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 as a result 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.
Indications and Contraindications
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 insertion of 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 are allowed to perform full range of motion. Crutches are often required until you regain your normal strength.
Risks and Complications
Knee stiffness and residual instability are the most common complications associated with MCL reconstruction. The other possible complications include:
- Blood clots (Deep vein thrombosis)
- Nerve and blood vessel damage
- Failure of the graft
- Loosening of the graft
- Decreased range of motion
Medial collateral ligament (MCL) injury is one of the most common knee injuries resulting from a direct impact to the knee. Surgical reconstruction is recommended for MCL tears which fail to heal or those associated with other ligament injuries. MCL reconstruction is a minimally invasive technique that involves the use of a tendon graft to reconstruct the injured MCL.