Definition
If one speaks of a torn ligament in the knee, this can refer to various ligaments. The knee can have torn both the collateral ligaments and the cruciate ligaments. In both cases a torn ligament (synonym: rupture of the ligament) is, as the name suggests, a tear or tear of the respective ligament structure. In principle, a torn ligament at the knee does not necessarily mean a complete tear, but it can also simply be a tear of the ligament structures. The knee is also considered a joint that is predisposed to a ligament injury because it has a long lever arm.
Forms
Important ligament structures that can tear are on the one hand the collateral ligaments (rupture of the outer ligament, rupture of the inner ligament), namely the inner and outer ligament, and the two cruciate ligaments (anterior cruciate ligament rupture, posterior cruciate ligament rupture), anterior cruciate ligament and posterior cruciate ligament. These ligaments can theoretically all rupture in isolation, but a combination of torn ligaments is much more frequent and probable. Worth mentioning is the knee injury called “Unhappy Triad”. Here, there is a simultaneous rupture of 3 structures: the inner ligament, the anterior cruciate ligament and the inner meniscus. In addition to classification according to the ligament structure affected, a torn ligament in the knee can also be classified as a fresh or chronic injury.
Cause
A frequent cause of ligament rupture is the rotational movement in the knee joint when the lower leg bone is fixed. As a result, the ligaments are put under so much stress that at a certain point they can no longer withstand it and then tear off. That certain point in time is called the elasticity point.
If this point is exceeded, the ligaments are torn, and before this point is reached, the ligaments may already be strained or stretched. Such rotational traumas are typical for sports activities such as soccer, squash or handball, as the knee often changes direction quickly and twists. In addition to the frequent sports injuries, traffic accidents can also lead to a rupture of the ligaments of the knee.
The posterior cruciate ligament is particularly susceptible. In a sitting position, our knee joint is angled at about 90°. At this moment, the collateral ligaments are somewhat loosened and not tightened as in the stretched or standing position.
This eliminates a major factor that secures and stabilizes the knee joint against rotation, so that external violent influences have an effect on the cruciate ligaments like a rear-end collision. As with the triple injury “Unhappy Triad”, it is not unusual for other structures of the knee joint, such as the menisci or bony parts, to be affected in addition to the ligaments. Nowadays, there is also a debate about the assumption that some people are predisposed to a torn ligament in the knee. It is currently assumed that the anterior cruciate ligaments of a woman tear more often than those of a man. Why this is the case cannot be explained.