The anterior cruciate ligament is particularly important for the stability of the knee, as it prevents the dislocation of the tibia during anterior translation or external rotation forces.
The anterior cruciate ligament can be torn by rotational injuries with the knee slightly flexed, as well as by a violent hyperextension or hyperflexion of the knee.
Menisci are crescent-shaped, fibrocartilaginous structures and their main function is to absorb vibrations (like shock absorbers) in the knee joint. Menisci may be torn as a result of an injury (e.g. when playing sports) or degenerate as a result of daily stress due to age or increased body weight.