PCL Reconstruction
Posterior cruciate ligament (PCL), one of four major ligaments of the knee, is situated at the back of the knee. It connects the thighbone (femur) to the shinbone (tibia). The PCL limits the backward movement of the shinbone.
PCL injuries are very rare and difficult to detect when compared to other knee ligament injuries.
The posterior cruciate ligament is usually injured by a direct impact, such as a motor vehicle accident when the knee forcefully strikes against the dashboard or during sports participation when a twisting injury or overextension of the knee can also cause PCL injury.
Injuries to the PCL are graded based on the severity of injury. In grade I the ligament is mildly damaged and slightly stretched, but the knee joint is stable. In grade II there is a partial tear of the ligament. In grade III there is a complete tear of the ligament and the ligament is divided into two halves making the knee joint unstable.
Patients with PCL injuries usually experience knee pain and swelling immediately after the injury. This may also be associated with instability of the knee joint and knee stiffness that causes limping and difficulty walking.
Diagnosis of a PCL injury is made based on symptoms, medical history, and physical examination of the knee. The doctor may order a few diagnostic tests such as X-rays and MRI scan. X-rays are useful to rule out avulsion fractures where the PCL tears off a piece of bone with it. An MRI scan is done for better visualization of the soft tissues.
Generally, surgery is considered in patients with a dislocated knee and multiple ligament injuries, including the PCL. Surgery involves reconstruction of the torn ligament using a tissue graft taken from another part of the body, or from a donor.
Surgery is usually carried out with the help of an arthroscope, using a few small incisions. The basic steps involved in PCL reconstruction are as follows:
• The surgeon inspects the knee and removes any remains of the native PCL, using an arthroscopic shaver. Care is taken to preserve the ligament of Wrisberg, if it is intact.
• The donor tendon is harvested from the patellar tendon or the semitendonosis and gracilis tendon.
• The soft tissue around the femur is debrided to assist the insertion of the graft.
• A tunnel is created in the femur at the anatomic attachment site of the anterolateral bundle at the anteromedial wall of the itercondylar notch. This tunnel is drilled about 6-8 mm from the articular surface of medial femoral condyle.
• The tibial attachment site is also prepared by identifying the normal attachment of the PCL, at the bottom of the PCL facet.
• For placing the graft, a tibial tunnel is created to the anatomic insertion of the PCL on the tibia.
• Once the tunnels are drilled, the sharp edges and soft tissues around the exit site of the tunnel are smoothed, with a rasp.
• The tendon allograft is inserted in the femoral tunnel and fixed with a cannulated interference screw.
• The graft is made taut distally by removing any slack in the graft.
• The graft is then fixed to the tibia, with the help of staples.
• After fixation, normal posterior stability of the knee is assessed by employing the posterior drawer test.
• The incision is closed with sutures and covered with sterile dressings.
Patients are advised to maintain the knee in full extension, supported by a knee brace, for a period of 2 to 4 weeks. Patients should not bear any weight on the operated knee. Pillows or other supports are placed under the tibia, for the first two months after surgery, to prevent any posterior subluxation of the tibia.
Weight bearing and rehabilitation is initiated after 8 weeks. Crutches are often required until you regain your normal strength.
Knee stiffness and residual instability are the most common complications associated with PCL reconstruction. The other possible complications include:
• Numbness
• Infection
• Blood clots (Deep vein thrombosis)
• Nerve and blood vessel damage
• Failure of the graft
• Loosening of the graft
• Decreased range of motion
MCL Reconstruction
Medial collateral ligament (MCL) is one of four major ligaments of the knee that connects the femur (thigh bone) to the tibia (shin bone) and is present on the inside of the knee joint. This ligament helps stabilize the knee. An injury to the MCL may occur because of direct impact to the knee. An MCL injury can result in a minor stretch (sprain) or a partial or complete tear of the ligament. The most common symptoms following an MCL injury include pain, swelling, and joint instability.
An MCL injury can be diagnosed with a thorough physical examination of the knee and diagnostic imaging tests such as X-rays, arthroscopy, and MRI scans. X-rays may help rule out any fractures. In addition, your doctor will perform a valgus stress test to check for stability of the MCL. In this test, the knee is bent approximately 30° and pressure is applied on the outside surface of the knee. Excessive pain or laxity is indicative of medial collateral ligament injury.
If the overall stability of the knee is intact, your doctor will recommend non-surgical methods including ice, physical therapy, and bracing.
Surgical reconstruction is rarely recommended for MCL tears but may be necessary in patients that fail to heal properly with residual knee instability. These cases are often associated with other ligament injuries. If surgery is required, a ligament repair may be performed, with or without reconstruction with a tendon graft; depending on the location and severity of the injury.
Medial collateral ligament reconstruction is indicated in patients with chronic MCL instability despite appropriate nonsurgical treatment.
Medial collateral ligament reconstruction is contraindicated in patients with degenerative changes in the medial or lateral compartment, active infection, ligament instability, or presence of chronic diseases that can hamper surgical management or compliance to postoperative rehabilitation instructions.
The procedure is performed under general anesthesia. Arthroscopic examination of the knee may be performed to rule out any associated injuries including anterior cruciate ligament (ACL) and posterior cruciate ligament PCL) tears.
The surgical procedure for medial collateral ligament reconstruction involves the following steps:
• Your surgeon will make an incision over the medial femoral condyle.
• Care is taken to move muscles, tendons and nerves out of the way.
• The donor tendon is usually harvested from the Achilles tendon.
• The soft tissue around the femur is debrided to assist the insertionof the Achilles bone plug.
• For placing the graft, a tunnel is created from a guide pin to the anatomic insertion of the MCL on the tibia, using the index finger and surgical scissors.
• The Achilles tendon allograft is inserted in the femoral tunnel and fixed using screws.
• The MCL graft is made taut, with the knee at 20° flexion under varus stress, and fixed to the tibia with a screw and a spiked washer.
• The incision is closed with sutures and covered with sterile dressings.
In the first two weeks after the surgery, toe-touch and weight-bearing is allowed with the knee brace locked in full extension. After 2 weeks 0° to 30° of motion is allowed at the knee. At 4 weeks, knee flexion is allowed from 60° to 90° of motion and full weight bearing is permitted. At 6 weeks, the brace is removed and you can perform full range of motion. Crutches are often required until you regain your normal strength.
Knee stiffness and residual instability are the most common complications associated with MCL reconstruction. The other possible complications include:
• Numbness
• Infection
• Blood clots (Deep vein thrombosis)
• Nerve and blood vessel damage
• Failure of the graft
• Loosening of the graft
• Decreased range of motion
