stronger than the anterior cruciate ligament, and a powerful force is required for its injury.
- A direct blow to the front of the knee (such as a bent knee hitting a dashboard in a car crash, or a fall onto a bent knee in sports)
- Pulling or stretching the ligament (such as in a twisting or hyperextension injury)
- Simple misstep
An injury to the PCL is commonly associated with damages to other structures in the rear compartment of the knee joint, such as lateral meniscus tears and articular cartilage.
The typical symptoms of a torn PCL include:
- Pain with swelling that occurs steadily and quickly after the injury
- Mild pain at the back of the knee that feels worse when the patient kneels
- Swelling that makes the knee stiff and may cause a limp
- Difficulty walking
- Discomfort especially in the back of the knee when bending it
- The knee feels unstable, like it may “give out”
In cases of just PCL injuries, the following simple nonsurgical options are recommended:
- RICE method — rest, ice, gentle compression and elevation— can help speed recovery.
- To prevent the knee from moving, immobilization using a brace is recommended. To further protect the knee, crutches may be used to keep from putting weight on the leg.
- Physical therapy. After a reduction in the swelling, a careful rehabilitation program is recommended for PCL injuries. Specific exercises will restore function to the knee and strengthen the leg muscles that support it. Strengthening the muscles in the front of the thigh (quadriceps) has been shown to be a key factor in a successful recovery.
Successful PCL reconstruction is challenging due to its complex structures and the difficult reconstruction techniques that are required. In general, surgery is not performed immediately after the injury. Rather, surgeons wait for few days to give inflammation a chance to resolve. Prior to surgery, physical therapy is recommended to regain as much normal range of motion as possible at the knee joint. Arthroscopic surgery is performed to rebuild the PCL, using a new ligament for the damaged one (allograft) or using tendons from other parts of the body to substitute as the PCL. Variables that affect the results of surgery to restore PCL function include combined associated ligaments injury, difficulty with duplicating the PCL anatomy, wide variation in broad femoral insertion footprint, difficulty in accurate placement of the transtibial tunnel, tunnel erosion, high internal graft stresses, and graft elongation.
Despite technological advances in orthopedic surgery, controversies still exist over the choice of graft tissue, one- or two-bundle reconstruction, location of tunnel placement, knee position when securing the graft, and fixation technique.
Post-operative rehabilitation is a critical component of PCL surgery. The use of crutches or a walker is recommended, and the patient is often advised to increase the amount of weight on the repaired leg gradually. Braces are used for support while the knee is healing and regaining strength. Physical therapy with specific exercises is recommended to regain and restore the knee TEXT OMITTED and strengthen the leg muscles that support it.