Posterior Cruciate Ligament
The posterior cruciate ligament (PCL) is the main ligament of the knee and measures approximately 35 millimeters in length. It is largely responsible for preventing the tibia from moving posteriorly in relation to the femur. Its injuries are much less frequent than injuries to the anterior cruciate ligament.
Anatomy of the Posterior Cruciate Ligament
The posterior cruciate ligament connects the femur to the tibia. It attaches to the innermost portion of the femur, in a region known as the medial condyle of the femur, runs along the knee joint, extending for approximately 35 millimeters, and attaches to the posterior portion of the tibia. The PCL is formed by two bundles, the anterolateral and posteromedial, which are tensioned according to the degree of flexion of the knee.
The PCL is stronger than the anterior cruciate ligament, but the injury may cause fewer symptoms to the patients.
How the Injury Occurs
Most often, a rupture of the posterior cruciate ligament occurs after a force is applied to the front of the tibia with the knee bent, such as in car accidents, when the driver suffers a trauma to the knee against the dashboard of the car. However, it can also happen in other ways, such as falling with the knee overbent.
What a Person Feels When the PCL Tears
After an injury, a patient may experience a bruise on the front of the leg if the mechanism of injury is trauma to the front of the knee. However, a posterior cruciate ligament injury often does not cause as many symptoms to the patient, such as a feeling of insecurity, as an anterior cruciate ligament injury does. There is not necessarily a popping sound or significant swelling in the knee.
Necessary Exams
Some imaging exams can help the doctor when there is a suspicion of a posterior cruciate ligament tear, such as X-rays and magnetic resonance imaging. In addition to visualizing the ligament itself, these tests allow a more detailed evaluation of other structures that may be injured during the twist, such as cartilage, menisci, other ligaments, among others. Injury to the posterior cruciate ligament alone is rare. It is common for the paciente to have other ligaments injuries in association with the PCL tear, such as the structures of the posterolateral corner of the knee.
Treatment
Less severe PCL injuries are typically treated non-operatively, with knee immobilization in the initial phase, followed by rehabilitation with physical therapy. Surgery to treat ligament tears is performed when there are other associated knee ligament injuries, when the PCL injury is more severe, causing greater knee instability, when there is a fracture in the area where the ligament inserts into the bone, or in other specific situations.
Rehabilitation with Physiotherapy
Rehabilitation after PCL reconstruction surgery is generally more difficult than that after anterior cruciate ligament reconstruction. Immediately after surgery, the knee is immobilized in extension. Passive mobilization, isometric quadriceps training, and straight leg raising can be initiated as soon as tolerated. The patient is encouraged to support the operated limb partially, with immobilization and the aid of two crutches, from the immediate postoperative period. Immobilization is usually maintained for 6 weeks. The patient returns to his or her usual activities 9 to 12 months after surgery.
