Medial and Lateral Collateral Ligaments
The medial collateral ligament (MCL) is a ligament extending from the upper-inside surface of the tibia to the bottom-inside surface of the femur. The MCL prevents knee injury by stabilizing the joint and preventing the knee from buckling inwards. The lateral collateral ligament (LCL) extends from the top-outside surface of the fibula (to the bottom-outside surface of the femur). The LCL is responsible for stabilizing the knee on the outside of the joint. The collateral ligaments, MCL and LCL are responsible for 25% of knee injuries in competitive athletes, though the LCL injury is much less frequent than MCL injuries in competitive athletes.
In contact sports, the MCL can be damaged when an opponent applies a force to the outside aspect of the leg, just above the knee. Alternatively the medial ligament can be damaged if the studs get caught in turf and the player tries to turn to the side, away from the planted leg. (12) This stress on the inside of the knee joint is known as valgus stress. In some cases, the MCL can be torn by a severe twisting motion of the knee.
The LCL is usually injured by pressure placed on the knee-joint from the inside, resulting in stress on the outside of the joint. The stress on the outside of the joint is known as varus stress.
The tearing of the lateral and medial collateral ligaments can be classified in three categories:
Grade I sprain: Ligament stretch, pain along ligament
Grade II sprain: Partial tear, mildly decreased stability
Grade III sprain: Complete tear, significantly abnormal stability (10)
Tearing of either of the collateral ligaments in athletes can be met by several therapies. In Grade I and Grade II sprains, a conservative approach is usually taken. The knee is immobilized by a knee brace and iced and elevated for a period of 3-8 weeks. After this time, the athlete can usually begin playing their respective sport. The recovery time for the LCL can be from 2-6 weeks longer than that of the MCL. The long-term effects of the conservative approach led to similar results of surgery on the PCL for these kinds of sprains. The main advantage of this is that the athlete can return to their sport sooner than if they had had surgery and they also exhibit similar long-term patency. (13)
In Grade III sprains, surgery is usually required for athletes. If the athlete were to not undergo the surgery, they would probably not be able to return to their previous level of play. The surgery for the collateral ligaments is comparable to the surgery for the PCL and ACL. Recovery time before the athlete can resume play has been shown to be between 3-9 months. (12)