Definition & Overview
The medial collateral ligament (MCL) is one of four major ligaments in the knee. It is located inside the knee’s joint, is responsible for controlling the sideways motion of the knee, and connects the thighbone (femur) to the shinbone (tibia). If the MCL becomes damaged and all non-surgical treatments fail to improve the condition, medial collateral ligament reconstruction is considered.
Who Should Undergo and Expected Results
The procedure can be considered in cases of major MCL injuries that commonly push the knee sideways. These injuries are often brought about by accidents, with most of them caused by direct contact to the knee. MCL injuries are very common among athletes and those who also suffer from a lateral collateral ligament (LCL) injury.
MCL injuries, which can range from a minor sprain to a completely torn ligament, can cause a wide range of symptoms, including pain, swelling, and total joint instability. For minor injuries that do not involve knee instability, doctors often prescribe non-surgical treatment methods such as physical therapy and the use of mobility aids, such as a knee brace. Those that are considered minor injuries include Grade 1 sprains, which means that the ligament is slightly stretched but still maintains knee joint stability, and Grade 2 sprains, wherein the ligament is partially torn. Meanwhile, an MCL reconstruction surgery is reserved for cases wherein the:
- MCL is completely torn, an injury rated as a Grade 3 sprain
- Patient suffers from a chronic MCL instability
- MCL tear does not heal or fails to heal properly
- MCL tear is associated with another ligament injury
- Appropriate non-surgical treatment methods do not work
Due to the recent advances in the field of orthopaedic, MCL reconstruction surgery can now be performed using minimally invasive techniques, which have been shown to reduce the risks associated with previous or traditional techniques as it only requires very small incisions.
As for the expected results, MCL reconstruction surgery can restore the affected ligament's original tautness leading to the relief of any symptom and restoration of the knee's motion, ligament laxity, and knee strength to normal up to five years after the procedure.
The prognosis is also good for patients who undergo the procedure as part of the treatment for a combined knee ligament injury. When MCL reconstruction is combined with a primary ACL reconstruction, pre-injury activity level is typically achieved after treatment. However, the same cannot be said when the procedure is combined with revision ACL reconstruction wherein patients are usually unable to return to their active lifestyles.
How is the Procedure Performed?
Prior to a medial collateral ligament reconstruction, the patient will undergo a physical examination and various imaging tests, such as X-rays, MRI scans, and arthroscopy to rule out other possible causes of the symptoms including a knee fracture, an anterior cruciate ligament tear, or a posterior cruciate ligament tear. Once other conditions have been ruled out, the valgus stress test will be carried out to assess the stability of the MCL.
During the procedure, the patient is placed under general anaesthesia, and an allograft is prepared. Studies show that an allograft taken from the Achilles' tendon is most effective in MCL reconstructions, as this helps reduce the risk of donor site morbidity associated with autograft use.
To begin the surgery, a 3-cm incision is made over the medial femoral condyle where a guide pin is inserted into the medial epicondyle. This is usually performed using a fluoroscopy to ensure that the intercondylar notch and other surrounding tissues will be not be inadvertently injured or damaged during the procedure.
After this, the surgeon will then create a tunnel from the guide pin going to the MCL to accommodate the graft. He then wraps the guide pin with a non-absorbable suture loop and passes its other end distally under the skin. The distal suture is then held against the tibia as the surgeon takes note of the tibia’s isometric point. He then debrides the soft tissue surrounding the femur, then inserts the allograft in the femoral tunnel. The allograft is tightened and made taut before fixed into place with screws. The surgeon then tests the tension in the graft before closing the subcutaneous tissue and the skin with sutures.
Possible Risks and Complications
A medial collateral ligament reconstruction is associated with some complications, including:
- Knee stiffness
- Residual instability of the MCL
- Gross misalignment or gait abnormalities, such as limps and varus/valgus thrusts
Knee flexion loss
Marx R., Hetsroni I. (2012). “Surgical Technique: Medial Collateral Ligament Reconstruction Using Achilles Allograft for Combined Knee Ligament Injury.” Clin Orthop Relat Res. 2012 Mar;470(3):798-805. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3270177/
Lind M., Jakobsen BW., Lund B., Hansen MS., Abdallah O., Christiansen SE. “Anatomical Reconstruction of the Medial Collateral Ligament and Posteromedial Corner of the Knee in Patients with Chronic Medial Collateral Ligament Instability.” The American Journal of Sports Medicine. http://ajs.sagepub.com/content/37/6/1116.short