What are knee ligament injuries?
The stability of the knee is dependent on powerful muscles which act as active restraints, and four strong ligaments which act as passive restraints. The four ligaments are as follows. • The medial collateral ligament (MCL) prevents the knee from buckling inwards (or valgus injury). • The lateral collateral ligament (LCL) prevents the knee from buckling outwards (or varus injury). • The anterior cruciate ligament (ACL) prevents the tibia from sliding forwards under the femur. • The posterior cruciate ligament (PCL) prevents the tibia from sliding backwards under the femur Together , these ligaments also provide rotatory stability to the knee, which is important in running sports like football and soccer where cutting (sudden change of direction while running at great speed) is often needed. Ligament injuries (sprains) are classified according to severity as follows. • Grade I – mild – where the ligament is stretched, but only a few fibers are disrupted • Grade II – moderate – where the
