Anterior cruciate ligament (ACL) ruptures are usually caused when the knee joint is subjected to external violence.
The anterior cruciate ligament is a ligament in the knee joint that serves to prevent the tibia from moving forward. When the knee is fully flexed and the tibia is internally rotated, the ligament is most tightly stretched and is susceptible to injury or even rupture.
In general, the ACL is rarely injured alone. The ACL is often injured at the same time as the medial and lateral collateral ligaments and meniscus injuries. However, when the knee is in hyperextension, the ACL can be injured alone. Anterior cruciate ligament ruptures are most commonly seen in competitive sports. An ACL can be ruptured by both an inversion injury with the knee in the extended position and a valgus injury with the knee in the flexed position.
In addition, violence from behind the knee, where the upper end of the tibia is subjected to the force of forward impact, can also rupture the ACL.
An ACL rupture requires active medical attention and appropriate treatment under the direction of a physician.