How Knee Injuries Occur

 

The ACL is the most commonly injured ligament in the knee. The ligament can be strained (stretched) or partially or completely torn. However, there are misconceptions regarding how the injury occurs. Over 70% of the time, a noncontact mechanism is the cause of a ruptured ACL (2). This type of injury is frequent in basketball, soccer, volleyball, and football. A majority of the time the injury takes place when the knee is close to full extension (leg straight) and the athlete suddenly decelerates, changes direction, or lands offbalance. When the knee is near extension the quadriceps is fully contracted and it is suggested that this position significantly increases the force applied to the ACL (2). In all of these noncontact situations the foot is fixed to the ground at thetime of injury and the tibia is forced into internal or external rotation (3). This sudden twisting motion causes the ACL to be pinched by the side of the intercondylar notch of the femur, thus tearing the ACL.
Adam Corporation at MEDLINEplus
In addition to noncontact injuries, there are situations where contact leads to an ACL injury. The most common contact scenario is a hit to the lateral portion of the knee causing internal collapse. Although less common, medial and anterior blows can also result in a rupture of the ACL (2). Obviously other ligaments can be damaged during these injuries, however the ACL is the most important for knee stability.
Adam Corporation at MEDLINEplus

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Home --- Knee Anatomy --- How Knee Injuries Occur --- Gender Differences --- Types of ACL Grafts --- Surgical Procedure
Other Structures Damaged --- Rehab/Recovery --- Prevention