ANTERIOR CRUCIATE LIGAMENT INJURY MECHANISM
Injuries of the anterior cruciate ligament in as many as 70-80% of cases occur without direct contact with, for example, a player of the opposing team in team sports. They most often occur after a jump, during a sudden change of direction or during a violent slowdown after a sprint. One of the most commonly described injury mechanisms involves landing on a leg that is extended at the hip and knee, with the knee “escaping” to the valgus position (leaning inward), the tibia rotating outward, and the foot in pronation. In this position, it is about the so-called. “Points of no return.”
There are common situations in which there is hyperextension (extension) of the knee, which is another mechanism of non-contact injury, and it occurs, for example, in football players after they break the ball. In addition, of the non-contact mechanisms of injury, the one in alpine skiers has been described, in which there is an internal rotation of the tibia in relation to the femur with a fully extended (extended) knee or a knee flexed (bent) over 90 °.
Contact or traumatic mechanisms of injury are most often associated with the action of strong forces on the femur along the fixed tibia or on the outside of the knee (various blows, levers), which creates stress-valgus position of the knee (knee moved “inward”). Traumatic injuries of the cruciate ligaments are most often accompanied by injuries of the medial meniscus and medial collateral ligament, which in medicine we call the “ominous triassic”, and often the symptoms of these two injuries hide the injury of the anterior cruciate ligament, which can pose a risk of chronic instability in the knee.
Anterior cruciate ligament injuries, similar to ligament injuries globally, are divided into three stages.
- Anterior cruciate ligament distension
- A condition after a traumatic event in which there is movement that usually leads to ligament rupture, but with insufficient force. The ligament stretches, and since it is an inextensible tissue, it remains stretched (distended) and it takes some time for it to return to its original state. In the distended state, we can find local microtraumas and edema in parts of the ligament, but it mostly still performs its function and the knee is mostly stable.
- Partial rupture of the anterior cruciate ligament
- In case of partial rupture, the continuity of a part of the fibers of the anterior cruciate ligament is interrupted. Depending on the extent of the injury, this degree of anterior cruciate ligament injury may be accompanied by a normal level of knee stability or various forms of knee instability.
- Total rupture of the anterior cruciate ligament
- Complete rupture of the anterior cruciate ligament fibers. Injury can occur at the origin of the ligament (lateral condyle of the femur), the grip of the ligament (the area on the tibia called the eminentia intercondylaris tibiae) or both of these localizations at the same time while maintaining the continuity of the anterior cruciate ligament fibers but not its insertion sites. on the femur and tibia. These injuries are often accompanied by avulsion (a type of injury in which a strong and sudden force on the ligament causes damage to the part of the bone from which the ligament originates or the part of the bone to which it is attached), so it is often advisable to take an X-ray to rule out this diagnosis. knees.